A storage-type multi-string lithium battery pack

Abstract

The present invention relates to a storage multi-string lithium battery pack, which includes a main lithium battery pack unit and a plurality of secondary lithium battery pack units. The main lithium battery pack unit is provided with a main lithium battery pack, a protection board, a plurality of groups of acquisition line groups, a positive current connection line, a negative current connection line and an acquisition line connection board. The acquisition line connection board is provided with a plurality of acquisition line connection ports, and each acquisition line connection port can be plugged with an acquisition line group. The plurality of groups of acquisition line groups are respectively connected to the main lithium battery pack, the protection board and the secondary lithium battery pack units. The main lithium battery pack and the protection board are also connected through the negative current connection line. A negative current connection terminal is also provided. The protection board is provided with a negative current output terminal. The main lithium battery pack is connected with a positive current connection line, and the front end of the positive current connection line is provided with a positive current connection terminal and a positive current output terminal. A sudden pressure difference detection and protection circuit is arranged in the secondary lithium battery unit. The present invention provides convenient configuration and reduces product specifications for different capacity energy storage product requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of storage batteries, and particularly to an energy storage multi-string lithium battery pack. Background Art

[0002] Currently, lithium battery packs are generally used as the core energy carriers in energy storage battery systems, and their series-parallel structure design directly affects energy density, safety, and system life. In the mainstream technical solutions, battery modules achieve cell integration through mechanical bundling or fixed brackets. For example, end plates, bottom plates, and CCS components are used for stack fixing and electrical connection. However, the existing technologies have the following limitations:

[0003] 1. Insufficient management of cell consistency: During the long-term charge and discharge process of multi-string lithium battery packs, due to the difference in internal resistance of cells, circulating current problems are likely to occur, resulting in a significant barrel effect and accelerating capacity decay;

[0004] 2. Difficulties in expansion and maintenance: The centralized energy storage system adopts a parallel architecture on the DC side. To expand the capacity, it is necessary to redesigned the layout of the battery cluster, and the compatibility of mixing new and old batteries is poor.

[0005] In the prior art such as Figure 1 , 2 shown, it can be multi-string and multi-parallel (generally within 4 strings or 4 parallel), but it has high production costs, small capacity, poor reliability, and few applications;

[0006] In the prior art such as Figure 3 shown, it is applied to commercial energy storage with large capacity and high voltage, has a single configuration, is difficult to dissipate heat, and does not allow additional stacking;

[0007] Therefore, it is very necessary to solve the above technical problems. Summary of the Invention

[0008] To overcome the above technical problems, the present invention provides an energy storage multi-string lithium battery pack, and provides a method that can be used in multiple groups in parallel, which can reduce the weight of each unit, bring convenience to production, transportation, and installation, provide appropriate selection for different capacity energy storage product requirements, can reduce the specifications of energy storage power products, and when a certain string of cells fails during use, it is easy to find and the repair is simple, bringing convenience to later maintenance.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] An energy storage type multi-string lithium battery pack includes a main lithium battery pack unit and several secondary lithium battery pack units. The main lithium battery pack unit is provided with a main lithium battery pack, a protection board, several groups of acquisition line groups, a positive current connection line, a negative current connection line, and an acquisition line connection board. The acquisition line connection board is provided with several acquisition line connection ports, and each acquisition line connection port can be plugged with a group of acquisition line groups. The several groups of acquisition line groups are respectively connected to the main lithium battery pack, the protection board, and the secondary lithium battery pack units through the acquisition line connection board. The main lithium battery pack and the protection board are also connected through the negative current connection line. The protection board is provided with a negative current output terminal, and the main lithium battery pack is also connected with a positive current connection line, and the front end of the positive current connection line is provided with a positive current output terminal.

[0011] Furthermore, the positive current output terminal and the negative current output terminal are also charging and discharging terminals at the same time. A positive current connection terminal is also provided between the main lithium battery pack and the positive current output terminal on the positive current connection line, and a negative current connection terminal is also provided between the main lithium battery pack and the protection board on the negative current connection line.

[0012] Furthermore, the secondary lithium battery pack unit is provided with a secondary lithium battery pack. The secondary lithium battery pack is connected with a secondary positive current connection line, a normally closed contact JK of a relay, a secondary negative current connection line, and several parallel secondary lithium battery pack unit burst voltage difference detection circuits. Each secondary lithium battery pack unit burst voltage difference detection circuit is connected to a secondary acquisition line. All the secondary acquisition lines and the secondary negative current connection line are close to the 0-potential line led out from the B- end of the lithium battery, and form a group of secondary acquisition lines.

