Liquid Cooling Thermal Management System Eliminates Temperature Gradients to Extend Lithium-Ion Battery Life

The Hidden Threat: Temperature Inconsistency Across Battery Cells

As global warming, energy shortages, and environmental pollution intensify, electric vehicles have emerged as a compelling alternative to conventional automobiles. However, during EV operation—particularly during acceleration and climbing—battery current surges rapidly, generating substantial heat. While excessive temperature is a well-known threat to battery performance and safety, a less visible but equally dangerous factor is temperature inconsistency across battery cells.

When different cells within a battery pack operate at different temperatures, their degradation rates diverge. Some cells age faster than others, reducing overall pack capacity, shortening system lifespan, and creating potential safety risks. Low temperatures also impair charging and discharging efficiency. To ensure lithium-ion battery performance, longevity, and safety under complex and variable driving conditions, a thermal management system must maintain not just optimal temperatures but also temperature uniformity.

To address this critical requirement, the Tenglong Automotive engineering team has developed a liquid cooling thermal management system designed specifically for electric vehicle lithium-ion battery packs.

Engineering Excellence: Intelligent Control with Temperature Uniformity Focus

The RD13 project introduces a sophisticated liquid cooling architecture featuring comprehensive monitoring and control capabilities:

▸ Integrated Microcontroller Network: A central microcontroller connects via wires to the vehicle's onboard power supply, air dampers, variable frequency drives, and temperature sensors. The variable frequency drives control both the blowers and circulation pumps, enabling precise cooling power adjustment based on real-time conditions.

▸ User Interface and Safety Features: The microcontroller interfaces with a display screen, warning module, parameter setting module, data comparison module, and data storage module, providing operators with full visibility and control over the thermal management system.

▸ Optimized Thermal Interface: A cooling plate is positioned beneath the power battery module. A thermally conductive pad is placed between the battery module bottom and the cooling plate to ensure excellent contact and maximize heat transfer efficiency.

▸ Series-Parallel Flow Configuration: The cooling circuit is designed using a combination of series and parallel connections, optimized to meet spatial layout requirements while maintaining uniform coolant distribution across all battery cells.

Key Innovations for Battery Longevity

▸ Variable Frequency Energy Savings: The system adjusts blower and water pump power based on detected temperature levels, significantly reducing energy consumption during normal operation.

▸ Temperature Gradient Elimination: By ensuring uniform temperature distribution across the battery pack, the system minimizes temperature differences between cells located in different positions. This causes all cells to age at nearly identical rates, substantially extending the overall battery system service life.

▸ Staged Cooling Strategy: A staged cooling approach reduces temperature differences within the battery module while accelerating cooling speed. This dual benefit ensures optimal battery performance, longevity, and safety under the complex and variable driving conditions that EVs routinely encounter.

Proven Results and Intellectual Property

The project represents the successful implementation of a national invention patent: "A Battery Cooling System for New Energy Vehicles" (Patent No. ZL201810502762.X). The patented design features a protective housing, strategically positioned air vents with dust screens and dampers, blowers for forced convection, thermal conductive plates mounted perpendicular to the housing walls, and integrated temperature sensors for real-time monitoring.

The final evaluation committee confirmed that the system has been successfully applied to the company's spraying vehicle product line, where it ensures battery performance, longevity, and safety under complex operating conditions. The product has achieved commercial sales, delivering positive economic returns.

Commitment to Precision Thermal Management

The RD13 project reinforces Xiangyang Tenglong Automotive's commitment to advanced battery protection through precision thermal control. By integrating this liquid cooling thermal management system into our vehicle lineup—including spraying vehicles, buses, and logistics vehicles—we ensure that every battery cell operates at optimal temperature, ages uniformly, and delivers maximum service life, providing our customers with safe, reliable, and durable electric vehicles.

RD13 Project Proposal for Design of a Liquid Cooling Thermal Management System for Electric Vehicle Lithium-Ion Batteries