Summer is Coming: Pay Attention to Electric Vehicle Battery Safety

As temperatures gradually rise, the number of people using electric vehicles (EVs) on the streets is increasing, and the safety of electric vehicle batteries is becoming a growing concern for consumers.

Based on battery types, electric vehicles currently on the market are mainly divided into lead-acid battery models and lithium battery models. Regardless of the type of battery, safety precautions should be observed during both the purchase and use of the vehicle.

There is a significant difference in the technological maturity and performance between lead-acid and lithium batteries. Lead-acid battery technology has a history of over 100 years and is widely used due to the high stability of lead elements. Lithium-ion batteries, developed over more than 30 years, are relatively mature in technology, but lithium’s active nature limits its application scope. The differences in the performance of these two types of batteries are as follows:

Environmental Impact: Lithium batteries are less polluting (not absolutely), while lead-acid batteries can cause heavy metal pollution if improperly recycled.

Energy Density: Lithium batteries have a 40% higher specific energy by both weight and volume compared to lead-acid batteries.

Price: Lithium batteries cost more than twice the price of lead-acid batteries for the same capacity.

Lifespan: The commonly used lithium iron phosphate batteries can be charged 1500 times without memory effect, retaining about 85% of their storage capacity after 1500 charges. Lead-acid batteries last around 500 cycles, with a significant memory effect.

Self-discharge Rate: The self-discharge rate of lithium batteries is less than 3% per month, while lead-acid batteries range from 15% to 30%.

Discharge Characteristics: For the same capacity, lithium batteries can discharge about 30% more power than lead-acid batteries under high current.

Voltage Plateau: The voltage plateau of lithium batteries is greater than 3V, while lead-acid batteries are at 2V.

It is important to highlight the safety characteristics of both types of batteries. Power lithium batteries (such as lithium manganese oxide and lithium iron phosphate) have different safety levels based on their materials, but lead-acid batteries, with their mature technology, generally have a higher overall safety level compared to lithium batteries.

Substandard Wiring: A Hazard to the Battery

Although lead-acid batteries are generally safer than lithium batteries, does this mean that electric vehicles with lithium batteries are more prone to explosions and fires? Actually, this is not the case.

The safety issues with electric vehicle batteries mostly arise during the charging process, and this is not primarily related to the battery’s inherent performance.

During charging, batteries themselves are not prone to short-circuits, explosions, or fires. Electric vehicle batteries and their chargers are generally equipped with protective devices. Lithium batteries have control circuits and protection boards, which automatically cut off power when excessive current or short-circuits occur, preventing explosions or fires caused by short-circuits.

In contrast, fires in lead-acid batteries usually occur due to aging wiring or the use of substandard materials that affect heat resistance. While lithium batteries may explode or catch fire, this could be due to wiring aging, heat resistance issues, or faults in the battery’s internal protection system.

Additionally, improper handling by consumers, such as battery damage or prolonged charging times, can increase the risk of short-circuits.

Loose Wiring: Potential Risks During Ride

Electric vehicles experience strong vibrations during operation, so the reliability of all connections should be thoroughly tested. Connectors should have a “self-locking” feature to prevent them from falling off due to vibration or pulling. The wiring to the battery should be connected with a connector and soldered securely, with press-fit connections for the wiring. If the connection is not secure, it could lead to poor conductivity, causing heating at the contact points, which increases the wear on the wiring, lowers the output voltage, reduces motor power, and shortens the riding range.

During riding or charging, poor connections may lead to a disconnection, which generates sparks that could ignite the flammable gases inside the battery, especially when the battery has just been charged, as the battery contains more explosive gases. The possibility of an explosion is higher when there is a strong spark in a fully charged battery.

Lithium Batteries: Avoid Overcharging and Overdischarging to Maintain Good Condition

Whether it’s a lead-acid battery or a lithium battery, charging times should be kept as short as possible, ideally not exceeding 8 hours per charge. Avoid violent collisions or contact with high-temperature objects. This is particularly important for lithium-ion batteries, where overcharging or always waiting for the battery to be completely drained before charging is incorrect.

Since lithium batteries do not have a memory effect, the amount charged does not affect their storage capacity. However, if the charging time is too long, it will affect the battery’s consistency, which impacts its lifespan. This reduction in lifespan is irreversible, so it is important to avoid fully charging the battery. It is recommended to charge the battery up to 80%.

Similarly, when discharging, the battery should not be completely drained. Always keep some charge left when charging the electric vehicle to avoid affecting the battery’s lifespan.

Moreover, after a complete discharge, consumers should charge the battery as soon as possible and avoid charging in low-temperature environments. If the electric vehicle is not used for a long time, remember to recharge the battery at appropriate intervals. This not only extends the battery’s lifespan but also ensures the stability of its performance.

Safety Starts at the Purchase of the Electric Vehicle

To ensure the safety of electric vehicles, consumers should start paying attention when purchasing. Currently, most reputable manufacturers provide a well-designed protection system, using high-quality materials for wiring and components. Consumers should avoid cheap options and choose electric vehicles from reputable manufacturers or well-known brands.

Additionally, during use, consumers must follow proper operating procedures for the vehicle and the battery to prevent overcharging or overdischarging. After heating, the electric vehicle battery should be cooled before charging. The installation location of the battery should ensure good heat dissipation, and if overheating occurs, charging should be stopped, and both the charger and battery should be checked. Charging time should be reduced if the battery has shallow discharge or if the environmental temperature is high. Over-discharging, which occurs when the battery continues to discharge beyond its cutoff voltage, will seriously damage the battery and negatively affect both its electrical performance and cycle life.

In conclusion, when purchasing an electric vehicle, consumers should not only consider factors like price and mileage but also pay attention to the quality of wiring materials and the reliability of connections. The battery should never have short-circuits, and proper precautions should be taken during installation and use. Tools should be insulated, and wiring should be properly checked for short circuits. Only with careful attention to these details can electric vehicles be made safer and more durable.