CN221448109U - Lithium titanate battery charging and discharging device for direct-current power supply of transformer substation - Google Patents

Abstract

The utility model discloses a lithium titanate battery charging and discharging device for a transformer substation direct-current power supply, which comprises a battery pack connected with a direct-current bus of the transformer substation direct-current power supply; the battery pack comprises a plurality of lithium titanate batteries; each lithium titanate battery is connected with a battery working state acquisition port of the BMS module; the BMS module collects corresponding SOC value and voltage data of the lithium titanate battery through each battery working state collection port, and sends the collected data to the direct current monitor; a control circuit is arranged between the positive electrode of the battery pack and the positive electrode of the direct current bus, and the negative electrode is connected with the negative electrode of the direct current bus; the control circuit comprises a bypass switch, a contactor and a diode which are connected in parallel; the bypass switch is a normally open switch; the charging and discharging control port of the BMS module is connected with the contactor; the bypass control port of the BMS module is connected with the bypass switch. The utility model solves the problem that each lithium titanate battery in the battery pack is inconsistent under long-term float charge cycle.

Description

Lithium titanate battery charging and discharging device for DC power supply in substations

Technical Field

The utility model relates to the technical field of charging and discharging direct current power supply of a transformer substation, in particular to a lithium titanate battery charging and discharging device used for the direct current power supply of the transformer substation.

Background technique

In the existing substation DC power supply system, the batteries and other components commonly used contain heavy metals inside and are prone to soil environmental pollution. Therefore, their service life is short (usually need to be replaced every 7 to 8 years) and the operating temperature range is small.

Lithium titanate batteries developed in recent years have solved the safety issues of traditional lithium batteries. Due to their large input and output power, wide operating temperature range, maintenance-free, ultra-long life, and green environmental protection, they are gradually becoming the protagonist of secondary batteries and have been widely used in the fields of energy storage and electric vehicles.

However, to realize the application of lithium titanate batteries in the DC power supply system of substations, the following problems need to be solved:

1. The system voltage of the DC system of the substation is 110V or 220V. The higher the voltage level of the substation, the greater the battery capacity requirement. For substations with a voltage level of 220kV or above, if 110V voltage is used, the battery capacity is generally greater than 1200AH. However, due to process limitations, the capacity of a single lithium titanate battery is relatively small, and it is impossible to obtain a large-capacity battery pack by simply connecting in series like traditional batteries.

2. The DC system of the substation adopts floating charging to keep the battery in standby state at full capacity. However, under the long-term floating charging cycle of lithium titanate batteries, the inconsistency of each monomer in the battery pack due to the differences in battery production process, connection method and use conditions will become more and more significant, thus causing the floating charging failure of the battery.

Therefore, how to combine lithium titanate batteries to obtain a large-capacity battery pack and solve the inconsistency problem caused by different battery production processes, connection methods and usage conditions in the DC power supply system of the substation during long-term floating charge cycles has become a technical problem that technical personnel in this field urgently need to solve.

Utility Model Content

In view of the above-mentioned defects of the prior art, the utility model provides a lithium titanate battery charging and discharging device for a substation DC power supply, the purpose of which is to solve the inconsistency problem caused by the differences in battery production processes, connection methods and usage conditions among the lithium titanate batteries in the battery pack during long-term floating charge cycles in the substation DC power supply system.

To achieve the above object, the utility model discloses a lithium titanate battery charging and discharging device for a substation DC power supply, comprising a battery pack connected to a DC busbar of the substation DC power supply.

Wherein, the battery pack includes a plurality of lithium titanate batteries;

Each of the lithium titanate batteries is connected to a battery working status collection port of a BMS module;

The BMS module collects the SOC value and voltage data of the corresponding lithium titanate battery through each battery working status collection port, and sends the collected data to the DC monitor;

A control circuit is provided between the positive electrode of the battery pack and the positive electrode of the DC bus, and the negative electrode is connected to the negative electrode of the DC bus;

The control circuit includes a bypass switch, a contactor and a diode connected in parallel;

The bypass switch is a normally open switch;

The charge and discharge control port of the BMS module is connected to the contactor;

The bypass control port of the BMS module is connected to the bypass switch;

When the battery pack is discharged, the diode conducts the positive electrode of the battery pack and the positive electrode of the DC bus.

Preferably, a plurality of the lithium titanate batteries are connected in series to form a lithium titanate battery string;

A plurality of the lithium titanate batteries are connected in series and in parallel to form a lithium titanate battery module;

A plurality of the lithium titanate battery modules are connected in series to form the lithium titanate battery cluster;

A plurality of the lithium titanate battery clusters are connected in parallel to form a battery pack.

