锂聚合物电池使用全攻略

liangfei1111

Data - Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports

After seeing the many many posts on LiPoly's and answering similar questions time after time I've decided to put up a guide for using LiPoly batteries.

Lithium batteries are the preferred power sources for most electric modelers today. They offer high discharge rates and a high energy storage/weight ratio. However, using them properly and charging them correctly is no trivial task. There are many things to consider before using lithium cells for e-flight. But none is more important than safety.

1. Charging/Saftey IMPORTANT!
Until you are willing to follow all saftey precautions, DO NOT use lithium batteries. If your a type of person that prefers to push the limits of products, or be haphazard about following saftey requirements. Lithium technology is not for you. Read on to find out why.

Lithium cells must be charged very differently than NiCad or NiMH. They require a special charger specifically designed to charge lithium cells. In general any charger that can charge lithium ion can charge lithium polymer, assuming that the cell count is correct. You must NEVER charge lithium cells with a NiCad or NiMH only battery charger. This is dangerous. Charging cells is the most hazardous part of using lithium batteries. EXTREME care must be taken when charging them. It is important to set your charger to the correct voltage or cell count. Failure to do this can cause the battery to spew violent flames. There have been many fires directly caused by lithium batteries. PLEASE BE RESPONSIBLE when charging lithium batteries.

Here are a few MANDATORY guidelines for charging/using LiPos (Lithium Polymer Batteries).


1. Use only a charger approved for lithium batteries. The charger may be designed for Li-Ion or Li-Poly. Both batteries are charged in exactly the same. Some older cell phone chargers may charge the batteries .1 volt to low (4.1 vs 4.2), but that will not harm the battery. However, inexpensive lithium chargers are widely available and the use of cellphone chargers is highly discouraged.
2. Make certain that the correct cell count is set on your charger. Watch the charger very closely for the first few minutes to ensure that the correct cell count continues to be displayed. If you don't know how to do that, get a charger that you do know how or don't charge the batteries.
3. Use the Taps. Before you charge a new Lithium pack, check the voltage of each cell individually. Then do this after every tenth cycle there after. This is absolutely critical in that an unbalanced pack can explode while charging even if the correct cell count is chosen. If the cells are not within 0.1 volts of each other then charge each cell individually to 4.2 volts so that they are all equal. If after every discharge the pack is unbalanced you have a faulty cell and that pack must be replaced.
Taps are provided on most new lithium packs. Taps give you the ability to check individual cell voltages and charge one cell at a time. Make sure and get the appropriate connector to go into your taps. Don't try to stick you volt meter probes in the taps to measure voltage. They could slip and short your cells. Don't try to charge more than one cell at a time from the taps. Unless you have an isolated ground charging system, you'll short your batteries out. Refer to your individual cell maker for tap pin-outs.
4. NEVER charge the batteries unattended. This is the number one reason for houses and cars being burned to a crisp by lithium fires.
5. Use a safe surface to charge your batteries on so that if they burst into flame no damage will occur. Vented fire safes, pyrex dishes with sand in the bottom, fireplaces, plant pots, are all good options.
6. DO NOT CHARGE AT MORE THAN 1C unless specifically authorized by the pack vendor. I have personally had a fire in my home because of violating this rule. Todays highest discharge batteries can supposedly be safely charged at greater than 1C, however so far in all cases doing so shortens the life of the pack. Better to buy 3 packs than to try to charge 1 pack 3 times quickly. This may change in the future but as of Winter 2005 1C is still the recommended charge rate.
7. DO NOT puncture the cell, ever. If a cell balloons quickly place it in a fire safe place, especially if you were charging it when it ballooned. After you have let the cell sit in the fire safe place for at least 2 hours. Discharge the cell/pack slowly. This can be done by wiring a flashlight bulb of appropriate voltage (higher is voltage is ok, lower voltage is no) up to your batteries connector type and attaching the bulb to the battery. Wait until the light is completely off, then throw the battery away.
8. If you crash with your lithium cells they may be damaged such that they are shorted inside. The cells may look just fine. If you crash in ANY way carefully remove the battery pack from the aircraft and watch it carefully for at least the next 20 min. Several fires have been caused by damaged cells being thrown in the car and then the cells catch fire later and destroys the car completely.
9. Charge your batteries in a open ventilated area. If a battery does rupture or explode hazardous fumes and material will spew from the battery.
10. Keep a bucket of sand nearby when you are flying or charging batteries. This is a cost effective way to extinguish fires. This is very cheap and absolutly necessary.
11. It can happen to you, do not think to yourself that “it won't happen to me” as soon as you do that it you'll be trying to rescue your kids from your burning house or car. I'm very serious about this.

