A multi-voltage mode integrated lithium battery energy storage system

Abstract

The present invention discloses a multi-voltage mode integrated lithium battery energy storage system, including a photovoltaic generator set, a power supply end control module, a dispatching switch S1~S8, a cascade utilization battery module, a power type lithium battery module, an energy type lithium battery module, a first DC / DC converter, a second DC / DC converter, a third DC / DC converter, a DC / AC converter and a power demand end control module. The power supply end control module controls the on-off of the dispatching switches S1~S5 according to the power generation power of the photovoltaic generator set and the output power of the cascade utilization battery module; the power demand end control module controls the on-off of the dispatching switches S6~S8 according to the power demand of the power grid. The present invention can meet the power demand of different voltages through multi-voltage mode integration, avoid the power loss caused by the external transformer, avoid the "abandonment of light" problem caused by the traditional photovoltaic energy storage system when the power generation power is too low, and improve the utilization rate of energy.

Description

Technical Field

[0001] The present invention belongs to the technical field of microgrids, and in particular relates to a multi-voltage mode integrated lithium battery energy storage system. Background Art

[0002] At present, the application scenarios of microgrids formed by solar energy, wind power generation and lithium battery energy storage are increasing. Building renewable energy storage power stations near local loads such as factories or industrial parks can effectively supply power and store excess power to cope with insufficient power generation at night or during peak power consumption. This lithium battery energy storage system can significantly improve the utilization efficiency of new energy.

[0003] At the same time, although the capacity of retired electric vehicle batteries has dropped to 70%~80% of the original, they still have high energy. If these batteries are not properly used, it will not only waste resources, but also have a negative impact on the environment, which is not conducive to achieving the "dual carbon" goal. Therefore, introducing cascaded battery or retired battery modules into the energy storage system can not only store and convert the energy of new energy power generation, but also promote the recycling of batteries.

[0004] However, the addition of second-life batteries increases the complexity of the energy storage system, requiring effective controllers and strategies to ensure efficient and stable operation of the system. In addition, most traditional energy storage devices are energy-type batteries, which may result in the inability to effectively utilize electricity when the power generation fluctuates, thereby affecting the power generation efficiency. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a multi-voltage mode integrated lithium battery energy storage system.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] The present invention provides a multi-voltage mode integrated lithium battery energy storage system, including a photovoltaic power generation group, a power supply end control module, a first dispatching switch S1, a second dispatching switch S2, a third dispatching switch S3, a fourth dispatching switch S4, a fifth dispatching switch S5, a sixth dispatching switch S6, a seventh dispatching switch S7, an eighth dispatching switch S8, a cascade utilization battery module, a power type lithium battery module, an energy type lithium battery module, a first DC / DC converter, a second DC / DC converter, a third DC / DC converter, a DC / AC converter and a power demand end control module, wherein:

[0008] The output end of the photovoltaic power generation group is connected to the power supply end control module and the first DC / DC converter, and the power supply end control module is also connected to the cascade utilization battery module;

[0009] The first dispatching switch S1 is connected between the photovoltaic power generation group and the DC / AC converter, the third dispatching switch S3 is connected between the first DC / DC converter and the cascade battery module, the fourth dispatching switch S4 is connected between the first DC / DC converter and the power lithium battery module, and the fifth dispatching switch S5 is connected between the first DC / DC converter and the energy lithium battery module; the seventh dispatching switch S7 and the second dispatching switch S2 are connected in series between the power lithium battery module and the DC / AC converter; the first end of the sixth dispatching switch S6 is connected to the cascade battery module, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2; the first end of the eighth dispatching switch S8 is connected to the energy lithium battery module, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2;

[0010] The second DC / DC converter is connected between the power type lithium battery module and the second-use battery module, the third DC / DC converter is connected between the power type lithium battery module and the energy type lithium battery module, the DC / AC converter is also connected to the power grid, the first end of the power demand end control module is connected to the power grid, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2;

[0011] The power supply end control module can control the on and off of the first dispatching switch S1, the second dispatching switch S2, the third dispatching switch S3, the fourth dispatching switch S4 and the fifth dispatching switch S5 according to the power generation power of the photovoltaic power generation group and the output power of the cascade utilization battery module;

[0012] The power demand-side control module can control the on and off of the sixth dispatching switch S6, the seventh dispatching switch S7 and the eighth dispatching switch S8 according to the power demand of the power grid.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention provides a multi-voltage mode integrated lithium battery energy storage system. The power supply-side control device in the lithium battery energy storage system can realize three mutually exclusive control functions of the dispatching switches S1~S5 through two control signals; the power demand-side control device can realize three mutually exclusive control functions of the dispatching switches S6~S8 through one control signal. Through the integration of multi-voltage modes, the power demand of different voltages can be met, the power loss caused by the external transformer can be avoided, and the "abandoned light" problem caused by the traditional photovoltaic energy storage system when the power generation power is too low can be avoided, thereby improving the utilization rate of energy.

