CN205509569U - Photovoltaic basic station is with lithium cell reserve electrical power generating system - Google Patents

Abstract

The utility model relates to a charging and discharging circuit that photovoltaic basic station is with lithium cell reserve electrical power generating system, this system include the group battery, are used for to detect the battery management system BMS of group battery information and be used for realizing the group battery charge -discharge, battery management system BMS control connection is used for controlling the switch of charging and discharging circuit break -make, and this system is still including the hot administrative unit that is used for keeping battery group temperature stable, hot administrative unit is connected with the dc bus that inserts the positive negative pole of group battery, hot administrative unit is including heating module and refrigerating module, battery management system BMS control connection heating module and refrigerating module. The utility model discloses a system makes in the basic station temperature of group battery suitable all the time, does not have under the condition of commercial power even in that the commercial power is unstable, still can guarantee suiting of in basic station temperature, the utility model discloses a system is applicable to the photovoltaic basic station that is in remote districts very much.

Description

A lithium battery backup power system for photovoltaic base stations

technical field

The utility model relates to a backup power supply system for a photovoltaic base station, in particular to a lithium battery backup power supply system for a photovoltaic base station.

Background technique

Traditional photovoltaic base stations use lead-acid batteries, and the state of the batteries can only be detected by switching power supplies. The detection items are only the overall state of the battery pack, and there is no information about the individual cells. This kind of base station has great defects. First, the lead-acid battery has its own defects. The short cycle life increases the frequency of battery replacement, and the large volume occupies the space of the base station. Second, the information collected by the system is not complete, only the overall information of the battery system is collected, and when some single batteries fail, the location of the faulty battery cannot be quickly judged; third, there is no data storage function, and it is difficult to quickly analyze the cause of battery failure without storing historical data , which is not conducive to avoiding the cause of failure in the later stage; fourth, the communication with the background monitoring system is not realized, and the battery information cannot be quickly uploaded to the background, which is not conducive to system information monitoring, increases the work of inspection personnel, and is not conducive to the later maintenance and use of equipment.

Compared with lead-acid batteries, iron-lithium batteries are safer to use, have a long life, do not contain any heavy metals and rare metals, are light in weight, small in size, stable in voltage platform, and have no memory effect. Since 2009, the three major operators have gradually applied iron-lithium batteries to the communication industry. In 2011, China Mobile Henan Company built 200 test stations. At the same time, the bidding of iron-lithium batteries by the three major operators led by various provinces and cities continued to appear. In 2012, Hebei Mobile began large-scale bidding for iron-lithium battery backup power. In 2013, China Telecom began centralized procurement. , In 2014, China Unicom started centralized purchasing. It is the future development trend to use iron-lithium battery as backup power instead of lead-acid battery as backup power.

The patent document "A Discrete Lithium Battery Backup Power Supply for Communication" discloses a lithium battery backup power system, which integrates the control circuit with the battery pack, and integrates the BMS drive unit, shunt, contactor , diodes and display screens are integrated together. Although the installation and maintenance are convenient, it also solves the defects of traditional lead-acid batteries to a certain extent, but it does not take into account the influence of temperature on the battery. The performance of iron-lithium batteries decays quickly in high and low temperature environments, which requires some methods to ensure that the ambient temperature of the batteries is suitable to prevent the rapid degradation of battery performance. The existing method is to set heating in the backup power system Module, wherein the heating module is powered by commercial power. For example, the patent document "A Backup Battery" discloses a backup battery that considers temperature changes, and the heating unit is powered by AC commercial power. For photovoltaic base stations, places with abundant solar energy are generally located in relatively remote places, with large temperature differences between day and night, unstable mains power or even no mains power, and it is impossible to use ordinary air conditioners to ensure the ambient temperature in the base station. It is also a thorny problem to ensure a suitable temperature in the base station under the condition of mains power.

Utility model content

The utility model provides a lithium battery backup power supply system for photovoltaic base stations, to solve the problem that the existing battery backup power supply system uses commercial power to supply power to the battery heating unit, which is not suitable for photovoltaic base stations in remote locations where the commercial power supply is unstable. question.

In order to solve the above technical problems, the lithium battery backup power system for photovoltaic base stations of the present invention includes a battery pack, a DC bus bar connected to the battery pack, a battery management system for detecting battery pack information, and a charging and discharging device for realizing charging and discharging of the battery pack. Circuit, the battery pack is an iron-lithium battery pack, characterized in that the system also includes a thermal management unit for keeping the temperature of the battery pack stable, the DC bus is connected to the thermal management unit, and the thermal management unit includes heating and cooling modules.