Now that we have covered that important topic let's move on to lighter matters:

2. Lithium What?
Lithium Polymer batteries are used in many electronic devices. Cell Phone, Laptops, PDA's, Hearing Aids just to name a few. Most, if not all, lithium polymer batteries are not designed for RC use, we use them in different applications than they were designed for. They are similar to Lithium Ion batteries in that they each have a nominal voltage of 3.6 volts, but dissimilar in that they do not have a hard metal casing but rather a flexible material encloses the chemicals inside. The "normal" lithium polymer batteries are thin rectangle shapes with two tabs on the top one positive one negative. The reason we use Lithium cells is that they are significantly lighter than comparable NiCad or NiMH batteries, which makes our planes fly longer and better.

3. Voltage and Cell Count:
LiPolys act differently than NiCad or NiMH batteries do when charging and discharging. Lithium batteries are fully charged when each cell has a voltage of 4.2 volts. They are fully discharged when each cell has a voltage of 3.0 volts. It is important not to exceed both the high voltage of 4.2 volts and the low voltage of 3.0 volts. Exceeding these limits can harm the battery.
The way to ensure that you do not go below 3.0 volts while flying is to set the low voltage cutoff (LVC) of your electronic speed control (ESC). It important to use a programmable ESC since the correct voltage cutoff is critical to the life of your batteries. Use the ESC's programming mode to set the LVC to 3.0 volts per cell with a hard cutoff, or 3.3 volts per cell with a soft cutoff. If your ESC does not have hard or soft cutoff, use 3.0 volts per cell. You will know when flying that it is time to land when you experience a sudden drop in power caused by the LVC.
If your ESC has an automatic lithium mode. Use it, it will correctly sense the number of cells and set the auto cutoff appropriately.
If you have previously been flying with NiCad or NiMH batteries, switching over to lithium polymer will result in a different number of cells being used. If you had 6 to 7 round cells then 2 lithium polymer cells will correctly duplicate the voltage of those cells. If you had 10-11 cells then 3 lithium polymer cells would be right for you. There are a lot of 8 cell flyer's out there that are stuck between 2 and 3 cells. In my experience the best option is to determine how many watts you were using before and duplicate that with your LiPos, Motor, and Prop. For example. If you were running 8 cells (9.6volts) at 10 amps on a speed 400 airplane, then you have 9.6 x10, 96 watts. So if you went with 2 lithium polymer cells (7.2 volts nominal) then you'd need to change your prop such that you used 13 amps. If you went to 3 LiPoly's (10.8 volts nominal) then you'd need to reduce the amperage to 8.9 amps. These estimates are approximate, and some experimentation is required for best results but conserving Watts is a good way to start.

4.10C from 3S4P? Naming conventions explained.
How fast a battery can discharge is it's maximum current capacity. Current is generally rated in C's for the battery. C is how long it takes to discharge the battery in fractions of an hour. For instance 1 C discharges the battery in 1/1 hours or 1 hour. 2 C discharges the battery in ½ or half an hour. All RC batteries are rated in milli