More preferably, 9 or 12 lithium titanate batteries are connected in series to form one lithium titanate battery string;

Three of the lithium titanate batteries are connected in series and in parallel to form a lithium titanate battery module;

Four of the lithium titanate battery modules are connected in series to form a lithium titanate battery cluster.

Preferably, a double switch is provided between the control circuit and the positive pole of the DC bus, and between the negative pole of the battery pack and the negative pole of the DC bus.

Beneficial effects of the utility model:

The application of the utility model can solve the inconsistency problem caused by different battery production processes, connection methods and use conditions of each monomer in the battery pack under long-term floating charge cycle, so that lithium titanate can be applied to DC power supply of substations.

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a conventional battery pack.

FIG2 is a schematic structural diagram of a charging and discharging device according to an embodiment of the present invention.

FIG3 shows a flow chart of intermittent charging in an embodiment of the present invention.

FIG. 4 shows a schematic structural diagram of a lithium titanate battery module formed by connecting 9 lithium titanate batteries in series in parallel in one embodiment of the present invention.

FIG5 shows a schematic structural diagram of a lithium titanate battery module formed by connecting 12 lithium titanate batteries in series in parallel in one embodiment of the present invention.

FIG6 is a schematic diagram showing the structure of a lithium titanate battery cluster in an embodiment of the present invention.

FIG. 7 is a schematic diagram showing the structure of a battery pack in an embodiment of the present invention.

Detailed ways

Example

As shown in FIG2 , a lithium titanate battery charging and discharging device for a DC power supply of a substation includes a battery pack connected to a DC bus 8 of the DC power supply of the substation.

Wherein, the battery pack includes a plurality of lithium titanate batteries 1;

Each lithium titanate battery 1 is connected to the battery working status acquisition port 61 of the BMS module 6;

The BMS module 6 collects the SOC value and voltage data of the corresponding lithium titanate battery 1 through each battery working status collection port 61, and sends the collected data to the DC monitor 7;

A control circuit is provided between the positive electrode of the battery pack and the positive electrode of the DC bus 8, and the negative electrode is connected to the negative electrode of the DC bus 8;

The control circuit includes a bypass switch 3, a contactor 4 and a diode 5 connected in parallel;

Bypass switch 3 is a normally open switch;

The charge and discharge control port 62 of the BMS module 6 is connected to the contactor 4;

The bypass control port 63 of the BMS module 6 is connected to the bypass switch 3;

When the battery pack is discharged, the diode 5 connects the positive electrode of the battery pack and the positive electrode of the DC bus 8 .

The BMS module 6, namely BMS, is the abbreviation of Battery Management System in English. Its function is to exchange information with the DC monitor 7 in real time on various battery parameters such as voltage, current, temperature, capacity, battery SOC state of charge measurement, and battery insulation state of the lithium titanate battery 1 in the form of CAN communication, so as to ensure that the energy of the battery is fully utilized and enable the user to grasp the working status of the battery at any time to ensure the safety of the battery.

In practical applications, since the lithium titanate battery 1 is not suitable for long-term floating charge, the BMS module 6 is used to monitor each lithium titanate battery 1, and combined with the DC monitor 7 to implement intermittent charging management. The intermittent charging management can adjust the time proportion of intermittent floating charge to charge the battery according to the battery voltage, current, internal resistance, temperature, SOC and other parameters monitored by the BMS module 6 without affecting the seamless power supply of the load, so that the battery is always in a good condition.

As shown in Figure 2, the working principle of intermittent charging management is as follows:

1. Usually, the bypass switch 3 is in the off state, and the contactor 4 is also in the off state. Since the reverse diode 5 is forward-conducting, the DC bus 8 cannot charge the lithium titanate battery 1. At this time, the lithium titanate battery 1 is in the discharge state to the DC bus 8.

2. The BMS module 6 calculates the battery SOC of each lithium titanate battery 1 in real time and uploads it to the DC monitor 7.

The DC monitor 7 determines whether charging is required based on parameters such as the SOC value and the battery voltage. If charging is required, the DC monitor 7 sends a control command to close the contactor 4 to the BMS module 6. The BMS module 6 controls the contactor 4 to close, and the DC bus 8 charges the lithium titanate battery 1.

3. When the DC bus 8 charges the lithium titanate battery 1 to a certain level, the BMS module 6 still calculates the battery SOC of each lithium titanate battery 1 in real time and uploads it to the DC monitor 7.

The DC monitor 7 determines whether to stop charging based on parameters such as the SOC value and the battery voltage to prevent the lithium titanate battery 1 from being overcharged, and then sends a contactor opening control command to the BMS module 6. The BMS module 6 controls the contactor 4 to open, and the lithium titanate battery 1 discharges to the DC bus 8, thereby not affecting the reliability of the DC system.

