1 INTRODUCTION. Due to their advantages of high-energy density and long cycle life, lithium-ion batteries have gradually become the main power source for new energy vehicles [1, 2].Because of the low voltage and …
(13) The parameter difference of the battery pack is caused due to the complex charging and discharging environment, temperature, and other external factors in the process of use, combined with differences in the capacity, internal resistance, and self-discharge rate of the individual cells in the manufacturing process.
A battery pack consists of hundreds of battery cells connected in series and parallel, which makes it difficult to manage . Due to inconsistencies (variation of the cells) in production, packaging, and usage, the state of health (SOH) of a battery pack deteriorates faster than a single-battery cell, making it hard to estimate .
Inconsistency of battery pack harms to increase failure rate, reduces overall performance, and accelerates life decay. To alleviate the inconsistency of the battery pack, the production process, sorting means, topology design, equalization control, and thermal management can be improved with advanced technology.
When the degree of the battery pack inconsistency does not exceed the threshold, it is judged to be normal. Otherwise, the corresponding measures need to be taken to reduce the inconsistency of the battery pack, such as equalization management and thermal management.
Inconsistency, also known as cell variation, is considered a significant evaluation index that greatly affects the degradation of battery pack. This paper proposes a novel joint inconsistency and SOH estimation method under cycling, which fills the gap of joint estimation based on the fast-charging process for electric vehicles.
Duan et al. used the capacity, internal resistance, and the ratio of constant current charge capacity to constant voltage charge capacity as evaluation factors, and employed information entropy to integrate the three metrics. The inconsistency of a battery pack composed of twelve cells was analyzed comprehensively. 4.3.
1 INTRODUCTION. Due to their advantages of high-energy density and long cycle life, lithium-ion batteries have gradually become the main power source for new energy vehicles [1, 2] cause of the low voltage and …
Experiment results on an 8-cell battery pack show that internal resistance difference is the main cause for voltage difference and a low charge current helps to make full use of the pack …
When the heat inside the battery pack accumulates to a certain extent and cannot be dissipated in time, the battery in the module will thermal runaway in sequence, which is the third stage of spontaneous combustion of the battery pack (15.322 h to 16.189 h). Due to the small air gap in the battery pack, the heat exchange between the battery ...
Here we present an experimental study of surface cooled parallel-string battery packs (temperature range 20–45 °C), and identify two main operational modes; convergent degradation with...
In addition, although this work mainly focuses on small battery packs, the proposed method is also applicable to fault diagnosis of high-power battery system, such as those in electric vehicles. Therefore, the method of combining data mining with machine learning will be further applied to security management of complex dynamic systems due to its great …
Inconsistency of battery pack harms to increase failure rate, reduces overall performance, and accelerates life decay. To alleviate the inconsistency of the battery pack, the production process, sorting means, topology design, equalization control, and thermal management can be improved with advanced technology. Moreover, the challenges and ...
Significant degradation in energy density, cycle life, and safety can occur with battery usage due to inconsistency among the cells. The inconsistency within Li-ion battery packs, also known as cell variation, manifests two main aspects.
Although the PCM can absorb some of the heat, the phase change process of melting is so quickly and the heat cannot be dissipated to the exterior of the battery pack timely due to its low thermal conductivity. The heat stored in the PCM is transferred back into the battery cell. At this point, the heat from the surrounding TR cells and the PCM both contribute to the …
Aging diagnosis of batteries is essential to ensure that the energy storage systems operate within a safe region. This paper proposes a novel cell to pack health and …
Capacity attenuation experiments: to further verify the performance of the proposed algorithm in this paper under the full life cycle of the battery pack, we perform a constant-current capacity attenuation cycle test on a battery pack formed by 10 LiFePO 4 cells in series to simulate the battery pack quickly aging in real applications. This battery pack is …
Significant degradation in energy density, cycle life, and safety can occur with battery usage due to inconsistency among the cells. The inconsistency within Li-ion battery …
The parameter difference of cells mainly comes from the manufacturing or storage process and the use process. The battery parameter difference in the manufacturing process is frequently decreased indirectly by …
Inconsistency, also known as cell variation, is considered a significant evaluation index that greatly affects the degradation of battery pack. This paper proposes a novel joint inconsistency and SOH estimation method …
To prevent the imbalances from affecting the battery pack''s safety and reliability, battery management of cell balancing is most often performed in series connections, whereas in parallel connections cell imbalances are seldom addressed. In a series connection, the current of each cell remains the same but the voltage and state of charge (SOC) of each cell differs. …
When considering the degradation of battery packs comprised of parallel strings, a primary research question is whether the initial parameter dispersion of the cells reduces through long-term operation or does the differences between cells diverge further. The degradation process of the battery pack and that of individual cells are correlated, however it is …
Inconsistency, also known as cell variation, is considered a significant evaluation index that greatly affects the degradation of battery pack. This paper proposes a novel joint inconsistency and SOH estimation method under cycling, which fills the gap of joint estimation based on the fast-charging process for electric vehicles.
Inconsistency of battery pack harms to increase failure rate, reduces overall performance, and accelerates life decay. To alleviate the inconsistency of the battery pack, the …
However, in application, the parameters such as the capacity and voltage of each cell in the battery pack are inconsistent due to unreasonable use, poor operating environment and other factors. In this paper, the qualitative relationship between the voltage variation of lithium-ion battery and the cell capacity and SOC is firstly analyzed, and ...
The findings reveal that when cells are connected in series, the capacity difference is a significant factor impacting the battery pack''s energy index, and the capacity difference and Ohmic resistance difference are significant variables affecting the …
Here we present an experimental study of surface cooled parallel-string battery packs (temperature range 20–45 °C), and identify two main operational modes; convergent …
The basis for quantifying the relationship between inconsistency and battery pack degradation is the acquisition of battery pack inconsistency. However, the inconsistency of lithium-ion battery packs cannot be acquired directly and requires indirect representation [10, 11].
To reduce the inconsistency of battery packs, this study innovatively proposes an integrated active balancing method for series-parallel battery packs based on LC energy storage. Only one inductor and one …
It is worth mentioning that, in practice, due to the close arrangement of the battery pack, the accumulation of heat generated by the single cells causes a temperature gradient inside the battery pack, which is more obvious in the battery pack containing faulty cells. And temperature changes will lead to voltage fluctuations, this effect will bring unnecessary …
However, in application, the parameters such as the capacity and voltage of each cell in the battery pack are inconsistent due to unreasonable use, poor operating environment and other …
To reduce the inconsistency of battery packs, this study innovatively proposes an integrated active balancing method for series-parallel battery packs based on LC energy storage. Only one inductor and one capacitor are used to store energy to achieve the balance of each cell in a series-parallel battery pack.
The findings reveal that when cells are connected in series, the capacity difference is a significant factor impacting the battery pack''s energy index, and the capacity difference and Ohmic resistance difference are …
Experiment results on an 8-cell battery pack show that internal resistance difference is the main cause for voltage difference and a low charge current helps to make full use of the pack capacity. Meanwhile, SOC difference can be easily detected at low SOC stage.
During the working period of the battery pack, these variables create nonuniform current, voltage, temperature, and battery characteristics, which can lead to battery pack aging. 13 The parameter difference of the battery pack is caused due to the complex charging and discharging environment, temperature, and other external factors in the process of use, combined with …
Aging diagnosis of batteries is essential to ensure that the energy storage systems operate within a safe region. This paper proposes a novel cell to pack health and lifetime prognostics method based on the combination of transferred …
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