liangfei1111

Amp hours. If a battery is rated at 2000 mAh and you discharge it at 2000mA (or 2 amps, 1 amp = 1000mA) it will be completely discharged in one hour. The C rating of the battery is thus based on its capacity. A 2000mAh cell discharged a 2 amps is being discharged at 1C (2000mA x 1), a 2000mAh cell discharged at 6 amps is being discharged at 3C( 2000mA x 3).
All batteries have limitations on how fast they can discharge. Because of this many LiPoly batteries are put in parallel to increase the current capacity of the battery pack. When 2 batteries are wired positive to positive and negative to negative they become like one battery with double the capacity. If you have 2 2000mAh cells and you wire them in parallel then the result is the same as 1 4000mAh cell. This 4000mAh cell has the same C rating as the original 2000mAh cells did. Thus if the 2000mAh cells could discharge at a maximum of 5C, or 10 amps then the new 4000mAh cell can also discharge at 5C or (4000mA x 5) 20 amps. This method of battery pack building allows us to use LiPoly batteries at higher currents than single cells could produce.
The naming convention that allows you to decipher how many cells are in parallel and how many are in series is the XSXP method. The number in front of the S represents the number of series cells in the pack so 3S means it's a 3 cell pack. The number in front of P means the number of cells in parallel. So a 3S4P pack of 2100mAh cells has a total of 12 cells inside. It will have the voltage of any other 3S pack since the number of cells in series determines the voltage. It will have the current handling of 4 times the maximum C rating of the 12 individual cells. So say our 3S4P pack had a maximum discharge of 6C. That means that it has a nominal voltage of 10.8 volts (3x3.6) and a maximum discharge rate of 50.4 amps (2100mAh x 6Cx4P ).

5. Which battery should you buy?
With so many choices out there it is difficult to decipher what is marketing hype, what is brand
loyalty, and what is outright lies. Battery manufacturers are constantly trying to one up one another. While capitalism can drive prices down, it also can give cause to false claims about products.
One great way to find out what the best battery is, is to look at graphs of the batteries performance. Looking at how low the voltage of the cell drops at various amperages will give you a metric to compare that battery to similar size/weight batteries.
If graphs aren't your thing then simply look at what other people are using in successful setups that are similar to your application. If a lot of people are reporting long flight times and lots of power from airplane X, with power system Y, and battery Z and you do the same, then if your setup is similar the same battery will probably work well for you.
It pays to learn something about Watts, Volts, and Amps. Understanding these concepts is beyond the scope of this document, but can serve you well in not only figuring out what battery is best but also in your electric aircraft hobby.
I'm not convinced that a 30C battery is really any better than a 10 or 20C battery. Sure a higher C rating means it can discharge faster. But at the same time a battery discharged at 20C continuously will be empty in 3 minutes. Do you really only want to use the battery for 3 minutes? I love having burst power in helicopters and boats, but in almost all other applications actually running a battery at or above 20C is useless to me. I prefer to run batteries at 8-10 C and have a little headroom if I need it.
A final note on choosing a battery. Don't cheap out. Confirm that your batteries are capable of running that the amperage level you plan to use them at. Running a cell at a higher C rating than the battery can handle can not only damage your batteries, but it can also damage your speed control. Castle Creations has an excellent article on how using a weak battery can destroy a perfectly good speed control of any brand. Better to buy a bit better battery than you need than to destroy your electronics.

6. Dealing with temperature.
Lithium batteries like heat, but not too much. In the winter time, try to keep your batteries from the cold as much as possible. Leave them in the car while your flying, or keep them in your cargo pants... etc. At the same time don't let them heat up too much. Try to keep your batteries from reaching 160F after use. This will prolong the life of the cells. A good way to measure temperature is a handheld IR meter, they can be found for around $50.00 at most hobby shops.

If you have any suggestions for future sections or additions to the current document let me know and I'll add the information requested...if I know the answer!

