Why is a lead-acid battery not as good as a lithium battery?

2. Longer cycle life

The lithium battery’s cycle life is long, generally more than 1,000 times, compared with only 300-500 times for lead-acid batteries. There is no memory effect with lithium batteries, and they can be charged and discharged at any time without the risk of losing their capacity. However, the lead-acid battery has a relatively short cycle life and obvious memory effects, needing to be fully discharged and recharged regularly to maintain performance.

3. Charging method

Lithium battery charging mode is relatively fixed, and adopts voltage and current limiting method. In the process of charging, lithium battery will go through three stages: constant current charging, constant voltage charging and trickle charging. There are many methods for charging lead-acid batteries, including constant current charging, constant voltage charging, stage charging, and intermittent charging. Constant current charging During the whole charging process, the charging voltage of power supply is generally adjusted or the resistance value of the battery is changed in series to keep the charging current of the battery. It has the advantages of simple control and is suitable for the charging of many packs in series. The disadvantage is that the acceptable charging ability of lithium batteries will gradually decrease with the charging process, and excessive charging current in the late charging period will cause bubbles inside the battery to damage the battery. Constant voltage charging means that throughout the charging process, the charging voltage remains constant and automatically adjusts the size according to the change in the battery status. In the process of charging, the charging current gradually decreases along with the process. Compared with the constant current charging, the charging process is closer to the best charging curve, and the control is simple with low cost. The disadvantage is that the charging time is longer, and the charging current of the battery is too large in the early charging period, which directly influences the life and use quality of the lithium battery. In the main charging stage of the variable current intermittent charging method, under the condition of limited charging voltage, the intermittent current is gradually reduced to increase the charging current, that is, to speed up the charging process and shorten the charging time. However, this charging mode circuit is more complex and high cost, and is generally only considered when high-power fast charging.

4. Lead-acid batteries are cheap and recyclable

Lithium batteries are expensive and usually about three times as expensive as lead-acid batteries. Most of the public lead-acid batteries sold on the market are around 450 yuan, and lithium batteries are more expensive than that, generally around 1,000 yuan. Lead-acid batteries can be recycled, replaced with new ones to reduce losses, and have a mature recycling market. Lead-acid batteries are mainly composed of electrodes made of electrolyte and lead plate, the main component of the battery is lead, accounting for about 75-85% of the battery, lead is a non-ferrous metal, with recycling value. Its manufacturing process is simple, very easy to disassemble, and can be easily reused after recycling.

However, in sharp contrast, lithium battery recycling technology is still immature and basically cannot realize much value for the present moment. The manufacturing process for a lithium battery is complicated. If you want to extract lithium metal in lithium batteries, first, you need to have high-level technology, then there comes high extraction costs, which results in no profit finally, so few people want to extract lithium metal; there is no industrial chain accordingly.

二. Security differences

1. Safety advantages of lead acid batteries

Lead acid battery has some advantages in terms of safety. First of all, lead acid battery is a kind of non-flammable battery; the usage of atmospheric pressure and low pressure design with stable sulfuric acid inside it. As long as extreme operation isn’t carried out such as frequent exposure and improper charge, the temperature of battery will not reach dangerous level. In the design and manufacturing process of lead-acid batteries, safety factors are fully considered, such as the adoption of sealed structure and the setting of safety valves. In the charge and discharge cycles of several lead-acid batteries, hydrogen and oxygen may precipitate at both the positive and negative poles, but once the designed pressure is reached, the exhaust valve will open to discharge the battery housing and improve safety. Moreover, the active materials of anode and cathode of the lead-acid battery are metallic lead and lead alloy respectively, glass fiber is used as diaphragm material, and the electrolyte is sulfuric acid and pure water, with basically no organic substance involved. Its material system has very low flammability. The safety risks are relatively more in lithium batteries. First, the electrolyte inside the lithium battery is easy to burn. During such abnormal working conditions as an external impact, overcharge and overdischarge, it may lead to battery short circuit and thermal runaway and further cause fire or even explosion.

三. Choose suggestions

1. Selection of different needs

If your battery life requirements are not high, while the pursuit of cost-effective, and the charging environment is more complex, then more safe, affordable lead-acid batteries will be a good choice. For example, some daily commuting distance is short, and the charging place is not fixed users, the stability and adaptability of lead-acid batteries can meet their needs.

If you want a lightweight vehicle, a long range, or need to frequently take out the battery to charge, then lithium batteries are more suitable. For example, for users who need to ride long distances or have high requirements for vehicle portability, the lightweight and high endurance of lithium batteries can bring a better use experience.

2. Combine factors

When choosing a battery, we need to consider many factors such as performance, price, safety, and use needs.

In terms of performance, lithium batteries have high energy density, long cycle life, and relatively fixed charging methods, but there are also security risks. Although the lead-acid battery has low energy density, short cycle life, many charging methods and each has advantages and disadvantages, it has certain advantages in safety.

In terms of price, the purchase price of lithium batteries is high, and the recycling value is relatively low at present; Lead-acid batteries are cheap to buy and recyclable, and can be replaced with new to reduce losses, and the recycling market is mature.

In terms of safety, the lead-acid battery is non-combustible, adopts normal pressure and low pressure design, has a stable internal structure, and is equipped with safety devices such as safety valves. The electrolyte of the lithium battery is flammable, and when it is subjected to external impact, overcharge, overdischarge and other abnormal conditions, it may cause problems such as battery short circuit and thermal runaway, which can lead to fire or explosion.

In terms of use demand, if there are high requirements for vehicle lightness and driving range, or you need to take out the battery frequently to charge, lithium batteries can better meet the needs. If you pay attention to cost performance, the charging environment is complex, and the battery life is not high, lead-acid batteries are a better choice.

In short, only by taking these factors into account can you choose the most suitable battery type for yourself.