Multi-string cell compatible energy storage system

Abstract

The utility model belongs to the technical field of energy storage battery discloses a kind of multi-string electric core compatible energy storage system, and the main input from output line MISO, main output from input line MOSI and clock line SCK of controller MCU connection high-speed serial bus SPI, main input from output line MISO connects A isolation IC and analog front-end chip AFE1, and main output from input line MOSI is connected A isolation IC and analog front-end chip AFE1 by A+1 diode respectively, wherein the positive terminal of diode is all connected main output from input line MOSI, clock line SCK connects A isolation IC and analog front-end chip AFE1, and one end of resistance R1 is connected main output from input line MOSI, and the other end of resistance R1 is connected port Vdd, and controller MCU is connected A isolation IC and analog front-end chip AFE1 by A+1 CS port respectively.The utility model has the beneficial effect: for an energy storage system, the present scheme can manage to each string monomer electric core state, to improve the stability and reliability of energy storage system.

Description

Technical Field

[0001] This utility model relates to the field of energy storage battery technology, and in particular to a multi-cell compatible energy storage system. Background Technology

[0002] With the continuous development of new energy technologies, the development of new energy storage technology is also receiving increasing attention. New energy storage technology stores unstable electrical energy and releases it when needed, achieving dynamic adjustment. Industrial and commercial energy storage is used for peak shaving and valley filling. It charges the energy storage battery during off-peak hours and discharges it during peak hours, thereby reducing peak load, filling the power shortage, and greatly improving the overall operating efficiency and economy of the power grid.

[0003] The field of energy storage batteries is very broad, and it also corresponds to different voltage platforms. There is a 48V platform for electric bicycles and home energy storage, which typically consists of 16 batteries connected in series. There is a 400V~800V platform for medium-sized energy storage and electric vehicles, which typically consists of 100~150 cells connected in series. There is a 1000V~1500V platform for containerized energy storage and large battery compartments, which typically consists of 280~320 cells. Generally, analog front-end chips (AFE) support a series number range of 16~25 cells. The series voltage cannot meet the needs of these different voltage platforms. There are usually two approaches in the industry to address this. The first is to use DC / DC conversion technology to handle voltage conversion, but the disadvantages are that it will increase additional hardware costs, reduce system efficiency, and increase space and weight. The second approach involves cascading AFEs in a daisy-chain configuration to support hundreds of cells. However, because this method uses serial communication, a failure in any node of the chain can cause the entire chain to break. Furthermore, when communication is interrupted, it's difficult to quickly locate the faulty node, increasing the difficulty of maintenance. Additionally, AFE chips supporting daisy-chaining are more expensive. Based on the economic requirements of their products, battery manufacturers and system integrators hope to use the same BMS hardware platform to adapt to energy storage products with different numbers of cells and different capacity levels.

[0004] Therefore, it is necessary to provide a multi-cell compatible energy storage system that can effectively improve economic efficiency and scalability to solve the above problems. Utility Model Content

[0005] This utility model discloses a multi-cell compatible energy storage system, which relates to the field of energy storage battery technology. It provides a multi-cell compatible architecture and energy storage system, which can effectively solve the technical problems involved in the background art.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows:

[0007] A multi-cell compatible energy storage system includes a battery module unit. The battery module unit includes a controller (MCU). The MCU is connected to a high-speed serial bus SPI with master input / slave output line MISO, master output / slave input line MOSI, and clock line SCK. The master input / slave output line MISO connects to A isolation ICs and an analog front-end chip AFE1. The master output / slave input line MOSI is connected to A of the isolation ICs and the analog front-end chip AFE1 via A+1 diodes, with the positive terminals of all diodes connected to the master output / slave input line MOSI. The clock line SCK connects to the A isolation ICs and the analog front-end chip AFE1. The master output / slave input line MOSI is connected to one end of a resistor R1. The other end is connected to port Vdd. The controller MCU is connected to A isolation ICs and analog front-end chip AFE1 through A+1 CS ports respectively. Each of the A isolation ICs is connected to an analog front-end chip AFE. The A analog front-end chips AFE are sequentially analog front-end chip AFE2, analog front-end chip AFE3... analog front-end chip AFEA+1. The analog front-end chips AFE1, AFE2... AFEA+1 are connected to cell group 1, cell group 2... cell group A+1 respectively. The cell group 1, cell group 2... cell group A+1 are connected in series. Each cell group 1, cell group 2... cell group A+1 includes one cell or multiple cells connected in series.

