An energy storage system and its control method suitable for use in communication base stations with a combination of lead-acid and lithium batteries

Abstract

An energy storage system and its control method suitable for using a combination of lead-acid and lithium batteries in communication base stations are disclosed. The energy storage system includes mains power, a switching power supply, communication equipment, and a mixed-use energy storage module. The mixed-use energy storage module includes a smart control box, a lead-acid battery pack, and multiple lithium battery packs. The smart control box includes a switching power supply input, a voltage conversion circuit, a battery input, and a management unit. The battery input has both lead-acid and lithium battery interfaces. The lead-acid and lithium battery interfaces are independently configured and independently controlled by the management unit, allowing for independent control of the battery charging and discharging channels. This enables different battery packs to work together and solves problems such as circulating current, bias current, and voltage difference between batteries with different internal resistances. Based on local peak and off-peak periods, different power sources are used at different times, making more rational use of electricity and improving overall work efficiency.

Description

Technical Field

[0001] This invention relates to the field of communication base station technology, and in particular to an energy storage system and control method suitable for communication base stations that use a combination of lead-acid and lithium batteries. Background Technology

[0002] A communication base station is a public mobile communication base station, serving as an interface device for mobile devices to access the internet. It is also a type of radio station, referring to a radio transceiver station that transmits information between a mobile communication switching center and a mobile phone terminal within a defined radio coverage area. Communication base station equipment is susceptible to damage from power outages or interruptions. To prevent malfunctions due to power outages, batteries have become a crucial component of the communication base station's power supply system.

[0003] Lead-acid batteries are commonly used as backup power for communication base stations. However, lead-acid batteries have a short lifespan, mainly due to frequent charging and discharging or being discharged again before being fully charged, leading to cumulative capacity loss and a short lifespan. Therefore, existing technologies often use a mix of lead-acid and lithium batteries to alleviate the drawbacks of frequent charging and discharging of lead-acid batteries to some extent, as exemplified by the battery hybrid application system for communication base stations disclosed in patent number CN201520429295.4. However, mixing old and new batteries under different conditions, especially with traditional lead-acid batteries, presents challenges. When the performance of old and new batteries is inconsistent, circulating and biased currents occur between battery packs. Batteries with lower internal resistance carry higher currents, while those with higher internal resistance carry lower currents, resulting in rapid capacity decay of the lower-resistance batteries and shortened battery life. Furthermore, the discharge of different battery packs is difficult to manage, leading to excessive consumption of some lithium battery packs or the inability of lithium battery packs to supply power in the event of a mains power outage, resulting in poor power supply stability for the base station. Summary of the Invention

[0004] In view of this, the present invention provides an energy storage system and control method suitable for the use of lead-acid and lithium batteries in communication base stations, so as to solve the above-mentioned technical problems.

[0005] A mixed-use energy storage system and control method for communication base stations using lead-acid and lithium batteries are disclosed. The system includes mains power, a switching power supply connected to the mains power, a communication device connected to the switching power supply, and a mixed-use energy storage module for both new and old batteries connected to the switching power supply. The switching power supply is used to detect whether the mains power is normal and to convert the mains power. The mixed-use energy storage module includes a smart control box connected to the switching power supply, at least two lead-acid battery packs connected to the smart control box, and multiple lithium battery packs connected to the smart control box. The smart control box includes a switching power supply input connected to the switching power supply, a voltage conversion circuit connected to the switching power supply input, a battery input connected to the voltage conversion circuit, and a management unit for controlling the smart control box. The voltage converted by the switching power supply is input to the voltage conversion circuit through the switching power supply input. The voltage conversion circuit is used for voltage isolation and conversion. The battery input has at least two lead-acid interfaces and multiple lithium battery interfaces. The two lead-acid interfaces are respectively connected to two lead-acid battery packs, and the lithium battery interfaces are connected to the lithium battery packs. The lead-acid interface and the lithium battery interface are each independently configured and controlled by the management unit. The lithium battery pack has an embedded BMS management system that collects battery data and turns the MOS on or off according to the battery status.

