Series-parallel connection conversion circuit of energy storage battery

Abstract

The utility model discloses a series-parallel connection conversion circuit of an energy storage battery. The series-parallel connection conversion circuit comprises a change-over switch S1, a change-over switch S2, a change-over switch S3, a first battery pack, a second battery pack, a pre-charging resistor, a micro-control unit, a first voltage measuring device and a second voltage measuring device. The fixed end of the change-over switch S1 is connected with the negative electrode of the first battery pack, the second movable end of the change-over switch S1 is connected with the first movable end of the change-over switch S2, the second movable end of the change-over switch S2 is connected with the fixed end of the change-over switch S3, the fixed end of the change-over switch S2 is connected with the positive electrode of the second battery pack, and the pre-charging resistor is connected between the first movable end and the second movable end of the change-over switch S3; each of the first voltage measuring device and the second voltage measuring device comprises three connecting wires, two connecting wires are respectively connected with two ends of the first battery pack and the second battery pack and acquire voltage signals, and the other connecting wire is respectively connected with a handle end of the change-over switch S1 and a handle end of the change-over switch S2; the signal acquisition end of the micro-control unit is connected with the first and second voltage measuring devices, so that the stability of the energy storage battery system is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electrochemical cell energy storage field, specifically, relate to a kind of energy storage battery's series-parallel conversion circuit. BACKGROUND

[0002] In recent years, with the rapid development of scale energy storage, the demand for lithium-ion batteries is increasing. However, the global reserves of lithium resources are limited and cannot meet the demand of future scale energy storage. Sodium-ion batteries have advantages such as abundant raw materials, wide operating temperature range, and low cost, and have begun to be applied in the market of scale energy storage. However, the voltage characteristics of sodium-ion batteries (1.5-3.95V) are relatively wide, which makes the discharge end voltage low when constant power output is required, resulting in excessive current. To solve this problem, current technologies use DC / DC converters to raise the voltage to meet the application conditions, but this technology increases the hardware cost and has high failure rate and poor anti-interference ability.

[0003] Therefore, there is an urgent need for a energy storage battery circuit technology to improve the efficiency and stability of the energy storage battery system SUMMARY

[0004] To solve the above problems, the purpose of the utility model is to provide a series-parallel conversion circuit for energy storage batteries, which changes the electrical connection of the energy storage battery system and adjusts the voltage state of the sodium-ion battery system to keep it within a relatively narrow voltage range.

[0005] To achieve the above purpose, the utility model provides a series-parallel conversion circuit for energy storage batteries, which includes switching switch S1, switching switch S2, switching switch S3, first battery pack, second battery pack, pre-charge resistor, micro control unit, first voltage measuring device, and second voltage measuring device, wherein:

[0006] The switching switch S1, the switching switch S2, and the switching switch S3 each have two contacts, wherein the fixed end of the switching switch S1 is connected to the negative electrode of the first battery pack, the first movable end contact of the switching switch S1 is connected to the output negative electrode of the series-parallel conversion circuit, and the second movable end contact of the switching switch S1 is connected to the first movable end contact of the switching switch S2. The second movable end contact of the switching switch S2 is connected to the fixed end of the switching switch S3, and the fixed end of the switching switch S2 is connected to the positive electrode of the second battery pack.

[0007] The positive electrode of the first battery pack is connected to the output positive electrode of the series-parallel conversion circuit, and the negative electrode of the second battery pack is connected to the output negative electrode of the series-parallel conversion circuit.

[0008] One end of the pre-charge resistor is connected to the second movable end contact of the switch S3, and the other end is commonly connected to the first movable end contact of the switch S3 to the positive output of the series-parallel conversion circuit.

[0009] The first voltage measuring device includes three wires, two of which are connected to the positive and negative poles of the first battery pack respectively, and the other wire is connected to the handle end of the switch S1.

[0010] The micro control unit includes a signal acquisition end connected to the first voltage measuring device and the second voltage measuring device.

[0011] Preferably, the micro control unit further includes a switch control end connected to the fixed end of the switch S3.

[0012] Preferably, the first battery pack and the second battery pack are both battery packs composed of one or more than one sodium ion battery cell in series.

[0013] Compared with the prior art, the series-parallel conversion circuit of the energy storage battery of the utility model saves the DC / DC converter to adjust the voltage of the energy storage battery system, and improves the flexibility of the energy storage battery system and the reliability of the power supply. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creative labor.

[0015] Figure 1 It is the series-parallel conversion circuit topology structure diagram of an embodiment of the utility model;

[0016] Figure 2 It is the energy storage battery system main backup power supply switching flow chart of an embodiment of the utility model;

[0017] Figure 3 It is the energy storage battery system charging flow chart of an embodiment of the utility model;

[0018] Figure 4 It is the energy storage battery system discharging flow chart of an embodiment of the utility model. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of the present application.

