Behaviors and mechanism for the performance degradation of lithium‐ion batteries with LiNi0.33Co0.33Mn0.33O2 cathode in the long‐term high‐temperature storage

2020 ◽  
Author(s):  
Junmin Nan ◽  
Zheng Wang ◽  
Peipei Pang ◽  
Zhen Ma ◽  
Hongyu Chen
Keyword(s):  
High Temperature ◽  
Lithium Ion Batteries ◽  
Lithium Ion ◽  
Performance Degradation ◽  
High Temperature Storage ◽  
Temperature Storage

scholarly journals Mathematical Models for the Performance Degradation of Lithium-Ion Batteries with Different Status of Charge (SOC) in Long-Term High Temperature Storage

2021 ◽  
Author(s):  
Zheng Wang ◽  
zhen Ma ◽  
Xiongfeng Hu ◽  
Ruirui Zhao ◽  
Junmin Nan
Keyword(s):  
High Temperature ◽  
Mathematical Models ◽  
Lithium Ion Batteries ◽  
Voltage Drop ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Performance Degradation ◽  
High Temperature Storage ◽  
Temperature Storage

Abstract Mathematical models to evaluate and predict the performance degradation of lithium-ion batteries (LIBs) with different status of charge (SOC) in long-term high-temperature storage which are also applicable for setting rational storage conditions (temperature, SOC, and time) of LIBs were established. Parameters including voltage drop (Delta V), reversible capacity (RC) loss, and internal impedance (IMP) increase of LIBs under different temperature (60, 45, and 25°C) are used to allow the model to clarify its function. According to the results obtained from commercial 18650 cylindrical batteries with LiNi0.33Co0.33Mn0.33O2 cathode, the mathematical relationship between Delta V and storage days (x) is fitted into a simple formula: Delta V =m.In(x)-n, and similarly, RC loss = m'.exp (n'.x) and IMP increase = m''.xn'' can also be acquired. In these formulas, m, n, m', n', m'' and n'' are constants when temperature and SOC are fixed. If only the temperature is fixed, the value of these constants can be derived into a function with SOC (y), respectively, while further plugging the function into the calculation formula of Delta V, RC loss, and IMP increase, respectively, allows the mathematical models to be set up.

scholarly journals FCCSP IMC growth under reliability stress follows automotive criteria

2019 ◽  
Vol 3 (1) ◽  
pp. 70-83
Author(s):  
Wei Wei Liu ◽  
Berdy Weng ◽  
Scott Chen
Keyword(s):  
High Temperature ◽  
Flip Chip ◽  
Stress Test ◽  
Temperature Cycling ◽  
Content Type ◽  
Initial Stage ◽  
High Temperature Storage ◽  
Temperature Cycling Test ◽  
Temperature Storage

Purpose The Kirkendall void had been a well-known issue for long-term reliability of semiconductor interconnects; while even the KVs exist at the interfaces of Cu and Sn, it may still be able to pass the condition of unbias long-term reliability testing, especially for 2,000 cycles of temperature cycling test and 2,000 h of high temperature storage. A large number of KVs were observed after 200 cycles of temperature cycling test at the intermetallic Cu3Sn layer which locate between the intermetallic Cu6Sn5 and Cu layers. These kinds of voids will grow proportional with the aging time at the initial stage. This paper aims to compare various IMC thickness as a function of stress test, the Cu3Sn and Cu6Sn5 do affected seriously by heat, but Ni3Sn4 is not affected by heat or moisture. Design/methodology/approach The package is the design in the flip chip-chip scale package with bumping process and assembly. The package was put in reliability stress test that followed AEC-Q100 automotive criteria and recorded the IMC growing morphology. Findings The Cu6Sn5 intermetallic compound is the most sensitive to continuous heat which grows from 3 to 10 µm at high temperature storage 2,000 h testing, and the second is Cu3Sn IMC. Cu6Sn5 IMC will convert to Cu3Sn IMC at initial stage, and then Kirkendall void will be found at the interface of Cu and Cu3Sn IMC, which has quality concerning issue if the void’s density grows up. The first phase to form and grow into observable thickness for Ni and lead-free interface is Ni3Sn4 IMC, and the thickness has little relationship to the environmental stress, as no IMC thickness variation between TCT, uHAST and HTSL stress test. The more the Sn exists, the thicker Ni3Sn4 IMC will be derived from this experimental finding compare the Cu/Ni/SnAg cell and Ni/SnAg cell. Research limitations/implications The research found that FCCSP can pass automotive criteria that follow AEC-Q100, which give the confidence for upgrading the package type with higher efficiency and complexities of the pin design. Practical implications This result will impact to the future automotive package, how to choose the best package methodology and what is the way to do the package. The authors can understand the tolerance for the kind of flip chip package, and the bump structure is then applied for high-end technology. Originality/value The overall three kinds of bump structures, Cu/Ni/SnAg, Cu/SnAg and Ni/SnAg, were taken into consideration, and the IMC growing morphology had been recorded. Also, the IMC had changed during the environmental stress, and KV formation was reserved.

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