[0006] Furthermore, there are two routes between the switching power supply input and the switching power supply, one of which is the main route and the other is the backup route.

[0007] Furthermore, the voltage conversion circuit is composed of a bidirectional DC-DC module. When the battery pack needs to be charged, it increases the voltage input from the switching power supply input to a level higher than the battery pack voltage and divides the total current into multiple paths flowing to the battery pack. When the battery pack is discharging, it raises the battery pack voltage to a level higher than the output voltage of the switching power supply and combines the battery pack current into two paths flowing back to the switching power supply. The voltage conversion circuit can also be composed of a unidirectional DC-DC module, which does not perform voltage transformation during charging but does perform voltage transformation during discharging.

[0008] Furthermore, the current of the lead-acid interface is 150A, the total channel current of the lithium battery interface is 1.5 times the load current, the current of a single lithium battery interface is in increments of 50A, and the operating voltage range of the lithium battery pack is 44 to 56.5V.

[0009] Furthermore, the energy storage system suitable for the mixed use of lead-acid and lithium batteries in communication base stations can also add an edge gateway between the switching power supply and the smart control box. The edge gateway interfaces with the switching power supply and the smart control box via the RS485 protocol, and issues commands to the entire energy storage system through the edge gateway.

[0010] Furthermore, the energy storage system suitable for the mixed use of lead-acid and lithium batteries in communication base stations can also eliminate the lead-acid interface, connect the lead-acid battery pack to the busbar of the switching power supply, and connect it to a smart circuit breaker for control. The smart circuit breaker and the smart control box are connected via RS485 protocol. When the mains power fails, the smart control box instructs the smart circuit breaker to open the switch and discharge the lead-acid battery pack.

[0011] A control method for an energy storage system that uses both lead-acid and lithium batteries in communication base stations includes the following steps:

[0012] Step S1: The intelligent control box sets the peak shaving and valley filling operation strategy according to the local peak and valley time periods. Peak electricity price period corresponds to peak shaving mode, valley electricity price period corresponds to valley filling mode, and flat electricity price period corresponds to standby mode. The intelligent control box sets the upper and lower limit voltages of output and input, single channel current limit value, minimum working channel and other parameters. The output voltage of the switching power supply is 53.5V and is in constant voltage output mode.

[0013] Step S2: The switching power supply detects whether the mains power is normal and transmits the information to the smart control box. The smart control box judges and activates the corresponding mode based on the time point and the received information.

[0014] Step S3.1: When the mains power is normal, and the smart control box determines that the time is in peak shaving mode based on the time point, the smart control box opens the output channel and the MOS of the lithium battery pack is turned on, so that the lithium battery pack discharges. After the voltage conversion circuit sums up the current discharged by the multiple lithium battery packs, the output voltage is raised to 55V, and then output to the switching power supply in two ways. At this time, the output voltage of the lithium battery pack is greater than the output voltage of the switching power supply (53.5V), the switching power supply stops outputting, and the lithium battery pack directly supplies power to the network load of the communication device.

[0015] Step S3.2: When the mains power is normal, and the smart control box determines that the time is in valley filling mode and the lithium battery pack is not fully charged, the smart control box opens the input channel. At this time, the switching power supply outputs in two ways: one to power the communication device and the other to charge the lithium battery pack. The voltage conversion circuit summarizes the input current of the switching power supply and distributes it to each battery channel to charge the battery in each channel.

[0016] Step S3.3: When the mains power is normal, the smart control box determines the time to be in standby mode based on the time point, the smart control box closes the input or output channel, the lithium battery pack does not work and is in a static state, and the switching power supply only supplies power to the communication device;

[0017] Step S3.4: When the switching power supply detects that the mains voltage is 0, the switching power supply sends a mains power failure message to the smart control box, the smart control box opens the output channel of the lead-acid battery pack, the lead-acid battery pack starts discharging, and supplies power to the communication device;

[0018] Step S3.5: Since the lead-acid battery pack outputs power and the lead-acid battery pack is depleted due to its own reasons, when the smart control box detects that the voltage of the lead-acid battery pack is lower than 50V and is not in the peak shaving mode period, the smart control box opens the input channel of the lead-acid battery pack to replenish the lead-acid battery pack.