[0015] 2. The second-use battery module of the present invention includes multiple retired lithium battery packs of 100 / 200V voltage type, which can meet the 100 / 200 / 300 / 500V low-voltage DC power demand and the diversified power replacement demand. The power type lithium battery module is composed of multiple power type lithium battery modules of 500V voltage type, which can charge the second-use battery module and the energy type lithium battery module. The energy type lithium battery module is composed of multiple energy type lithium battery modules of 300V voltage type, which can meet the 300 / 600 / 1200 / 1500V medium and high voltage DC power demand.

[0016] 3. The low-voltage battery exchange unit in the cascade utilization battery module of this embodiment can also serve as an energy storage module to supply power to small-power individual power users and power grids. The present invention can meet the power demand of different voltages through multi-voltage mode integration, avoiding the power loss caused by the external transformer. At the same time, the use of different types of energy storage batteries avoids the "abandonment" problem caused by the traditional photovoltaic energy storage system when the power generation is too low, thereby improving the utilization rate of energy. In addition, the multi-voltage battery exchange unit can also serve as an energy storage module, effectively improving the utilization rate of retired batteries and realizing the on-site storage and consumption of new energy power generation.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a multi-voltage mode integrated lithium battery energy storage system provided by an embodiment of the present invention;

[0019] Figure 2 is a structural schematic diagram of a power supply end control module provided by an embodiment of the present invention;

[0020] Figure 3 It is a structural schematic diagram of a power demand end control module provided by an embodiment of the present invention;

[0021] Figure 4 It is a structural schematic diagram of a second-use battery module provided by an embodiment of the present invention;

[0022] Figure 5 is a control flow chart of a power supply end control module provided by an embodiment of the present invention;

[0023] Figure 6 is a control flow chart of a power demand end control module provided by an embodiment of the present invention;

[0024] Figure 7 It is a hysteresis control diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a multi-voltage mode integrated lithium battery energy storage system proposed in accordance with the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] The above and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific implementation modes in conjunction with the accompanying drawings. Through the description of the specific implementation modes, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation purposes and are not used to limit the technical solutions of the present invention.

[0027] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the statement "including one..." do not exclude the existence of other identical elements in the article or device including the elements.

[0028] Embodiment 1

[0029] See also Figure 1 , Figure 1 It is a structural schematic diagram of a multi-voltage mode integrated lithium battery energy storage system provided by an embodiment of the present invention. The multi-voltage mode integrated lithium battery energy storage system includes a photovoltaic power generation group, a power supply end control module, a first dispatching switch S1, a second dispatching switch S2, a first DC / DC converter, a third dispatching switch S3, a fourth dispatching switch S4, a fifth dispatching switch S5, a cascade battery module, a power type lithium battery module, an energy type lithium battery module, a second DC / DC converter, a third DC / DC converter, a sixth dispatching switch S6, a seventh dispatching switch S7, an eighth dispatching switch S8, a DC / AC converter and a power demand end control module.

[0030] Specifically, the photovoltaic power generation group of this embodiment is a photovoltaic power generation group with an output voltage of 1500V. The output end of the photovoltaic power generation group is connected to the power supply end control module and the first DC / DC converter, and the power supply end control module is also connected to the cascade utilization battery module; the first scheduling switch S1 is connected between the photovoltaic power generation group and the DC / AC converter, the third scheduling switch S3 is connected between the first DC / DC converter and the cascade utilization battery module, the fourth scheduling switch S4 is connected between the first DC / DC converter and the power type lithium battery module, and the fifth scheduling switch S5 is connected between the first DC / DC converter and the energy type lithium battery module; the seventh scheduling switch S7 and the second scheduling switch S2 are connected in series between the power type lithium battery module and the DC / AC converter; the first end of the sixth scheduling switch S6 is connected to the cascade utilization battery module, and the second end is connected between the seventh scheduling switch S7 and the second scheduling switch S2; the first end of the eighth scheduling switch S8 is connected to the energy type lithium battery module, and the second end is connected between the seventh scheduling switch S7 and the second scheduling switch S2.

