Estimating core temperatures of battery cells in a battery pack

A method of estimating core temperatures of battery cells in a battery pack, the method comprising:

• a) dynamically receiving a surface temperature of at least one battery cell in the battery pack, a current of the at least one battery cell, an inlet temperature of coolant provided to the battery pack, and a flow rate or velocity of the coolant;
• b) dynamically estimating a cell-lumped internal electrical resistance of the at least one battery cell, a cell-lumped conduction resistance between a core and a surface of the at least one battery cell, and a cell-lumped convection resistance between the surface of the at least one battery cell and the coolant, the estimations based upon the received values of step a);
• c) dynamically estimating a core temperature of the at least one battery cell and a surface temperature of the at least one battery cell, based upon the received values of step a) and based upon the estimated values of step b);
• and
• d) comparing the received surface temperature values of step a) and the estimated surface temperature values of step c) in order to correct the estimation of the core and surface temperatures of the at least one battery cell of step c).

A system for estimating core temperatures of battery cells in a battery pack, the system comprising:

• at least one sensor coupled to at least one battery cell of the battery pack in order to measure a surface temperature of the at least one battery cell;
• a controller coupled to the at least one sensor in order to receive the measured surface temperature, wherein the controller performs the steps of:
• i) receiving a current of the at least one battery cell, an inlet temperature of coolant provided to the battery pack, and a flow rate or velocity of the coolant;
• ii) estimating a cell-lumped internal electrical resistance of the at least one battery cell, a cell-lumped conduction resistance between a core and a surface of the at least one battery cell, and a cell-lumped convection resistance between the surface of the at least one battery cell and the coolant, the estimations based upon the measured surface temperature and the received values of step i);
• iii) estimating a core temperature of the at least one battery cell based upon the measured surface temperature, the received values of step i), and the estimated values of step ii);
• and
• iv) using thermal energy transfer effects between the coolant and the battery cells, thermal energy transfer effects among the battery cells, and the estimated core temperature values of step iii), in order to estimate the core temperatures for all of the battery cells in the battery pack;
• and
• a battery thermal management assembly coupled to the controller and controlled by the controller based upon the estimated core temperatures for all of the battery cells in the battery pack.