The charging and discharging circuit includes a charging contactor K3 and a discharging contactor K4 connected in series, a diode with a current direction opposite to that of the charging contactor K3 is connected in parallel on the charging contactor K3, and a diode opposite to the current direction of the charging contactor K3 is connected in parallel on the discharging contactor K4. K4 Diode with opposite current direction.

The system also includes a DC/DC converter, the input terminal 1 of the DC/DC converter is connected to the positive pole of the battery pack and the positive terminal of the DC bus; the input terminal 2 of the DC/DC converter is connected to the negative pole of the battery pack through a control switch and a diode connected to the negative terminal of the DC bus, the input terminal 2 of the DC/DC converter is also connected to the negative pole of the battery pack through the charging and discharging circuit, and the output terminal of the DC/DC converter is connected to the power interface of the battery management system.

The control switch includes a manual switch K2 and a relay switch K5.

A stop switch K1 is also connected between the input terminal 1 of the DC/DC converter and the positive pole of the battery pack.

The battery management system controls and connects the heating module and the cooling module.

A fuse is connected in series between the battery pack and the charging and discharging circuit.

A shunt is connected in series between the battery pack and the fuse.

The lithium battery backup power system for photovoltaic base stations also includes a display unit connected to the battery management system for displaying battery information.

The lithium battery backup power system for the photovoltaic base station is provided with a communication interface for communicating with the monitoring background.

The beneficial effects of the utility model are: the system is equipped with a thermal management system, which can control the temperature of the battery pack, so that the temperature of the battery pack in the base station is always suitable, and prevents the performance of the battery from decaying quickly in high and low temperature environments, and the thermal management The unit is directly powered by a battery pack or a photovoltaic power generation unit. In the case of unstable or even no mains power, it can still ensure a suitable temperature in the base station. The system of the utility model is very suitable for photovoltaic base stations in remote areas.

The battery management system BMS of the system is connected to the positive and negative poles of each single battery in the battery pack to obtain the information of each single battery, ensuring complete collection of battery information, and quickly judging the faulty battery when some single batteries fail Location. At the same time, the control unit of the system can realize the self-power-off function to prevent the overcharging and discharging of the battery pack. The system can automatically shut down and restart automatically, with high reliability and stable operation. It is suitable for long-term unattended photovoltaic base stations.

The system of the utility model can realize the communication with the background monitoring system, and quickly upload the battery information to the background, which is beneficial to the system information monitoring and the later maintenance of the equipment.

The battery pack in the system of the utility model uses a lithium iron phosphate battery as a power source, thereby reducing the occupied space of the system, increasing the service life of the system, shortening the number of system maintenance, and being environmentally friendly.

Description of drawings

Fig. 1 is the backup power supply system block diagram of the present embodiment;

Fig. 2 is the electrical connection diagram of the backup power supply system of the present embodiment;

Fig. 3 is the schematic diagram of the heating system of the present embodiment;

In Figure 1, 1 is the internal load of the communication base station, 2 is the heating unit, 3 is the photovoltaic power generation unit, 4 is the refrigeration unit, 5 is the battery pack, 6 is the control unit, 7 is the storage device, and 8 is the display screen;

In Figure 2, K1 is the stop switch, K2 is the start switch, K3 is the charging contactor, K4 is the discharging contactor, and K5 is the BMS self-locking contactor.

detailed description

Below in conjunction with accompanying drawing, the technical solution of the utility model is described in further detail.

As shown in Figure 1, the battery backup power supply system of this embodiment includes the system including a battery pack, a battery management system BMS for measuring battery pack information, and a charging and discharging circuit for realizing charging and discharging of the battery pack, the battery management system BMS controls Connect the switch used to control the on-off of the charging and discharging circuit. The system also includes a thermal management unit used to keep the temperature of the battery pack stable. The heating management unit is connected to the DC bus connected to the positive and negative poles of the battery pack. The heating management unit includes a heating module And the cooling module, the battery management system BMS controls the connection of the heating module and the cooling module.

The battery pack in this embodiment includes a battery module and a battery standard subrack, wherein the battery module integrates a silicone heater, a battery collection harness, and a quick connection port. The number of battery standard subracks depends on the number of single batteries in the battery pack, and each battery standard subrack is provided with a quick connection port. The quick connection ports can be quickly plugged and unplugged without connecting the load, and each connection port has foolproof measures. The battery management system BMS is connected to the battery pack to measure the information of each single battery in the battery module.

