Corrosion risk planning – 1 – Lead acid battery

Corrosion is a quality, environment, and safety issue. Hence, it has to come under the cope of integrated management system audits

However at the moment, it is more or less considered a quality issue.

As such, the general tendency is to solve corrosion issues as they come.

Especially in new inventions, the foresight to look for potential corrosion risk gets lost in the attempt to focus and highlight the amazing qualities of the said inventions.

Hence, I have initiated this series, where I will take a component and point out the potential corrosion and damage risk areas. 

Here goes the first one – lead acid battery cell. (Source:https://opentextbc.ca/chemistry/chapter/17-5-batteries-and-fuel-cells/)

  1.  Protective casing – 
      • effect of temperature + electrolyte + contamination in electrolyte on the polymer
      • crevice corrosion at fixtures
      • mechanical damage during handling leading to voids for moisture ingress and oxygen/electrolyte leakage
  2. Positive terminal –
      • corrosion of the material of terminal due to remnant moisture
      • galvanic corrosion due to terminal and adjoining wires/components
      • crevice corrosion at fixtures
      • effect of anodic potential generated during battery operation – polarization
      • preferential corrosion due to connection with a polymer casing
  3. Negative terminal – 
      • corrosion of the material of terminal due to remnant moisture
      • galvanic corrosion due to terminal and adjoining wires/components
      • crevice corrosion at fixtures
      • effect of cathodic potential generated during battery operation – polarization and cathodic reactions
      • preferential corrosion due to connection with a polymer casing
  4. Cell divider –
      • corrosion of material in the electrolyte
      • degradation of coating on cell divider
      • effect of the generated ions during battery operation on coating
      • mechanical damage during installation
      • friction between divider plate and electrodes
      • for thin polymer coating, possibility of filiform corrosion
  5. Positive electrode –
      • corrosion of material in electrolyte at high temperature
      • cathodic reactions during battery operation
      • excessive localized dissolution due to electrolyte contamination
      • remnant reaction products during charging/discharging leading to localized pH changes and possible galvanic coupling
      • mechanical damage due to friction with adjoining parts (casing/divider)
  6. Negative electrode –
      • corrosion of material in electrolyte at high temperature
      • partially irreversible anodic dissolution
      • excessive localized dissolution due to electrolyte contamination
      • remnant reaction products during charging/discharging leading to localized pH changes and possible galvanic coupling
      • mechanical damage due to friction with adjoining parts (casing/divider)
  7. Dilute H2SO4 –
      • dilution not sufficient for safe handling and disposal
      • contamination due to reaction products
      • concentration modification due to temperature and cathodic reactions
  8. Fixtures for cell construction –
      • Mechanical damage due to friction/installation/handling
      • galvanic coupling with surrounding components
      • localized corrosion due to moisture deposition
      • crevice corrosion

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