KR-20260063075-A - Battery cell balancing control system

Abstract

The present invention relates to a battery cell balancing control system capable of increasing the stability and accuracy of cell balancing by balancing with a constant current regardless of voltage deviation, comprising: a battery cell unit having a plurality of unit cells; a voltage status monitoring unit that monitors the voltage status of each cell of the battery cell unit; a Battery Management System (BMS) that reads data regarding the voltage, temperature, charging current, and discharging current of each battery cell and detects and manages the status of the battery pack; and a balancing control module that balances with a constant current regardless of voltage deviation of each cell based on the voltage status monitoring results of the voltage status monitoring unit. This invention is a research result carried out under the 2024 Growth Ladder Support Project.

Inventors

• 이상근
• 황의원
• 김민제

Assignees

• 주식회사 모펙

Dates

Publication Date

20260507

Application Date

20241030

Claims (5)

1. Battery cell section having multiple unit cells; A voltage status monitoring unit that monitors the voltage status of each cell of the battery cell unit above; A Battery Management System (BMS) that reads data regarding the voltage and temperature of each battery cell and the charging and discharging currents of the battery pack to detect and manage the state of the battery pack; A battery cell balancing control system characterized by including a balancing control module that balances to a constant current regardless of the voltage deviation of each cell based on the voltage status monitoring result of the voltage status monitoring unit.
2. In claim 1, the balancing control module is, A battery cell balancing control system characterized by having a structure inserted inside a Battery Management System (BMS) to reduce current consumption, controlling the operation settings of an active balance, and performing a balancing operation only when necessary.
3. In claim 1, the balancing control module is, A battery cell balancing control system characterized by storing the average value of energy charged in a capacitor corresponding to each cell in a main capacitor, boosting the voltage to DC/DC to balance each cell, and increasing the balancing speed through constant current charging.
4. In claim 1, the balancing control module is, A charging average value storage control unit that controls the storage of the average value of energy charged in the capacitor corresponding to each cell in the main capacitor, and A boost control unit that boosts the average value of the energy stored in the main capacitor to DC/DC to balance each cell, and A balancing current value setting unit that monitors battery cells to catch voltage deviations and sets the balancing current value to a value least affected by noise or heat generation in order to control balancing with a fixed current value, and A cell voltage monitoring unit that monitors each cell voltage to adjust the voltage deviation of each battery cell to a target value through an active balance algorithm, and A battery cell balancing control system characterized by including a balancing reference value setting control unit that sets first and second setting values to reduce voltage deviation by charging the current of the high cell to the low cell when the sum of each cell is greater than or equal to a first setting value, and to cut off the charger to prevent overcharging when the second setting value is reached, so that the balancing operation continues to operate until a target value is reached.
5. In Clause 4, when charging each cell through the charger, the battery cell charge cut-off voltage is 3.6V, but for the safety of the battery, it is set to 3.55V to have a total voltage of 14.2V with 4 cells, and A battery cell balancing control system characterized by setting a first setting value to 14V and a second setting value to 14.2V, ensuring that the voltage deviation target value of each battery cell is within 0.01V, and having a balancing current value of 400mA to 500mA.

Description

Battery cell balancing control system The present invention relates to battery cell balancing technology, and specifically to a battery cell balancing control system that can improve the stability and accuracy of cell balancing by balancing with a constant current regardless of voltage deviation. Secondary battery packs use a battery management device called a BMS (Battery Management System) to safely protect the battery from overcharging, over-discharging, high temperatures, low temperatures, etc. This BMS reads data regarding the voltage and temperature of each battery cell constituting the battery pack, as well as the charging and discharging currents of the battery pack, to detect the state of the battery pack and thereby safely protect the battery. Meanwhile, when a battery pack is manufactured by combining multiple individual battery cells in series, parallel, or series-parallel and subjected to repeated charging and discharging, imbalances may occur due to differences in the characteristics of each battery cell. These differences in characteristics may occur during use or may already exist at the time of manufacturing. In other words, the components constituting each battery cell, such as the positive electrode, negative electrode, separator, and electrolyte, cannot all be manufactured identically during production. Therefore, differences occur in the area, thickness, weight, and amount of composition of the battery cells, and these differences lead to imbalance in the battery cells. If the battery pack is used while this imbalance is left unchecked, the State of Charge (SOC) decreases due to the voltage difference between the battery cells, which can lead to a decrease in the overall capacity of the battery pack. In addition, if charging or discharging is performed while there is an imbalance between battery cells, cells in poor condition may become overcharged or overdischarged, and as a result, the lifespan of the overcharged or overdischarged cells may be shortened. Cell balancing technologies to solve these problems are broadly classified into active cell balancing methods and passive cell balancing methods. However, these conventional cell balancing technologies have the following problems. First, if the voltage of any one of the multiple battery cells included in the battery pack is much lower than the voltage of the other battery cells, using the passive balancing method results in significant losses in terms of time or cost. Figure 1 is a schematic diagram showing a cell balancing structure of the prior art. The cell balancing method of the conventional technology charges the energy stored in the individual capacitors of each cell into the corresponding cell to charge it up to the maximum range of the battery, and charges with a lower current as the voltage deviation decreases. The active balancing method of the conventional technology described above is a method in which the balancing current changes according to the magnitude of the voltage difference between cells. When the cell voltage difference is large, balancing is performed with a large current, but when the voltage difference decreases, the balancing current also decreases, which has the problem of increasing the time required to balance to the target value and slowing down the total balancing time. Therefore, there is a need to develop a new battery cell balancing control system that can improve cell safety and charging speed by rapidly balancing to a target value even when the voltage deviation is small. FIG. 1 is a schematic diagram showing a cell balancing structure of the prior art. FIG. 2 is a configuration diagram showing the cell balancing structure of a battery cell balancing control system according to the present invention. FIG. 3 is a configuration diagram showing the overall structure using a battery cell balancing control system according to the present invention. FIG. 4 is a detailed configuration diagram of a battery cell balancing control module according to the present invention. Hereinafter, a preferred embodiment of the battery cell balancing control system according to the present invention will be described in detail as follows. The features and advantages of the battery cell balancing control system according to the present invention will become apparent through the detailed description of each embodiment below. FIG. 2 is a configuration diagram showing the cell balancing structure of a battery cell balancing control system according to the present invention. The terms used in this disclosure have been selected to be as widely used and general as possible, taking into account their functions within this disclosure; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been selected at the applicant's discretion, and in such cases, their meanings will be described in detail in the relevant