Lithium - thionyl chloride battery passivation solution 锂-亚硫酰氯电池钝化特性解决方案

Lithium - thionyl chloride battery passivation solution

锂-亚硫酰氯电池钝化特性解决方案

Chemical reactions and protective film 化学反应和保护膜
The electrochemical reaction equations in the process of discharge.
在放电过程中，整体的电化学反应方程式为：
4Li + 2SOCI2 — SO + S + 4LiCl
* “ LiCl ”Is the material make the battery produces passivating, as long as the battery electrolyte and anode contact, LiCl protective layer would be built up.
LiCl ”是使电池产生钝化的物质，只要在电池制造过程中电解液与阳极接触就会立即产生LiCl保护层。

Passivation problem 钝化问题
♦The voltage response lag电压反应滞后
• - when lithium thionyl chloride battery after long time storage, there will be a voltage hysteresis, the curve shown below.当锂-亚硫酰氯电池经过长时间存放后，会出现电压滞后现象，如下曲线所示。

Voltage curve (set for the cut-off voltage of 3.0 V)
瞬间电压曲线（设3.0V为截止电压）

A small current: no voltage hysteresis;
A小电流：无电压滞后现象；

B: medium current： voltage drop more than A， while above 3.0V;
B中等电流：电压大于截止电压；

C: big current: Voltage drops rapidly to less than 3. 0 V.
C大电流：电压瞬间下降至截止电压以下，出现电压滞后现象。

Voltage hysteresis电压滞后现象说明
•When the ER battery access to load circuit for the first time after storage, the voltage between the battery would change from the open circuit voltage drop to work voltage.当锂亚电池结束存储，首次接入负载电路时，电池电压会从开路电压下 降至工作电压。

•When load current is small, the work voltage would keep stable like curve A
在小电流情况下，电压基本保持稳定，如曲线A所示。
•When load current is bigger enough, the work voltage would instantly drop lower than cut-off voltage. The transient minimum voltage (TMV), is caused by passivation, like curve C.
在大电流情况下，电压可能会低于截止电压。这个最低电压值就是瞬间 最低电压（TMV），如曲线C所示。电压滞后是电池钝化引起的。
The passivation degree is related to storage temperature and storage time and current mechanical movement and so on. Like all the chemical reactions, passivation speed is closely related to the temperature. The higher the temperature the faster the passivation speed. The longer storage time, the passivation phenomenon is more serious. The greater the current, the TMV more obvious.
锂亚电池的钝化程度与存储期间的存储时间、电流、存储温度以及机械 运动等有关：跟所有化学反应一样，钝化速度与温度密切相关，温度越 高速度越快，时间越长，钝化现象就越严重，电流越大越明显。

•The reasons of the lagging of voltage 电压反应滞后的原因
After long stored, Li and SOCI2 reaction in lithium metal surface will be a layer of passivation film. The passivation membrane can prevent Li and SOCI2 further reaction. So when battery first time to load finished storage, there will be a voltage hysteresis. However, as the battery discharge, the passivation film will gradually be eliminated, load voltage rise gradually.
当锂亚电池经过长期存放后，Li和SOCI2反应会在金属锂表面产生一层致 密的钝化膜，钝化膜可以防止Li和SOCI2进一步反应。所以存储后的电池首 次接上负载，会出现电压滞后现象。但随着电池放电的进行，钝化膜会逐渐 被消除，负载电压逐渐上升。
The advantages of the passivation钝化的优点
The passivation film can be prevent further reaction, so the lithium battery storage time can be up to 10 ~ 15 years. 因为Li和SOCI2反应可产生致密的钝化膜防止反应进一步进行，所以锂 亚电池的存储时间可达10~15年。
The disadvantage of passivation钝化的缺点
The MPV would lead the equipment can't boot up after long time storage.锂亚电池经过长期存放后，电池钝化会降低大电流脉冲输出能力，使得 电池瞬间最低电压会低于应用的截止电压。
•结论