威达铅蓄电池故障分析

在威达铅蓄电池的检测过程中，经常会碰到威达铅蓄电池出现故障和异常数据而使检测无法进行或使试验提前终止。因此，把握故障分析对检测工作是很重要的。

一、故障现象及原因

1、反极的现象及原因

威达铅蓄电池的反极系指蓄电池的正负极发生了改变，反极现象反映在两个方面，一是由于铅蓄电池在装配组装时某单格电池极群组接反或整个电池极群组接反。这种情况下会出现铅蓄电池灌完酸用电压表丈量端电压时其端电压值小于各单体蓄电池额定电压之和的现象或出现端电压为负的现象。另一方面是铅蓄电池在容量放电时在多个串联使用中，由于某个蓄电池(或某单体蓄电池)容量较低或完全丧失容量。在放电时这个电池很快被放完电被其它电池进行反充电，使原来的负极变成正极，原来的正极变成负极，端电压出现负值的现象。

对于前一种反极故障，在丈量蓄电池端电压时(多个单体电池组成的蓄电池)都可发现，若有一个单体电池反极，不仅失往该电池的2 V电压，而且还要增加2 V反电压，端电压要降低4V左右。例如，对于额定电压为12 V的电池，如丈量其端电压为8 V左右，说明有1个单格电池反极。如丈量其端电压为4 V左右说明有2个单格反极，如丈量其端电压为—4 V左右说明有4个单格反极，如丈量其端电压为—12 V说明6个单格均反极。

对于后一种反极故障，其端电压值(负值)随放电情况而不同。一般在检测时，对于这种情况要及时将蓄电池从放电线路中摘除下来，以免对蓄电池有所损坏。

2、短路现象及原因

铅蓄电池的短路系指铅蓄电池内部正负极群相连。铅蓄电池短路现象主要表现在以下几个方面：

(1)开路电压低，闭路电压(放电)很快达到终止电压。

(2)大电放逐电时，端电压迅速下降到零。

(3)开路时，电解液密度很低，在低温环境中电解液会出现结冰现象。

(4)充电时，电压上升很慢，始终保持低值(有时降为零)。(5)充电时，电解液温度上升很高很快。

(6)充电时，电解液密度上升很慢或几乎无变化。

(7)充电时不冒气泡或冒气出现很晚。

造成铅蓄电池内部短路的原因主要有以下几个方面：

(1)隔板质量不好或缺损，使极板活性物质穿过，致使正、负极板虚接触或直接接触。

(2)隔板窜位致使正负极板相连。

(3)极板上活性物质膨胀脱落，因脱落的活性物质沉积过多，致使正、负极板下部边沿或侧面边沿与沉积物相互接触而造成正负极板相连。

(4)导电物体落进电池内造成正、负极板相连。

(5)焊接极群时形成的“铅流”未除尽，或装配时有“铅豆”在正负极板间存在，在充放电过程中损坏隔板造成正负极板相连。

3、极板硫酸化现象及原因

极板硫酸化系指在极板上天生白色坚硬的硫酸铅结晶，充电时又非常难于转化为活性物质的硫酸铅。铅酸蓄电池极板硫酸化后主要有以下几种现象。

(1)铅蓄电池在充电过程中电压上升的很快，其初期和终期电压过高，终期充电电压可达2.90V／单格左右。

(2)在放电过程中，电压降低很快，即过早的降至终止电压，所以其容量比其它电池明显降低。

(3)充电时，电解液温度上升的快，易超过45℃。

(4)充电时，电解液密度低于正常值，且充电时过早地发生气泡。

(5)电池解剖时可发现极板的颜色和状态不正常。正极板呈浅褐色(正常为深褐色)，极板表面有白色硫酸铅斑点，负极板呈灰白色(正常为灰色)极板表面粗糙，触摸时如同有砂粒的感觉，并且极板发硬。

