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Li-Po over Li-ion. why?
5872 23 2018-7-5
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Kevinab
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Ever since the mavic pro came out iv always wondered why DJI goes with Lithium Polymer over Lithium ion for their batteries. Lithium ion takes a lot more cycles and degrades a lot less, it also has a more stable nominal voltage and can be charged a tad bit faster. Iv googled a bunch and done some research here and there and can't find any valid points as to why they aren't making an effort toward Li-ion. It's a little more expensive yes but it's been used at DJI ever since their first drones came to market, and never has DJI, at least openly tried to make an effort towards a switch.


Why is this?, maybe some of u got more info than i found online
2018-7-5
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HedgeTrimmer
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The following article gives good run down as to why, along with pros and cons.
What is the difference between Li-Ion and Li-Po Power Banks?
2018-7-5
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DJI Gamora
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Hi thanks for reaching DJI Forum, We do understand you are having confusions on why DJI goes with the  Lithium Polymer ( Li-Po ) versus the Lithium Ion ( Li-ion).  The great difference is that Lipo batteries give higher specific energy than the Li-ion. Thus giving such amount energy propels the motor without suffering the flight time. Another thing is most Li-ion batteries are not rechargeable.  Thank You
2018-7-5
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AlansDronePics
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Just a thought, the Li-Ion are cylinders so when packed together, there is a lot of wasted space. The battery pack would be much larger for the same power.
The extra weight of Li-Ion is a flight time killer.
If other things are relatively similar, Li-Po is a clear winner for a drone.
2018-7-5
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Kevinab
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HedgeTrimmer Posted at 2018-7-5 08:30
The following article gives good run down as to why, along with pros and cons.
What is the difference between Li-Ion and Li-Po Power Banks?

https://i.imgur.com/TNVOKG7.png

prooves my exact point in why ion is better
2018-7-5
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Kevinab
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DJI Gamora Posted at 2018-7-5 08:47
Hi thanks for reaching DJI Forum, We do understand you are having confusions on why goes with the  Lithium Polymer ( Li-Po ) versus the Lithium Ion ( Li-ion).  The great difference is that Lipo batteries give higher specific energy than the Li-ion. Thus giving such amount energy propels the motor without suffering the flight time. Another thing is most Li-ion batteries are not rechargeable.  Thank You

ah. thank you for clearing it up
2018-7-5
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HedgeTrimmer
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Kevinab Posted at 2018-7-5 08:55
https://i.imgur.com/TNVOKG7.png

prooves my exact point in why ion is better

Higher Density is size, not weight.

Additionally despite Higher Density, the Li-Ion batteries are canned (cylinder shaped) leaving gaps around the cans when staked.  The Li-Pos are generally flat / oblong in shape, allowing for efficient staking.

There is also safety factor the Li-Pos bring to table over Li-Ion.
2018-7-5
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Kevinab
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HedgeTrimmer Posted at 2018-7-5 09:02
Higher Density is size, not weight.

Additionally despite Higher Density, the Li-Ion batteries are canned (cylinder shaped) leaving gaps around the cans when staked.  The Li-Pos are generally flat / oblong in shape, allowing for efficient staking.

the canned part isnt true. phone batteries are almost flatter than the cells in DJI batteries and their Ion not Polymer
https://i.imgur.com/Z5vpFuG.jpg
2018-7-5
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HedgeTrimmer
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Kevinab Posted at 2018-7-5 09:04
the canned part isnt true. phone batteries are almost flatter than the cells in DJI batteries and their Ion not Polymer
https://i.imgur.com/Z5vpFuG.jpg

Agreed, Li-Ion can be made flat.  However in doing so it requires protection over large surface area due to Li-Ion batteries being more dangerous than Li-Po.
2018-7-5
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AlansDronePics
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HedgeTrimmer Posted at 2018-7-5 09:10
Agreed, Li-Ion can be made flat.  However in doing so it requires protection over large surface area due to Li-Ion batteries being more dangerous than Li-Po.

Can Li-Ion be made flat? Something else I didn't know. Thanks.
2018-7-5
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HedgeTrimmer
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AlansDronePics Posted at 2018-7-5 09:14
Can Li-Ion be made flat? Something else I didn't know. Thanks.