[0019] Furthermore, in step S3.1 above, when the set peak shaving mode time expires or the smart control box detects that the battery voltage is lower than the cutoff voltage, the smart control box shuts down the output channel and sends a command to the switching power supply to stop the lithium battery pack from supplying power, and the switching power supply resumes operation to supply power at a constant voltage of 53.5V.

[0020] Furthermore, in step S3.2 above, when the voltage of the lithium battery pack is lower than 53.5V, the voltage changing circuit does not change the voltage, but only shuns the current. When the voltage of the lithium battery pack is higher than 53.5V, the voltage changing circuit changes the voltage, raises the input voltage, and then shuns the input current to charge the battery.

[0021] Furthermore, in step S3.2 above, when a single lithium battery pack is fully charged, the BMS turns off the charging MOS. At this time, the smart control box notifies the switching power supply to reduce the corresponding output current to avoid floating charging. When the switching power supply detects that the load suddenly has a large current and exceeds the current limit point, the switching power supply notifies the smart control box to close the input channel and reduce the output of the switching power supply.

[0022] Compared with existing technologies, the energy storage system provided by this invention, suitable for the mixed use of lead-acid and lithium batteries in communication base stations, independently sets up two lead-acid interfaces for lead-acid battery charging and backup power during power outages. After a mains power failure, the system can quickly respond by opening the lead-acid battery pack to supply power to the network load, with a response speed of ≤10ms, thus achieving power supply after a mains power failure. The lead-acid interface and the lithium battery interface are set independently, and the management unit independently sets the parameters of each channel and independently controls each channel, thereby enabling independent control of the battery charging and discharging channels. This allows battery packs with different usage levels, capacities, and brands to work together, and solves problems such as circulating current, bias current, and voltage difference between batteries with different internal resistances. Simultaneously, based on local peak and off-peak periods, different power sources are used at different times. The batteries are charged during the low load period of the base station's off-peak hours and discharged during the high load period of the base station's peak hours, making more rational use of electricity and improving overall working efficiency. The design is more rational. Attached Figure Description

[0023] Figure 1 This invention provides a structural schematic diagram of an energy storage system suitable for using a combination of lead-acid and lithium batteries in communication base stations.

[0024] Figure 2 for Figure 1 A schematic diagram of the structure of a mixed-use energy storage module for lead-acid and lithium batteries suitable for communication base stations.

[0025] Figure 3 for Figure 1 A schematic diagram of the structure of an energy storage system for communication base stations that uses a combination of lead-acid and lithium batteries, with the addition of an edge gateway.

[0026] Figure 4 for Figure 1 A schematic diagram of the cross-sectional structure of an energy storage system for communication base stations that uses a combination of lead-acid and lithium batteries, with the addition of a smart circuit breaker.

[0027] Figure 5 for Figure 1 A flowchart of a control method for an energy storage system that uses both lead-acid and lithium batteries in a communication base station. Detailed Implementation

[0028] The following provides a more detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0029] like Figures 1 to 5The diagram shows a structural schematic of an energy storage system for communication base stations using a combination of lead-acid and lithium batteries, provided by the present invention. The energy storage system includes a mains power supply 10, a switching power supply 20 connected to the mains power supply 10, a communication device 30 connected to the switching power supply 20, and a mixed-use energy storage module 40 for both new and old batteries connected to the switching power supply 20. It is conceivable that the energy storage system for communication base stations also includes other functional modules, such as circuit elements and control modules, etc., which are well-known to those skilled in the art and will not be described in detail here.

