24V 20Ah Lithium Ion Battery Design Solution of Intelligent Cleaning Robot

Foreword: (keyword: automatic cleaning robot battery) as the rapid development of intelligent controlling technology and sensing device, there are more and more robots in different fields. Special robot replaces human to work in more and more special environment. Large Power invents lithium ion battery of intelligent cleaning robot for solar photovoltaic power station. It has wonderful weather resistance. Its lowest working temperature is -25℃, while its highest working temperature is 65℃, so that this battery is adaptable for large temperature difference places, such as Tibet Plateau. Besides, it has high energy density, high voltage and high rate, so the power with same volume can provide the robot with longer working hours, adapt to different severe environment, and solve the problem of working in different climate.

Ⅰ. 24V20Ah battery design requirements of intelligent cleaning robot

Based on the requirements and specifications of customer, design a battery pack adapted to the environment and equipped with the host machine. Add heating module into the design, so that the device can charge and discharge normally at below -25℃. Solve the problem of low charging security at below 0℃ so as to help the device work normally under extreme environment.

1）Battery appearance: adopt LiFePO4 power battery with square aluminum housing (LP2770134-8S1P/20Ah/25.6V).

2) Structure design requirement: the battery has exquisite appearance and meets the requirements of waterproof, dustproof and shock-resistant. Battery room: 75*145*300mm

3) Battery design requirements: 24V/20Ah, normal charging current 6A, normal working current 9A, instant maximum working current 15A; normal protective function with equalization circuit, which can remedy the difference between single battery during application and expand the cycle life; the working temperature is -25℃-60℃. The battery needs auxiliary heating before heat up at low temperature.

Ⅱ. 24V20Ah battery design solution of intelligent cleaning robot

1）Metal plate housing spraying powder: design exquisite metal plate housing according to the customer’s requirements and spray matte black on the surface so as to prevent oxidation stain on housing affected by environment.

2）Guard plate (PCM):

Guard plate design: the solution adopts high precision BMS as acquisition unit with protective functions of overcharging, over-discharging, overcurrent, short circuit, high& low temperature protection, which can equalize the voltage and current of single battery.

Heating part design: as for preheating at low temperature charging, we adopt 9 pcs 5W power flexible heating film in parallel. Each surface of the battery has heating film and the preheating takes about 30 minutes. In order for the heating effect, when the temperature inside the battery box is 0℃, customer’s charging terminal gets 0℃ signal, and then it will heat up after 10 minutes so as to make sure the temperature consistency of the whole battery pack.

3）Overcurrent protection (PTC): it is designed for secondary protective function. Restorable PTC fuse has dual functions of overcurrent protection and self-recovery. PTC of the product can prevent high-temperature discharging and unsafe large current.

4）LP2770134-8S1P/20Ah/25.6V battery pack

Ⅲ. 24V20Ah battery features of intelligent cleaning robot:

Ultra-long cycle life (1000 cycles and over 70% of capacity is maintained);

Outstanding working temperature (can operate stably at -20℃～+60℃ for a long time.

Building up detecting unit inside the battery pack can check accurately for voltage, temperature, capacity, etc. and send these information to the main system by communication system, which fully improves the security of the product.

The housing of battery pack has metal plate design with shock resistance, high and low temperature resistance and flame retardant, which can make sure that the battery pack always has effective protective capability when impacted by external force.

The battery has passed all the security tests of PRC vehicle standards QC/T743-2006 lithium ion battery of electric car and met various indicators of the standards.

Simple installation (the design of unit module makes product have flexible and reliable installation)

Ⅳ. Block diagram of designing scheme