(6)严重的硫酸盐化，极板形成的硫酸铅白色结晶体粗大，在一般情况下不能复原成活性物质。

造成极板硫酸化主要有以下几方面的原因。

(1)铅蓄电池初充电不足或初充电中断时间较长。

(2)铅蓄电池长期充电不足。

(3)放电后未能及时充电。

(4)经常过量放电或小电流深放电。

(5)电解液密度过高或者温度过高，硫酸铅将深进形成不易恢复。

(6)铅蓄电池搁置时间较长，长期不使用而未定期充电。

(7)内部短路局部作用或电池表面水多造成漏电。

(8)电解液不纯，自放电大。

(9)电池内部电解液面低，使极板裸露部分硫酸化。

铅蓄电池在正常使用的情况下，正、负极板上的活性物质(Pb02和Pb)大部分转变为小粒晶状的硫酸铅，这些松软小粒晶状的硫酸铅是均匀地分布在多孔性的活性物质上，在充电时很轻易和电解液接触起作用恢复为原来的物质PbO2和Pb。

假如在使用中由于上述的使用不当的诸原因，极板上的活 性物质会逐渐形成结晶粒粗大的硫酸铅，这些粗而硬的硫酸铅晶体体积大，导电性差，因而会堵塞极板活性物质的细孔，阻碍了电解液的渗透和扩散作用，增加了电池的内电阻，同时，在充电时，这种粗而硬的硫酸铅不如软小晶粒的硫酸铅轻易转化为PbO2、和Pb。若历时过久，这些粗而硬的硫酸铅就会失往可逆作用，结果使极板的有效物质减少放电容量降低，使用寿命缩短。

4、极板弯曲和腐蚀断裂

极板弯曲多发生于正极板，而负极板很少发生，有的负极板弯曲则是由于正极板弯曲过甚而迫使负极板亦随之弯曲所致。

In the process of testing Viada lead-acid batteries, it is often encountered that the failure of Viada lead-acid batteries and abnormal data make the test can not be carried out or the test is terminated in advance. Therefore, it is very important to grasp fault analysis for detection work.

1. Fault phenomena and causes

1, the phenomenon and causes of the reverse pole

The reverse pole of the lead battery means that the positive and negative poles of the battery have changed, and the reverse pole phenomenon is reflected in two aspects, one is because a single cell battery pole group is reversed or the entire battery pole group is reversed when the lead battery is assembled. In this case, the end voltage value of the lead-acid battery is less than the sum of the rated voltage of each single battery or the end voltage is negative when the voltmeter is used to measure the end voltage. On the other hand, the lead battery is used in multiple series when the capacity is discharged, due to the low capacity of a battery (or a single battery) or the total loss of capacity. When discharging, the battery is quickly discharged and counter-charged by other batteries, so that the original negative electrode becomes positive, the original positive electrode becomes negative, and the terminal voltage appears negative.

For the former reverse pole fault, when measuring the battery terminal voltage (a battery composed of multiple single batteries), it can be found that if there is a single battery reverse pole, not only loses the 2V voltage of the battery, but also increases the 2V reverse voltage, and the end voltage should be reduced by about 4V. For example, for a battery with a rated voltage of 12 V, if the terminal voltage is measured to be about 8 V, there is a single cell battery reverse pole. If the measured terminal voltage is about 4 V, there are two single cell inverse poles, if the measured terminal voltage is about -4 V, there are four single cell inverse poles, if the measured terminal voltage is -12 V, there are six single cell all inverse poles.

For the latter type of inverse fault, the terminal voltage value (negative) varies with the discharge condition. In general, when testing, the battery should be removed from the discharge line in time for this situation, so as not to damage the battery.

2. Short-circuit phenomenon and causes

The short circuit of the lead battery refers to the connection of the positive and negative electrode groups inside the lead battery. The short-circuit phenomenon of lead battery is mainly manifested in the following aspects:

(1) The open circuit voltage is low, and the closed circuit voltage (discharge) soon reaches the termination voltage.

(2) When the large current is expelled, the terminal voltage drops rapidly to zero.

(3) When opening the circuit, the electrolyte density is very low, and the electrolyte will freeze in a low temperature environment.