[0031] The second DC / DC converter is connected between the power type lithium battery module and the cascade utilization battery module, the third DC / DC converter is connected between the power type lithium battery module and the energy type lithium battery module, the DC / AC converter is also connected to the power grid, the first end of the power demand end control module is connected to the power grid, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2; the power supply end control module can control the on and off of the first dispatching switch S1, the second dispatching switch S2, the third dispatching switch S3, the fourth dispatching switch S4 and the fifth dispatching switch S5 according to the power generation power of the photovoltaic power generation group and the output power of the cascade utilization battery module; the power demand end control module can control the on and off of the sixth dispatching switch S6, the seventh dispatching switch S7 and the eighth dispatching switch S8 according to the demand power of the power grid.

[0032] For further information, see Figure 2 , Figure 2 1 is a schematic diagram of a power supply end control module provided by an embodiment of the present invention. The power supply end control module includes a switch relay J1, a switch relay J2, a switch relay J3, a switch relay J4, a switch relay J5, a contact switch S21, a contact switch S22, a contact switch S41, a contact switch S51, a grounding resistor R1 and a grounding resistor R2.

[0033] The switch relay J1 and the switch relay J2 are connected in parallel between the first input terminal and the ground terminal of the power supply end control module. The first input terminal of the power supply end control module is connected to the output terminal of the photovoltaic power generation group to obtain the power generation power of the photovoltaic power generation group as the first control signal. The contact switch S21 and the switch relay J4 are connected in series between the first input terminal and the ground terminal of the power supply end control module, and the grounding resistor R1 is connected between the ground terminal and the first input terminal of the power supply end control module; the contact switch S22, the contact switch S41, the contact switch S51 and the switch relay J3 are connected in series between the second input terminal and the ground terminal of the power supply end control module, and the second input terminal of the power supply end control module is connected to the cascade utilization battery module to obtain the output power of the cascade utilization battery module as the second control signal.

[0034] The first end of the grounding resistor R2 is connected between the contact switch S41 and the contact switch S51, the second end of the grounding resistor R2 is connected to the ground end, the first end of the switch relay J5 is connected between the contact switch S41 and the contact switch S51, and the second end of the switch relay J5 is connected to the ground end; the switch relay J1 is used to control the on and off of the first scheduling switch S1, the switch relay J2 is used to control the on and off of the second scheduling switch S2, the contact switch S21 and the contact switch S22, the switch relay J3 is used to control the on and off of the third scheduling switch S3, the switch relay J4 is used to control the on and off of the fourth scheduling switch S4 and the contact switch S41, and the switch relay J5 is used to control the on and off of the fifth scheduling switch S5 and the contact switch S51.

[0035] Furthermore, the second dispatching switch S2, the contact switch S21, the contact switch S22, the contact switch S41 and the contact switch S51 are all normally closed switches; the first dispatching switch S1, the third dispatching switch S3, the fourth dispatching switch S4 and the fifth dispatching switch S5 are all normally open switches.

[0036] The switch relay J1 and the switch relay J2 are triggered when the first control signal is higher than the upper limit value of the predetermined power generation power of the photovoltaic power generation group; the switch relay J4 is triggered when the first control signal is between the upper limit value and the lower limit value of the predetermined power generation power; the switch relay J3 is triggered when the second control signal is lower than the lower limit value of the predetermined output power of the cascade utilization battery module; the switch relay J5 is triggered when the second control signal is higher than the upper limit value of the predetermined output power of the cascade utilization battery module.

[0037] In other words, when the output power of the photovoltaic power generation group is between the upper limit and the lower limit of the predetermined power generation power (the first control signal is a medium level), the switch relay J4 is triggered; when the power output of the photovoltaic power generation group is higher than the upper limit of the predetermined power generation power (the first control signal is a high level), the switch relay J1 and the switch relay J2 are triggered; when the output power of the cascade utilization battery module is lower than the lower limit of the predetermined output power (the first control signal is a low level), the switch relay J3 is triggered; when the output power of the cascade utilization battery module is higher than the upper limit of the predetermined output power (the second control signal is a high level), the switch relay J5 is triggered.

