Suppose the battery cell is compared to the heart of the human body, and the modules and battery packs are compared to a muscular physique. In that case, the entire power lithium battery system must run smoothly, and an intelligent brain that dominates the body is required, which is BMS.

Battery Management System (BMS for short) is an essential link between batteries and electric vehicles, and its precise control and management ensure the perfect application of batteries.

The dragon gave birth to nine sons, each of which is different. Even if two single cells are produced in the same batch, due to production process errors and differences in the use environment, their performance may not be entirely consistent; in the process of use, this inconsistency will gradually expand, and there may be overcharging and overcharging. The danger of discharge and local overheating will seriously affect the service life and safety of the battery pack.

At this time, it is time for BMS to show its talents.

So the question is, what is BMS necessary for?

Functional use of battery management system BMS

1. Accurately estimate the state of charge of the power lithium battery pack

Accurately estimate the state of charge (SOC) of the power lithium battery pack, that is, the remaining power of the battery, to ensure that the SOC is maintained within a reasonable range, to prevent damage to the battery due to overcharge or over-discharge, to predict the hybrid vehicle at any time. How much energy is left in the energy storage battery or the state of charge of the energy storage battery?

2. Dynamically monitor the working status of the power lithium battery pack

In battery charging and discharging, the terminal voltage and temperature of each battery in the power lithium battery pack, the charging and discharging current, and the total voltage of the battery pack are collected in real-time to prevent the battery from overcharging or over-discharging.

At the same time, it can give the battery status in time, select the battery in question, maintain the reliability and high efficiency of the entire battery group, and realize the remaining power estimation model possible. In addition, it is necessary to establish the use history file of each battery, further optimize and develop the supply data of new electricity, chargers, motors, etc., and provide the basis for offline analysis of system failures.

3. Balance between single cells

The single battery is charged in a balanced manner so that each battery in the battery pack reaches a balanced and consistent state. Equalization technology is a crucial battery energy management system technology that the world is currently researching and developing.

Regarding BMS functions, there are different ways of classifying it in the industry. However, from the user's point of view, it can be roughly divided into two primary functions: battery physical examination and safety guard.

Instant physical examination

Accurately grasp the battery status.

Instant physical examination refers to battery data collection and status assessment.

Data collection can be understood as a routine physical examination of the battery; during the charging and discharging process, the terminal voltage, temperature, charging and discharging current and total voltage of each battery pack are collected in real-time to prevent overcharging or over-discharging of the battery. 

This check-up is online, ongoing, and uninterrupted. When abnormal data is found, the corresponding battery status can be inquired about in time, and the problematic battery can be selected to maintain the reliability and efficiency of the entire battery group.