In the thermal management laboratory of new energy sources, there is a goal called "Holy Grail" by engineers-to control the maximum temperature difference of battery pack packages within 3℃. This figure seems insignificant, but it carries the huge value of extending the cycle life by 20%. Because every time the temperature difference of 1℃ is increased, the aging rate of cell will accelerate by 5%, and after thousands of cycles, the life gap between the edge cell and the center cell can reach more than 30%. The accumulation of thermal management technology for ten years of energy gathering new energy will change "3℃ obsession" from ideal to reality.

Bionic Runner: from human blood vessels to battery cooling. The liquid cold plate design of new energy sources draws lessons from the branch structure of human blood vessels. Main pipe is as strong as the aorta, distributing the coolant evenly to dozens of fine branches, covering every cell "fever hinterland" like capillary ". Through CFD simulation optimization, the flow channel elbow adopts a large radius of curvature (R/D ≥ 3), and the inner side is arranged Baffler to restrain the flow separation in the minimum range. The measured data show that the design compresses the temperature difference between the import and export of liquid cold plate from 6℃ in the industry to less than 2℃, which lays a physical foundation for the whole package of 3℃ temperature difference.

Gradient heat conduction: a material revolution about "adjusting measures to local conditions. Cell heat generation concentration in the central area and low heat load in the Edge area-this non-uniformity is a classic problem of heat management. The new energy source has developed "gradient thermal silicone pad": the central area adopts a high thermal conductivity material with a thermal conductivity coefficient of 8W/(m · K) to quickly export heat; The Edge area adopts phase change material (PCM) buffer temperature fluctuation to realize the dynamic balance of "hot spot fast dispersion and cold zone Insulation. This heat conduction strategy of "adjusting measures to local conditions" further compresses the maximum temperature difference of the whole package from 5℃ to 3℃.

Intelligent temperature control: from "passive response" to "Active Prediction". Self-developed BMS of energy-gathering new energy sources, no longer respond passivelyThe temperature exceeds the limit, but the heat load is predicted based on the cell heat generation model, and coolant rate and temperature are adjusted in advance. After deep coupling with the heat pump air conditioning system of the whole vehicle, the waste heat of electric drive can be used to preheat the battery in winter. In summer, the battery heat is directed to the cabin for heating, and the energy efficiency of the system is increased by 15%. A high-end passenger car is battery pack. In the extremely cold environment of-30 ℃, the temperature of cell is increased from-20 ℃ to 5 ℃ within 5 minutes through pulse self-heating technology, which meets the fast charging start conditions.

Phase change energy storage: the next generation of thermal management "mute solution". The new energy source is verifying the "all-solid state phase changes thermal management" technology-using the huge latent heat of paraffin phase change materials during solid-liquid phase transformation to absorb cell thermal fluctuation during charging and discharging. This solution does not require moving parts such as water pumps and fans, and realizes completely silent thermal management. It is especially suitable for noise-sensitive service robots and home energy storage scenarios.

The ultimate pursuit of thermal management is not to make the battery "Not Hot", but to make each cell "evenly hot". The trio of bionic flow channel, gradient heat conduction and intelligent temperature control for energy gathering new energy will change the temperature difference of 3℃ from obsession to normal. Because they know very well that in the world of power batteries, temperature uniformity is not the icing on the cake, but the cornerstone of life, the bottom line of safety and the ceiling of performance.