Estimating core temperatures of battery cells in a battery pack

Patent metadata

Field	Value
Publication number	US-10230137-B2
Application number	US-201314403057-A
Country	US
Kind code	B2
Filing date	May 23, 2013
Priority date	May 23, 2012
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

A method and a system of estimating core temperatures of battery cells in a battery pack can include several steps. In one step, a surface temperature of one or more battery cell(s) is received, a current of the one or more battery cell(s) is received, an inlet temperature of coolant provided to the battery pack is received, and a flow rate or velocity of the coolant is received. In another step, estimations are made including those of a cell-lumped internal electrical resistance of the battery cell(s), a cell-lumped conduction resistance between a core and a surface of the battery cell(s), and a cell-lumped convection resistance between the surface and the coolant. In yet another step, an estimation is made of a core temperature of the battery cell(s) based upon the received and estimated values of previous steps.

First claim

The invention claimed is:

1. A method of estimating core temperatures of battery cells in a battery pack, the method comprising:
a) dynamically receiving a surface temperature of less than all of the battery cells in the battery pack, a current of the less than all battery cells, 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 less than all battery cells, a cell-lumped conduction resistance between a core and a surface of the less than all battery cells, and a cell-lumped convection resistance between the surface of the less than all battery cells and the coolant, the estimations based upon the received values of step a);
c) dynamically estimating a core temperature and a surface temperature of the less than all battery cells based upon the received values of step a) and based upon the estimated values of step b); and
d) 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 c), in order to estimate the core temperatures for all of the battery cells in the battery pack; and
e) 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 temperatures of all of the battery cells in the battery pack.

2. The method of claim 1 further comprising determining a quantity and a location of at least one sensor with respect to the battery cells based at least in part upon an observability analysis and thermal energy transfer effects in the battery pack.

3. The method of claim 1 wherein step b) further comprises dynamically estimating a heat capacity of the core of the less than all battery cells, and a heat capacity of the surface of the less than all battery cells, the estimations based upon the received values of step a).

4. The method of claim 3 further comprising determining the state of health of the battery pack based upon the dynamically estimated internal electrical resistance of the less than all battery cells.

5. The method of claim 3 wherein the thermal energy transfer effects between the coolant and the battery cells comprise convection effects between the coolant and the battery cells, and the thermal energy transfer effects among the battery cells comprise conduction effects among the battery cells.

6. The method of claim 3 wherein steps a), b), c), and d) are performed on a controller, and the estimated core temperatures are used for thermal management of the battery pack.

7. The method of claim 6 wherein at least some of the received surface temperature, current, inlet temperature, and flow rate or velocity are measured via at least one sensor coupled to the controller.

8. The method of claim 3 further comprising determining a connection construction among the battery cells and a spacing distance among the battery cells based at least in part upon an observability analysis and thermal energy transfer effects in the battery pack.

9. A computer readable medium comprising a non-transient data storage device having stored thereon instructions that carry out the method of claim 3 .

10. 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).

11. The method of claim 10 further comprising using thermal energy transfer effects between the coolant and the battery cells, and thermal energy transfer effects among the battery cells in order to estimate the core temperatures for all of the battery cells in the battery pack.

12. The method of claim 10 further comprising dynamically estimating a heat capacity of the core of the at least one battery cell, and a heat capacity of the surface of the at least one battery cell, the estimations based upon the received values of step a).

13. The method of claim 10 further comprising determining the state of health of the battery pack based upon the dynamically estimated internal electrical resistance of the at least one battery cell.

14. A computer readable medium comprising a non-transient data storage device having stored thereon instructions that carry out the method of claim 10 .

15. 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);
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
v) estimating a surface temperature of the at least one battery cell and comparing the measured surface temperature and the estimated surface temperature in order to correct the estimation of 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.

16. The system of claim 15 wherein the controller further performs the step of determining the state of health of the battery pack based upon the estimated internal electrical resistance of the at least one battery cell.

Assignees

• Univ Michigan Regents
• The Us Secretary Of The Army Washington D C
• The United States Of America By Sec Of The Army

Inventors

• Lin Xinfan
• Ding Yi
• Castanier Matthew P
• Stefanopoulou Anna G

Classifications

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M10/633

  characterised by algorithms, flow charts, software details or the like · CPC title

• G01R31/389

  Measuring internal impedance, internal conductance or related variables · CPC title

• G01R31/3648

  comprising digital calculation means, e.g. for performing an algorithm · CPC title

• G01K7/42

  Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature · CPC title