[0008] As a preferred improvement of this utility model: the energy storage system further includes a battery cluster controller (BCU), and the number of battery module units is multiple. The battery cluster controller (BCU) is connected to each of the battery module units respectively via a CAN bus.

[0009] As a preferred improvement of this utility model: the battery cluster controller (BCU) is connected to the energy management system (EMS) and the energy storage converter (PCS).

[0010] As a preferred improvement of this utility model: the battery cluster controller BCU is connected to a dehumidifier, an industrial air conditioner and a fire protection system.

[0011] As a preferred improvement of this utility model: the number of cells in the cell group 1, the cell group 2...the cell group A+1 are all different or not completely the same.

[0012] As a preferred improvement of this utility model: the battery cell group 1, the battery cell group 2... the battery cell group A+1 each include 3-16 battery cells.

[0013] As a preferred improvement of this utility model: the controller MCU is connected to an air-cooling device and a heating film, and the air-cooling device and the heating film are used for cell temperature regulation.

[0014] As a preferred improvement of this utility model: the MCU model is AT32F415CCU7, and the analog front-end chip AFE model is MP3716.

[0015] As a preferred improvement of this utility model: the isolation IC includes isolators NSi8221N1 and NSi8220N0, the master input-slave output line MISO and the master output-slave input line MOSI are connected to isolators NSi8221N1, and the clock line SCK and the CS port are connected to isolators NSi8220N0.

[0016] As a preferred improvement of this utility model, A is 5-15.

[0017] The beneficial effects of this utility model are as follows:

[0018] It facilitates tiered management for fine-grained control, enables multiple cells to achieve various series and parallel combinations, and allows its battery clusters and pack voltages to be flexibly adapted to various energy storage battery voltage platforms without the need for DC / DC circuits. It features a low-cost, compatible, and scalable design philosophy. For an energy storage system, this solution can manage the state of each individual cell in a string, thereby improving the stability and reliability of the energy storage system. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 This is a schematic diagram of a multi-cell compatible energy storage system according to the present invention;

[0021] Figure 2 This is a diagram showing the structural composition of the energy storage system of this utility model;

[0022] Figure 3 This is a communication connection topology diagram of the BMU in this utility model;

[0023] Figure 4 This is a flowchart of the multi-cell management process of this utility model;

[0024] Figure 5 This is a schematic diagram of a connection method according to the present invention. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0027] Furthermore, in this utility model, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0030] Please see Figure 1As shown, this utility model provides a multi-cell compatible energy storage system and a multi-cell compatible architecture. The battery management system (BMS) in this energy storage system mainly consists of modules such as a battery cluster control unit (BCU), a battery module control unit (BMU), and an analog front-end chip (AFE). The multi-cell compatible architecture is manifested in two aspects: firstly, the battery cluster controller is compatible with multiple battery module controllers, so a battery cluster can be composed of one or more battery packs connected in series and parallel; secondly, the battery module controller is compatible with multiple analog front-end chips, so a battery pack can be composed of one or more battery modules connected in series. These two aspects realize compatible control of multi-cell arrays and management of each individual cell.

[0031] The battery cluster control unit manages one or more battery module control units via CAN communication, thereby monitoring one or more battery packs. It communicates with the energy management system (EMS) and energy storage converter (PCS) and is responsible for controlling high-voltage boxes, fire protection systems, industrial air conditioning, dehumidifiers, etc. The battery module control unit manages one or more analog front-end chips, which are responsible for multiple battery modules. The analog front-end chip, in response to the MCU's synchronous sampling command, synchronously collects the voltage and temperature of multiple strings of cells in the connected battery module and sends them to the microcontroller via the communication link.

[0032] The energy storage system compatible with multiple battery cells is implemented through a combination of hardware and software methods.

