Temperature control to reduce capacity mismatch in parallel-connected lithium ion cells

Conference · Tue Oct 08 04:00:00 EDT 2019

OSTI ID:1560648

Tanim, Tanvir R ^[1]; Garg, Mayank ^[2]; Rahn, Christopher D ^[2]; Bryngelsson, Hanna ^[3]; Legnedahl, Niklas ^[3]

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1. Idaho National Laboratory
2. Penn State University
3. Volvo Trucks Technologies

The temperature and capacity of individual cells affect the current distribution in a battery pack. Non uniform current distribution among parallel-connected cells can lead to capacity imbalance and premature aging. This paper develops models that calculate the current in parallel-connected cells and predict their capacity fade. The model is validated experimentally for a nonuniform battery pack at different temperatures. The paper also proposes and validates the hypothesis that temperature control can reduce capacity mismatch in parallel-connected cells. Three Lithium Iron Phosphate cells, two cells at higher initial capacity than the third cell, are connected in parallel. The pack is cycled for 1500 Hybrid Electric Vehicles cycles with the higher capacity cells regulated at 40 C and the lower capacity cell at 20 C. As predicted by the model, the higher capacity and temperature cells age faster, reducing the capacity mismatch by 48% over the 1500 cycles. A case study shows that cooling of low capacity cells can reduce capacity mismatch and extend pack life.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1560648
• Report Number(s): INL/CON-18-51538-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
Hybrid Electric Vehicles
Lithium ion battery
Reduced order modeling