[0030] The mains power 10 is industrial frequency alternating current (AC) and is mainly used to charge the communication equipment 30 and the hybrid energy storage module 40. By introducing AC 380V mains power, the mains power 10 supplies electricity for household use such as air conditioning and lighting. After conversion by the switching power supply 20, the AC 380V is inverted into DC 48V to power the communication equipment 30 or charge the hybrid energy storage module 40. The switching power supply 20 is used to detect whether the mains power 10 is normal, i.e., to detect whether the mains power 10 suddenly experiences a large current or a power outage. Simultaneously, it converts the mains power 10 into DC 48V to serve as the power source for the communication equipment 30 and the charging source for the hybrid energy storage module 40.

[0031] The network load current of the communication equipment 30 during operation is 20-300A, and the magnitude of the load current depends on the number of communication equipment. All DC-side equipment has a nominal output of 48V. Each individual communication equipment needs to meet a working voltage range of 44V-57V. Since the voltage after the communication equipment is mounted on the tower is not lower than 48V and there is a voltage drop of nearly 2V on the tower, its effective working range should be 50V-57V. The full-charge voltage of the lead-acid power supply is 53.5V. To ensure that the output voltage of the switching power supply 20 is balanced with the lead-acid voltage, i.e., the full-charge voltage of the lead-acid power supply is also the constant voltage output voltage of the switching power supply 20, the switching power supply 20 experiences a voltage fluctuation of 0.5V during voltage regulation, ranging from 53V to 54V.

[0032] The hybrid energy storage module 40 includes a smart control box 41 connected to the switching power supply 20, at least two lead-acid battery packs 42 connected to the smart control box 41, and multiple lithium battery packs 43 connected to the smart control box 41. The lithium battery packs 43 are used for peak shaving of the DC-side communication equipment of the base station. When the mains power is at its peak, the lithium battery packs 43 provide power; when the mains power is at its off-peak, the lithium battery packs 43 charge. When the mains power is normal, the mains power provides direct power. When the mains AC point is 0, the lead-acid battery packs 42 provide power. The smart control box 41 controls the switching of the power supply systems of the lithium battery packs 43, lead-acid battery packs 42, and mains power, as well as data transmission, command issuance, and management of common charging and discharging and step charging and discharging of the batteries.

[0033] The smart control box 41 includes a switching power input 411 connected to the switching power supply 20, a voltage conversion circuit 412 connected to the switching power input 411, a battery input 413 connected to the voltage conversion circuit 412, and a management unit 414 for controlling the smart control box 41.

[0034] The voltage after being inverted by the switching power supply 20 is input into the voltage conversion circuit 412 through the switching power supply input 411. There are two paths between the switching power supply input 411 and the switching power supply 20, one of which is the main path and the other is the backup path. When one path is damaged, the other path can still work normally, thus improving the overall stability.

[0035] The voltage conversion circuit 412 consists of a bidirectional DC-DC module and is used for voltage isolation and conversion. When the battery pack needs charging, the voltage conversion circuit 412 increases the voltage input from the switching power supply input 411 to a level higher than the battery pack voltage, and divides the total current into multiple paths flowing to the battery pack, thereby charging the battery pack. When the battery pack discharges, the voltage conversion circuit 412 raises the battery pack voltage higher than the output voltage of the switching power supply 20, and combines the battery pack current and divides it back to the switching power supply 20 in two paths, thereby discharging the battery pack to supply power to the network load. It is conceivable that the voltage conversion circuit 412 could also be composed of a unidirectional DC-DC module, which does not perform voltage conversion during charging but does so during discharging.

[0036] The battery inlet 413 is provided with at least two 150A lead-acid interfaces 4131 and multiple lithium battery interfaces 4132.