[0038] Specifically, the power supply-end control module of this embodiment can realize three working modes of five scheduling switches (first scheduling switch S1, second scheduling switch S2, first DC / DC converter, third scheduling switch S3, fourth scheduling switch S4, and fifth scheduling switch S5) through only two control signals (first control signal and second control signal); the power supply-end control module controls strong electricity through weak electricity, wherein the first control signal is the power generation signal of the 1500V photovoltaic power generation group, and the second control signal is the current power signal of the cascade utilization battery module.

[0039] The three working modes include:

[0040] When the first control signal is at a high level, the switch relay J1 and the switch relay J2 are triggered, the switch relay J1 controls the first scheduling switch S1 to be turned on, and the switch relay J2 controls the second scheduling switch S2 and the corresponding contact switches S21 and S22 to be turned off.

[0041] When the first control signal is at a medium level, the switch relay J1 and the switch relay J2 are not triggered, the switch relay J1 controls the first scheduling switch S1 to be disconnected, and the switch relay J2 controls the second scheduling switch S2 and the corresponding contact switches S21 and S22 to be turned on; the switch relay J4 is triggered, and the switch relay J4 controls the fourth scheduling switch S4 to be turned on, and at the same time controls the contact switch S41 to be disconnected.

[0042] When the first control signal is at a low level, the switch relay J1, the switch relay J2 and the switch relay J4 are not triggered, and the switch relay J4 controls the fourth scheduling switch S4 to be disconnected, and controls the contact switch S41 to be closed. At this time, since the contact switch S22 is turned on, the second control signal is connected to the circuit. When the second control signal is at a high level, the switch relay J5 is triggered, and the switch relay J5 controls the fifth scheduling switch S5, and controls the contact switch S51 to be disconnected, so the switch relay J3 disconnects the circuit, and the switch relay J3 controls the scheduling switch S3 to be disconnected. When the second control signal is at a low level, the switch relay J5 cannot be triggered, and the switch relay J5 controls the scheduling switch S5 to be disconnected, and controls the contact switch S51 to be closed, so the switch relay J3 is triggered, and the switch relay J3 controls the scheduling switch S3 to be closed.

[0043] See also Figure 3 , Figure 3 It is a control flow chart of a power demand end control module provided by an embodiment of the present invention. The power demand end control module includes a switch relay J6, a switch relay J7, a switch relay J8, a contact switch S71, a contact switch S72, a contact switch S81 and a grounding resistor R3. The input end of the power demand end control module is connected to the power grid to receive the power grid demand power signal from the power grid as the third control signal, and the contact switch S71, the contact switch S81 and the switch relay J6 are connected in series between the input end and the grounding end of the power demand end control module.

[0044] The switch relay J7 is connected between the input end and the ground end of the power demand end control module, the grounding resistor R3 is connected between the input end and the ground end of the power demand end control module, the contact switch S72 and the switch relay J8 are connected in series between the input end and the ground end of the power demand end control module; the switch relay J6 is used to control the on and off of the sixth dispatching switch S6, the switch relay J7 is used to control the on and off of the seventh dispatching switch S7, the contact switch S71 and the contact switch S72, and the switch relay J8 is used to control the on and off of the eighth dispatching switch S8 and the contact switch S81.

[0045] The sixth dispatching switch S6, the seventh dispatching switch S7 and the eighth dispatching switch S8 are all normally open switches; the contact switch S71, the contact switch S72 and the contact switch S81 are all normally closed switches.

[0046] When the third control signal is higher than the predetermined upper limit value of the normal power grid demand power (the third control signal is at a high level), the seventh dispatching switch S7 is triggered; when the third control signal is between the predetermined upper limit value and the lower limit value of the normal power grid demand power (the third control signal is at a medium level), the eighth dispatching switch S8 is triggered; when the third control signal is lower than the predetermined lower limit value of the normal power grid demand power (the third control signal is at a low level), the sixth dispatching switch S6 is triggered.

[0047] In other words, when the current power demand of the power grid is higher than the predetermined upper limit of the normal power demand of the power grid, the seventh dispatching switch S7 is triggered; when the current power demand of the power grid is between the upper limit and the lower limit of the predetermined normal power demand of the power grid, the eighth dispatching switch S8 is triggered; when the current power demand of the power grid is lower than the predetermined lower limit of the normal power demand of the power grid, the sixth dispatching switch S6 is triggered.

