Manufacturing of 18650 lithium batteries for electric bamboo scooters

The use of batteries as an energy source that can convert chemical energy into electrical energy is used to drive a dynamo (BLDC) through the controller. Electric scooter batteries are made using 18650 batteries arranged in series. The series circuit of the 18650 battery that is arranged can be known by the number of series circuits based on the BMS used. The Battery Management System (BMS) acts as a system that can manage the use of battery power and an auxiliary system for charging from a series of batteries. This research aims to develop efficient and reliable batteries for use in electric scooters. The research method used is qualitative by analyzing the manufacture of batteries starting from assembling a series of batteries to the stage of testing the battery on an electric scooter. Battery arrangement is done by using holders in each row and connected using a nickel plate on the positive and negative poles in one row, then connecting the battery to BMS is done by soldering the positive and negative pole wires from BMS to the battery circuit with 20 series circuits and connecting the BMS cables. with a circuit as a battery charging system. Test results show that the 18650 series and BMS 72V 20 series are able to provide good performance. The 18650 and BMS 72V 20 series battery range can be a promising solution to increase the performance and battery life in electric scooter.


Introduction
Electric-based transportation has become a major focus in efforts to reduce air pollution, greenhouse gas emissions and dependence on fossil fuels.Electric scooters are a type of electric-based transportation that is increasingly popular among people, especially in urban areas.Electric scooters offer advantages in terms of energy efficiency, lower operating costs and reduced environmental impact compared to combustion engine vehicles.Reasons for the increase include zero emissions, more bicycle infrastructure, higher cost of gasoline, and lower travel cost compared to gas-powered vehicles [1].
One of the main components in an electric scooter is the battery.The battery has a crucial role in storing and supplying the electrical energy required for the operation of the scooter.Therefore, it is important to develop batteries that are efficient, reliable and have good durability to meet the needs of electricity-based transportation.Generally, LIB packs are consisting of parallel or in series 18650 LIBs in most EVs, such as Tesla.In spite that the complex battery management system (BMS) has been used in EVs, battery abuse as a consequence of the battery inconsistency, which resulting in a series of safety problems, is still difficult to avoid [2].
In this research, our focus is on developing an electric scooter battery using a series of 18650 batteries and a 72V 20 series BMS.The 18650 battery is renowned for its small size but high energy capacity.Lithium Ion Battery or lithium-ion battery is a type of rechargeable secondary current source battery.A series of 20 series batteries with a voltage of 72V were selected to meet the power requirements required by electric scooters.Battery Management System (BMS) is a device used for balancing, monitoring and protecting batteries which are arranged in series in battery packs, apart from that, installing a BMS (Battery Management System) on the battery will provide better monitoring and control of battery condition, increasing energy use efficiency, and maintaining battery safety and durability.Vehicle Control Unit (VCU) and Battery Management System (BMS) are the major components in the Electric Vehicle's (EV) energy system.VCU functioning as the brain of EV coordinates various parts of control unit and makes them work synergetic [3].
BLDC or dynamo is the driver of an electric scooter which is located on the back like a motorbike.Brusshless Direct Current (BLDC) motors are motors that do not use brushes and commutators.The output from the BLDC itself can be regulated by the controller using Bluetooth which is connected to the application from the controller itself.In the case of BLDC motors, with control method, a quadratic current in the motor phases so that it passes only two phases of the motor at any time [4].

Research Methodology
In this research, we use a structured methodological approach to develop an electric scooter battery with a series of 18650 batteries and a 72V 20 series BMS.The steps we took in this research were data collection and analysis of 18650 batteries which was carried out by starting to collect various types of 18650 battery cells available on the market.Each battery cell is then analyzed to ensure proper quality, consistency and performance.We look at the capacity, nominal voltage, durability and other characteristics of each battery cell to select the most suitable for use in an electric scooter.
The battery circuit design is done after selecting the right battery cells, we design the battery circuit by arranging the cells in a 20 series configuration.This configuration provides a total voltage of 72V, which is suitable for the operational needs of electric scooters.We pay attention to proper placement and connection to ensure smooth flow of electricity between cells.Installation of BMS (Battery Management System) on a series of batteries that have 20 series of battery series.
The BMS is responsible for monitoring and controlling battery performance.This includes monitoring voltage, temperature, current, and protection against unsafe conditions, such as overcharging, overdischarging, and overtemperature.The installation of this BMS is important to maintain the security and durability of the battery as well as to increase the efficiency of energy use.Battery Assembly is done by assembling the battery cells in the configuration that has been designed and connecting them to the BMS.Special attention is paid to ensuring a safe and stable connection, as well as adequate protection to prevent the risk of short circuits or other failures.
Assembled battery performance testing is useful for evaluating battery performance.Tests include measuring battery capacity, charging time, maximum usage time, and energy efficiency.We also monitor voltage stability during use of electric scooters with pre-assembled batteries.Analyzing and Interpreting data collected from testing is analyzed and interpreted to gain a comprehensive understanding of battery performance with the 18650 battery pack and 72V 20 series BMS.We analyze test results by comparing them with established standards and specifications, and formulate appropriate conclusions.
This research methodology helps us in developing an electric scooter battery with a series of 18650 batteries and a 72V 20 series BMS in a systematic and structured manner.Through this approach, we can ensure reliability, efficiency and battery life to support better electric scooter applications.