The charging and discharging circuit of this embodiment includes a charging contactor K3 and a discharging contactor K4 connected in series. A diode with a current direction opposite to that of the charging contactor K3 is connected in parallel on the charging contactor K3, and a diode with a current direction opposite to that of the charging contactor K3 is connected in parallel on the discharging contactor K4. Contactor K4 diode with opposite current direction. The battery management system BMS controls and connects the charging contactor and the discharging contactor. The charge and discharge port can realize zero-delay conversion.

The thermal management unit of the system for keeping the battery pack temperature stable includes a heating unit and a cooling unit, wherein the heating unit includes a heating device and a switch, and the cooling unit includes a power switch, a cooling device and a temperature detection module. By analyzing the actual situation of the photovoltaic base station, combined with the performance of the lithium battery itself (the charging temperature is not allowed to be too high or too low), a reasonable control method is formulated to make the thermal management unit work reasonably, improve the utilization rate of solar energy, reduce the power consumption of the battery pack, and extend the load working time .

The heating unit in this embodiment is inherited from the inside of the battery standard subrack, and the heating device therein can be a heating sheet, a resistance wire, etc. Negative; the negative poles of the heating plates are connected together to form a heating total positive. A heating relay is connected in series on the heating total negative connection line. The contact of the heating relay is a normally open contact. This normally open contact heats the battery pack. A temperature detection device can be installed in the heating unit, which is connected to the battery management system and sends temperature information to the battery management system. When the temperature is too high, the battery management system controls the heating relay to disconnect and stop heating. When the temperature is too low , the control heating relay is turned on for heating. Of course, as other implementations, timing heating can also be used, that is, no heating during the day and heating at night. The refrigerating unit is preferably an air conditioner with better refrigerating effect, of course, a cooling fan can also be used. The heating management unit of this embodiment is connected to the DC bus connected to the battery pack. When there is sufficient sunlight during the day, it can be powered by the DC bus of the photovoltaic power generation system used to charge the battery pack. At night or in rainy weather, when the solar energy is insufficient, Can be powered by battery pack.

The system also includes a DC/DC converter, which is used to convert the voltage of the battery pack to the voltage required by the BMS to supply power to the BMS. The input terminal 1 of the DC/DC converter is connected to the positive pole of the battery pack and the positive terminal of the DC bus; the input terminal 2 of the DC/DC converter is connected to the negative pole of the battery pack and a diode to the negative terminal of the DC bus through a control switch, so The input terminal 2 of the DC/DC converter is also connected to the negative electrode of the battery pack through the charging and discharging circuit, and the output terminal of the DC/DC converter is connected to the power interface of the battery management system. Wherein, the control switch includes a manual switch K2 and a relay switch K5. A diode is also connected between the input terminal 2 of the DC/DC converter and the control switch.

A stop switch K1 is also connected between the input terminal 1 of the DC/DC converter in this embodiment and the positive pole of the battery pack. The stop switch is a normally closed switch. The setting of the start switch and the stop switch above can form a self-starting and self-power-off circuit between the lithium-ion battery pack and the control unit to protect the lithium-ion battery pack from being discharged and reduce labor maintenance costs.

A fuse is connected in series between the battery pack and the charging and discharging circuit in this embodiment.

In this embodiment, a shunt is connected in series between the battery pack and the fuse, and the shunt is connected to the battery management system. The battery management system obtains the current information of the battery pack through the shunt.

The control unit in this embodiment also includes a display unit connected to the battery management system for displaying battery information.

The control unit of this embodiment is provided with a communication interface for communicating with the monitoring background, and the battery information can be quickly uploaded to the background, which is beneficial to system information monitoring, reduces the work of patrol personnel, and facilitates later maintenance and use of equipment

The control unit and the battery pack in this embodiment are integrated in a standard battery subrack, and the heating management unit and the battery pack are also integrated in a standard battery subrack.

The battery pack in this embodiment is a lithium iron phosphate battery or a lithium battery.

The working principle of the backup power supply system in this embodiment is as follows:

The environment of a photovoltaic base station is generally abundant in solar energy during the day, part of which supplies power to the load, and part of it charges the battery. The base station supplies power to the load at night. In case of cloudy and rainy weather, the battery capacity generally needs to work for the load for 7 consecutive days. For normal operation, turn off K2 when starting for the first time, power on the battery management system (BMS for short), and turn off K3, K4, K5 after the self-test is normal, and the system starts to work; when disconnecting the power system, turn off the stop switch K1, and the BMS is powered off. The system stops working.