[0013] Furthermore, the secondary lithium battery pack unit burst voltage difference detection circuit is composed of a self-resetting fuse, a diode in an optocoupler, and a current-limiting resistor. The current-limiting resistor is in series with the diode in the optocoupler and is jointly in parallel with the self-resetting fuse. The secondary lithium battery pack unit burst voltage difference detection circuit is optically connected to a triode in the optocoupler that is in parallel with the secondary positive current connection line through the diode in the optocoupler, and the triode in the optocoupler is also connected with a protection circuit.

[0014] Furthermore, the triode in the optocoupler is connected to the secondary negative current connection line through resistors R5 and R6 connected in series in the protection circuit, and resistor R6 is in parallel with a zener diode D1 and the gate of a MOS transistor T1.

[0015] Furthermore, an alarm B, a diode D2, and a relay J are connected in parallel in the protection circuit. One end of the alarm B, the diode D, and the relay J is connected to the secondary positive current connection line, and the other end is connected in series with the drain of the MOS transistor T1. The source of the MOS transistor T1 is connected to the secondary negative current connection line. The relay J is provided with a relay normally closed contact JK. One end of the relay normally closed contact JK is connected to the secondary positive current connection line, and the other end is the secondary positive current output terminal B+ of the secondary lithium battery pack unit, which is then connected to the positive current connection terminal of the main lithium battery pack unit. The secondary negative current output terminal B- of the secondary negative current connection line is connected to the negative current connection terminal of the main lithium battery pack unit. The secondary collection line group is connected to the collection line connection port in the collection line connection board of the main lithium battery pack unit.

[0016] The current circuit diagram describes a 4-series lithium battery pack as an example, with 5 collection lines in a group. Similarly, it can also be used for 8-series, 16-series, or even higher-series lithium battery packs. For an 8-series lithium battery pack, there are 9 collection lines in a group, and for a 16-series lithium battery pack, there are 17 collection lines in a group. The 8-series lithium battery pack is about 25V, and the 16-series lithium battery pack is about 50V. The number of secondary lithium battery pack units should not be greater than 4 groups. It can also be 1 group, or the main lithium battery pack unit can be used alone.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The present invention can be applied to home energy storage, electric tricycles, and small cars. As long as the number of series and voltage are the same, they can be used in parallel, providing convenience for configuring different-capacity energy storage product requirements, reducing the specifications of energy storage power products, and thus laying a foundation for the standardization, scale, and intensification of energy storage products. Description of the Drawings

[0019] Figure 1 It is a schematic circuit structure diagram of the prior art.

[0020] Figure 2 It is a schematic circuit structure diagram of the prior art.

[0021] Figure 3 It is a schematic circuit structure diagram of the prior art with large capacity and high voltage.

[0022] Figure 4 It is a schematic circuit structure diagram of the present invention.

[0023] Figure 5 It is a schematic circuit structure diagram of the main lithium battery pack unit in the present invention.

[0024] Figure 6 It is a schematic circuit structure diagram of the secondary lithium battery pack unit in the present invention.

[0025] In the figure: 1 main lithium battery pack unit, 2 secondary lithium battery pack units, 5 positive current connection line, 6 negative current connection line, 11 main lithium battery pack, 12 protection board, 13 acquisition line group, 18 acquisition line connection board, 19 acquisition line connection port, 21 secondary lithium battery pack, 22 secondary positive current connection line, 23 secondary negative current connection line, 24 sudden voltage difference detection circuit for secondary lithium battery pack unit, 25 diode, 26 triode, 27 secondary acquisition line, 28 secondary acquisition line group, 51 positive current output terminal, 52 positive current connection terminal, 61 negative current output terminal, 62 negative current connection terminal, HF1 - HF4 are all self - reset fuses, R1 - R4 are all current - limiting resistors, G1 - G4 are all optocouplers, U1 - U4 are all acquisition lines or secondary acquisition lines. Detailed implementation mode

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0027] The present invention provides an energy - storage multi - string lithium battery pack and a method that can be used in parallel for multiple groups, which can reduce the weight of a single cell, bring convenience to production, transportation, and installation, provide appropriate selection for different capacity energy - storage product requirements, reduce the specifications of energy - storage power products, and in the process of use, it is easy to find and simple to repair when a certain string of battery cells fails, bringing convenience to later maintenance.

[0028] Specifically, an energy - storage multi - string lithium battery pack includes a main lithium battery pack unit 1 and several secondary lithium battery pack units 2. The main lithium battery pack unit 1 is provided with a main lithium battery pack 11, a protection board 12, several groups of acquisition line groups 13, a positive current connection line 5, a negative current connection line 6, and an acquisition line connection board 18. The acquisition line connection board 18 is provided with several acquisition line connection ports 19. One group of acquisition line groups 13 can be plugged into each acquisition line connection port 19. Several groups of acquisition line groups 13 are respectively connected to the main lithium battery pack 11, the protection board 12, and the secondary lithium battery pack units 2 through the acquisition line connection board 18. The main lithium battery pack 11 and the protection board 12 are also connected through the negative current connection line 6. The protection board 12 is provided with a negative current output terminal 61. The main lithium battery pack 11 is also connected with a positive current connection line 5, and the front end of the positive current connection line 5 is provided with a positive current output terminal 51.