[0033] The hardware configuration is as follows: the battery module control unit (BMU) consists of a microcontroller (MCU) connected in parallel to one or more AFE chips via a high-speed serial bus (SPI). The AFE shares three SPI clock lines, master output / slave input lines, and master input / slave output lines, and controls are distinguished by chip select pins. At the same time, the MCU and AFE are isolated in the sampling communication.

[0034] The software approach involves data sampling, fault protection, and cell balancing across multiple battery cells, along with a cell management process, specifically comprising the following steps:

[0035] Step 1: Poll to obtain all AFE sampling data;

[0036] Step 2: Periodically execute fault protection logic;

[0037] Step 3: Perform temperature compensation on the cell voltage;

[0038] Step 4: Determine the equilibrium conditions and execute the equilibrium logic;

[0039] Step 5: Data sampling and equalization are performed in a time-sharing manner;

[0040] Step 6: After balancing, return to step 1;

[0041] Step 1 involves polling to obtain individual cell data from the battery module connected to the AFE, and then integrating and updating the battery status. Step 2 involves periodically executing fault protection logic at short intervals to determine whether the cell voltage and temperature have reached the protection threshold. For some protections, a three-level fault mechanism is set to prevent overcharging and over-discharging. Step 3 involves performing temperature compensation on the cell voltage to obtain voltage data for all cells at the same temperature level. Step 4 involves determining whether the compensated cell voltage meets the equalization voltage condition, calculating the equalization list, and setting the equalization time to execute the equalization logic. Step 5 requires ensuring that data sampling and equalization are performed in a time-sharing manner, synchronously monitoring the battery cell status to ensure the stability of the equalization process. Step 6 involves determining whether the equalization completion condition has been met. If it has, the current equalization process is exited, and the next multi-cell management process begins. This utility model's technical solution, compared to the existing technologies, combines the advantages of lower cost, better compatibility, higher real-time performance, and easier fault diagnosis.

[0042] Example 1

[0043] Reference Figure 1 As shown in the diagram, this schematic illustrates a communication connection framework compatible with multiple battery cells. This example proposes a BMS communication connection framework compatible with multiple battery cells, where the BMS has a two-layer architecture. The BCU is the master controller of the system, and the BMU is the slave controller. The BCU communicates with multiple BMUs via CAN bus, so the cluster-level battery cabinet can be composed of multiple packs connected in series. The BCU monitors the battery status of each pack in real time via CAN bus. Within a single pack, the slave controller BMU is connected to multiple AFEs via SPI by an MCU. Each AFE is connected to a battery module with 3 to 18 battery cells connected in series. The MCU in the BMU can monitor the status of each individual cell in real time through communication. Therefore, this multi-cell compatible architecture is more flexible in terms of battery cluster voltage platform, pack voltage platform, and cell selection. The layered architecture improves the compatibility and scalability of the BCU and BMU. The energy storage system designed in this example has the core advantages of improved flexibility, reduced cost, and simplified operation and maintenance.

[0044] Reference Figure 2As shown in the diagram, the energy storage system includes a Battery Cluster Control Unit (BCU), a Battery Module Control Unit (BMU), a Power Conversion System (PCS), and an Energy Management System (EMS). The BCU communicates with the PCS via a separate CAN bus, while the BMS communicates with the EMS via a Local Area Network (LAN). The BMU connects to one or more AFE chips via SPI communication and communicates with the BCU via a separate CAN bus. The BCU acts as the master controller of the battery management system and interacts with the dehumidifier and industrial air conditioner via RS485. The BCU controls the fire switch via I / O ports. In practical applications, one BCU connects to multiple BMUs. The BMUs collect battery module sampling data from all AFEs, including individual cell voltage, current, and temperature. Based on the data, they perform equalization judgment, fault detection, and data storage, and upload the data to the BCU in real time. After receiving the pack data from all BMUs, the BCU performs SOC estimation, fault detection, thermal management, and charge / discharge management.