The utility model collects the SOC value and voltage data of the multiple lithium titanate batteries 1 of each unit through the BMS module 6, so that the user can grasp the working status of the battery at any time to ensure the safety of the battery. At the same time, the SOC value and voltage data of the multiple lithium titanate batteries 1 of each unit are monitored through the DC monitor 7. At the same time, the contactor 4 is controlled by the BMS module 6 to control charging and discharging. The BMS module 6 and the DC monitor 7 are used to implement the intermittent charging technology and overcharge protection of the lithium titanate battery 1 to ensure that each lithium titanate battery 1 can play the maximum efficiency, and solve the inconsistency problem caused by the different battery production processes, connection methods and usage conditions of each monomer in the battery pack under long-term floating charge cycles.

In some embodiments, a plurality of lithium titanate batteries 1 are connected in series to form a lithium titanate battery string;

Multiple lithium titanate batteries are connected in series and parallel to form a lithium titanate battery module;

Multiple lithium titanate battery modules are connected in series to form a lithium titanate battery cluster;

Multiple lithium titanate battery clusters are connected in parallel to form a battery pack.

In some embodiments, 9 or 12 lithium titanate batteries 1 are connected in series to form a lithium titanate battery string;

Three lithium titanate batteries are connected in series and parallel to form a lithium titanate battery module;

Four lithium titanate battery modules are connected in series to form a lithium titanate battery cluster.

In some embodiments, a double switch 2 is provided between the control circuit and the positive pole of the DC bus 8 , and between the negative pole of the battery pack and the negative pole of the DC bus 8 .

As shown in Figures 4 and 5, for the substation DC power supply system with a large battery pack capacity requirement, a typical module combination of lithium titanate batteries is used. The typical modules of lithium titanate batteries are shown in the following table.

As shown in FIG6 , multiple lithium titanate battery modules are connected in series to form a lithium titanate battery cluster after reaching the DC voltage (110V or 220V) required by the DC power supply system of the substation.

As shown in FIG7 , multiple sets of lithium titanate battery clusters are connected in parallel to achieve the capacity required by the DC power supply system, thus forming a complete lithium titanate battery pack that can be used in the DC power supply system of a substation.

Typical solutions for lithium titanate battery pack battery module combination are as follows:

The above describes in detail the preferred specific embodiments of the utility model. It should be understood that ordinary technicians in this field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, all technical solutions that can be obtained by technicians in this technical field based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims (4)

1. A lithium titanate battery charging and discharging device for a DC power supply of a substation, comprising a battery pack connected to a DC busbar (8) of the DC power supply of the substation; characterized in that: The battery pack comprises a plurality of lithium titanate batteries (1); Each of the lithium titanate batteries (1) is connected to a battery operating status collection port (61) of a BMS module (6); The BMS module (6) collects the SOC value and voltage data of the corresponding lithium titanate battery (1) through each of the battery working status collection ports (61), and sends the collected data to the DC monitor (7); A control circuit is provided between the positive electrode of the battery pack and the positive electrode of the DC bus (8), and the negative electrode is connected to the negative electrode of the DC bus (8); The control circuit comprises a bypass switch (3), a contactor (4) and a diode (5) connected in parallel; The bypass switch (3) is a normally open switch; The charge and discharge control port (62) of the BMS module (6) is connected to the contactor (4); The bypass control port (63) of the BMS module (6) is connected to the bypass switch (3); When the battery pack is discharged, the diode (5) causes the positive electrode of the battery pack and the positive electrode of the DC bus (8) to be conductive. 2. The lithium titanate battery charging and discharging device for a substation DC power supply according to claim 1, characterized in that a plurality of the lithium titanate batteries (1) are connected in series to form a lithium titanate battery string; A plurality of the lithium titanate batteries are connected in series and in parallel to form a lithium titanate battery module; A plurality of the lithium titanate battery modules are connected in series to form the lithium titanate battery cluster; A plurality of the lithium titanate battery clusters are connected in parallel to form a battery pack. 3. The lithium titanate battery charging and discharging device for a DC power supply for a substation according to claim 2, characterized in that 9 or 12 lithium titanate batteries (1) are connected in series to form one lithium titanate battery string; Three of the lithium titanate batteries are connected in series and in parallel to form a lithium titanate battery module; Four of the lithium titanate battery modules are connected in series to form a lithium titanate battery cluster. 4. The lithium titanate battery charging and discharging device for a substation DC power supply according to claim 1 is characterized in that a double switch (2) is provided between the control circuit and the positive pole of the DC bus (8), and between the negative pole of the battery pack and the negative pole of the DC bus (8).