Multi-stage safety isolation framework of measurement and control system for echelon utilization power lithium battery energy storage systemTechnical Field
The invention relates to the technical field of energy storage system safety of power electronics and a power lithium battery with a power of retirement, in particular to a multistage safety isolation framework of the power lithium battery energy storage system with the power of retirement.
Background
Compared with other energy storage modes, the energy storage mode based on the lithium battery has the advantages of high energy density, long cycle life, high efficiency and the like, but the price of the energy storage mode is high. With the recent popularization of electric vehicles, a large number of retired power lithium batteries are generated. The retired batteries generally have the residual capacity with the initial capacity of 70% -80%, so that the gradient utilization of the retired power lithium batteries is beneficial to reducing the construction cost of a large-scale energy storage system and the popularization of energy storage technology.
The capacity of the batteries which are intensively placed in the energy storage power station is huge, and the potential safety hazard of the centralized application of the lithium batteries is very prominent and ignored for a long time, and under the current state of the art and the state of the art, the thermal runaway and deflagration of the battery cells of the lithium batteries have higher probability. A large number of electric automobile combustion accidents reflect that the traditional fire-fighting measures are extremely difficult to control fire. The power battery intensively placed in the electric power energy storage station is equivalent to the battery of tens or even hundreds of automobiles, such as a battery module is opened and laminated in the space of a goods shelf, and if one of tens of thousands of single battery cores is used for causing deflagration, the whole station can be ignited, and the existing fire-fighting measures can not be extinguished at all. At present, in korea where centralized energy storage demonstration engineering is active, over 40 sites have spontaneous combustion and total site burnout, which accounts for most of all energy storage sites. Therefore, in the prior art, a mode of mutually isolating the bin spaces is adopted to prevent the lithium battery pack from knocking and burning the whole station, and fire fighting is performed in the bin spaces. However, although physically separated, conventionally, the control power of the BMS of each battery pack is connected to the CAN bus, and an unknowingly high voltage is generated on the CAN bus during one of the battery packs to affect other BMS boards and upper computers connected to the CAN, thereby causing a secondary disaster, as shown in fig. 1 of the accompanying drawings.
Therefore, the electric and control signal structure of the control power supply and communication of the BMS board corresponding to each battery pack needs to ensure the safety of other battery packs and the upper computer of the energy storage station when one battery pack knocks. Therefore, a new multi-level security isolation architecture is needed for electrical and control signal architecture.
Disclosure of Invention
The invention aims to solve the technical problem that the invention provides a multi-stage safety isolation architecture of a measurement and control system of a power lithium battery energy storage system, which achieves the control electric isolation of BMS (battery management system), the isolation between each BMS board and a communication bus and the isolation between the communication bus and an upper computer. The safety of the bin and the upper computer on the electric and control signal architecture is greatly improved.
The technical scheme of the invention is that a multi-stage safety isolation framework of a measurement and control system of a power lithium battery energy storage system is utilized in a echelon manner, wherein the multi-stage safety isolation framework comprises an isolation link of a control power supply of a BMS board, an isolation link between the BMS board of a battery pack in each bin and a communication bus, and an isolation link between the communication bus and an upper computer;
the isolation link of the control power supply of the BMS board is that the BMS board is respectively powered by the corresponding battery packs, is isolated by the control power supply, collects state data of the corresponding battery packs, and is summarized to the upper computer through the communication bus;
the isolation link between the BMS plates of the battery pack in each bin and the communication bus is that each BMS plate is connected with the communication bus through the isolation link, and the communication bus is the only electric signal connection between the BMS plates and the upper computer;
The isolation link between the communication bus and the upper computer is that the communication bus is connected with the upper computer through the isolation link, so that the upper computer is ensured to reliably operate when the battery pack in a certain bin knocks down, and when the isolation link between the BMS board and the communication bus breaks down due to the accident, the total station control still operates.
As a further scheme of the invention, the battery packs connected and monitored by the BMS board are respectively floated independently or further connected in series-parallel to form groups.
As a further aspect of the present invention, the control power of the BMS board is supplied by the battery pack connected to the monitoring thereof through the voltage conversion isolation circuit, instead of the unified power supply or the external power supply.
As a further aspect of the present invention, the communication bus is a CAN bus.
As a further scheme of the invention, an optical fiber or optical coupling mode is adopted as an isolation link between the upper computer and each BMS board as well as the communication bus.
The beneficial effects of the invention are as follows:
1. the multi-stage safety isolation architecture of the measurement and control system of the retired power lithium battery energy storage system provided by the invention has the advantages that the power supply of the BMS board is different from the traditional unified power supply, and the battery pack for acquiring information of the BMS board is used for supplying power. And the control power isolation of the BMS board is realized according to the fact that the cathodes of the battery pack are not connected.
