CN207117203U - A kind of lithium-ion energy storage unit and unit group - Google Patents

Abstract

The utility model relates to a lithium ion energy storage unit and a unit group. By setting a battery management system, a battery group and a charging circuit correspondingly connected to the energy storage unit, the integration of battery charging and management is realized. The storage unit of the utility model The connection line of the energy unit is short, the structure is simple, and it is easy to implement, which effectively solves the problem that the existing lithium-ion battery peripheral charger and BMS cause the connection line to easily fail.

Description

A lithium ion energy storage unit and unit group

technical field

The utility model belongs to the technical field of backup power supply energy storage, in particular to a lithium ion energy storage unit and a unit group.

Background technique

Traditional UPS (uninterruptible power supply) systems generally use lead-acid batteries as backup energy storage units, but with the same capacity battery packs, lead-acid batteries have the disadvantages of large size, heavy weight, and a large footprint. As a substitute for lead-acid batteries , due to its small size and high energy density, lithium batteries have great economic and social value in today's increasingly tight space. In particular, the ternary lithium-ion battery of Boston Company has a high energy density, which can reach 207Wh/kg; it has a wide temperature range, and can be charged within the range of -20°C to 60°C, and can be charged at -40°C Discharge in the range of ~70°C; it has a high service life, the cycle life of 100% DOD (100% discharge) is not less than 1000 times, the cycle life of 90% DOD is not less than 2000 times, and the cycle life of 80% DOD is not less than 3000 times Second-rate.

Unlike lead-acid batteries that are directly connected in series to form battery packs of different voltage levels, ternary batteries need to be assembled in groups before they can be used. Moreover, since lithium batteries cannot be floated for a long time, it is generally necessary to configure a battery management system (BMS) externally. Control the charger to ensure that the battery is not overcharged.

In daily maintenance, in order to test and maintain the charge and discharge of each battery pack, a charger must be installed outside the battery, coupled with the battery management system also located outside the battery, making the external wiring of the lithium-ion battery much and complicated. , prone to line faults, inconvenient to use and later maintenance; and, in the prior art, only one charger completes the charging of all the single cells in the battery pack, which will lead to unbalanced charging of the single cells, which is not conducive to battery life. service life. Therefore, how to reasonably design a set of energy storage units with high energy density, complete functions, and ease of use and maintenance has become a major problem facing the use and promotion of ternary lithium-ion batteries.

Utility model content

The purpose of the utility model is to provide a lithium-ion energy storage unit and a unit group, which are used to solve the problem that the existing lithium-ion battery peripheral charger and BMS cause the connection line to easily fail.

In order to solve the above technical problems, the utility model proposes a lithium ion energy storage unit, including five unit solutions:

Unit scheme 1, the energy storage unit includes a battery pack formed by more than two lithium-ion single cells connected in series, a battery management system, and more than one charging circuit; the battery management system is connected to the battery pack by sampling, and the battery The management system also includes a communication interface for connecting to an upper computer; the output end of the charging circuit is connected to a corresponding number of lithium-ion single batteries, and the input end of the charging circuit is used for connecting to a charging power source.

Unit solution two, on the basis of unit solution one, the charging circuit is a rectifying circuit, and the charging power supply is an AC power supply.

Unit solution three, on the basis of unit solution one, the charging circuit is a DC conversion circuit, and the charging power supply is a DC power supply.

Unit scheme four, on the basis of unit scheme one, the communication interface is a CAN interface.

Unit solution five, on the basis of unit solution one, the battery management system includes a power interface for external low-voltage DC power supply.

In order to solve the above technical problems, the utility model proposes a lithium ion energy storage unit group, including five unit group solutions:

Unit group scheme 1 includes more than two series-parallel energy storage units, each energy storage unit includes a battery pack formed by more than two lithium-ion single cells connected in series, and also includes a battery management system and more than one charging circuit; The battery management system is sampled and connected to the battery pack, and the battery management system also includes a communication interface for connecting to the host computer; the output end of the charging circuit is connected to a corresponding number of single batteries, and the input end of the charging circuit is used to connect to the charging unit. power supply.

In the unit group solution 2, on the basis of the unit group solution 1, the charging circuit is a rectifying circuit, and the charging power source is an AC power supply.

In the unit group scheme three, on the basis of the unit group scheme one, the charging circuit is a DC conversion circuit, and the charging power supply is a DC power supply.

