基于模糊PID算法的动力电池液体冷却策略

Liquid cooling strategy of power battery based on fuzzy PID algorithm

中文关键词  锂离子电池  集中质量热模型  直接式液冷  模糊PID算法

英文关键词  lithium-ion batteries  lumped mass thermal model  direct liquid cooling  fuzzy PID algorithm

中文摘要

      为防止动力电池组温度过高、温度均匀性差影响其性能和电动汽车运行安全, 必须对其采取有效的冷却策 略. 本文提出了一种基于模糊PID算法的动力电池组直接式液体冷却策略. 首先, 根据Bernardi生热率模型和牛顿冷 却定律, 建立了电池内阻随温度变化、对流换热系数随冷却液流速变化的单体电池集中质量热模型. 然后, 利用冷 却液单向流动的温度变化特性递推出电池组集中质量热模型, 并对其准确性进行验证. 考虑到电池组热模型的非 线性和时变特性, 设计了基于模糊PID算法的液体冷却策略. 最后, 将该冷却策略用于电池组冷却系统, 仿真结果表 明, 与传统PID冷却策略相比, 模糊PID冷却策略可以缩短系统调节时间、减小电池组温度不一致性、提高抵抗电流 扰动的能力, 具有更好的冷却效果.

英文摘要

      In order to prevent the excessive temperature and poor temperature uniformity of the power battery pack from affecting its performance and the operation safety of electric vehicles, an effective cooling strategy must be adopted. A direct liquid cooling strategy for power battery pack based on fuzzy PID algorithm is proposed in this paper. First, according to Bernardi’s heat generation rate model and Newton’s law of cooling, a lumped mass thermal model of single cell is established, which considers the change of internal resistance with temperature and the change of convective heat transfer coefficient with coolant flow rate. Next, the lumped mass thermal model of battery pack is derived by using the temperature change characteristics of unidirectional coolant flow, and its accuracy is verified. Considering the nonlinear and time-varying characteristics of the thermal model of the battery pack, the liquid cooling strategy based on fuzzy PID algorithm is designed. Finally, the cooling strategy is applied to the battery pack cooling system. The simulation results show that compared with the traditional PID cooling strategy, the fuzzy PID cooling strategy has a better cooling effect, which can shorten the regulation time of the system, reduce the temperature inconsistency of the battery pack, and improve the ability of resisting the current disturbance.