The Current Problem Of Power Battery Temperature
The cost, performance and life of the power battery have a key impact on the cost and safety of electric vehicles; the temperature of the battery can directly determine the performance, usage time and safety of the lithium-ion battery.
Lithium-ion battery heat generation characteristics: complex, transient
- Temperature is too high
- Significantly reduced performance and lifespan
- extremely high temperature
- Temperature too low
- The cruising range is greatly reduced
- Extremely low temperature
- Car not working
Characteristics of thermal conductive materials
- soft texture
- High thermal conductivity
- specific heat capacity
- flame retardant
- low density
- cheap price
Special requirements for thermal conductive materials for lithium-ion battery packs
The amount of thermally conductive material is large: the density is low – reducing the density of thermally conductive materials helps to reduce the weight of the car and improve the endurance.
The heat generation of the battery is complex and transient: high heat capacity – increasing the heat capacity of the material can effectively absorb the instantaneous heat and keep the battery temperature stable.
Battery safety: High flame retardant – Reinforcing the flame retardant properties of the material can improve the safety of the battery pack under abnormal conditions and reduce losses.
Automotive DC-DC Converters
● Hybrid electric vehicles (HV) and electric vehicles (EV) use DC-DC converters
● The DC-DC converter adjusts the DC power of the battery to a DC voltage suitable for each electronic equipment part and distributes it.
● The loss during voltage adjustment generates heat, so the DC/DC converter needs to dissipate heat to the outside.
● A heat-dissipating silicone rubber sheet is required between components such as transistors, the converter case and the vehicle body.
Power battery thermal management goals
Safe · Stable · Efficient · Cheap
- High temperature heat dissipation, low temperature heating, to ensure that the single battery is in a suitable working temperature range;
- Reduce the temperature difference inside the single battery to ensure the uniform temperature distribution of the single battery;
- Maintain the temperature balance inside the battery pack to avoid the imbalance between the batteries and reduce the performance;
- Eliminate the danger of battery failure or even explosion caused by thermal runaway;
- Effective ventilation to ensure that the potentially harmful gas generated by the battery can be discharged in time to ensure the safety of the battery;
- Accurate and sensitive monitoring and management of temperature and other related parameters, with reasonable response strategies for abnormal situations;
- Meet the requirements of light and compact electric vehicles, low cost, easy installation and maintenance;