[0037] The two lead-acid interfaces 4131 serve as lead-acid battery interfaces, respectively connecting to the two lead-acid battery packs 42, and are used for replenishing lead-acid battery power and providing backup power during power outages. When the lead-acid battery pack 42 is fully charged, the lead-acid interface 4131 is in a normally closed state. When the mains power fails or is replenished, the lead-acid interface 4131 is in an open state. The number of lead-acid interfaces 4131 is the same as the number of lead-acid battery packs 42. Since two sets of 48500-48800 lead-acid battery packs are typically used in the base station, two lead-acid interfaces are provided. The lithium battery interface 4132 is connected to the lithium battery pack 43. The lithium battery interface 4132 is configured according to the actual load current of the communication base station. The total current of the channels of the lithium battery interface 4132 is 1.5 times the load current. The current of a single lithium battery interface 4132 is in 50A increments. For example, if the base station load current is 50A, the number of lithium battery interfaces 4132 is two 50A interfaces; for example, if the base station load current is 100A, the number of lithium battery interfaces 4132 is three 50A interfaces. The lithium battery pack 43 has an embedded BMS management system that collects data such as battery, voltage, current, and capacity, and turns the MOS on or off according to the battery status. The operating voltage range of the lithium battery pack 43 is 44–56.5V.

[0038] The lead-acid interface 4131 and the lithium battery interface 4132 are independently configured, and each channel is independently controlled by the management unit 41. The management unit 414 communicates with the switching power supply interface 411, the voltage conversion circuit 412, the battery interface 413, and the BMS of the lithium battery pack via CAN, enabling information exchange such as voltage compensation function, battery voltage, current, temperature, input current, input / output voltage of a single channel, and channel open status. The management unit 414 interfaces with the switching power supply 20 via RS485 protocol, enabling information exchange between the switching power supply 20 and the intelligent control box 41. The switching power supply 20 transmits information such as the voltage and current of the mains power 10, load, and switching power supply output voltage to the intelligent control box 41, and the intelligent control box 41 also sends peak shaving and valley filling commands, charging and discharging strategies, and other strategies to each module. The management unit 414 independently sets the peak shaving and valley filling strategies, charging and discharging voltages, charging and discharging current coefficients, charging and discharging sequences, battery overvoltage, undervoltage, overcurrent, and overheating protection parameters for each channel. This allows for independent control of the battery charging and discharging channels, enabling battery packs of different usage levels, capacities, and brands to work together, and resolving issues such as circulating current, bias current, and voltage differences between batteries with different internal resistances.

[0039] The energy storage system described above, which is suitable for the use of both lead-acid and lithium batteries in communication base stations, is also applicable to secondary lithium batteries. Simply replace the lead-acid battery pack 42 with a secondary lithium battery and set it in the same location to achieve the same effect.

[0040] like Figure 3 As shown, the energy storage system suitable for using a combination of lead-acid and lithium batteries in communication base stations can also have an edge gateway 44 added between the switching power supply 20 and the intelligent control box 41. The edge gateway 44 interfaces with the switching power supply 20 and the intelligent control box 41 via the RS485 protocol to achieve information exchange. Through the edge gateway 44, the entire energy storage system can be controlled effectively, including issuing commands, modifying peak shaving and valley filling parameters, and uploading data.

[0041] like Figure 4 As shown, the energy storage system suitable for the mixed use of lead-acid and lithium batteries in communication base stations can also eliminate the lead-acid interface 4131, connecting the lead-acid battery pack 42 to the busbar of the switching power supply 20 and connecting it to the intelligent circuit breaker 45 for control. The circuit breaker 45 is in the normally open state, keeping the lead-acid battery pack 42 in a static state. The intelligent circuit breaker 45 interfaces with the intelligent control box 41 via RS485 protocol. When the mains power fails, the intelligent control box 41 instructs the intelligent circuit breaker 45 to open the switch, allowing the lead-acid battery pack 42 to discharge, thus providing power through the lead-acid battery when the mains power fails. The intelligent circuit breaker 45 has a time control function, opening the switch every half month to replenish the lead-acid battery; the specific time can be set according to actual needs.