(4) When charging, the voltage rises very slowly and always maintains a low value (sometimes falling to zero). (5) When charging, the electrolyte temperature rises very quickly.

(6) When charging, the electrolyte density rises very slowly or almost no change.

(7) No bubbles or gas appear very late when charging.

The main reasons for the internal short circuit of lead batteries are as follows:

(1) The quality of the partition is not good or defective, so that the plate active material passes through, resulting in positive and negative plate virtual contact or direct contact.

(2) The baffle channeling causes the positive and negative plates to be connected.

(3) The active material on the plate expands and falls off. Due to excessive deposition of the shed active material, the lower edge or side edge of the positive and negative plate is in contact with the sediment, causing the positive and negative plates to be connected.

(4) conductive objects fall into the battery to cause the positive and negative plates to be connected.

(5) The "lead current" formed by the welding pole group is not eliminated, or the "lead bean" exists between the positive and negative plates when assembled, and the positive and negative plates are connected due to the damage of the partition during the charge and discharge process.

3, plate sulfation phenomenon and causes

Plate sulfation refers to the natural white hard lead sulfate crystal on the plate, and it is very difficult to convert lead sulfate into active substances when charging. There are several main phenomena after sulfation of lead-acid battery plate.

(1) The voltage of the lead battery rises very quickly during the charging process, and the initial and final voltage is too high, and the final charging voltage can reach 2.90V/single cell or so.

(2) In the discharge process, the voltage is reduced quickly, that is, it is prematurely dropped to the termination voltage, so its capacity is significantly reduced than that of other batteries.

(3) When charging, the electrolyte temperature rises quickly and easily exceeds 45 ° C.

(4) When charging, the electrolyte density is lower than normal, and bubbles occur prematurely when charging.

(5) The color and state of the plate can be found abnormal when the battery is dissected. The positive plate is light brown (normal dark brown), the surface of the plate has white lead sulfate spots, the negative plate is gray (normal gray) the surface of the plate is rough, as if there is a feeling of sand when touched, and the plate is hard.

(6) severe sulfation, the white crystal of lead sulfate formed by the plate is coarse, and can not be restored to active substances under normal circumstances.

The main causes of plate sulfation are as follows.

(1) The initial charge of the lead battery is insufficient or the initial charge interruption time is long.

(2) The lead battery is not charged for a long time.

(3) Failure to charge in time after discharge.

(4) Frequent excessive discharge or small current deep discharge.

(5) The electrolyte density is too high or the temperature is too high, and the lead sulfate will be deeply formed and not easy to recover.

(6) Lead batteries are shelved for a long time, and are not used for a long time without regular charging.

(7) Internal short circuit local action or battery surface water caused by leakage.

(8) The electrolyte is not pure and the self-discharge is large.

(9) The internal electrolyte level of the battery is low, so that the exposed part of the plate is sulfated.

Under normal use of lead batteries, most of the active substances (Pb02 and Pb) on the positive and negative plates are transformed into small crystalline lead sulfate, and these soft small crystalline lead sulfate are evenly distributed on the porous active substances, and it is easy to contact with the electrolyte when charging and restore to the original substances PbO2 and Pb.

If in use due to the above improper use of various reasons, the active substance on the plate will gradually form the lead sulfate with coarse crystalline particles, these coarse and hard lead sulfate crystals are large in volume and poor in conductivity, which will block the pores of the active substance of the plate, hinder the penetration and diffusion of the electrolyte, increase the internal resistance of the battery, and at the same time, when charging, This coarse and hard lead sulfate is not as easily converted to PbO2, Pb as the soft and small grain lead sulfate. If it lasts too long, these coarse and hard lead sulfate will lose its reversible effect, resulting in the reduction of the effective substance of the plate, the reduction of discharge capacity, and the shortening of service life.

4, plate bending and corrosion fracture

Plate bending occurs mostly in the positive plate, and the negative plate rarely occurs, and some negative plate bending is caused by the positive plate bending too much and forcing the negative plate to bend.