-Jim

liangfei1111

老外写的，安全理念值得借鉴

锂聚合物电池
在经过许多锂聚合物电池的使用和一次又一次回答类似的问题以后我决定写出下面的锂聚合物电池使用全攻略。
在今天锂聚合物电池是电池供电的首选方式。锂聚合物电池能提供较高的放电速率和较高的单位重量存储量。无论如何，正确的使用和充电是重要的。在使用锂聚合物电池飞行之前有许多需要考虑的问题，安全是首要的问题。
1．  安全充电。重要！
使用锂聚合物电池你必须遵从下面的安全守则。
锂聚合物电池的充电与镉电池和氢电池区别很大。锂聚合物电池充电要求专门的充电器。通常充锂离子电池的充电器可以用来充锂聚合物电池，只要电池串联的个数相同。
记住：一定不要用镉和氢电池的专用充电器充锂电池。这是非常危险的。充电是使用锂聚合物电池最危险的阶段。充电过程应有人照管。正确设置充电电压或电池组单体个数非常重要。
否则可能引起电池爆裂或燃烧。已有许多电池燃烧的先例。记住：你对充电的安全负有责任。
下面是几条锂聚合物电池充电必须遵守的守则。
1．              使用专用的充电器。这个充电器可以是锂离子或锂聚合专用充电器。两者非常接近。部分移动电话的充电器可以用来充锂聚合物电池。（输出电压4.1~4.2），这不会损坏电池。但大多数便宜的移动电话充电器充电效果让人失望。
2．              准确设置电池组的电池单体个数（充电电压）。充电的头几分钟你必须仔细的观察充电器的显示屏，在上面会显示电池组的电池个数。假如你不清楚，那你就不应当充电或使用你熟悉的充电器。
3．              第一次充一个新的锂电池组，检查电池组每个电池单体的电压，以后每10次充放电也应做同样的工作。这样做是绝对的必要，一个电压不平衡的电池组当电池个数选择正确充电时仍会爆裂。假如电池组内电池单体电压相差超过0.1伏，你就应当分别把每个电池的电压充到4.2伏使之相等。假如每次放电后电池单体的电压差均超过0.1伏，则表示你的电池已经出现故障，应当更换。（使用非平衡充）
4．              无人照看不要充电。已有数起因为锂电池充电烧毁房屋和汽车的例子。
5．              使用安全的表面放置充电的电池和充电器，假如燃烧产生明火也不会损坏。耐热玻璃上边放上沙子，壁炉，花盆均是不错的选择。地方应通风良好。
6．              无厂家的特别说明，充电电流不要超过1C。我曾经有过违反上述规定导致燃烧的经历。现在支持大电流放电的电池也支持超过1C的电流充电。但将大大缩短电池的寿命，买3个电池比买一个电池而不得不快充更划算。在将来有可能会有所改变，但在2005年冬天1C还是被推荐的标准充电电流。
7．              不要刺破电池。假如电池鼓包，那就存在着火的安全隐患。特别是正在充电时鼓包，你应当立即停止充电，将电池移到安全的地方，静置两小时后小电流放电，电压较高的小电珠是一个不错的选择。直到电池放完电后再扔掉。
8．              撞击会损坏你的锂聚电池，有可能电池看起来好象是好的但内部已经短路。假如电池受到撞击请小心地将电池从飞机上取下来移到安全的地方，小心观察，静置20分钟。有过着火的电池被扔进汽车将汽车完全烧毁的先例。
9．              在通风良好和空旷的地方充电。假如电池爆裂开会有浓烟和内容物喷射出来。
10．          准备一桶沙。当你飞行或充电时灭火是非常有效和绝对必须的。
11．          你有可能碰到。不要认为你不会碰到，假如你使用你就应准备营救你的孩子；汽车和房子。
好了，继续下面的话题
2．  锂聚合电池是什么？
锂聚合物电池在许多电器中被使用。移动电话，笔记本电脑，掌上电脑，助听器等。但都不是为遥控模型设计的。我们超过它们的设计使用领域使用他们。锂聚合电池类似锂离子电池，他们的电压都是3.6伏，但不同之处是锂聚合电池没有坚硬的金属外壳，它被封装在一个柔软的金属外套内。通常锂聚合电池被做成四方型带有两个标记，一个是“正”；一个是“负”。锂聚合电池比镉；氢电池更轻这就是我们使用他们的原因，它能使我们的飞机飞行时间更长更好。
3．电压和串联的电池数：
锂聚合电池的电压与镉；氢电池不同。锂聚合电池充满电的电压是4.2伏。放完电的电压是3.0伏。充电不超过4.2伏；放电不超过3.0伏非常重要，超限度充放电会损坏电池。控制放电下限的方法是设定放电速度控制（ESC）的低压关断（LVC）。使用可编程ESC控制低压关断保护电池是非常重要的。使用ESC的程序模式设定LVC到每个电池3.0伏硬关断或3.3伏软关断。假如你的ESC没有硬或软关断就设定到每个电池3.0伏关断。你的经验将告诉你好长时间应当着陆，也就是你的LVC起作用动力突然下降的时间。假如你的ESC有自动模式，应当使用它。它将自动诊测电池的个数和设置关断电压。假如你先前使用镉或氢电池，现换为锂电池则电池的数量会与先前不同。假如你先前使用6到7个电池串联只需2个锂电池串连电压就够了。你先前使用10到11个电池串联只需3个锂电池串连电压就够了。
先前大量8个电池的飞机现在则需2到3个电池。以我的经验是找出原先使用电机的电压和螺旋桨消耗的功率。例如速度400的飞机运行8个电池（9.6伏）10安培，功率就是9.6x10，96瓦特。要是你想换为两个锂电池（通常7.2伏）就需要更换你的浆使电流在13安培。要是你想换为三个锂电池（通常10.8伏）就需要更换你的浆使电流减少到8.9安培。这样估算是近似的，还需考虑其他的因素但还是不失为一个不错的方法