[0029] The positive current output terminal 51 and the negative current output terminal 61 are also charge and discharge terminals at the same time. A positive current connection terminal 52 is also provided between the main lithium battery pack 11 and the positive current output terminal 51 on the positive current connection line 5. A negative current connection terminal 62 is also provided between the main lithium battery pack 11 and the protection board 12 on the negative current connection line 6.

[0030] The secondary lithium battery pack unit 2 is provided with a secondary lithium battery pack 21. The secondary lithium battery pack 21 is connected with a secondary positive current connection line 22, a normally closed contact JK of a relay, a secondary negative current connection line 23, and a plurality of parallel secondary lithium battery pack unit sudden voltage difference detection circuits 24. Each secondary lithium battery pack unit sudden voltage difference detection circuit 24 is connected to a secondary acquisition line 27. All the secondary acquisition lines 27 and the secondary negative current connection line 23 are close to the 0 potential line led out from the B- end of the lithium battery, forming a secondary acquisition line group 28.

[0031] The secondary lithium battery pack unit sudden voltage difference detection circuit 24 is composed of self - recovering fuses HF1 - HF4, diodes 25 in optocouplers G1 - G4, and current - limiting resistors R1 - R4. The current - limiting resistors are in series with the diodes 25 in the optocouplers and are jointly in parallel with the self - recovering fuses. The secondary lithium battery pack unit sudden voltage difference detection circuit 24 is optically and electrically connected to the triodes 26 in the optocouplers that are connected in parallel on the secondary positive current connection line 22 through the diodes 25 in the optocouplers. The triodes 26 in the optocouplers are also connected with a protection circuit.

[0032] The triodes 26 in the optocouplers are connected to the secondary negative current connection line 23 through the series - connected resistors R5 and R6 in the protection circuit. The resistor R6 is in parallel with the zener diode D1 and the gate of the MOS transistor T1; An alarm B, a diode D2, and a relay J are also installed in parallel in the protection circuit. One end of the alarm B, the diode D2, and the relay J is connected to the secondary positive current connection line 22, and the other end is in series with the drain of the MOS transistor T1. The source of the MOS transistor T1 is connected to the secondary negative current connection line 23. The relay J is provided with a normally closed contact JK of the relay. One end of the normally closed contact JK of the relay is connected to the secondary positive current connection line 22, and the other end is the secondary positive current output terminal B+ of the secondary lithium battery pack unit 2, and then connected to the positive current connection terminal 52 of the main lithium battery pack unit 1. The secondary negative current output terminal B- of the secondary negative current connection line 23 is connected to the negative current connection terminal 62 of the main lithium battery pack unit 1. The secondary acquisition line group 28 is connected to the acquisition line connection port 19 in the acquisition line connection board 18 of the main lithium battery pack unit 1.

[0033] The main lithium battery pack unit 1 and several secondary lithium battery pack units 2 are connected in parallel through the acquisition line connection board 18 and the charge and discharge connection terminals to form an integrated unit, enabling a single lithium battery protection board 12 to protect multiple parallel-connected lithium battery packs, thus forming a low-cost, high-efficiency, and convenient-to-install and use energy storage lithium battery pack. This solves the difficult problems of large size, heavy weight, and inconvenient transportation and installation of energy storage lithium batteries in certain application scenarios, realizes a lithium battery product, and forms application scenarios with various different capacity requirements, so as to solve a series of problems such as a wide variety of external shapes and structures of energy storage lithium battery packs, and complex production, distribution, and operation.

[0034] During specific use, after the main lithium battery pack unit 1 and several secondary lithium battery pack units 2 are integrated, if any one battery cell experiences severe leakage or short circuit, the secondary lithium battery pack unit 2 can be separated from the output of the main lithium battery pack unit 1 and an alarm can be triggered to prevent the situation from worsening. The method is that when a certain battery cell experiences severe leakage or short circuit, the current in a certain acquisition line of each unit will increase significantly, triggering the resettable fuse to disconnect. When the voltage difference is greater than 0.7V, the light-emitting diode 25 of the optocoupler conducts, and the triode 26 in the optocoupler provides a voltage bias to the MOS tube T1, turning on the normally closed relay J to disconnect JK, interrupting the current output, and simultaneously turning on the alarm B to emit corresponding alarm signals. Although the resettable fuse can conduct with a delay, it will disconnect again shortly to continue the alarm. A self-locking function can also be added so that once the alarm is triggered, the separation will continue indefinitely; if the voltage difference is less than 0.7V and the acquisition line current is small, and the resettable fuse is around 1A, during the parallel balancing of lithium batteries, it does not pose a safety risk. If it can be repaired, it can continue to be used. If it cannot be repaired, when the voltage drops to the lithium battery protection voltage, the lithium battery protection board conducts overall protection. It is very easy to disassemble the main and secondary lithium battery pack units to find out which lithium battery unit or which string of lithium batteries is damaged, and subsequent maintenance is very convenient.