[0048] The power demand-side control module of this embodiment controls strong electricity through weak electricity, and can realize three working modes of three dispatching switches (sixth dispatching switch S6, seventh dispatching switch S7 and eighth dispatching switch S8) through one control signal (third control signal).

[0049] The three working modes include:

[0050] When the second dispatching switch S2 is turned on and the third control signal is at a high level, the switch relay J7 is triggered, and the switch relay J7 controls the dispatching switch S7 to close, and controls the contact switch S71 and the contact switch S72 to open. Then the switch relay J6 and the switch relay J8 disconnect the circuit, and the dispatching switch S6 and the dispatching switch S8 are disconnected.

[0051] When the second dispatching switch S2 is turned on and the third control signal is at a medium level, the switch relay J7 is not triggered, the dispatching switch S7 is disconnected, and the contact switches S71 and S72 are closed. Then the switch relay J8 is triggered, and the switch relay J8 controls the dispatching switch S8 to close, and controls the contact switch S81 to open. Then the closing relay J6 disconnects the circuit, and the dispatching switch S6 is disconnected.

[0052] When the second dispatching switch S2 is turned on and the third control signal is at a low level, the switch relays J7 and J8 are not triggered, the dispatching switch S7 and the dispatching switch S8 are disconnected, and at the same time, the contact switch S71, the contact switch S72 and the contact switch S81 are closed. Then the switch relay J6 is triggered, and the switch relay J6 controls the dispatching switch S6 to close.

[0053] See also Figure 4The second-life battery module of this embodiment includes a low-voltage battery exchange unit and multiple lithium battery packs with an output voltage of 100V and multiple lithium battery packs with an output voltage of 200V. The above lithium battery packs are all retired lithium battery packs. The low-voltage battery exchange unit is a detachable battery slot. The lithium battery pack can be installed on the low-voltage battery exchange unit in a detachable manner, which can meet the 100 / 200 / 300 / 500V low-voltage DC power demand and the diversified power exchange demand. These retired lithium battery packs can be reassembled into a 1500V battery module and then connected in parallel to increase the capacity of the second-life battery module.

[0054] The low-voltage battery swap unit is equivalent to a replaceable battery slot. When battery swapping is needed, the battery swap module of the corresponding voltage, such as a 200V lithium battery module to be charged, can be replaced with one of the 200V modules that has been fully charged. After that, the newly replaced 200V battery module will be charged separately. If the battery swap module is 300V, the module can be replaced with fully charged 200V and 100V modules for battery swapping, after which the newly replaced 300V battery module will be charged. When the battery swap user does not take away the battery swap module for a long time, it can also act as an energy storage module and form a 1500V lithium battery energy storage module with other lithium battery packs, which can eventually supply power to 100V / 200V / 300V / 500V small-power individual power units, or supply power to the power grid through a DC / AC converter.

[0055] The energy type lithium battery module of this embodiment includes multiple 300V energy type lithium batteries, which can meet the 300 / 600 / 1200 / 1500V DC power demand and supply power to the power grid. When the current power of the energy type lithium battery module is low, the power type lithium battery module will charge the energy type lithium battery module through the third DC / DC converter to ensure the stable operation of the 300 / 600 / 1200 / 1500V medium and high power independent power unit connected to the energy type lithium battery module.

[0056] Furthermore, the power lithium battery module of this embodiment includes three 500V power lithium batteries connected in sequence.

[0057] See also Figure 5 , Figure 5 1 is a control flow chart of a power supply end control module provided by an embodiment of the present invention. The control method of the power supply end control module of this embodiment is as follows:

[0058] When the power generation power of the 1500V photovoltaic power generation group is greater than the upper limit of the predetermined power generation power, the first control signal is at a high level, the switch relay J1 and the switch relay J2 are triggered, the switch relay J1 controls the first dispatching switch S1 to turn on, and the switch relay J2 controls the second dispatching switch S2 and the corresponding contact switches S21 and S22 to turn off, and the photovoltaic power generation group directly supplies power to the power grid through the DC / AC converter.

