March 14, 2024
Electric bike lead-acid batteries guide: price, lifespan, and how to maintain it
Among many battery technologies, lead-acid batteries occupy an important position with their mature technology, relatively low cost and wide range of application scenarios. From car starting to backup power to electric bicycles, lead-acid batteries can be seen everywhere.
This article will explore the principle, structure, advantages and disadvantages, failure causes, and maintenance points of lead-acid batteries in depth, and compare them with lithium batteries, looking forward to future development trends, and helping readers fully understand this important energy storage device.
Table of Contents
Add a header to begin generating the table of contents
The basic principle of lead-acid batteries
Lead-acid batteries are batteries that use lead and sulfuric acid solutions to store and release electrical energy through chemical reactions. Since its invention by Plant in 1859, after more than a century of development, its technology has become very mature and widely used in various fields.
Working principle
The core of lead-acid batteries lies in their electrochemical reactions. The battery contains a positive electrode (lead dioxide, PbO2), a negative electrode (fleece lead, Pb) and dilute sulfuric acid (H2SO4) as an electrolyte.
Discharge process:
The lead dioxide at the positive electrode reacts with sulfuric acid to form lead sulfate (PbSO4) and water (H2O).
The lead at the negative electrode reacts with sulfuric acid to form lead sulfate.
During the whole process, chemical energy is converted into electrical energy to provide power for the external circuit.
Charge process:
Apply voltage to the battery through an external power supply to reverse the chemical reaction during discharge.
Lead sulfate is converted into lead dioxide and lead at the positive and negative electrodes respectively, and the concentration of sulfuric acid is restored.
Electrical energy is converted into chemical energy and stored in the battery.
Structural composition of lead-acid batteries
Lead-acid batteries are mainly composed of the following parts:
- Positive and negative plates: This is the core of the battery, consisting of a lead alloy grid and active materials. The active material of the positive plate is lead dioxide, and the active material of the negative plate is fleece lead.
- Separator: Used to separate the positive and negative plates to prevent short circuits while allowing the electrolyte to pass through.
- Electrolyte: Usually a dilute sulfuric acid solution, providing a medium for ion conduction.
- Pole: Used to connect to external circuits, divided into positive pole and negative pole.
- Container: Used to hold the various components and the battery electrolyte, usually made of plastic or rubber.
Types of lead-acid batteries
Ordinary lead-acid battery (flooded): This is the most traditional lead-acid battery, the electrolyte is liquid, and needs to be checked and replenished regularly. The advantage is low price, but maintenance is more cumbersome.
Maintenance-free lead-acid battery: It adopts a sealed structure, with less electrolyte loss and no need to add water regularly. The gas generated inside is converted into water through recombination reaction, thereby maintaining the level of electrolyte. Although it is called “maintenance-free”, it is still necessary to pay attention to the charging method and use environment.
Gel lead-acid battery: The gel batteries‘ electrolyte is made into a colloid state, which has better high temperature resistance, vibration resistance and deep cycle performance. The over-discharge, self-recovery ability and low-temperature charging and discharging performance of the colloid battery are better.
Lead-carbon battery: Adding carbon materials (such as graphene) to the negative electrode can effectively inhibit the sulfation of the negative electrode and improve the battery’s cycle life and charging acceptance. Lead-carbon batteries add carbon (graphene) to the electrolyte to prevent the sulfation of the negative electrode, improve the problem of battery failure, and thus greatly increase the battery’s service life.
Advantages and disadvantages of lead-acid batteries
Advantages
- Low cost: Raw materials such as lead and sulfuric acid are easy to obtain, and the production cost is relatively low.
- High rate discharge performance: It can provide a large current and is suitable for occasions that require instantaneous high power, such as car starting.
- Wide operating temperature range: It can work normally in the temperature range of -40℃ to +60℃.
- Long floating charge service life: In the floating charge state, it can maintain a long service life, which is suitable for applications such as backup power supply.
- Easy to recycle: The recycling technology of waste batteries is mature and environmentally friendly.
Disadvantages
- Low specific energy: Low battery energy density, generally 30-40Wh/kg, relatively large volume and weight.
- Short service life: Compared with other types of batteries, the service life is relatively short.
- Environmental pollution: Lead pollution may be generated during production and recycling, and corresponding treatment equipment is required.
Causes of lead-acid battery failure
The failure of lead-acid batteries is a complex process involving multiple factors. Understanding these failure causes will help take corresponding measures to extend the service life of the battery.
- Corrosion and deformation of the positive plate: The positive plate will gradually corrode during the charging and discharging process, resulting in a decrease in active substances, an increase in porosity, and even deformation and fracture, which will eventually lead to battery failure.
- Dehydration: Due to the decomposition of the electrolyte and the escape of gas, the battery will gradually lose water during use, affecting the performance of the battery.
- Sulfation: In the case of long-term power loss, over-discharge, undercharging, etc., hard lead sulfate crystals will form on the surface of the negative electrode, hindering the charging process and reducing the battery capacity.
