29th Nov, 2020
Lebanese University
Question
Asked 4th Apr, 2014
How can I calculate the life cycles of a battery?
How can I calculate life cycle of a battery if it's charging rate and discharging rates are given?
Most recent answer
It is difficult question to answer, but it is important to go to the battery manufacturer specifications. Stop charging at 90% and start recharging at 30% will lengthen the battery life span.
Popular answers (1)
Calculating the life-cycle of a battery based only on its allowable charge rate and discharge rate is unrealistic. The life-cycle of a battery depends not only on its charge levels, but its chemistry, environmental factors (e.g. temperature, ageing, etc), whether the battery is over-charged or under-charged, and how it is loaded (e.g. are there regular high-current pulses or a steady load). Then, of course, there are various failure-modes of a battery. These include design faults, manufacturing faults, abuse of the battery, uncontrolled operating conditions, breakdown of electrolyte, and so on. The typical method for estimating the life-cycle of a battery is statistical and based on historical data. For example, a battery of a particular chemistry (e.g. lead-acid, Lithium) will on average fail according to a particular statistical distribution. Battery manufacturers will often have an mean-time-before-failure (MTBF) metric that helps to estimate the life-time of the battery. I hope this helps.
6 Recommendations
All Answers (6)
Calculating the life-cycle of a battery based only on its allowable charge rate and discharge rate is unrealistic. The life-cycle of a battery depends not only on its charge levels, but its chemistry, environmental factors (e.g. temperature, ageing, etc), whether the battery is over-charged or under-charged, and how it is loaded (e.g. are there regular high-current pulses or a steady load). Then, of course, there are various failure-modes of a battery. These include design faults, manufacturing faults, abuse of the battery, uncontrolled operating conditions, breakdown of electrolyte, and so on. The typical method for estimating the life-cycle of a battery is statistical and based on historical data. For example, a battery of a particular chemistry (e.g. lead-acid, Lithium) will on average fail according to a particular statistical distribution. Battery manufacturers will often have an mean-time-before-failure (MTBF) metric that helps to estimate the life-time of the battery. I hope this helps.
6 Recommendations
As James stated it is a difficult question.
You may decide to ask uncle Google: Battery Lifetime Model. A few good papers will appear. No one shows an easy way.
Following some research on lithium-ion battery cycle life estimation (currently undergoing peer-review), I recently decided to build an online calculator - http://bit.ly/cyclelifecalculator
The tool is based on experimental data published in literature. Note that it is still very much work in progress and requires some further validation. If you use it, let me know your thoughts as well as any suggestions for improvement you have.
1 Recommendation
Generally, battery life is calculated based on the current rating in Milliampere (mA) and the capacity of the battery in Milliampere Hours (mAh). The battery life can be calculated from the input current rating of the battery and the load current of the circuit. Battery life will be high when the load current is low and vice versa. The capacity of the battery can be mathematically derived from the following formula:
Battery Life = Battery Capacity in mAh / Load Current in mA * 0.70
*The factor of 0.7 makes allowances ( temperatures, ageing etc.) for external factors which can affect battery life.
Runtime = (10 * Ampere Hours) / Load in Watts
But in LI-ion battery, It is simply the number of times the discharge / charging cycles before comedown 85% to its initial capacity.
e.g.
For 1100 cycles, lifetime of battery is about 5 yrs.
The manufacturer's data sheet provides the life cycles of a battery in controlled conditions. If you manage to charge and discharge according to their limit at a specified temperature, you may get life cycles close to the specified by the manufacturer. One full cycle is charging from 0-100% and discharging it to 0% again. So if you know how much the charge is transferred to the battery and discharged from it, you can estimate the battery cycles remaining.
What I think more important is to calculate battery health. Battery health can be determined by knowing the original charge holding capacity of the battery when it was new and over time it reduces. (iPhones have this feature)
1 Recommendation
Similar questions and discussions
Related Publications
Lithium-ion batteries have recently been in the spotlight as the main energy source for the energy storage devices used in the renewable energy industry. The main issues in the use of lithium-ion batteries are satisfaction with the design life and safe operation. Therefore, battery management has been required in practice. In accordance with this d...
The state of charge (SOC), as an important parameter of the lithium-ion battery management system (BMS), is an important factor affecting the current battery detection and safety issues. Due to the non-linear characteristics of the lithium-ion battery charging and discharging process, it is difficult to model the BMS and estimate the SOC accurately...
Efficient energy storage is crucial in future energy systems. The management of lithium-ion based batteries is a challenging topic of research in this area. To improve management systems, monitoring data is indispensable, be it for single battery cells, be it for systems of multiple cells --- the topic of this article. However, regarding such modul...