[0059] When the power generation power of the 1500V photovoltaic power generation group is greater than the lower limit value of the predetermined power generation power and less than the upper limit value, the first control signal is at a medium level, the power supply end control module controls the first scheduling switch S1 to be disconnected, the fourth scheduling switch S4 to be turned on, the second scheduling switch S2 to be turned on, the third scheduling switch S3 and the fifth scheduling switch S5 to be disconnected, and the photovoltaic power generation group charges the power type lithium battery module through the first DC / DC converter.

[0060] When the power generation power of the 1500V photovoltaic power generation group is less than the lower limit of the predetermined power generation power and the power of the cascade utilization battery module is less than the lower limit of the predetermined output power, the first control signal is at a low level, and the power supply end control module controls the first scheduling switch S1 to be disconnected, the third scheduling switch S3 to be turned on, the second scheduling switch S2 to be turned on, and the fourth scheduling switch S4 and the fifth scheduling switch S5 to be disconnected, and the photovoltaic power generation group charges the cascade utilization battery module through the first DC / DC converter.

[0061] When the power generation power of the 1500V photovoltaic power generation group is less than the lower limit of the predetermined power generation power and the power of the battery module in cascade utilization is greater than the lower limit of the predetermined output power, the power supply end control module controls the first scheduling switch S1 to be disconnected, the fifth scheduling switch S5 to be turned on, the second scheduling switch S2 to be turned on, the third scheduling switch S3 and the fourth scheduling switch S4 to be disconnected, and the photovoltaic power generation group charges the energy type battery group through the first DC / DC converter.

[0062] See also Figure 6 , Figure 6 This is a control flow chart of a power demand side control module provided by an embodiment of the present invention. The control method of the power demand side control module of this embodiment is as follows:

[0063] When the second dispatching switch S2 is disconnected, the power demand end control module controls the sixth dispatching switch S6, the seventh dispatching switch S7 and the eighth dispatching switch S8 to be disconnected, and each battery module (cascade utilization battery module, power lithium battery module, energy lithium battery module) does not supply power to the power grid.

[0064] When the second dispatching switch S2 is turned on and the power demanded by the power grid is greater than the predetermined upper limit of the normal power demanded by the power grid, the power demand end control module controls the seventh dispatching switch S7 to be turned on, and the sixth dispatching switch S6 and the eighth dispatching switch S8 are turned off, and the power type lithium battery module supplies power to the power grid through the DC / AC converter.

[0065] When the second dispatching switch S2 is turned on, and the power demanded by the power grid is greater than the upper limit of the predetermined normal power demanded by the power grid and less than the upper limit, the power demand end control module controls the eighth dispatching switch S8 to be turned on, and the sixth dispatching switch S6 and the seventh dispatching switch S7 are turned off, and the energy-type lithium battery module supplies power to the power grid through the DC / AC converter.

[0066] When the second dispatching switch S2 is turned on and the power demanded by the power grid is less than the predetermined lower limit of the normal power demanded by the power grid, the power demand end control module controls the sixth dispatching switch S6 to turn on, the seventh dispatching switch S7 and the eighth dispatching switch S8 to turn off, and the battery module is used in cascade to supply power to the power grid through the DC / AC converter.

[0067] For further information, see Figure 7 , Figure 7 It is a hysteresis control diagram provided by an embodiment of the present invention. The upper and lower limits of the power generation power of the photovoltaic power generation group and the upper and lower limits of the power demand of the power grid can be designed as a hysteresis interval of 5% to avoid the scheduling switch and the DC-DC converter from frequently switching the working mode in the area near the upper and lower limits.

[0068] In summary, the present invention provides a multi-voltage mode integrated lithium battery energy storage system, in which the power supply-side control device can realize three mutually exclusive control functions of the dispatching switches S1~S5 through two control signals; the power demand-side control device can realize three mutually exclusive control functions of the dispatching switches S6~S8 through one control signal. Through the integration of multi-voltage modes, the power demand of different voltages can be met, the power loss caused by the external transformer can be avoided, and the "abandoned light" problem caused by the traditional photovoltaic energy storage system when the power generation power is too low can be avoided, thereby improving the energy utilization rate.

[0069] The second-use battery module of the present invention includes multiple retired lithium battery packs of 100 / 200V voltage type, which can meet the 100 / 200 / 300 / 500V low-voltage DC power demand and the diversified power replacement demand. The power type lithium battery module is composed of multiple power type lithium battery modules of 500V voltage type, which can charge the second-use battery module and the energy type lithium battery module. The energy type lithium battery module is composed of multiple energy type lithium battery modules of 300V voltage type, which can meet the 300 / 600 / 1200 / 1500V medium and high voltage DC power demand.