[0020] Figure 1 For the series-parallel conversion circuit structure topology of an embodiment of the present application, as shown in the figure, Figure 1 a series-parallel conversion circuit of an energy storage battery is provided, which comprises switching switch S1, switching switch S2, switching switch S3, first battery pack Moudle1, second battery pack Moudle2, pre-charge resistor R, first voltage measuring device V1, and second voltage measuring device V2, wherein:

[0021] The switching switch S1, the switching switch S2, and the switching switch S3 all have two contacts, which are used to connect the energy storage battery system to different states when the switching switch is connected to different contacts. The fixed end of the switching switch S1 is connected to the negative electrode of the first battery pack Moudle1, the first movable end contact a1 of the switching switch S1 is connected to the total negative electrode of the output of the series-parallel conversion circuit, Figure 1 the second movable end contact b1 of the switching switch S1 is connected to the first movable end contact a2 of the switching switch S2, the second movable end contact b2 of the switching switch S2 is connected to the fixed end of the switching switch S3, and the fixed end of the switching switch S2 is connected to the positive electrode of the second battery pack Moudle2. In the embodiment, all the switching switches (S1, S2, and S3) can manually or electrically convert the switching action of the switching switch. In other embodiments of the present application, the switching switch can also be a combination of components such as a relay, an IGBT, a MOSFET, and the like, which can control the on-off and selection switching.

[0022] In the embodiment, the first battery pack Moudle1 and the second battery pack Moudle2 are both composed of one or more than one sodium-ion battery monomer in series, the positive electrode of the first battery pack Moudle1 is connected to the total positive electrode of the output of the series-parallel conversion circuit, Figure 1 and the negative electrode of the second battery pack Moudle2 is connected to the total negative electrode of the output of the series-parallel conversion circuit.

[0023] One end of the pre-charge resistor R is connected to the second movable end contact b3 of the switch S3, and the other end is commonly connected to the output positive pole of the series-parallel conversion circuit with the first movable end contact a3 of the switch S3, and the pre-charge resistor R is connected to the battery system in the embodiment, so that the voltage difference between the two battery groups is eliminated, and the instantaneous circulating current impact caused by the excessive voltage difference between the first battery group Moudle1 and the second battery group Moudle2 when the series-parallel conversion is switched is prevented.

[0024] The first voltage measuring device V1 includes three wires, two of which are connected to the positive pole and the negative pole of the first battery group Moudle1 respectively, and the other wire is connected to the handle end of the switch S1, and the second voltage measuring device V2 includes three wires, two of which are connected to the positive pole and the negative pole of the second battery group Moudle2 respectively, and the other wire is connected to the handle end of the switch S2, so as to measure the voltage of the corresponding battery group.

[0025] The signal collection end of the micro control unit MCU is connected to the first voltage measuring device V1 and the second voltage measuring device V2, so as to collect the voltage of the first battery group Moudle1 and the second battery group Moudle2.

[0026] In another embodiment of the utility model, the switch control end of the micro control unit MCU of the series-parallel conversion circuit of the energy storage battery is connected to the fixed end of the switch S3, and the micro control unit MCU of the embodiment can have the functions of information collection and outputting corresponding control signals according to the collected information, the micro control unit MCU can send corresponding switch instructions to control the switch according to the voltage signals detected by the first voltage measuring device V1 and the second voltage measuring device V2, so that the energy storage battery system can work between different switching states.

[0027] The specific process of the series-parallel conversion circuit of the energy storage battery provided in the embodiment when in use can be but is not limited to the following: the first voltage measuring device V1 collects the voltage signals at the two ends of the first battery group Moudle1 and transmits the signals to the micro control unit MCU, and the micro control unit MCU sends corresponding instructions to control the state of the switch S1 to switch between a1 and b1 according to the collected voltage; the second voltage measuring device V2 collects the voltage signals at the two ends of the second battery group Moudle2 and transmits the signals to the micro control unit MCU, and the micro control unit MCU sends corresponding instructions to control the state of the switch S2 to switch between a2 and b2 according to the collected voltage.

[0028] For example, when the energy storage battery system needs one main and one standby power supply, that is, a single battery group supplies power to the system, the control process can be as follows, but is not limited to:

[0029] For example, when the energy storage battery system needs one main and one standby power supply, that is, a single battery group supplies power to the system, the control process can be as follows, but is not limited to: Figure 2As shown, the switch S1 is connected to the a1 contact, the S2 is connected to the a2 contact, at this time, only the first battery module Moudle1 is connected to the system for working between the output positive and negative of the energy storage battery system; when the battery module Moudle1 is used up or needs to be connected to the second battery module Moudle2 alone, the micro control unit MCU (or manually) connects the switch S1 to the b1 contact, the switch S2 to the b2 contact, and the switch S3 to the a3 contact, at this time, only the battery module Moudle2 is connected to the system for working between the output positive and negative of the energy storage battery system.

