Since November 2022, companies such as Zhitai New Energy, Wanlishi, and SVOLT Energy have successively launched electrochemical energy storage deployments, and the electrochemical energy storage market has continued to be hot.
The core components of an electrochemical energy storage system include: battery compartment, battery management system (BMS), energy management system, and energy storage inverter (PCS).
This article will mainly introduce three aspects of energy storage BMS: first, the role of energy storage BMS in electrochemical energy storage systems; second, the factors restricting the development of energy storage BMS; and third, the enterprises in my country that have deployed energy storage BMS.
Introduction to Battery Management System
A battery management system (BMS), as the name suggests, is responsible for managing the working status of a battery.
The working principle of BMS is as follows: During the charging and discharging process of the energy storage battery, BMS monitors the temperature, voltage, current and main charging status (SOC) of the energy storage battery module and each battery cell in real time. Once abnormal data is detected, an alarm signal is issued and the battery module contactor is disconnected, thereby avoiding safety risks.
As the most mature and widely used electrochemical energy storage battery safety assurance solution, BMS is beginning to show its limitations in the context of the rapid development of electrochemical energy storage technologies such as lithium iron phosphate batteries and sodium-ion batteries.
There are two main factors that restrict the development of BMS: accurate measurement and algorithm development.
Precise measurement and monitoring of the cage
In terms of accurate measurement, the BMS needs to monitor the data of the energy storage battery module and the individual battery cells that make up the battery module, which is the key to improving the performance of the energy storage system.
Take a standard 20-foot high cube container (6.058 m × 2.438 m × 2.896 m) energy storage system with a capacity of 2.75 MWh and a rated voltage of 1228.8 V as an example.
It consists of 8 battery clusters connected in parallel, each battery cluster consists of 8 battery packs connected in series, and each battery pack consists of 48 EVE Energy square aluminum-shell lithium iron phosphate LF280K cells (3.2 V/280 Ah).
In other words, a standard 20-foot high cube container energy storage system with a capacity of 2.75 MWh and a rated voltage of 1228.8 V includes 3072 EVE Energy square aluminum-shell lithium iron phosphate LF280K cells (3.2 V/280 Ah).
The BMS needs to monitor the performance data of the entire battery module and 3072 cells in real time, providing extremely accurate data such as temperature, voltage, current and SOC, so as to make the fastest response and ensure the safe operation of the energy storage system.
However, this constraint may be somewhat resolved as leading semiconductor companies such as Texas Instruments deploy energy storage BMS.
According to Texas Instruments' official Weibo account, in response to the challenges posed by BMS (Battery Management System), Texas Instruments' battery acquisition chip can significantly improve the data measurement speed of energy storage batteries, achieving a cell voltage sampling accuracy of 1.5mV and a sub-millisecond sampling time.
Algorithm development, self-developed barriers
The BMS (Battery Management System) is the "brain" of an electrochemical energy storage system. It is responsible for collecting and analyzing data such as temperature, current, voltage, and SOC (State of Charge) during the charging and discharging process of the energy storage system, and making relevant responses.
As mentioned above, a containerized energy storage system can be composed of 3072 battery cells connected in series and parallel.
These 3072 battery cells have different power consumption and charging speeds during operation. In extreme cases, some cells may be fully charged while others have been depleted, which could pose a significant safety hazard.
This is usually addressed by developing algorithms for power meters, but the development of energy storage BMS algorithms has very high requirements.
For algorithm development teams, in addition to having rich practical experience, they also need knowledge and skills in multiple disciplines such as physics, electrochemistry, electrical engineering, firmware development and data analysis, making independent research and development extremely difficult.
Chinese companies deploying energy storage BMS
With the booming development of the energy storage industry, BMS, as one of the core components of electrochemical energy storage, has also experienced rapid growth.
The companies in my country that have deployed energy storage BMS mainly consist of energy storage battery companies and professional third-party BMS companies.
Energy storage battery companies include CATL (Contemporary Amperex Technology Co., Limited) and BYD Co., Ltd.
There are numerous third-party BMS companies. According to incomplete statistics from Vico.com, these include Beijing Haibosichuang Technology Co., Ltd., Hangzhou Gaote Electronic Equipment Co., Ltd. (hereinafter referred to as "Gaote Electronics"), Zhejiang Gaotai Haoneng Technology Co., Ltd., Hongzheng Energy Storage (Shanghai) Technology Co., Ltd., Hangzhou Huasuo Technology Co., Ltd., Zhejiang Gaotai Haoneng Technology Co., Ltd., Hangzhou Lide Communication Co., Ltd., and Shenzhen Peicheng Electronic Technology Co., Ltd.
Energy storage battery companies that operate their own BMS have the advantage of not having to deal with third parties for key data such as battery temperature, current, voltage, and SOC, thus ensuring high information security. At the same time, energy storage battery companies are the ones who know their own batteries best, which can provide strong support for cost reduction and efficiency improvement in BMS development and enhance market competitiveness.
Energy storage battery companies can reduce initial investment costs by outsourcing their battery management systems (BMS). While BMS outsourcing companies are generally highly professional and offer high-performance products, the security of battery data information is difficult to guarantee.
