Electric vehicle rickshaw battery and charging technology: technological breakthrough from range improvement to rapid energy replenishment

Keywords: electric vehicle, rickshaw, battery technology, fast charging, battery swapping mode BMS

abstract

The battery system is the core bottleneck of electric vehicles and human powered vehicles. This article analyzes the technical solutions and commercial applications of battery selection, charging protocols, and battery swapping modes.

2.1 Comparison of lithium battery types

Lithium iron phosphate (LFP) battery:

Energy density 120-150Wh/kg, cycle life>2000 times (80% capacity retention rate), cost $150/kWh, suitable for high-intensity operation scenarios (such as the Indian OLA S1 Pro model).

Three element lithium (NCM) battery:

The energy density is 200-250Wh/kg, but the cycle life is only 1000 times, with a cost of $200/kWh, suitable for high-end customized car models.

2.2 Implementation of Fast Charging Technology

High rate cell design:

Using porous electrodes (porosity of 40%) and thin membranes (thickness of 20 μ m), it supports 5C fast charging (such as CATL NCM811 battery cells, which can be charged to 80% SOC in 10 minutes).

Liquid cooled cooling system:

Integrate a serpentine cooling tube (flow rate 0.5L/min) inside the battery pack, combined with a 50% ethylene glycol aqueous solution, to achieve a temperature rise of less than 10 ℃ during charging (such as the BYD blade battery solution).

2.3 Innovation of battery swapping mode

Standardized battery pack:

Define a unified size (such as 400mm × 300mm × 150mm) and interface protocol (such as CAN bus communication) to achieve cross brand battery swapping (such as Singapore Gogoro Network).

Automated battery swapping station:

Adopting a six axis robot (with a load capacity of 50kg), the battery swapping time is less than 1 minute (such as the Bounce Infinity battery swapping station in India).

2.4 BMS Function Upgrade

Accurate SOC estimation:

Combining open circuit voltage method (OCV) with Kalman filter, with an error of less than 2% (such as TI BQ76PL455A-Q1 chip), to avoid overcharging/overdischarging.

Thermal runaway warning:

By using distributed temperature sensors (spaced 100mm apart) and gas detection modules (such as CO ₂ sensors), thermal runaway can be alerted 30 minutes in advance (such as Tesla BMS strategy).

2.5 Commercial Application Cases

India OLA Electric:

Launch the "Mobile Charging Car" service, equipped with a 20kWh energy storage cabinet, which can replenish the vehicle's 50km range within 15 minutes.

Grab Indonesia:

Cooperate with Shell to build a battery swapping station network, with a daily average of over 200 battery swaps per station, reducing operating costs by 40%.

conclusion

Fast charging and battery swapping modes need to be developed in synergy. By using high rate battery cells, liquid cooled heat dissipation, and standardized battery packs, the bottleneck of battery life and energy replenishment can be overcome.