Result and Discussion
The battery used to make electric scooter batteries uses 100 18650 batteries which are arranged using a holder with 16 series of 20 series using a BMS measuring 72v 20 series.Battery connection is done by 3 using a nickel plate on each row.The manufacture of this battery uses a battery that has been fully charged, so it will not drop when used.The additions installed on the scooter battery are the XT90 socket to connect the electric current between the battery and the controller, and an additional socket for charging.Making scooter batteries starts with charging the batteries which will be assembled as many as 100 items.Charging is carried out so that the batteries to be assembled do not drop easily when used.After charging the 100 batteries, a check is carried out using a multimeter with the aim of ensuring that the batteries used are in a suitable condition for use and that the battery is fully charged.The batteries that have been checked are then arranged using a holder consisting of 20 rows arranged with 5 items in each row.Arranging the battery using a holder is done so that the battery is arranged neatly and makes it easier to install the nickel plate because there is space for installing the nickel plate so that it can be more precise which can be seen in Figure 1.Furthermore, the process of installing nickel plates which were made into a series of 20 series by means of spot welding using a spot welder, the installation of nickel plates is useful for connecting batteries in a series to unite the battery power that has been arranged.Connection is made at the top or bottom of the battery.The series that has been connected is followed by a checking process so that the welded nickel sticks tightly to the battery.If the nickel plate has adhered tightly to all the arrangements, the resulting voltage will be 72v on the entire battery circuit.The series that has been spot welded can be seen in Figure 2.
The next process connects the cable from the BMS to the battery circuit in each series circuit.There are 20 series circuits that will be connected with 20 cables from the BMS consisting of 2 types of red and black cables, the red cable is connected to the positive pole of the series circuit, while the black cable is connected to the negative pole of the series circuit.The connection is done with a soldering iron and tin so that the cable does not come off easily.The BMS cable connection to the battery can be seen in Figure 3. Connecting the BMS to the Battery Circuit.The connection of the BMS and battery cables has been completed, followed by connecting the XT90 socket to connect the battery to the controller and adding a charger socket for the connector to charge the battery.The battery connection with the BMS can be seen in Figure 3.After the battery assembly has been completed, proceed with checking using a multimeter to ensure that there is current in each charger and XT90 socket that will connect to the controller (Figure 4).Then the battery is covered with an insulating gel that cannot conduct electricity (insulator) thoroughly so that a short circuit does not occur in the battery circuit and the cables that have been connected.
After the battery coating is done, then proceed with the manufacture of battery boxes using fiberglass which is cut and assembled using gel insulation so that the adhesion between the parts remains strong.The manufacture of the battery box can be seen in Figure 5.The research results obtained from the research conducted are on battery capacity, battery charging time, maximum battery usage time, and the resulting energy efficiency.First, the battery capacity resulting from the tests carried out shows that the battery is capable of storing enough energy to provide the power needed to operate an electric scooter.Second, the charging time of the battery used is very efficient, because using the battery from a full condition, the battery can be recharged in 5 hours.This allows the user to charge the battery quickly and minimizes waiting time while charging the battery.
Third, based on the results of testing the maximum usage time on the battery, it shows that a battery with 20 series in this series can cover a distance of 30 km, so for operational use a battery with 72v specifications 20 in this series can support the use of an electric scooter for quite a long distance before it needs to be recharged.Fourth, based on the test results of the 18650 battery assembled and connected to the BMS 72v 20 series, the resulting performance is very efficient both from the output of the scooter power produced and the stability of the electricity connected to the controller.Following Based on the research results, we can conclude that the use of 18650 battery series and 72V 20 series BMS in electric scooter batteries provides good performance.These batteries are capable of storing sufficient energy, charging quickly, providing adequate usage time and achieving high energy efficiency.

Conclusion
The 18650 lithium batteries that are assembled with a series circuit of 100 items must have stable power on each battery that is connected into a series circuit, so that they can be used and connected via BMS, so that there is no drop during use.The use of the number of batteries can affect the performance of the scooter, because the more batteries used the greater the battery capacity so that the distance from the scooter will be longer.The BMS used in the manufacture of batteries greatly influences the controller and dynamo (BLDC) used, because the voltage distribution from the BMS that is connected through the battery circuit must have the same voltage as the controller and dynamo (BLDC), therefore the power generated from the scooter can be channelled properly.

Figure 1 . 2 .
Figure 1.Arranging the battery in the holder Figure 2. Nickel plate welding on the battery series

Figure 3 . 4 .
Figure 3. Connection of the BMS with Figure 4. Installation of the charger the battery circuit

Figure 5 .
Figure 5. Formation of the scooter battery fiberglass box