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Scene Analysis
“Customers often complain that when they go to energy storage exhibitions, they see a dazzling array of products from various companies, but they are completely confused when others try to explain the main components of an energy storage system to them. When they try to explain it to their own people, they find that they can’t say anything at all.”
Energy storage cabinet physical display and explanation
Today, we’ll take a closer look at the most mainstream products on the market. Currently, while there are various types of energy storage products available, there are two main types: integrated energy storage cabinets for low-voltage projects (0.4kV) and MWh-level energy storage containers for high-voltage projects (10kV and above).
Below is a schematic diagram of a TAICO 200kWh small energy cabinet:
An energy storage system consists of battery cells, a power converter (PCS), a battery management system (BMS), an energy management system (EMS), a temperature control system, and a fire suppression system. This is the content we will be discussing in this energy storage system series. This installment starts with the most crucial component: the battery cell. More content will be updated later.
(1) Battery cells and BMS
A typical energy storage system contains hundreds, thousands, or even tens of thousands of battery cells. How can so many cells be managed in unison, operating precisely where needed? The answer lies in hierarchical cell management.
The entire battery system can be divided into three levels: battery pack (PACK), battery cluster, and battery stack.
Similarly, the Battery Management System (BMS) is also divided into three levels: PACK level, cluster level, and compartment level, also known as Level 1, Level 2, and Level 3.
(Some say there are four levels. My personal understanding is that, for example, if an independent energy storage power station has between 40 and 200 battery stacks, one more level must be added to facilitate operation and management. In the field of industrial and commercial energy storage, there are basically three levels.)
A battery pack typically consists of a 4×12, 4×13, or 4×14 cell array, with the cells connected in series (“hand-in-hand”) to form the pack.
A battery cluster typically consists of 5 or 8 battery packs connected in series (“hand-in-hand”).
Finally, there’s the battery stack, which generally refers to all the battery clusters within an energy storage container. These stacks are connected in parallel (“head-to-head, tail-to-tail”).
(2) High voltage box and PCS
Different types of batteries have different voltages and voltage fluctuation ranges. For example, the nominal voltage of a lithium iron phosphate battery is 3.2V, and the fluctuation range is 2.8-3.6V. The nominal voltage of a ternary lithium battery is 3.7V, and the voltage fluctuation range is 3.0-4.2V.
When series voltages are added together, parallel voltages remain unchanged.
The cells in the PACK and battery cluster are connected in series, while the battery stack is connected in parallel. Therefore, the final output voltage is equal to the voltage of the battery cluster, which is generally between 500 and 1000V (1000V system) or between 1000 and 1500V (1500V system).
The high-voltage box’s function is to distribute and manage high-voltage power. Like a dormitory supervisor, it constantly receives feedback from each battery cell. Upon detecting an abnormal voltage (such as overcharging or over-discharging), it immediately reports to the BMS and simultaneously stabilizes the output voltage to the PCS.
Currently, PCS on the market typically have DC input voltages of 1000V and 1500V.
(3) Liquid cooling unit
Temperature control systems generally come in three forms: air cooling, cold plate liquid cooling, immersion liquid cooling, and phase change cooling.
Air cooling is becoming increasingly inadequate in terms of temperature control capability and precision, and is essentially on the verge of being phased out.
Phase change cooling is still immature and has not been widely adopted.
Currently, most temperature control systems are cold plate liquid cooling systems. Immersion liquid cooling has existed for some time, but has never become the mainstream in the market.
The central liquid cooling unit delivers coolant to the bottom of each battery pack through liquid cooling pipes, carrying away the heat from the pack and keeping the cell temperature difference within 2°C.
(4) Fire protection system and EMS
Fire suppression systems are typically installed on the side or top; due to their small size, they are not shown in the diagram.
EMS (Energy Management System) is generally not installed inside the energy storage cabinet; it is installed in the monitoring room or equipment room, depending on the specific project requirements.
Summary of integrated energy storage cabinet
Alright, after all that text above, you clever reader probably already know most of it.
Below, we will summarize the entire energy storage cabinet’s structure:
(1) Battery cells are arranged in a 4×13 array to form a PACK, and 5 PACKs form a battery cluster.
(2) The BMS is also divided into two levels: the primary BMS is integrated with the PACK, and the secondary BMS is independent at the bottom.
(3) The battery system composed of battery cells transmits electrical energy through a high-voltage box and a PCS AC/DC converter.
(4) The liquid cooling unit controls the temperature of the PACK through liquid cooling pipes.
Future Outlook for Industrial and Commercial Energy Storage
After in-depth analysis of the structure of integrated energy storage cabinets, TAICO predicts the following future development trends for industrial and commercial energy storage:
- The mainstream single-cell capacity in the market will be 280Ah in 2024 and 314Ah in 2025.
This year, with the continuous increase in single-cell capacity, large-capacity cells such as 500Ah+, 600Ah+, 700Ah+, and even 1000Ah+ are emerging, such as CATL’s 587Ah, EVE Energy’s 628Ah, and Haichen Energy Storage’s 1175Ah.
The single-cell capacity of integrated energy storage cabinets will inevitably increase in 2026, and new mainstream capacities such as 488kWh and 522kWh will gradually appear.
2. As the single-cell capacity gradually increases, the demand for heat dissipation will also gradually increase, highlighting the importance of immersion liquid cooling. However, its high cost in the short term makes it difficult to promote, and it is expected to become the mainstream approach after 2027.
That concludes today’s sharing. You can also visit the TAICO website: taicoower.com to leave comments about what you’d like to see. If you find any errors in the article, please feel free to point them out and let’s discuss them together!