- Antimony accumulation on active materials: Antimony in the positive plate grid will gradually transfer to the surface of the negative active material, affecting the charging performance of the battery.
- Thermal runaway: Excessive charging voltage or poor heat dissipation will cause the battery temperature to rise, the internal resistance to drop, and the charging current to increase, forming a vicious cycle, and eventually leading to battery damage.
- Negative plate corrosion: In some cases, the negative plate will also corrode, causing the pole ear to be disconnected from the busbar and the battery to fail.
- Internal short circuit of the battery: Damage to the diaphragm or impurities penetrating the diaphragm may cause a short circuit between the positive and negative poles, causing the battery to fail (explore lithium battery internal short circuit).
Key points for lead-acid battery maintenance
Proper maintenance is the key to extending the life of lead-acid batteries. Here are some important maintenance points:
- Check the electrolyte level regularly: For flooded batteries, the electrolyte level should be checked regularly, and distilled water or special replenishing fluid should be added when it is below the scale.
- Keep the battery surface clean: Clean the battery surface regularly with soapy water to prevent corrosion of the pole.
- Control the depth of charge and discharge: avoid over-discharge, and it is recommended to charge when the remaining power is 20%.
- Pay attention to the ambient temperature: avoid using in high or low temperature environments, and take warming or heat dissipation measures if necessary.
- Choose the appropriate charging mode: use a dedicated charger, and adopt the three-stage charging mode of constant current, constant voltage, and floating charge.
- Perform balanced charging regularly: For occasions where multiple batteries are used in series, perform balanced charging regularly to ensure that the voltage of each battery is consistent.
Lead-acid battery vs lithium battery: comparison of performance and application
In the field of electric vehicles and energy storage, lead-acid batteries face competition from new battery technologies such as lithium batteries. Here are the main differences between lead acid battery vs lithium ion:
| Feature | Lead-Acid Battery | Lithium Battery |
|---|---|---|
| Energy Density | Low (30–50 Wh/kg) | High (160–180 Wh/kg for ternary lithium) |
| Cycle Life | Short (300–400 cycles) | Long (Over 2000 cycles for LiFePO₄) |
| Cost | With a charge every three days, their lifespan is about 2–3 years. Over five years, they may need replacing 2–3 times, costing around RMB 1,000–1,500 in total, or RMB 200–300 per year on average. | Lithium iron phosphate batteries last over 2,000 cycles, supporting daily use for 5+ years. With a total cost of RMB 1,000–1,500, the average annual cost is just RMB 180–250—making them more cost-effective. |
| Weight | Heavy | Lightweight |
| Safety | Relatively safe, but overcharging may cause electrolyte to boil | Risk of thermal runaway exists, but safety technologies are continuously improving |
| Environmental Impact | Lead pollution risk during production, but recycling technologies are mature | Recycling technologies are still under development; second-life utilization is costly |
| Application Scenarios | Electric bicycles, tricycles, backup power supplies | Electric motorcycles, electric vehicles, home energy storage, grid peak shaving |
| Maintenance | Requires regular electrolyte checks and refilling. Water in the electrolyte evaporates during charge/discharge, so levels should be checked every 1–2 months. Charge when battery reaches around 20% to avoid irreversible plate damage. | Requires a dedicated charger using constant current and constant voltage (CC/CV) mode. Voltage accuracy should be within ±0.5%. Keep battery level between 20%–80% to avoid overcharging and deep discharging. |
Future trends of lead-acid batteries
Despite the challenges of emerging technologies such as lithium batteries, lead-acid batteries are still developing and innovating. Future development trends are mainly concentrated in the following aspects:
- Application of new materials: Use new materials such as graphene to improve the energy density, cycle life and charging performance of batteries.
- Intelligent management: Introduce battery management system (BMS) to achieve real-time monitoring, balanced charging and fault diagnosis of batteries.
- Improvement of environmental protection technology: Optimize production processes and recycling processes, reduce lead pollution, and improve environmental protection.
- Expansion of application fields: Expand applications in energy storage, microgrids, electric vehicles and other fields to give play to their cost and reliability advantages.
Conclusion
As a classic energy storage technology, lead-acid batteries have some shortcomings, but they still play an important role in many fields due to their cost advantages, reliability and mature technology. By strengthening maintenance, adopting new technologies and optimizing recycling processes, lead-acid batteries are expected to continue to maintain their competitiveness in the future energy storage market. When choosing an energy storage solution, the most suitable battery type should be selected based on specific application scenarios and needs, taking into account factors such as cost, performance, and safety.
Related post
October 2, 2023
September 19, 2023
Willow
Willow is a materials engineer with a Master’s degree in Materials Science and Engineering, specializing in lithium-ion battery materials and energy storage technologies.
Her work focuses on EV battery swapping solutions, battery innovation, and new energy industry trends, aiming to translate research insights into practical applications for sustainable transportation.
Leave a comment