Comprehensive Guide to Battery Lifespan Diagnosis and Performance Checks(2024 Updated)

Large batteries, such as lead-acid batteries, play a crucial role in power plants. This post will cover battery lifespan diagnosis and performance checks methods, referencing IEEE and EPRI standards to highlight important metrics.

Managing battery performance and lifespan is crucial to ensuring system stability and reliability. Regular checks and proper diagnostics help monitor battery status and detect problems early for preventative measures.

ⓘ The content of this post is based on the results of studies conducted using information and materials from reputable institutions, technical data from the internet and professional books, etc. It is recommended to use this information as a reference for related work, but to consult with an expert for practical application if necessary. Also, please note that the images in the post, unless otherwise specified, are either drawn by the author or created with the help of artificial intelligence.

Battery Basics

Battery Types

Major battery types include lead-acid batteries and lithium-ion batteries. Each battery type is selected based on specific applications and requirements.

Working Principle

Batteries convert chemical energy into electrical energy through electrochemical reactions. They consist of two electrodes, an anode (negative) and a cathode (positive), separated by an electrolyte.

During discharge, the anode undergoes oxidation, releasing electrons that flow through an external circuit, while the cathode undergoes reduction, accepting electrons. The electrolyte facilitates ion movement between the electrodes. This process allows the battery to store energy and supply it when needed, making it essential for various applications.

Battery Performance Check

Importance of Regular Checks

Regular battery performance checks are essential to prevent unexpected failures and ensure longevity. They help detect potential issues early, allowing for timely maintenance and extending the battery’s operational life.

Regular inspections also optimize efficiency and reliability, critical for systems relying on continuous power.

Checkpoints

• Voltage Measurement: Measure open circuit voltage and float voltage to assess battery status.
• Internal Resistance Measurement: Check cell resistance to understand internal conditions.
• Electrolyte Level: Inspect the state and level of electrolytes.
• Physical Damage: Examine the battery case and terminals for physical damage.

Battery Lifespan Diagnosis

Lifespan Indicators

SOC (State of Charge) and SOH (State of Health) are critical indicators for evaluating battery lifespan.

SOC indicates the current charge level relative to the battery’s capacity, informing users of how much energy is available.

SOH assesses the overall health and efficiency of the battery, reflecting its ability to store and deliver energy effectively compared to when it was new.

These metrics are essential for predicting battery life and planning maintenance or replacements.

Diagnosis Methods

• Capacity Testing: Measure the actual capacity of the battery to evaluate performance.
• Charge and Discharge Cycle Analysis: Analyze charge and discharge cycles to understand the battery condition.
• Temperature Impact: Evaluate the effect of temperature on battery performance and suggest proper management methods.

Battery Maintenance Tips

Regular Charging and Discharging

Regular charging and discharging are crucial for maintaining battery performance. It helps prevent sulfation in lead-acid batteries, a common issue where lead sulfate crystals form on the battery plates, reducing capacity and lifespan.

For lithium-ion batteries, it’s important to avoid deep discharges and charge them to about 80-90% capacity rather than 100% to prolong their life.

Implementing a regular maintenance schedule that includes partial discharges followed by recharging can significantly enhance battery efficiency and longevity.

Environmental Condition Management

Batteries should be stored in an environment with controlled temperature and humidity. Extreme temperatures can accelerate battery aging and reduce capacity.

For lead-acid batteries, the optimal storage temperature is around 25°C (77°F). Higher temperatures can cause the electrolyte to evaporate, leading to sulfation, while freezing temperatures can cause the electrolyte to expand and damage the battery casing.

Humidity should be kept low to prevent corrosion of battery terminals and other components. Regularly monitoring the storage conditions and using climate control systems can prevent these issues and maintain battery health.

Preventive Maintenance

Preventive maintenance involves regular inspections and minor adjustments to keep batteries in optimal condition. This includes:

• Cell Balancing: Ensuring all cells within a battery pack are equally charged to prevent overcharging or deep discharging of individual cells, which can lead to premature failure.
• Electrolyte Replenishment: For lead-acid batteries, checking and maintaining the proper electrolyte level is crucial. Distilled water should be added as needed to keep the electrolyte covering the plates.
• Cleaning and Inspecting Terminals: Corrosion on battery terminals can lead to poor electrical connections and reduced performance. Regularly cleaning the terminals with a mixture of baking soda and water, followed by a protective coating, can prevent this.

Determining When to Replace a Battery

End-of-Life Signals

There are several indicators that a battery may be nearing the end of its useful life:

• Decreased Capacity: If a battery’s capacity drops below 80% of its original capacity, it’s a strong sign that it’s nearing the end of its lifespan.
• Increased Charging Time: If the battery takes significantly longer to charge than usual, it may be due to internal resistance buildup.
• Voltage Drop: A noticeable drop in voltage under load can indicate that the battery can no longer supply the necessary power.
• Physical Symptoms: Swelling, leaking, or unusual odors are clear signs that a battery needs to be replaced immediately.

