Introduction

In lithium battery manufacturing, low voltage during the formation process is a common but critical defect that can significantly affect battery performance, safety, and lifecycle.

As a leading provider of industrial energy storage solutions, EverExceed focuses on delivering high-reliability lithium batteries for UPS systems, data centers, and telecom applications, where voltage stability and long-term performance are essential.

This article analyzes the root causes of low voltage defects during formation and their impact on battery performance.

1. Root Cause Analysis of Low Voltage During Formation

1.1 Insufficient Pre-Formation

 • Impurity Residue
If the pre-formation cutoff voltage is too low, impurities such as moisture and metal particles cannot be effectively removed. These impurities consume active lithium, resulting in reduced initial coulombic efficiency and lower voltage platforms.

 • Defective SEI Formation
When the voltage does not reach the activation threshold of electrolyte additives, the formation of a stable SEI (Solid Electrolyte Interphase) layer is disrupted, leading to increased internal resistance and poor lithium-ion transport.

1.2 Improper Charging Cut-off Voltage

 • Overcharging Risk
Excessive charging voltage can cause over-delithiation of the cathode and lithium plating on the anode, forming dendrites that may pierce the separator and cause internal short circuits.

 • Insufficient Charging Voltage
For example, in LiFePO₄ batteries, if the voltage does not reach 3.65V, the graphite anode cannot be fully activated, resulting in low capacity utilization and insufficient discharge performance.

1.3 Metal Contamination and Interface Issues

 • Foreign Metal Particles
Contaminants such as copper particles can create micro short circuits, directly leading to voltage drop.

 • Poor Electrode Contact
Gas generated during formation, if not properly released, may lead to uneven contact between electrodes and separator, increasing polarization and forming lithium compound deposits.

1.4 Process Parameter Deviations

 • Temperature Abnormalities
High temperatures accelerate electrolyte decomposition and gas generation, while low temperatures hinder lithium-ion diffusion and intercalation.

 • Insufficient ضغط（Pressure）
Lack of proper الضغط during formation increases internal فاصلة distances, raising impedance and reducing battery capacity.

2. Impact of Low Voltage on Battery Performance

2.1 Degraded Cycle Life

Unstable SEI layers and lithium dendrite growth increase internal resistance, leading to higher polarization and reduced capacity retention over cycles.

2.2 Safety Risks

Lithium dendrites may penetrate the separator and cause internal short circuits, potentially triggering thermal runaway, swelling, or even explosion.

2.3 Increased Self-Discharge

Defective SEI or contamination leads to continuous side reactions, accelerating voltage decay during storage.

2.4 Higher Manufacturing Cost

Low voltage defects require rework or scrapping, increasing energy consumption and extending production cycles.

3. EverExceed Quality Control Advantages

At EverExceed, strict control over the formation process ensures high consistency and reliability:

 • Advanced impurity control and cleanroom standards

 • Optimized formation voltage profiles for lithium batteries

 • Precise temperature and pressure management systems

 • Comprehensive quality inspection for UPS and data center battery applications

These measures ensure that EverExceed lithium batteries deliver:

✔ Stable voltage performance
✔ Long cycle life
✔ High safety standards
✔ Reliable backup power for critical infrastructure

Conclusion

Low voltage during formation is not just a manufacturing issue—it directly impacts battery reliability, safety, and lifecycle.

Through advanced process control and strict quality management, EverExceed ensures high-performance lithium battery solutions tailored for data centers, UPS systems, and mission-critical applications.