The integrated control unit mainly includes BMS, contactors, diodes, switches, etc. When the battery fails, such as overcharge, overdischarge, high temperature, low temperature, etc., the BMS controls the corresponding contactor to disconnect to avoid battery abuse. The start switch K2 is an automatic reset switch. After the system is turned on, it is automatically disconnected. When the battery pack is over-discharged, the BMS disconnects K4 first, and the entire power circuit stops working. The BMS and DC/DC still consume battery power, and then the BMS turns off its own power supply. That is, disconnect K5 to prevent the battery pack from continuing to over-discharge. When the external power supply charges the battery, activate the BMS, turn off K4 and K5, and the system starts to charge normally, thereby realizing the self-power-off of the entire system. The BMS system can provide external communication, realize communication with switching power supply and dynamic ring system, and upload battery information in real time.

The entire power system is integrated inside the cabinet, which has the function of heat preservation. The cabinet is divided into a battery box and an electrical box. Quick connectors are used between the boxes to realize power connection and communication connection, which is convenient for quick installation and maintenance of the backup power supply. The thermal management unit is integrated in the cabinet. The charging temperature range of the iron-lithium battery is small (0-45°C), and the discharge temperature range is large (-20-55°C). When the temperature in the cabinet is turned on, the cabinet air conditioner is turned on to reduce the temperature in the cabinet. When the temperature in the cabinet drops to an appropriate value, the air conditioner is automatically turned off. When the ambient temperature drops to a low temperature critical value and the battery is charging, the heating relay is closed to heat the battery pack, and the battery temperature rises to When the appropriate value is reached, disconnect the heating relay.

The battery management system can be equipped with a display unit and a storage device. By communicating with the BMS, the battery information is displayed on the display screen, and at the same time, the battery information is stored on the storage device. The storage device is a USB interface, and the information can be quickly transmitted through the computer Export, and all data are in EXCEL format, which is conducive to data analysis.

Claims (10)

1. a photovoltaic base station lithium battery backup power system, this system includes set of cells, connect the dc bus of set of cells, for measuring the battery management system of battery pack information and for realizing the charge-discharge circuit of battery set charge/discharge, described set of cells is lithium iron battery group, it is characterised in that this system also includes for keeping the stable thermal management unit of battery pack temperature, the described described thermal management unit of DC bus powered connection, described thermal management unit includes heating module and refrigeration module.

Photovoltaic base station lithium battery backup power system the most according to claim 1, it is characterized in that, described charge-discharge circuit includes charging contactor K3 and the electric discharge catalyst K4 being serially connected, a diode contrary with the charging contactor K3 sense of current in parallel on charging contactor K3, a diode contrary with the electric discharge catalyst K4 sense of current in parallel on electric discharge catalyst K4.

Photovoltaic base station lithium battery backup power system the most according to claim 1, it is characterised in that this system also includes that DC/DC changer, the input terminal 1 of described DC/DC changer connect battery anode and dc bus plus end；The input terminal 2 of described DC/DC changer controls switch by one and connects battery electrode and a diode connection dc bus negative terminal, the input terminal 2 of described DC/DC changer connects battery electrode also by charge-discharge circuit, and the outfan of described DC/DC changer connects battery management system power interface.

Photovoltaic base station lithium battery backup power system the most according to claim 3, it is characterised in that described control switch includes hand switch K2 and relay switch K5.

Photovoltaic base station lithium battery backup power system the most according to claim 4, it is characterised in that be also associated with a shutdown switch K1 between input terminal 1 and the battery anode of described DC/DC changer.

Photovoltaic base station lithium battery backup power system the most according to claim 1, it is characterised in that described battery management system controls to connect described heating module and refrigeration module.

Photovoltaic base station lithium battery backup power system the most according to claim 1, it is characterised in that be serially connected with fuse between described set of cells and charge-discharge circuit.

Photovoltaic base station lithium battery backup power system the most according to claim 1, it is characterised in that be serially connected with diverter between described set of cells and fuse.

Photovoltaic base station lithium battery backup power system the most according to claim 1, it is characterised in that described photovoltaic base station lithium battery backup power system also includes display unit, and described display unit is connected with battery management system, is used for showing battery information.

10. according to claim 1-9 arbitrary described photovoltaic base station lithium battery backup power system, it is characterised in that described photovoltaic base station lithium battery backup power system is provided with for the communication interface with monitoring Background communication.