Replacement Procedure

Replacing a battery involves several steps to ensure safety and efficiency:

1. Safety First: Wear appropriate protective equipment, including gloves and safety glasses, to protect against acid spills or electrical shorts.
2. Disconnecting the Old Battery: Turn off and disconnect any connected equipment. Remove the negative terminal first, followed by the positive terminal to prevent short circuits.
3. Removing the Battery: Carefully remove the old battery, avoiding any contact with spilled electrolyte.
4. Cleaning Terminals: Clean the battery tray and terminals with a mixture of baking soda and water to neutralize any spilled acid.
5. Installing the New Battery: Place the new battery in the tray, ensuring it is secure. Connect the positive terminal first, followed by the negative terminal.
6. Disposal of Old Battery: Dispose of the old battery according to local regulations, as improper disposal can be harmful to the environment.

Conclusion

Summarize the importance of battery performance checks and lifespan diagnostics, emphasizing that regular checks and proper maintenance are essential for ensuring system stability and reliability.

Key Metrics and Standards

• IEEE 450: Offers recommended practices for maintaining, testing, and replacing large lead-acid batteries, recommending replacement when battery capacity drops below 80% of the initial capacity.
• IEEE 1188: Details regular inspection and maintenance procedures, indicating a potential problem when internal resistance increases by more than 20%.
• EPRI Revision of TR-100248: Includes graphs showing the relationship between internal resistance and battery lifespan, indicating a significant increase in internal resistance as the battery nears the end of its life.

Interpreting the Graph
The provided graph shows the relationship between lead-acid battery life and two key parameters: capacity (in percentage) and internal resistance (in percentage). This data is derived from EPRI (Electric Power Research Institute) studies.

Red Line: Capacity (%)
The red line represents the capacity of the battery as a function of its rated lifespan.
Early Life (0-20%): Initially, the battery capacity increases slightly as the battery "settles" into use.
Mid-Life (20-60%): The capacity remains relatively stable, staying close to 100% of its rated capacity.
Late Life (60-100%): Capacity starts to decline significantly. As the battery approaches the end of its rated life, the capacity drops sharply, indicating the battery can no longer hold as much charge as it could when new.

Blue Line: Internal Resistance (%)
The blue line represents the internal resistance of the battery over its lifespan.
Early Life (0-20%): Internal resistance starts at a baseline level of around 100%.
Mid-Life (20-60%): Internal resistance gradually increases as the battery ages. This is a normal part of the battery's aging process.
Late Life (60-100%): Internal resistance increases sharply as the battery nears the end of its life. A significant rise in internal resistance indicates that the battery's internal components are degrading, making it harder for the battery to deliver power efficiently.

Key Takeaways
Capacity Decline: As a battery ages, its ability to store and deliver energy declines, especially as it reaches the latter part of its lifespan.
Increased Resistance: Higher internal resistance means the battery will have a harder time delivering power, which can cause issues in applications requiring reliable and consistent power output.
Maintenance and Monitoring: Regularly monitoring both capacity and internal resistance can help predict when a battery is approaching the end of its useful life, allowing for timely maintenance or replacement to ensure system reliability.

Case Studies(from NRC LER Search)

Gas and Heat Causing Excess Electrolyte

• Year: 1989
• Plant: C Power Plant
• Cause: Gas generation and heat during charging and discharging increased electrolyte levels, making battery trains inoperable.
• Actions: Electrolyte levels were reduced, and procedures were revised to prevent recurrence.

Internal Short Circuit

• Year: 1989
• Plant: T Power Plant
• Cause: Battery cell voltage dropped below the technical specification limit due to an internal short circuit.
• Actions: The cell was replaced, and maintenance procedures were enhanced.

Battery Cell Leakage

• Year: 1982
• Plant: I Power Plant
• Cause: Cell #31 leaked electrolyte and exhibited low levels.
• Actions: The affected cell was replaced, and the entire battery was inspected.

End of Service Life

• Year: 1982
• Plant: A Power Plant
• Cause: Battery reached the end of its service life, failing to start the diesel-driven fire pump.
• Actions: Batteries were replaced, and procedures were updated.

High Resistance in Jumper Cables

• Year: 1988
• Plant: Q Power Plant
• Cause: High resistance in jumper cables caused a battery discharge test to fail.
• Actions: Cables were replaced, and regular checks were enhanced.

Low Specific Gravity

• Year: 1981
• Plant: N Power Plant
• Cause: Diesel generator battery cell’s specific gravity fell below acceptable levels, violating technical specifications.
• Actions: The low specific gravity cell was replaced, and procedures were revised.