Unit group plan four, on the basis of unit group plan one, the communication interface is a CAN interface.

Unit group solution five, on the basis of unit group solution one, the battery management system includes a power interface for external low-voltage DC power supply.

The beneficial effects of the utility model are: by setting a battery management system, a battery pack and a charging circuit correspondingly connected to the energy storage unit, the integration of battery charging and management is realized. The connection circuit of the energy storage unit of the utility model is short and the structure It is simple and easy to implement, and effectively solves the problem that the existing lithium-ion battery peripheral charger and BMS cause the connection line to easily fail.

Description of drawings

Fig. 1 is a schematic diagram of a lithium ion energy storage unit group;

2 is a schematic diagram of a lithium ion energy storage unit;

Fig. 3 is a logic control diagram of the energy storage unit charging circuit program;

Fig. 4 is a program logic control diagram of the energy storage unit battery management system.

Detailed ways

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described further.

An embodiment of a lithium ion energy storage unit group of the present utility model:

The energy storage unit group includes energy storage units that are connected in series first and then in parallel, wherein each series branch includes at least two energy storage units, and each energy storage unit includes a battery pack formed by more than two lithium-ion single cells in series. Management system and more than one charging circuit; the battery management system is connected to the battery pack for sampling, and the battery management system also includes a communication interface for connecting to the upper computer; the output end of the charging circuit is connected to the corresponding number of single batteries, and the input end of the charging circuit Used to connect to a charging power source.

As shown in Figure 1, it is a 116.8V/265Ah energy storage unit group composed of 10 energy storage units connected in series and parallel. Since the electrical parameters of each battery group are 58.4V/53Ah, in order to meet the DC110V DC power supply system, two The energy storage units are first connected in series to meet the needs of the system voltage level; every two energy storage units are connected in series and then in parallel to ensure battery charging balance and meet the requirements of discharge current and backup working time, which is conducive to improving the reliability of the system. If a battery pack fails or a branch circuit fails, the other branches can still work normally, and the entire system powered by it can still output reliably without power failure. It is especially suitable for the backup energy storage system of the UPS system.

A lithium ion energy storage unit as shown in FIG. 2 includes a battery management system, which is provided with a CAN interface for connecting to a host computer, and is connected to a battery pack, a first charging circuit, and a second charging circuit through a CAN bus. Among them, the battery management system is powered by 24V DC, and is connected to the 24V DC source through the power interface; the battery pack is composed of 10 and 16 series of single batteries, and the positive pole of the battery pack is equipped with an anti-reverse diode, which allows the battery pack to be connected in series and parallel. Avoid discharge between battery packs and meet the design requirements of DC busbars with different voltage levels of DC48V, DC110V, and DC220V; the negative pole is equipped with a Hall current sensor to detect the total output current of the battery pack to calculate the SOC of the energy storage unit. Provide reference for users.

The above-mentioned single batteries are divided into the first 8 series and the last 8 series. The first charging circuit charges the first 8 series of single batteries, and the second charging circuit charges the last 8 series of single batteries. The single battery is a Boston ternary battery with a high volumetric energy density. The volumetric energy density is as high as 490Wh/L, and the electrical parameters of a single battery pack are 58.4V/53Ah.

Both the first charging circuit and the second charging circuit are rectifying circuits powered by a 220V AC source. The above rectifying circuit includes an AC/DC unit and a DC/DC unit; among them, the AC/DC unit adopts VICOR’s FE175D480TD033FP with a high power unit -00 module, the AC input voltage is between AC85V~264V, and the output is stable DC48V direct current; the DC/DC unit adopts a double-tube BUCK-BOOST circuit to convert the input DC48V into a voltage range of DC22V~DC33.6V direct current.

As another embodiment, the first charging circuit and the second charging circuit are DC conversion circuits, which are directly powered by a DC source, that is, the DC conversion circuit uses a double-tube BUCK-BOOST circuit to convert the input DC source to the required DC power.

The external interface of the energy storage unit is divided into a main circuit interface and a control circuit interface. The main circuit interface is the positive interface and the negative interface of the energy storage unit, which are single-pin interfaces. The control circuit interface is used by the battery management system to control the battery pack and charging circuit. The interface is an 8-pin interface, and the interfaces are all aviation plugs. It has the characteristics of reliable connection, convenient use, and has the function of preventing wrong insertion. The 6 pins of the 8-pin interface of the control circuit are the charging circuit input power L terminal, the charging circuit input power N terminal, the communication terminal CANH, the communication terminal CANL, the auxiliary power supply 24V+, and the auxiliary power supply 24V-.

