Mar 11, 2020 Pageview:2023
Can you mix lithium ion battery with lead acid batteries?
While lead-acid and lithium-ion technologies each have their pros and cons, they have a tendency to mitigate a number of each other’s technical and economic shortcomings in mixed systems.
Strategic advantages of mixed-mode systems can include:
A vehicle to urge field “run time” with lithium ion technologies with lower technical and business risk than would be assumed with fully lithium-ion based sites.
Effective reserve system capacity growth alternatives avoid the replacement of entire existing lower capacity battery systems.
Using what is called the mixed systems can help to provide an economically attractive growth alternative that will in return avoid site expansion or even whole new construction.
Of course, there's no gift here. Mixing these technologies successfully requires addressing “rubber on the road” systems dynamics challenges, some directly apparent and some other more subtle, that we explore here also.
Now let us start to compare and contrast some attributes and behaviors of lead-acid and lithium-ion battery technologies from a strategic business point of view. The mature VRLA battery technologies, despite all the technological advances, still have some issues regarding service life and reliable life prediction. These issues are manifested especially in non-temperature controlled outdoor cabinets and vehicles. However, the telecom class lithium-ion battery technologies are promising way better (still unproven to this date) field life, life prediction, and even better life cycle cost, they, despite all of that, continue to be a drain of the research budgets of this year’s budget to deploy than what was reserved to the researchers of the VRLAs.
So how do mixed-mode systems behave and compare? Tradeoffs of space vs. weight vs. power density vs. cost are straightforward and repair providers will make choices according to their business strategies. Mixed-mode systems have a greatly reduced voltage. We call that voltage the Coup de Fouet voltage transient. Moreover, they have a tendency to scale back the number of discharge cycles on the lead-acid batteries thereby extending their service life. for instance, allow us to examine a discharge/recharge cycle for a system with a float voltage of 52.08V, 100A of load with a continuing power characteristic, 150A of the rectifier capacity, not only that but also, the battery reserve that is consisting of 400Ahr of lead-acid flooded batteries. In addition, the 400Ahr of compatible lithium-ion batteries. When the rectifiers of the system lose power, the BMS of the Lithium ion batteries see a load that transient from 0 to 100A. Thanks to the lower internal resistance, the flooded batteries deliver most of the load current until the bus voltage falls to around 50V where the lithium-ion batteries begin to deliver energy. The lithium-ion batteries still deliver nearly all the load current and deliver an outsized percentage of their energy by the time they reach 47V. When the bus voltage drops to around 47V, the flooded batteries begin to deliver significant current. It is important to note that when the power should be restored before the bus voltage reaches the number 47V. Because at that point, the flooded cell batteries are negligibly discharged.
In mixed systems, the lead-acid batteries will not begin to discharge and can not be degraded by outages with discharge that does not even reach 47V. In order to have a longer service life a reduced number of discharge cycles on the lead-acid batteries are being conducted.
Since the fact that lithium-ion batteries have the ability to deliver almost 100% of its load and capacity immediately during the first portion of the discharge cycle, the battery cables and the disconnects for the lithium ion batteries all must be checked so that they can support the whole load current at 47V.
The telecom grade lithium ion batteries, on the other hand, can limit discharge current by the control circuitry or even by fuses.
To present service providers with an entire mixed-mode battery solution, existing battery capacity testing methods and existing battery life prediction algorithms must be extended to use to mixed systems.
Finally, mixing both lead-acid and lithium-ion battery systems have the potential to give service providers some economically attractive growth alternatives to site expansion or even full battery system replacement that would benefit the whole industry
Mixed system behavior is stable, with beneficial synergies
Practical mixed systems require special attention to battery cable and disconnect sizing, battery discharge rates, and recharge current limits.
Which batteries are better for car, lithium ion battery or lead acid?
Lead acid batteries have been the go-to choice for car batteries for as long as the industry existed. However, nowadays with the technological advances Lithium ion batteries have encountered, lead acid batteries are slowly being replaced by Lithium ion ones. Specifically, the LiFePO4, which is a much safer version of Lithium ion batteries.
To illustrate more, here are the advantages Lithium ion batteries have over lead acid batteries that make them the better choice:
You will not need an external charger to charge your Lithium ion battery. The alternator will charge the new Lithium ion battery the same as it charges the lead acid batteries. Moreover, trickle charging is not required. Unlike lead acid batteries, Lithium ion batteries do not lose charge by sitting unused.
Lithium ion batteries are waterproof. It is safe to wash the inside of the car with the battery inside.
Before buying the new Lithium ion battery, figure out the Ah size pack you need. This is an important step.
Lithium ion batteries have the Battery Management System (BMS), which means that you will not encounter the dead battery situation ever.
Lithium ion batteries have a protection circuit that prevents them from draining.
Lithium ion batteries can be mounted in any position, it does not matter if they are upside down. There is no acid inside that would be spilled.
Lithium ion batteries last from five to ten years. That is at least double the cycle life of the lead acid batteries.
What are the differences between lithium ion car battery and lead acid?
There are many aspects where lithium ion batteries differ from lead acid batteries. However, the most obvious difference is in fields of charging time, the type of chargers used, depth of charge and efficiency.
Charging
Charging Lithium ion batteries in comparison to the lead acid batteries is a subject that concerns many. Lithium ion batteries, specifically the new "much safer" LiFePO4 batteries, can be charged in as little as one hour. That is true; you can charge the lithium ion battery in only one hour. However, it is recommended that you charge the batteries in two hours.
Type of chargers used
When charging Lithium ion batteries, you do not need to buy another charger. The same charger used to charge the lead acid batteries could be used to charger Lithium ion batteries as well. Most chargers available now contain a lithium charge profile. However, on some occasions, some chargers do not contain that profile, which makes charging Lithium ion batteries with extremely dangerous. These second types of chargers are called "flooded charger profile chargers".
Depth of Charge
The depth of charge, which is the percentage of the battery that can be drained safely from the battery without causing any damage, in Lithium ion battery is greater than that of the lead acid battery. Lithium ion batteries use 85% or more from its total capacity in a single cycle. While lead acid batteries can only use 50% of its capacity in a single cycle.
Efficiency
The efficiency of the Lithium ion batteries is so high when compared to the lead acid batteries. Lithium ion batteries are 95% efficient. While lead acid batteries are only 80 - 85% efficient. This efficiency means that Lithium ion batteries can handle much higher amperage coming from the charger, which in return cuts down charging time tremendously. On the other hand, lead acid batteries can handle a limited charge current coming from the charger, anything above that amount and they would overheat. That is why in terms of charging time, Lithium ion batteries have the upper hand.
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