Discussion on Energy Density of Lithium Polymer Battery

Aug 23, 2019   Pageview:56

Without a doubt, the lithium-ion batteries are the powerhouse of all the digital electronic revolutions that we have today. Starting with the electronic revolution in the modern mobile society as used in laptop computers and other mobile devices. However, you need to understand that the success of the Li-ion battery was not achieved overnight.


This took a lot of effort from many great engineers and scientist in order to improve their performance over the years. However, there was a need to introduce batteries that can provide a higher and more specific level of energy. This is the lithium-ion polymer battery which is in most cases abbreviated as LiPo.


The Lithium Polymer battery is a rechargeable battery, also of the lithium-ion technology. All in all, these batteries use polymer as their electrolyte instead of a liquid. The polymer can be made from high conductivity semisolid polymers such as gels. These polymers are now what forms the electrolytes of the battery.


And since the Lithium polymer batteries are capable of producing more specific energy, they are most applicable where weight happens to be a critical feature. Such as in aircraft that are radio controlled and mobile devices.


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Deposition of Energy Density of Lithium Polymer Battery


When it comes to Lithium batteries, deposition happens to be one of the most vital safety concerns. That is because these batteries tend to form high surface lithium deposits during the normal cell operation.


Deposition of energy density in lithium polymer batteries happens when the electrode potential is more negative when compared to the Lithium metal potential. Deposition can occur in several instances. This includes:


· When there is the improper alignment of the electrode during the assembly of cells

· Contamination of the metal particle from the positive electrode side

· Extreme operating conditions such as too low or high temperatures during charging

· Cells overcharge beyond certain cut off potential

· Improper balancing of the cells with a capacity ratio of the lower anode to cathode


The lithium deposits formed form a dendritic shape that features what looks like needle-like structures. These deposits form structures that look like branches and they get even larger during the cell discharge process.


The Li deposits rates play a key role as they determine the safety and the life of your battery. However, you can reduce this deposition by altering the electrode dimensions such that the negative electrodes extend by at least 2mm beyond where the positive electrode is aligned.


This way, the current gets distributed throughout an extended area instead of flowing to the edges as it happens when the design is evenly aligned. The extended capacity comes in handy as it helps to reduce the possibility of conditions that would favour deposition of lithium.


How Important is Energy Density in a Lithium Polymer Battery?


The Lithium-Ion Polymer Battery is one of the Li-Ion batteries technology. However, when compared to the liquid ion batteries, the lithium polymer has a higher energy density, lightweight, offers ultimate security, has an ultra-thin miniature design among other pros. The higher energy density is one of the most important aspects of this battery. This gives us a great definition of the new generation batteries.


How to Protect Energy Density of Lithium Polymer Battery?


Lithium polymer batteries tend to have a higher energy density as well as voltage when compared to conventional batteries. That is why lithium polymer batteries are the go-to power source for most portable electronic devices.


Therefore, for you to be able to use the lithium polymer batteries safely, you need to pair them with a protection circuitry model (PCM). This helps to keep the batteries functioning within their specific operating range.


And at the same time, offering the batteries protection from discharge and overcharge, current limitation, short circuit protection and voltage balancing. These factors play a key role in obtaining the longest life cycle of the lithium polymer battery and maximising on its output as well.


1.Embedded PCM


The Protection Circuit Model can be either attached to individual battery cells or permanently imbedded in the charger. Each of the methods offers a certain level of protection. While on the charger, the PCM offers protection towards;


· Balancing the battery cell functions

· Protection against short circuits

· Overcharge protection

· Current change limitation


Hover, this system is not capable of protecting the battery once it's disconnected from the charger. This means that the battery lacks elements of active circuits that will monitor its operations.


Advantages of Charger Embedded PCM


· You will enjoy the reduced weight of the battery

· Only one PCM is used

· Cost reduction on multiple batteries


Disadvantages of Charger Embedded PCM


· The increased safety risk of the user

· Reduced battery life and performance

· It lacks active battery protection after being disconnected from the charger


2.On-board PCM


The PCM could also be attached to the individual batteries permanently. This best suits rechargeable lithium polymer batteries with multiple cells. At the same time, you should make sure that the extra amount from PCM on battery cells will not affect their performance.


Advantages of PCM Onboard Battery


· Increased safety of the system

· Optimal battery life and performance

· Fulltime active protection of the battery

· Safe for use with unspecialized sources of power


Disadvantages of PCM Onboard Battery


· The higher cost incurred with multiple batteries

· Increased complexity and weight of batteries

· Individual batteries require individual PCMs


On-board PCMs are usually worth the initial increased cost as well as the weight. That is because the cost is later recouped in the increased performance of the battery, extended life and in-place charging.


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Final Verdict


Given the recent popularity of the Lithium polymer batteries, I wouldn’t be wrong to say the LiPo batteries are the future. The lithium polymer batteries feature a wide variety of advantages that help to improve the efficiency of the battery and user-friendliness.


However, the battery also features a few disadvantages that we should be able to comfortably face. The fact that it is more expensive to manufacture the lithium polymer batteries in the small scale production, the batteries are mostly applicable only in large consumer markets.


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