2022-12-17 14:24:58


The design of the lithium battery charger

KM Nor

The design of the lithium battery charger KM Nor Introduction Li-Ion rechargeable batteries are finding their way into many applications due to their size, weight and energy storage advantages.These batteries are already considered the preferred battery in portable computer applications, displacing NiMH and NiCad batteries, and cellular phones are quickly becoming the second major marketplace for Li-Ion. The reason is clear. Li-Ion batteries offer many advantages to the end consumer. In portable computers,Li-Ion battery packs offer longer run times over NiCad and NiMH packs for the same form factor and size, while reducing weight. The same advantages are true for cellular phones. A phone can be made smaller and lighter using Li-Ion batteries without sacrificing run time. As Li-Ion battery costs come down, even more applications will switch to this lighter and smaller technology. Market trends show a continual growth in all rechargeable battery types as consumers continue to demand the convenience of portability. Market data for 1997 shows that approximately 200 million cells of Li-Ion will be shipped, compared to 600 million cells of NiMH. However, it is important to note that three cells of NiMH are equivalent to one Li-Ion cell when packaged into a battery pack. Thus, the actual volume is very close to the same for both. 1997 also marked the first year Li-Ion was the battery type used in the majority of portable computers, displacing NiMH for the top spot. Data for the cellular market showed a shift to Li-Ion in the majority of phones sold in 1997 in Europe and Japan.Li-Ion batteries are an exciting battery technology that must be watched. To make sense of these new batteries, this design guide explains the fundamentals, the charging requirements and the circuits to meet these requirements.

Along with more and more the emergence of the handheld electric appliances, to the high performance, baby size, weight need of the light battery charger also more Come more big.The battery is technical to progress to also request continuously to refresh the calculate way more complicatedly is fast with the realization, safety of refresh.Therefore need Want to carry on the more accurate supervision towards refreshing the process, to shorten to refresh time and attain the biggest battery capacity, and prevent°from the battery Bad.The AVR has already led the one step in the competition, is prove is perfect control chip of the next generation charger. The microprocessor of Atmel A VR is current and can provide Flash, EEPROM and 10 ADCses by single slice on the market Of 8 RISC microprocessors of the tallest effect.Because the saving machine of procedure is a Flash, therefore can need not elephant MASK ROM Similar, have a few software editions a few model numbers of stock.The Flash can carry on again to weave the distance before deliver goods, or in the PCB Stick after pack carry on weaving the distance through an ISP again, thus allow to carry on the software renewal in the last one minute.

The EEPROM can used for conservancy mark certainly coefficient and the battery characteristic parameter, such as the conservancy refreshes record with the battery that raise the actual usage Capacity.10 A/ Ds conversion machine can provide the enough diagraph accuracy, making the capacity of the good empress even near to its biggest capacity. And other project for attaining this purpose, possible demand the ADC of the exterior, not only take up the space of PCB, but also raised the system Cost.

The AVR is thus deluxe language but 8 microprocessors of the designs of unique needle object' C' currently.The AT90S4433 reference The design is with' C' to write, the elucidation carries on the software designs is what and simple with the deluxe language.Code of C this design is very Carry on adjust easily to suit current and future battery.But the ATtiny15 reference design then use edit collected materials the language to write of, with Acquire the biggest code density. An electric appliances of the modern consumption mainly uses as follows four kinds of batteries:

  1. Seal completely the sour battery of lead( SLA)
  2. The battery of NiCd
  3. The NiMHhydrogen battery( NiMH)
  4. Lithium battery( Li- Ion)

At right choice battery and refresh the calculate way need to understand the background knowledge of these batteries. Seal completely the sour battery( SLA) of lead seals completely the sour battery of lead to mainly used for the more important situation of the cost ratio space and weights, such as the UPS and report to the police the backup battery of the system.

The battery of SLA settles the electric voltage to carry on , assist limits to avoid with the electric current at refresh the process of early battery lead the heat.Want ~only the electricity .The pond unit electric voltage does not exceed the provision( the typical model is worth for the 2.2 Vs) of produce the company, the battery of SLA can refresh without limit. The battery of NiCd battery of NiCd use very widespread currently.Its advantage is an opposite cheapness, being easy to the usage;Weakness is from turn on electricity the rate higher.The battery of NiCd of the typical model can refresh 1,000 times.The expired mechanism mainly is a pole to turn over.The first in the battery pack drive over.The unit that all turn on electricity will take place the reversal.For prevent°froming damage the battery wrap, needing to supervise and control the electric voltage without a break.Once unit electric voltage Descend the 1.0 Vs must shut down.