[0042] This invention also provides a control method for an energy storage system that uses both lead-acid and lithium batteries in communication base stations, such as... Figure 5 As shown, it is powered by different power sources at different times according to local peak and valley periods, specifically including the following steps:

[0043] Step S1: The intelligent control box 41 sets a peak shaving and valley filling operation strategy according to the local peak and valley time periods. Peak electricity price periods correspond to peak shaving mode, valley electricity price periods correspond to valley filling mode, and flat electricity price periods correspond to standby mode. The intelligent control box 41 sets parameters such as output and input upper and lower limit voltages, single channel current limit value, and minimum operating channel. The output voltage of the switching power supply 20 is 53.5V and is in constant voltage output mode.

[0044] Step S2: The switching power supply 20 detects whether the mains power is normal and transmits the information to the smart control box 41. The smart control box 41 judges and starts the corresponding mode based on the time point and the received information.

[0045] Step S3.1: When the mains power is normal, and the intelligent control box 41 determines that the time is in peak shaving mode based on the time point, the intelligent control box 41 opens the output channel and the MOS of the lithium battery pack 43 is turned on, so that the lithium battery pack 43 discharges. The voltage conversion circuit 412 summarizes the current discharged by the multiple lithium battery packs 43 and raises the output voltage to 55V. Then, it is output to the switching power supply 20 in two paths. At this time, the output voltage of the lithium battery pack 43 is greater than the output voltage of the switching power supply 20, which is 53.5V. The switching power supply stops outputting, and the lithium battery pack 43 directly supplies power to the network load of the communication device 30.

[0046] Step S3.2: When the mains power is normal, and the smart control box 41 determines that the time is in valley filling mode and the lithium battery pack 45 is not fully charged, the smart control box 41 opens the input channel. At this time, the switching power supply 20 outputs in two ways: one to power the communication device and the other to charge the lithium battery pack 43. The voltage conversion circuit 412 summarizes the input current of the switching power supply and distributes it to each battery channel to charge the battery in each channel.

[0047] Step S3.3: When the mains power is normal, the smart control box 41 determines the time to be in standby mode based on the time point. The smart control box 41 closes the input or output channels, the lithium battery pack 43 does not work and is in a static state, and the switching power supply 20 only supplies power to the communication device 30.

[0048] Step S3.4: When the switching power supply 20 detects that the mains voltage is 0, the switching power supply 20 sends a mains power failure message to the smart control box 41. The smart control box 41 opens the output channel of the lead-acid battery pack 42, and the lead-acid battery pack 42 starts discharging to supply power to the communication device 30.

[0049] Step S3.5: Since the lead-acid battery pack 42 outputs power and the lead-acid battery pack 42 is depleted due to its own reasons, when the intelligent control box 41 detects that the voltage of the lead-acid battery pack 42 is lower than 50V and is not in the peak shaving mode period, the intelligent control box 41 opens the input channel of the lead-acid battery pack 42 to replenish the lead-acid battery pack 42.

[0050] In step S3.1 above, when the set peak shaving mode time expires or the intelligent control box 41 detects that the battery voltage is lower than the cutoff voltage, the intelligent control box 41 shuts down the output channel and sends a command to the switching power supply 20 to stop the lithium battery pack 43 from supplying power, and the switching power supply 20 resumes operation to supply power at a constant voltage of 53.5V.

[0051] In step S3.1 above, when the battery configuration capacity redundancy of the lithium battery pack 43 is large, the intelligent control box 21 can open the output channels in stages. When the battery voltage of a certain channel is lower than 50V, another output channel is opened, the battery pack starts to discharge and the low voltage channel is turned off.

[0052] In step S3.2 above, when the voltage of the lithium battery pack 43 is lower than 53.5V, the voltage changing circuit 412 does not change the voltage, but only shuns the current. When the voltage of the lithium battery pack 43 is higher than 53.5V, the voltage changing circuit 412 changes the voltage, raises the input voltage and shuns the input current to charge the battery.