[0045] Reference Figure 3 As shown, this system employs BMU-AFE communication, based on SPI parallel communication compatible with multiple battery cells. One battery management controller (MCU) connects to multiple AFE chips, thereby connecting multiple battery modules. Each battery module contains multiple battery cells. The system includes an isolation circuit located on the SPI communication bus between the MCU and each AFE, achieving electrical isolation. In the system framework shown, AFE1 and the MCU share the same ground, saving one isolation chip. In the topology shown, the AFEs share three SPI clock lines, master-slave output lines, and master-slave output lines, differentiated and controlled by chip select pins. When the MCU reads the cell sampling data from one AFE, the chip select pins CS of the other AFEs are pulled high, and the chip select pin CS of the current AFE is pulled low to enable it. In the topology shown, the diodes on the MOSI signal lines work in conjunction with the pull-up resistor R1 to prevent mutual interference between AFEs from preventing the MOSI signal level from being pulled low.

[0046] Reference Figure 4 As shown, it includes the following steps:

[0047] Step 1: The MCU sends a synchronous sampling signal to all AFEs. After sampling is completed, it polls and reads the sampling data of all AFEs to integrate the data of individual cells for multiple battery modules.

[0048] Step 2: Monitor cell data at 50ms intervals and execute fault protection logic to determine whether cell voltage and cell temperature have reached the protection trigger value. To meet battery safety requirements, the fault protection includes three levels of protection. Different levels of protection correspond to different strategies and different trigger times. Some protections have self-recovery logic, while severe protections require manual inspection before the fault can be manually cleared.

[0049] Step 3: Due to the different battery stacking technologies, it is unavoidable that the cell temperature is inconsistent. The battery voltage is greatly affected by temperature. Therefore, the sampled cell voltage is temperature compensated to obtain a voltage at a uniform temperature level. The compensated voltage can be used to better compare the differences in cell energy, making the balancing strategy more reasonable.

[0050] Step 4: Determine whether the cell voltage after temperature compensation meets the equalization voltage conditions. For lithium iron phosphate batteries, the equalization conditions must meet the following requirements: 1. The battery is in charging or standby mode; 2. The cell has not triggered over-temperature protection; 3. The cell voltage difference exceeds 30mV; 4. The cell voltage of the cell to be equalized is greater than 3.4V. Based on the above conditions, an equalization list is obtained, the equalization time is set, and the MCU sends equalization logic instructions to the AFE. If no cell needs to be equalized, skip the subsequent steps and return to step 1 for data sampling.

[0051] Step 5: In order to ensure that the cell status can be monitored during equalization, data sampling and equalization need to be performed in separate time. The status of the battery cells is monitored synchronously to ensure the stability of the equalization process. At the same time, the temperature of the equalization circuit needs to be monitored during equalization to avoid heat dissipation during equalization affecting the overall temperature.

[0052] Step 6: Determine whether the cell status has met the conditions for balancing. If the conditions are met, meaning no cells need balancing, then exit the current balancing process and proceed to the next cell management process.

[0053] The system architecture for multi-cell batteries used in energy storage systems is implemented using both hardware and software methods. The Battery Management System (BMS) mainly consists of modules such as the Battery Cluster Control Unit (BCU), the Battery Module Control Unit (BMU), and the Analog Front-End Chip (AFE). The BMS communicates with the Battery Module Control Unit via CAN communication. The BCU is responsible for data integration, cell state estimation, thermal management, and charge / discharge management. In the shown Battery Module Control Unit, the MCU communicates with the analog front-end chip via SPI parallel communication to obtain information about the battery modules connected to the analog front-end chip. The voltage and temperature sampling lines connecting the AFE to the battery modules are connected using a flexible PCB. The Battery Cluster Control Unit manages one or more Battery Module Control Units, which in turn manage one or more analog front-end AFEs. The battery modules connected to the AFEs contain multiple cell strings. The MCU connects to multiple AFE analog front-end chips via SPI parallel communication, using digital isolation. The AFEs share three SPI clock lines, master output / slave input lines, and master input / slave output lines, and are differentiated by chip select pins. The software implementation involves sending a synchronous sampling trigger signal to all analog front-end units (AFEs). After sending the synchronous sampling trigger signal, the system uses the multiplexed SPI communication bus and chip select pin to poll and read the cell data collected by the AFEs. The document outlines the approach and process for data sampling, fault protection, and cell balancing across multiple cell strings, including cell data such as individual cell voltage and temperature.