2. Based on the physical isolation of the battery components in different bins, the invention designs electrical and control signal isolation at multiple locations within the energy storage system. Each BMS board is connected with the communication bus only through an isolation link, namely, the BMS of each bin is isolated, and the communication bus is the only electric signal connection between the BMS board and the upper computer. The isolation link between the communication bus and the upper computer is that the communication bus is connected with the upper computer through the isolation link, so that the upper computer is ensured to reliably operate under the condition that the battery pack at a certain bin knocks down and when the isolation link between the BMS board and the communication bus breaks down due to the accident.
Drawings
FIG. 1 is a schematic diagram of a secondary disaster caused by detonation of a battery pack at a certain bin under a conventional control and communication bus architecture;
fig. 2 is a control power isolation schematic diagram of the BMS;
fig. 3 is an isolation between each BMS board and a communication bus;
FIG. 4 is a schematic diagram of isolation between a communication bus and an upper computer;
FIG. 5 is a schematic diagram of a disaster being confined to a single bin when the multi-level security isolation architecture of the present invention is employed.
Detailed Description
In order to make the objects, technical solutions and advantageous effects of the present invention more clear and apparent, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to facilitate understanding of the skilled person.
The embodiment 1 is a multi-stage safety isolation architecture of a measurement and control system of a power lithium battery energy storage system, wherein the multi-stage safety isolation architecture comprises an isolation link of a control power supply of a BMS board, an isolation link between the BMS board of a battery pack in each bin and a communication bus, and an isolation link between the communication bus and an upper computer;
the isolation link of the control power supply of the BMS board is that the BMS board is respectively powered by the corresponding battery packs, is isolated by the control power supply, collects state data of the corresponding battery packs, and is summarized to the upper computer through the communication bus;
the isolation link between the BMS plates of the battery pack in each bin and the communication bus is that each BMS plate is connected with the communication bus through the isolation link, and the communication bus is the only electric signal connection between the BMS plates and the upper computer;
The isolation link between the communication bus and the upper computer is that the communication bus is connected with the upper computer through the isolation link, so that the upper computer is ensured to reliably operate when the battery pack in a certain bin knocks down, and when the isolation link between the BMS board and the communication bus breaks down due to the accident, the total station control still operates.
As a further scheme of the invention, the battery packs connected and monitored by the BMS board are respectively floated independently or further connected in series-parallel to form groups.
As a further aspect of the present invention, the control power of the BMS board is supplied by the battery pack connected to the monitoring thereof through the voltage conversion isolation circuit, instead of the unified power supply or the external power supply.
As a further aspect of the present invention, the communication bus is a CAN bus.
As a further scheme of the invention, an optical fiber or optical coupling mode is adopted as an isolation link between the upper computer and each BMS board as well as the communication bus.
In example 2, the number of the battery packs may be plural, and the present invention will be described in detail by taking four battery packs as examples.
As shown in fig. 1, a process of damaging an upper computer and other BMS boards by unknown high voltage caused by detonation of a battery pack 1 along a communication bus by a measurement and control system of a power lithium battery energy storage system without adopting a multi-layer safety isolation architecture is shown;
As shown in fig. 2, the BMS boards BMS1, BMS2, BMS3, BMS4 are respectively powered by voltages of the battery packs 1,2, 3, 4 in the respective bins through buck isolation conversion to 5V. The isolation of the BMS board control electricity is achieved.
As shown in fig. 3, after each BMS board has a control power supply, state data of the collected battery pack is transmitted to a communication bus through an isolation link, so that isolation between each BMS board and the communication bus is realized.
As shown in fig. 4, after the information collected by each BMS board is summarized to the communication bus, the information must be transmitted to an upper computer connected to the communication bus through optical fiber (optocoupler) isolation.
Fig. 5 illustrates the beneficial effects of the present invention. When the battery pack 1 in the embodiment knocks, the disaster is limited in the bin 1 by the isolation link between the BMS1 and the CAN bus, and an unknowingly high voltage cannot be generated on the communication bus. Even if the isolation link between the BMS1 and the communication bus is broken down, another layer of isolation link is arranged between the communication bus and the upper computer and other BMS boards for protection.
According to the invention, the safety isolation is inserted into each stage of link of energy storage system measurement and control to form a multi-stage safety isolation framework, so that when a battery deflagration accident occurs, unknown high voltage generated by deflagration can be prevented from breaking through other BMS plates in the system and causing short circuit of battery cells of other groups, and the safety of the lithium battery centralized energy storage system is greatly improved.
Finally, the above preferred embodiments are only used to illustrate the technical solution of the invention, and not to limit the invention, wherein the isolation between the BMS board and the communication bus can be optical coupling isolation, optical fiber isolation, magnetic coupling isolation, etc. The interaction mode of the BMS board and the upper computer CAN adopt a CAN bus or other communication modes, and an isolation link is added in the middle. While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.