See Kevinab's post above showing a picture of a flat Li-Ion battery used with cell phone.
2018-7-5
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3-D
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Kevinab Posted at 2018-7-5 08:55
https://i.imgur.com/TNVOKG7.png

prooves my exact point in why ion is better

So you're just gonna skip over that explosive risk one?
2018-7-5
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Kevinab
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HedgeTrimmer Posted at 2018-7-5 09:10
Agreed, Li-Ion can be made flat.  However in doing so it requires protection over large surface area due to Li-Ion batteries being more dangerous than Li-Po.

in my opinnion pretty much all lithium based batteries are so safe that it isnt an issue anymore. as long as ur protection circuit protects against:

1. Overcharge
2. over discharge
3. over current
4. over voltage

5. (optional, most dont have) over heating current limiter/disconnector
2018-7-5
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Kevinab
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3-D Posted at 2018-7-5 09:18
So you're just gonna skip over that explosive risk one?

read the response i gave to HedgeTrimmer
2018-7-5
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3-D
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Kevinab Posted at 2018-7-5 11:29
read the response i gave to HedgeTrimmer

I agree, and normally wouldn't even consider the safety of batteries.  But I actually had one of the Samsung Note 7 phones that exploded. (actually just kind of smoldered)
So anything with less chance of that, is what I want.    Maybe I'm a little more sensitive to that than others.
2018-7-5
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HedgeTrimmer
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Kevinab Posted at 2018-7-5 11:28
in my opinnion pretty much all lithium based batteries are so safe that it isnt an issue anymore. as long as ur protection circuit protects against:

1. Overcharge

You need to look at differences to battery cells themselves when it comes to risk.  Unlike Li-Ion batteries, Li-Po batteries are resistant to damage by nature of their cell materials and design.
Li-Po batteries use either gel or dry form of electrolyte and cells themselves are semi flexible.  Li-Ion use liquid electrolyte and are not flexible.  

Hence the issues of cellphones catching fire when people bent cellphones with Li-Ion batteries.  Drone crashing could result in either deformed battery casing or punctured battery casing. Li-Po battery is more likely to withstand deformed casing, and if punctured gel/dry electrolyte stay in battery (or in case of gel slowly pool out and stay near battery).

2018-7-5
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HedgeTrimmer
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Don't forget there is also the weight advantage Li-Po batteries have over Li-Ion batteries as in mAH / gram.   Less weight with same amount of power means longer flight times and faster response.
2018-7-5
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Kevinab
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HedgeTrimmer Posted at 2018-7-5 11:56
You need to look at differences to battery cells themselves when it comes to risk.  Unlike Li-Ion batteries, Li-Po batteries are resistant to damage by nature of their cell materials and design.
Li-Po batteries use either gel or dry form of electrolyte and cells themselves are semi flexible.  Li-Ion use liquid electrolyte and are not flexible.  

good point, agree
2018-7-5
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Weiguoorng
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We CTECHI Group is a leading lithium manganese dioxide battery, lithium iron disulfide battery,lithium sulfur dioxide battery and lithium iron phosphate battery manufacturer and exporter in China, we are not only focus on provide single cell but provide battery assembly and do OEM service for customers, CTECHI has captured 80 percent of overseas markets in the past 16 years with more than 2000 reliable customers in our customer management system, which has been being one of the leading enterprises with the most complete category in China's battery industry.

We have some topics about vasious kinds of lithium batteries and their advantages. If you have any interest, please visit www.superlithiumbattery.com/arti ... dvantages-1374.html
2018-10-15
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Paul_
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HedgeTrimmer Posted at 2018-7-5 11:59
Don't forget there is also the weight advantage Li-Po batteries have over Li-Ion batteries as in mAH / gram.   Less weight with same amount of power means longer flight times and faster response.

I agree. For this application I would take the Po without question.
2018-10-26
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mrpenguin
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I have been into RC for years, and LiPo where always used, not Li-ion. I have packs for my buggy that are rated at 40-50c, which means, being a 5000mah pack, thats 200-250 amp max discharge rate.
2018-10-26
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djiuser_yDTyPSpwzyld
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The most significant difference between lithium-ion and lithium-polymer batteries is the chemical electrolyte between their positive and negative electrodes. Read more at IronEdison.com
2019-6-13
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Trevor George
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DJI Gamora Posted at 2018-7-5 08:47
Hi thanks for reaching DJI Forum, We do understand you are having confusions on why DJI goes with the  Lithium Polymer ( Li-Po ) versus the Lithium Ion ( Li-ion).  The great difference is that Lipo batteries give higher specific energy than the Li-ion. Thus giving such amount energy propels the motor without suffering the flight time. Another thing is most Li-ion batteries are not rechargeable.  Thank You

Hi DJI Gamora . . you wrote . . "Another thing is most Li-ion batteries are not rechargeable"
That's nonsensical coming from a DJI rep, as Li-ion batteries were used in previous DJI Drones, and in most eBikes, so they are obviously rechargeable.
Thank you.
2020-10-28
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Ian in London
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Trevor George Posted at 10-28 04:59
Hi DJI Gamora . . you wrote . . "Another thing is most Li-ion batteries are not rechargeable"
That's nonsensical coming from a DJI rep, as Li-ion batteries were used in previous DJI Drones, and in most eBikes, so they are obviously rechargeable.
Thank you.

I did wonder about that sentence.........
2020-10-28
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