As long as the energy storage unit is connected to 220V AC power supply and 24V DC power supply, it can be charged automatically without other external charging and testing equipment. Its working principle is as follows:

The output voltage of the first charging circuit and the second charging circuit is set to 32V, the charging current limit value is set to 8A, and the protection value of the single battery overcharge protection voltage is 4.2V. The battery management system controls the first charging circuit to charge the first 8 strings of single batteries, and controls the second charging circuit to charge the last 8 strings of single batteries. When the voltage of one of the single batteries reaches the first set value, the battery management system The system controls the corresponding charging circuit to stop charging the single battery through the CAN bus.

The built-in battery management system can collect the voltage of the single battery, the temperature of the battery pack, the discharge current of the battery pack, the charging current of the battery pack, the voltage of the battery pack, etc. in real time. When the voltage of a single battery reaches the first set value, such as 4.2V, the charging circuit for charging the single battery will stop charging under the control of the battery management system to ensure that the battery is not overcharged and effectively prolong the battery life. The service life of the battery is extended, while the charging process of other charging circuits is not affected, and it has a significant effect on improving the consistency of the voltage of the single cells in the battery pack.

At the same time, the battery management system can calculate based on the collected data of the voltage of the single cell, determine the highest battery voltage and the lowest battery voltage in the battery pack and display the serial number of the corresponding battery, and estimate the current battery capacity and SOC. The battery management system also has an alarm function, which can upload alarm information such as single battery overvoltage, single battery undervoltage, battery pack overtemperature, and battery pack capacity low through CAN communication.

In this embodiment, as long as a single battery pack in a single energy storage unit is connected to 220V AC and 24V auxiliary DC, automatic charging can be realized, which is convenient for separate maintenance and does not need to be connected to other charging circuits.

Claims (10)

1. a kind of lithium-ion energy storage unit, include the battery pack of the lithium ion single battery formation of two or more series connection, its feature It is, battery management system and more than two charging circuits is set inside the lithium-ion energy storage unit；The battery management Systematic sampling connects the battery pack, and the battery management system also includes being used for the communication interface for connecting host computer；Each charging The lithium ion single battery of the corresponding number of output end connection of circuit, the input of charging circuit are used to connect charge power supply, respectively The lithium ion single battery sum of the corresponding number of the output end connection of charging circuit is equal to lithium ion in lithium-ion energy storage unit The total number of cell.

2. lithium-ion energy storage unit according to claim 1, it is characterised in that the charging circuit is rectification circuit, institute It is AC power to state charge power supply.

3. lithium-ion energy storage unit according to claim 1, it is characterised in that the charging circuit is DC converting electricity Road, the charge power supply are dc source.

4. lithium-ion energy storage unit according to claim 1, it is characterised in that the communication interface is CAN interface.

5. lithium-ion energy storage unit according to claim 1, it is characterised in that the battery management system is included for outer Connect the power interface of low-voltage dc power supply.

6. a kind of lithium-ion energy storage unit group, including the series-parallel energy-storage units of two or more, each energy-storage units include two The battery pack that the lithium ion single battery of series connection is formed above, it is characterised in that set inside the lithium-ion energy storage unit electric Pond management system and more than two charging circuits；The battery management system sampling connects the battery pack, the cell tube Reason system also includes being used for the communication interface for connecting host computer；The monomer electricity of the corresponding number of output end connection of each charging circuit Pond, the input of charging circuit are used to connect charge power supply, the lithium ion of the corresponding number of the output end connection of each charging circuit Cell sum is equal to the total number of lithium ion single battery in lithium-ion energy storage unit.

7. lithium-ion energy storage unit group according to claim 6, it is characterised in that the charging circuit is rectification circuit, The charge power supply is AC power.

8. lithium-ion energy storage unit group according to claim 6, it is characterised in that the charging circuit is DC converting electricity Road, the charge power supply are dc source.

9. lithium-ion energy storage unit group according to claim 6, it is characterised in that the communication interface is CAN interface.

10. lithium-ion energy storage unit group according to claim 6, it is characterised in that the battery management system includes using In the power interface of external low-voltage dc power supply.