[0035] One set of acquisition lines can be used to connect to the overall balancing circuit of the main and secondary lithium battery packs in the main lithium battery pack unit, can also be externally connected to a high-current balancing circuit and a lithium battery parameter detection connector, or can be used to connect in parallel with another set of secondary lithium battery pack units.

[0036] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and the inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A multi-string lithium battery pack with energy storage function, characterized in that: It includes a main lithium battery pack unit (1) and several secondary lithium battery pack units (2). The main lithium battery pack unit (1) is provided with a main lithium battery pack (11), a protection board (12), several groups of acquisition line groups (13), a positive current connection line (5), a negative current connection line (6), and an acquisition line connection board (18). The acquisition line connection board (18) is provided with several acquisition line connection ports (19). One group of acquisition line groups (13) can be plugged into each acquisition line connection port (19). The several groups of acquisition line groups (13) are respectively connected to the main lithium battery pack (11), the protection board (12), and the secondary lithium battery pack units (2) through the acquisition line connection board (18). The main lithium battery pack (11) and the protection board (12) are also connected through the negative current connection line (6). The protection board (12) is provided with a negative current output terminal (61). The main lithium battery pack (11) is also connected with the positive current connection line (5). The front end of the positive current connection line (5) is provided with a positive current output terminal (51).

2. The energy storage type multi-string lithium battery pack according to claim 1, wherein: The positive current output terminal (51) and the negative current output terminal (61) are also charge and discharge terminals at the same time. A positive current connection terminal (52) is also provided between the positive current connection line (5) and the positive current output terminal (51) of the main lithium battery pack (11). A negative current connection terminal (62) is also provided between the negative current connection line (6) and the protection board (12) of the main lithium battery pack (11).

3. The energy storage type multi-string lithium battery pack according to claim 1, wherein: The secondary lithium battery pack unit (2) is provided with a secondary lithium battery pack (21). The secondary lithium battery pack (21) is connected with a secondary positive current connection line (22), a normally closed contact JK of a relay, a secondary negative current connection line (23), and several parallel secondary lithium battery pack unit sudden pressure difference detection circuits (24). Each of the secondary lithium battery pack unit sudden pressure difference detection circuits (24) is connected to a secondary acquisition line (27). All the secondary acquisition lines (27) and the secondary negative current connection line (23) are close to the 0-potential line led out from the B - end of the lithium battery, forming a secondary acquisition line group (28).

4. The energy storage type multi-string lithium battery pack according to claim 3, characterized in that: The secondary lithium battery pack unit sudden pressure difference detection circuit (24) is composed of a self - reset fuse, a diode (25) in an optocoupler, and a current - limiting resistor. The current - limiting resistor is in series with the diode (25) in the optocoupler and is jointly in parallel with the self - reset fuse. The secondary lithium battery pack unit sudden pressure difference detection circuit (24) is electro - optically connected to a triode (26) in the optocoupler that is in parallel with the secondary positive current connection line (22) through the diode (25) in the optocoupler. The triode (26) in the optocoupler is also connected to a protection circuit.

5. The energy storage type multi-string lithium battery pack according to claim 4, wherein: The triode (26) in the optocoupler is connected to the secondary negative current connection line (23) through the resistor R5 and the resistor R6 connected in series in the protection circuit. The resistor R6 is in parallel with the zener diode D1 and the gate of the MOS transistor T1.

6. The energy storage type multi-string lithium battery pack according to claim 5, characterized in that: The protection circuit further includes an alarm B, a diode D2, and a relay J connected in parallel with each other. One end of the alarm B, the diode D2, and the relay J is connected to the secondary positive current connection line (22), and the other end is connected in series with the drain of the MOS transistor T1. The source of the MOS transistor T1 is connected to the secondary negative current connection line (23). The relay J is provided with a relay normally closed contact JK. One end of the relay normally closed contact JK is connected to the secondary positive current connection line (22), and the other end is the secondary positive current output terminal (B+) of the secondary lithium battery pack unit (2), and is further connected to the positive current connection terminal (52) of the primary lithium battery pack unit (1). The secondary negative current output terminal (B-) of the secondary negative current connection line (23) is connected to the negative current connection terminal (62) of the primary lithium battery pack unit (1). The secondary collection wire group (28) is connected to the collection wire connection port (19) in the collection wire connection board (18) of the primary lithium battery pack unit (1).

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