[0030] The energy storage battery system can also be charged and discharged by converting the series and parallel connection between the battery modules, and the specific control process is as follows, but not limited to:

[0031] When the system is charged, the first battery module Moudle1 and the second battery module Moudle2 enter the series state, and the energy storage battery system is in the series switching state to start charging, and the flow chart is as shown in Figure 3 At this time, the switch S1 is connected to the b1 contact, the switch S2 is connected to the a2 contact, the first voltage measuring device V1 measures the voltage between the first battery module Moudle1, the second voltage measuring device V2 measures the voltage between the second battery module Moudle2, when the voltage of the battery module reaches the parallel condition limit value V (for example, V can be taken as 1.8-2.8 times the number of battery modules), the micro control unit MCU controls the energy storage battery system to suspend charging and switch to the pre-charge loop before switching from series to parallel, at this time, the switch S1 is connected to the a1 contact, the switch S2 is connected to the b2 contact, and the switch S3 is connected to the b3 contact, and the pre-charge resistor R is connected to the energy storage battery system, when the voltage difference between the two battery modules is less than the set limit value, the first battery module Moudle1 and the second battery module Moudle2 enter the parallel state, and the energy storage battery system continues to charge until the voltage reaches the set charging cutoff voltage, that is, the charging is stopped;

[0032] When the first battery module Moudle1 and the second battery module Moudle2 enter the parallel state, the energy storage battery system is in the parallel switching state, as shown in Figure 4As shown, at this time, the switching switch S1 is connected to the a1 contact, the switching switch S2 is connected to the b2 contact, and the switching switch S3 is connected to the a3 contact, at this time, the first battery module Moudle1 and the second battery module Moudle2 are in parallel state, the energy storage battery system continues to discharge, the first voltage measuring device V1 measures the voltage between the first battery module Moudle1, the second voltage measuring device V2 measures the voltage between the second battery module Moudle2, until the battery voltage reaches the series condition limit value V (for example, V can be 1.8-2.8 times the number of battery modules), the micro control unit MCU controls the energy storage battery system to switch to the series switching state, at this time, the voltage of the energy storage battery system is twice that in parallel state, under the condition of equal output power, the current is only half of that in parallel state, and the energy storage battery system continues to discharge to the set cut-off voltage.

[0033] Those skilled in the art can understand that the drawings are only schematic diagrams of an embodiment, and the modules or flows in the drawings are not necessarily necessary for implementing the present application.

[0034] Those skilled in the art can understand that the modules in the device in the embodiment can be distributed in the device of the embodiment according to the embodiment description, or can be changed and located in one or more devices different from the embodiment. The modules of the above embodiment can be combined into one module, or can be further split into multiple sub-modules.

[0035] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A series-parallel conversion circuit for an energy storage battery, characterized in that: The circuit comprises: a switching switch S1, a switching switch S2, a switching switch S3, a first battery pack, a second battery pack, a pre-charge resistor, a micro control unit, a first voltage measuring device, a second voltage measuring device, wherein: The switching switch S1, the switching switch S2 and the switching switch S3 each have two contacts, wherein the fixed end of the switching switch S1 is connected to the negative electrode of the first battery pack, the first movable end contact of the switching switch S1 is connected to the output negative electrode of the series-parallel conversion circuit, and the second movable end contact of the switching switch S1 is connected to the first movable end contact of the switching switch S2; the second movable end contact of the switching switch S2 is connected to the fixed end of the switching switch S3, and the fixed end of the switching switch S2 is connected to the positive electrode of the second battery pack; The positive electrode of the first battery pack is connected to the output positive electrode of the series-parallel conversion circuit, and the negative electrode of the second battery pack is connected to the output negative electrode of the series-parallel conversion circuit; One end of the pre-charge resistor is connected to the second movable end contact of the switching switch S3, and the other end is commonly connected to the first movable end contact of the switching switch S3 and the output positive electrode of the series-parallel conversion circuit; The first voltage measuring device comprises three wires, two of which are connected to the positive electrode and the negative electrode of the first battery pack respectively, and the other wire is connected to the handle end of the switching switch S1; the second voltage measuring device comprises three wires, two of which are connected to the positive electrode and the negative electrode of the second battery pack respectively, and the other wire is connected to the handle end of the switching switch S2; The micro control unit comprises a signal acquisition end connected to the first voltage measuring device and the second voltage measuring device.

2. The series-parallel conversion circuit according to claim 1, characterized by The micro control unit further comprises a switch control end connected to the fixed end of the switching switch S3.

3. The series-parallel conversion circuit according to claim 1, characterized by The first battery pack and the second battery pack are each a battery pack composed of one or more sodium ion battery monomers in series.

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