Why Lithium-ion Batteries Require BMS While Lead-acid Batteries Do Not?-SYCAINTECH

Why Lithium-ion Batteries Require BMS While Lead-acid Batteries Do Not?

A customer recently messaged me with the question: "Do your lithium batteries have a BMS installed?" This customer runs a cleaning services company in the United States and is one of the most stringent customers I've come across when it comes to battery safety. He had thoroughly reviewed all of our battery test reports and certifications, and even sent me various videos of lithium battery explosions to have in-depth discussions on the conditions under which batteries could catch fire. Of course, I had already addressed this question in previous articles.


In this article, I want to reassure you that all lithium batteries have a Battery Management System (BMS) installed without question. The BMS acts as the "brain" of a lithium battery, precisely monitoring the battery pack's usage conditions. Why is a BMS so important for lithium batteries? This comes down to lithium batteries' inherent characteristics.


Lithium batteries are small in size, light in weight, and have a high energy density - making them an excellent energy carrier. However, their advantages and disadvantages are two sides of the same coin. Lithium is the most reactive metal element, which leads to higher risks compared to lead-acid batteries. This is why battery management systems are needed to control battery risks.


Let's look at what happens during lithium battery charging. During charging, lithium ions are ionized at the positive electrode and travel through the electrolyte and separator to the negative electrode. However, overcharging can cause issues. Just like overeating is dangerous for our bodies, overcharging a battery is equivalent to the negative electrode "eating" too many lithium ions. Over time, this can cause needle-like crystal formations to pile up and puncture the separator, leading to a short circuit and rapid temperature rise. When the temperature reaches the battery's thermal runaway threshold, the battery casing will bulge and rupture when the external oxygen enters, causing the battery to combust or even explode - all within a matter of seconds.


Now let's consider lithium battery discharging. During discharge, lithium ions move from the negative to the positive electrode. However, over-discharging means all lithium ions would migrate to the positive electrode. When recharging, the lithium ions would no longer be able to return to the negative electrode because its "housing" has collapsed. This causes a rapid capacity decline and potential battery failure.


Therefore, to prevent overcharging and over-discharging of lithium batteries and ensure safety, the charging and discharging process must be carefully managed through real-time monitoring of current and voltage distributed to each individual cell, keeping them within safe parameters. A BMS directly determines a battery pack's stability and safety.


Not only do we install a BMS, but Sycain lithium batteries are further upgraded with an active balancing BMS. A standard BMS can only control risks at the battery pack level, but our BMS balances energy redistribution during charge/discharge according to each cell's actual condition for more precise protection of each individual cell.


We firmly believe that product quality is the lifeline of any brand. Only by providing outstanding product quality can we earn customer trust. Therefore, we have always taken battery quality very seriously. We employ the most advanced technologies and processes with strict controls over every manufacturing stage to ensure each battery meets the highest quality standards.


If you need to purchase lithium batteries, please visit the product page for more information.