The battery of NiCd carries on refresh in settling the electric current by forever . The NiMH hydrogen battery( NiMH) holds to shoot the elephant machine 26 such as the cellular phone, hand in the hand that the importance measure hold equipments, the etc. NiMHhydrogen battery is




KM Nor




已经在竞争中领先一步,堪称是下一代充电器的完美控制芯片。Atmel A VR微处理器目前市面上最高效的8位RISC微处理器可提供Flash,EEPROM和10位ADC(因为程序存储器Flash),因此可以不用象MASK ROM相似,有一些软件版本的一些型号。闪存可以在发货前再进行编织距离,或者通过一个ISP进行编程后再通过ISP进行编程,从而允许进行软件更新在最后一分钟。

EEPROM可用于保存系数和电池性能参数,如保存更新记录和提高实际使用容量的电池10 A / D转换器可以提供足够的测量精度,使得产品的容量甚至接近其最大容量。而为达到此目的的其他项目,可能要求外部ADC,不仅占用PCB空间,还提高了系统成本。

AVR是目前唯一针对象“C”设计的高级语言8位微处理器。AT90S4433参考设计以“C”编写,说明用高级语言进行软件设计的是简单而又简单的。C 本设计的代码很容易进行调整以适应当前和未来的电池。但ATtiny15参考设计则使用编辑采集的材料的语言编写,并获得最大的代码密度。现代消费电器主要使用四种电池:






SLA电池在刷新早期电池过程中用电流设定电压进行辅助限制以避免电流过热。只有〜池单位电压不超过规定值(典型值型号为生产公司的2.2V),SLA的电池可以无限制地刷新。目前NiCd镍镉电池的使用非常普遍。其优点是相对便宜,易于使用;弱点是从接通电源的速率更高。典型型号NiCd电池可刷新1,000次。过期机构主要是一个极翻。首先在电池组中驱动。所有接通电源的单元将发生反转。为防止损坏电池包,无需监控电压单位电压下降1.0 Vs必须关闭。





最大刷新电流最大刷新电流与电池容量(C)有关。最大通常刷新电流与电池容量的数量意味着。例如,电池容量为750 mAhs,刷新电流为750 mAs,然后以1C(1倍电池容量)刷新电流。如果电流刷新为C / 40,则再为电池容量刷新电流除了为40。热电池更新是电力输送电池的过程。化学反应保护的能量下降。但并非全部。电能都是为了化学能在电池能力上的转换。一些电能转换成了热能,对电池具有加热功能。通电时,池塘充满后,如果继续刷新,则所有电能转换为电池的热能。快速充电会使电池快速升温,如果小时不能与停止刷新相比会造成电池损坏。因此,在设计电池充电器时,对温度进行测量。监督结合起来,及时停止更新。

判断方法电池停止刷新不同的应用场合和工作环境限制了判断停止刷新的方法的选择。有时候温度允许不容易测量,但可以测量电压,或者是其他情况。本文以电压变化率(- dV / dt)为基本判断停止。刷新方法,但以温度和绝对电压值辅助备份。但本文描述的硬件支持讲述如下。说的方法t时间该方法是停止刷新时最主要的决定方法。通常用于快速充电时间的备用项目。有时也是.Refresh(14-16小时)方法的基本工程。适用于各种电池。当V -

的电压超过上限时停止刷新。通常与永久安定电流刷新匹配使用。最大电流由电池决定,通常为1C。为防止更新电流导致电池过热导致电池过热,此时电流的限制非常关键。此方法是锂电池基本刷新停止工程。实际的锂电池充电器通常还会在达到最大电压后继续进行第二阶段更新,以达到100%的电池容量。对于NiCd电池和镍氢电池本身的方法可以是备用判断停止刷新项目。dV / dt - 电压变化率的这个判断的方法开发停止刷新负电压变化率。对于某些类型的电池,是电池被充电的子序列刷新持续会导致电压下降。此时该项目非常合适。该方法通常用于永久性稳定电流刷新,适用于NiCd电池和NiMH电池的快速充电。I - 的电流是在一定数量的刷新电流中预先设定的停止刷新。通常用于永久性解决电压刷新的方法。适用于SLA电池和锂电池。

T - 温度绝对零点可以作为NiCd电池和NiMH电池停止刷新的基础,但是甚至适合做备份项目。任何温度超过初始值的电池都不得不停止刷新。

dT / dt - 温升速度快速充电时的温度变化率可以停止刷新的基础。请参考电池生产公司的规范(镍镉电池的典型型号为1 oC / min ) 适用于NiCd电池和NiMH7电池。

当DT-超过环境温度的温度值时,需要停止刷新为不良电池温度和环境温度超过一定的阈值。此方法可以是NiCd的电池和SLA停止刷新的电池项目。在寒冷环境中刷新时,此方法比较绝对零度以更好地判断方法。因为大多数系统通常只有一个温度向前延伸,必须将以前的温度刷新为环境温度.VV / dt = 0 - s零电压与该方法不同- dV / dt的方法非常类似,并且在电压不会再上升的情况下更准确。适用于镍镉电池和镍氢电池。




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