liangfei1111

1．  电池组10C3S4P的含义
“10C”表示电池的最大放电速率—电池最大能以好大的电流放电。“C”是1小时电池放完电的电流。“2C”放电表示电池半小时放完电。RC电池的放电电流单位通常用毫安mA(1A=1000mA).假如电池容量2000mAh表示电池以2000mA电流放电1小时放完。电池的最大放电电流还取决于电池的容量。一个2000mAh电池2安放电放电率是1C。2000mAh电池6A放电放电率是3C。电池的最大放电电流是有限的但可以通过并联电池提高最大放电电流。当两个相同电池正极接正级；负级接负级变成一个电池最大放电电流和容量加倍。如2个2AH的电池并联相当于一个4AH的电池。C数不变。假如单个电池是5C最大放电电流是10A，并联后还是5C，最大放电电流变为20A。这个方法可以提高电池的容量和最大放电电流。XSXP表示好多电池串联好多电池并联。S前的数值表示电池组中串联的电池个数。P前的数值表示电池组中并联的电池数。3S4P表示电池组3串4并共12个电池。电压是串联电池数的倍数，电池容量和最大放电电流是并联电池数的倍数。
2．  你需要买那种电池？
市场上有许多电池可供选择，最好的方法是看电池的放电曲线，比较近似尺寸重量和电池数的电池看在各种放电电流下电压下降快慢。假如曲线上没有你所需的参数可以参考别人的使用情况。假如很多人都说动力足，飞行时间长，而你使用相同的电池，设置也相同照理也会很好。学习关于瓦特；电压；安培明白他们的含义将有助于你用好你的电池而且不仅仅会有助于你的业余爱好。我不认为30C的电池就一定比10C或20C的电池好。高C放电意味着电会很快放完，一个电池以20C放电3分钟就会放完，你真的想你的电池仅仅支撑3分钟吗？在飞直升机和玩船时我喜欢暴力，但在大多数别的场合我还是喜欢让我的电池以8到10C放电。选择电池还要注意，电池并不便宜。不要让你的电池超过最大放电电流放电，这将会损伤电池，也可能损坏你的电调。城堡主有一篇精彩的文章讲述差的电池能够毁坏电调，多花点钱买好的电池比你的电子设备被损坏划算。
3．  控制温度
锂电池会发热，但温度不太高。冬天注意给你的电池保温，放在车内或裤袋内等。也不要让你的电池温度太高，尽量等你的电池到华氏160度后使用将会延长电池的使用寿命。用红外线温度计是一个不错的方法。

N8

:em26: 好帖！

N8

1. Charging/Saftey IMPORTANT!
Until you are willing to follow all saftey precautions, DO NOT use lithium batteries. If your a type of person that prefers to push the limits of products, or be haphazard about following saftey requirements. Lithium technology is not for you. Read on to find out why.

楼主；这段话请补上。

大砍刀

好!顶!!!!非常好啊,我收藏啦!谢谢liangfei1111 兄弟啦!

依然爱我

哦------———— :em04: :em04:

liangfei1111

1. Charging/Saftey IMPORTANT!
Until you are willing to follow all saftey precautions, DO NOT use lithium batteries. If your a type of person that prefers to push the limits of products, or be haphazard about following saftey requirements. Lithium technology is not for you. Read on to find out why.

楼主；这段话请补上。
大意是：你不愿遵循下列安全条例你就不应该使用锂电池。否则使用锂电池对你是非常危险的，继续阅读并找出原因。

bevinice2

学习

dpcom

:em26:

love

:em26: :em26: :em26:

zxj13708380359

学习了,并记住.本来经常冲着电,人不在.现在看来是不行的了

yidy122

注意充电!.不要过放电!