[0053] In step S3.2 above, when a single lithium battery pack 43 is fully charged, the BMS turns off the charging MOS. At this time, the smart control box 41 notifies the switching power supply 20 to reduce the corresponding output current to avoid floating charging. When the switching power supply 20 detects that the load suddenly has a large current and exceeds the current limit point, the switching power supply notifies the smart control box to close the input channel and reduce the output of the switching power supply.

[0054] Compared with existing technologies, the energy storage system provided by this invention, suitable for the mixed use of lead-acid and lithium batteries in communication base stations, independently sets up two lead-acid interfaces 4131 for lead-acid battery charging and backup power during power outages. After a mains power failure, the system can quickly respond by opening the lead-acid battery pack to supply power to the network load, with a response speed of ≤10ms, thus achieving power supply after a mains power failure. The lead-acid interface 4131 and the lithium battery interface 4132 are set independently, and the management unit 414 independently sets the parameters of each channel and independently controls each channel, thereby enabling independent control of the battery charging and discharging channels. This allows battery packs with different usage levels, capacities, and brands to work together, and solves problems such as circulating current, bias current, and voltage difference between batteries with different internal resistances. Simultaneously, based on local peak and off-peak periods, different power sources are used at different times. The batteries are charged during the low load period of the base station's off-peak hours and discharged during the high load period of the base station's peak hours, making more rational use of electricity and improving overall working efficiency. The design is more reasonable.

[0055] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions or improvements within the spirit of the present invention are covered within the scope of the claims of the present invention.

Claims

1. A control method for an energy storage system that uses both lead-acid and lithium batteries in communication base stations, comprising the following steps: The energy storage system suitable for use with both lead-acid and lithium batteries in communication base stations includes mains power, a switching power supply connected to the mains power, a communication device connected to the switching power supply, and a mixed-use energy storage module for both new and old batteries connected to the switching power supply. The switching power supply is used to detect whether the mains power is normal and to convert the mains power. The mixed-use energy storage module includes a smart control box connected to the switching power supply, at least two lead-acid battery packs connected to the smart control box, and multiple lithium battery packs connected to the smart control box. The smart control box includes a switching power supply input connected to the switching power supply, a voltage conversion circuit connected to the switching power supply input, and a battery input connected to the voltage conversion circuit. The system includes a management unit that controls the smart control box. The voltage converted by the switching power supply is input into the voltage conversion circuit through the switching power supply input. The voltage conversion circuit is used for voltage isolation and conversion. The battery input has at least two lead-acid interfaces and multiple lithium battery interfaces. The two lead-acid interfaces are respectively connected to two lead-acid battery packs, and the lithium battery interfaces are connected to the lithium battery packs. The lead-acid interfaces and lithium battery interfaces are independently configured and independently controlled by the management unit. The lithium battery pack has an embedded BMS management system that collects battery data and turns the MOS off or on according to the battery status. The control method for the energy storage system suitable for communication base stations using a combination of lead-acid and lithium batteries includes the following steps: Step S1: The intelligent control box sets the peak shaving and valley filling operation strategy according to the local peak and valley time periods. Peak electricity price period corresponds to peak shaving mode, valley electricity price period corresponds to valley filling mode, and flat electricity price period corresponds to standby mode. The intelligent control box sets the upper and lower limit voltages of output and input, the current limit value of single channel, and the minimum working channel parameters. The output voltage of the switching power supply is 53.5V and is in constant voltage output mode. Step S2: The switching power supply detects whether the mains power is normal and transmits the information to the smart control box. The smart control box judges and activates the corresponding mode based on the time point and the received information. Step S3.1: When the mains power is normal, and the smart control box determines that the time is in peak shaving mode based on the time point, the smart control box opens the output channel and the MOS of the lithium battery pack is turned on, so that the lithium battery pack discharges. After the voltage conversion circuit sums up the current discharged by the multiple lithium battery packs, the output voltage is raised to 55V, and then output to the switching power supply in two ways. At this time, the output voltage of the lithium battery pack is greater than the output voltage of the switching power supply (53.5V), the switching power supply stops outputting, and the lithium battery pack directly supplies power to the network load of the communication device. Step S3.2: When the mains power is normal, and the smart control box determines that the time is in valley filling mode and the lithium battery pack is not fully charged, the smart control box opens the input channel. At this time, the switching power supply outputs in two ways: one to power the communication device and the other to charge the lithium battery pack. The voltage conversion circuit summarizes the input current of the switching power supply and distributes it to each battery channel to charge the battery in each channel. Step S3.3: When the mains power is normal, the smart control box determines the time to be in standby mode based on the time point, the smart control box closes the input or output channel, the lithium battery pack does not work and is in a static state, and the switching power supply only supplies power to the communication device; Step S3.4: When the switching power supply detects that the mains voltage is 0, the switching power supply sends a mains power failure message to the smart control box, the smart control box opens the output channel of the lead-acid battery pack, the lead-acid battery pack starts discharging, and supplies power to the communication device; Step S3.5: Since the lead-acid battery pack outputs power and the lead-acid battery pack is depleted due to its own reasons, when the smart control box detects that the voltage of the lead-acid battery pack is lower than 50V and is not in the peak shaving mode period, the smart control box opens the input channel of the lead-acid battery pack to replenish the lead-acid battery pack.

2. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: In step S3.1 above, when the set peak shaving mode time expires or the smart control box detects that the battery voltage is lower than the cutoff voltage, the smart control box shuts down the output channel and sends a command to the switching power supply to stop the lithium battery pack from supplying power, and the switching power supply resumes operation to supply power at a constant voltage of 53.5V.

3. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: In step S3.2 above, when the voltage of the lithium battery pack is lower than 53.5V, the voltage changing circuit does not change the voltage, but only shuns the current. When the voltage of the lithium battery pack is higher than 53.5V, the voltage changing circuit changes the voltage, raises the input voltage, and then shuns the input current to charge the battery.

4. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: In step S3.2 above, when a single lithium battery pack is fully charged, the BMS turns off the charging MOS. At this time, the smart control box notifies the switching power supply to reduce the corresponding output current to avoid floating charging. When the switching power supply detects that the load suddenly has a large current and exceeds the current limit point, the switching power supply notifies the smart control box to close the input channel and reduce the output of the switching power supply.

5. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: The switching power supply input is connected to the switching power supply via two routes, one of which is the main route and the other is a backup route.

6. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: The voltage conversion circuit consists of a bidirectional DC-DC module. When the battery pack needs to be charged, it increases the voltage input from the switching power supply to a level higher than the battery pack voltage and divides the total current into multiple paths flowing to the battery pack. When the battery pack is discharging, it raises the battery pack voltage to a level higher than the output voltage of the switching power supply and combines the battery pack current into two paths flowing back to the switching power supply. The voltage conversion circuit also consists of a unidirectional DC-DC module, which does not perform voltage transformation during charging but does perform voltage transformation during discharging.

7. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: The lead-acid interface has a current of 150A, the total channel current of the lithium battery interface is 1.5 times the load current, the current of a single lithium battery interface is 50A, and the operating voltage range of the lithium battery pack is 44 to 56.5V.

8. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: The energy storage system suitable for communication base stations using a combination of lead-acid and lithium batteries adds an edge gateway between the switching power supply and the smart control box. The edge gateway interfaces with the switching power supply and the smart control box via the RS485 protocol, and issues commands to the entire energy storage system through the edge gateway.

9. The control method for an energy storage system using both lead-acid and lithium batteries in a communication base station as described in claim 1, characterized in that: The energy storage system suitable for communication base stations using a combination of lead-acid and lithium batteries eliminates the lead-acid interface, connects the lead-acid battery pack to the busbar of the switching power supply, and connects to a smart circuit breaker for control. The smart circuit breaker interfaces with the smart control box via RS485 protocol. When the mains power fails, the smart control box instructs the smart circuit breaker to open the switch, allowing the lead-acid battery pack to discharge.

Images