How to Customize a Robot Battery Pack

Robots used in warehouses, factories, agriculture, inspection, cleaning, healthcare, and service applications require battery packs that match their operating conditions. Battery selection involves more than voltage and capacity. Installation space, discharge current, charging method, communication, temperature, and battery protection also need to be considered.

First Power provides OEM and ODM lithium battery pack development for AGVs, AMRs, mobile robots, inspection robots, cleaning robots, service robots, and industrial equipment. The development process covers battery cells, electrical design, BMS, enclosure structure, connectors, communication, testing, and production.

1. Define the Robot Battery Requirements

The battery design starts with the robot application and operating conditions.

The following information is normally required:

• Robot application

• Operating voltage

• Required capacity

• Motor power

• Continuous current

• Peak current

• Required operating time

• Charging method

• Charging time

• Daily operating cycles

• Battery installation space

• Operating temperature

• Communication requirements

An AGV used for material handling may have different power requirements from a cleaning robot or inspection robot. The battery specification should therefore be based on the actual operating cycle of the equipment.

First Power can use the collected information to prepare an initial battery specification for the project.

2. Select the Battery Cell

Lithium ion and LiFePO4 cells are used in robot battery applications.

Cell selection depends on the required voltage, capacity, discharge current, operating temperature, battery size, cycle requirements, and application conditions.

For example, a robot with limited installation space may require a specific cell size and pack configuration. A robot operating with frequent charge and discharge cycles may require a cell specification based on its operating schedule.

First Power can develop battery packs according to customer requirements and specified cell models. Cell capacity, internal resistance, consistency, and incoming inspection can be included in the battery production process.

3. Calculate Capacity and Energy

Battery capacity is normally measured in ampere hours, or Ah.

Battery energy can be estimated with the following formula:

Energy in Wh = Voltage in V x Capacity in Ah

The actual operating time of a robot depends on its power consumption and operating conditions.

Factors such as motor load, payload, acceleration, driving surface, duty cycle, controller power consumption, and ambient temperature can affect energy use.

4. Configure the Battery Management System

The Battery Management System, also called BMS, monitors and controls important battery parameters.

A custom robot battery BMS may include:

• Cell voltage monitoring

• Temperature monitoring

• Overcharge protection

• Over-discharge protection

• Overcurrent protection

• Short circuit protection

• Cell balancing

• Charging control

• Battery status information

• Communication with the robot controller

CAN, UART, and RS485 can be used for battery communication depending on the robot control system.

During the design stage, the battery communication requirements should be defined together with the robot controller. The required data may include voltage, current, temperature, battery status, and fault information.