[0054] Specifically, the solution includes the overall architecture of the energy storage system, communication connection methods, hardware circuit design, and algorithms for multi-module, multi-cell sampling and balancing. One energy storage system architecture design includes a battery cluster master controller managing one or more battery module slave controllers, and an MCU in the battery module slave controller managing one or more analog front-end chips (AFEs) to manage more individual cells, synchronously sampling data from multiple cell strings, and the MCU determining whether the cell state meets the balancing conditions, calculating a balancing list, and synchronously controlling the AFEs to perform cell balancing. Applicable to industrial and commercial energy storage BMS system architectures, it includes two layers of control units, facilitating layered management for fine-grained control. Multiple cells can be combined in various series and parallel configurations. Its battery cluster and pack voltages can be flexibly adapted to various energy storage battery voltage platforms without the need for DC / DC circuits. It features a low-cost, compatible, and scalable design philosophy. For an energy storage system, this solution can manage the state of each individual cell string, thereby improving the stability and reliability of the energy storage system.

[0055] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A multi-cell compatible energy storage system, characterized in that: The system includes a battery module unit, which includes a controller MCU. The MCU is connected to the master input / slave output line MISO, the master output / slave input line MOSI, and the clock line SCK of a high-speed serial bus SPI. The master input / slave output line MISO connects to A isolation ICs and an analog front-end chip AFE1. The master output / slave input line MOSI is connected to A of the isolation ICs and the analog front-end chip AFE1 through A+1 diodes, with the positive terminals of the diodes all connected to the master output / slave input line MOSI. The clock line SCK connects to A of the isolation ICs and the analog front-end chip AFE1. The master output / slave input line MOSI is connected to one end of a resistor R1, and the other end of the resistor R1 is connected to the port Vdd. The controller MCU connects to A isolation ICs and analog front-end chip AFE1 through A+1 CS ports respectively. Each of the A isolation ICs is connected to an analog front-end chip AFE. The A analog front-end chips AFE are sequentially named analog front-end chip AFE2, analog front-end chip AFE3, and so on to analog front-end chip AFEA+1. Analog front-end chips AFE1, AFE2, and AFEA+1 are connected to cell group 1, cell group 2, and cell group A+1 respectively. Cell group 1, cell group 2, and cell group A+1 are connected in series. Each cell group includes one or more cells connected in series. A is 5-15.

2. The multi-cell compatible energy storage system according to claim 1, characterized in that: The energy storage system also includes a battery cluster controller (BCU), and there are multiple battery module units. The battery cluster controller (BCU) is connected to each of the battery module units via a CAN bus.

3. The multi-cell compatible energy storage system according to claim 2, characterized in that: The battery cluster controller (BCU) is connected to the energy management system (EMS) and the energy storage converter (PCS).

4. The multi-cell compatible energy storage system according to claim 2, characterized in that: The battery cluster controller (BCU) is connected to a dehumidifier, an industrial air conditioner, and a fire suppression system.

5. The multi-cell compatible energy storage system according to claim 1, characterized in that: The number of cells in cell group 1, cell group 2, and cell group A+1 are all different or not completely the same.

6. The multi-cell compatible energy storage system according to claim 1, characterized in that: Each of the cell group 1, cell group 2, and cell group A+1 includes 3-16 cells.

7. The multi-cell compatible energy storage system according to claim 1, characterized in that: The controller MCU is connected to an air-cooling device and a heating film, which are used for cell temperature regulation.

8. The multi-cell compatible energy storage system according to claim 1, characterized in that: The MCU model is AT32F415CCU7, and the analog front-end chip AFE model is MP3716.

9. A multi-cell compatible energy storage system according to claim 1, characterized in that: The isolation IC includes isolators NSi8221N1 and NSi8220N0. The master input-slave output line MISO and the master output-slave input line MOSI are connected to isolators NSi8221N1, and the clock line SCK and the CS port are connected to isolators NSi8220N0.

Images