[0070] The low-voltage battery exchange unit in the cascade utilization battery module of this embodiment can also act as an energy storage module to supply power to small-power individual power users and power grids. The present invention can meet the power demand of different voltages through multi-voltage mode integration, avoiding the power loss caused by the external transformer. At the same time, the use of different types of energy storage batteries avoids the "abandonment" problem caused by the traditional photovoltaic energy storage system when the power generation is too low, thereby improving the utilization rate of energy. In addition, the multi-voltage battery exchange unit can also act as an energy storage module, effectively improving the utilization rate of retired batteries and realizing the on-site storage and consumption of new energy power generation.

[0071] In the several embodiments provided by the present invention, it should be understood that the apparatus and method disclosed by the present invention can be implemented in other ways. For example, the apparatus embodiments described above are only illustrative, for example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation, for example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0072] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0073] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A multi-voltage mode integrated lithium battery energy storage system, characterized in that: It includes a photovoltaic power generation group, a power supply end control module, a first dispatching switch S1, a second dispatching switch S2, a third dispatching switch S3, a fourth dispatching switch S4, a fifth dispatching switch S5, a sixth dispatching switch S6, a seventh dispatching switch S7, an eighth dispatching switch S8, a cascade utilization battery module, a power type lithium battery module, an energy type lithium battery module, a first DC / DC converter, a second DC / DC converter, a third DC / DC converter, a DC / AC converter and a power demand end control module, wherein: The output end of the photovoltaic power generation group is connected to the power supply end control module and the first DC / DC converter, and the power supply end control module is also connected to the cascade utilization battery module; The first dispatching switch S1 is connected between the photovoltaic power generation group and the DC / AC converter, the third dispatching switch S3 is connected between the first DC / DC converter and the cascade battery module, the fourth dispatching switch S4 is connected between the first DC / DC converter and the power lithium battery module, and the fifth dispatching switch S5 is connected between the first DC / DC converter and the energy lithium battery module; the seventh dispatching switch S7 and the second dispatching switch S2 are connected in series between the power lithium battery module and the DC / AC converter; the first end of the sixth dispatching switch S6 is connected to the cascade battery module, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2; the first end of the eighth dispatching switch S8 is connected to the energy lithium battery module, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2; The second DC / DC converter is connected between the power type lithium battery module and the second-use battery module, the third DC / DC converter is connected between the power type lithium battery module and the energy type lithium battery module, the DC / AC converter is also connected to the power grid, the first end of the power demand end control module is connected to the power grid, and the second end is connected between the seventh dispatching switch S7 and the second dispatching switch S2; The power supply end control module can control the on and off of the first dispatching switch S1, the second dispatching switch S2, the third dispatching switch S3, the fourth dispatching switch S4 and the fifth dispatching switch S5 according to the power generation power of the photovoltaic power generation group and the output power of the cascade utilization battery module; The power demand-side control module can control the on and off of the sixth dispatching switch S6, the seventh dispatching switch S7 and the eighth dispatching switch S8 according to the power demand of the power grid.

2. The multi-voltage mode integrated lithium battery energy storage system according to claim 1, characterized in that: The power supply end control module includes a switch relay J1, a switch relay J2, a switch relay J3, a switch relay J4, a switch relay J5, a contact switch S21, a contact switch S22, a contact switch S41, a contact switch S51, a grounding resistor R1 and a grounding resistor R2, wherein: The switch relay J1 and the switch relay J2 are connected in parallel between the first input terminal and the ground terminal of the power supply end control module, the first input terminal of the power supply end control module is connected to the output terminal of the photovoltaic power generation group to obtain the power generation power of the photovoltaic power generation group as a first control signal, the contact switch S21 and the switch relay J4 are connected in series between the first input terminal and the ground terminal of the power supply end control module, and the grounding resistor R1 is connected between the ground terminal and the first input terminal of the power supply end control module; The contact switch S22, the contact switch S41, the contact switch S51 and the switch relay J3 are connected in series between the second input end of the power supply end control module and the ground end, and the second input end of the power supply end control module is connected to the cascade utilization battery module to obtain the output power of the cascade utilization battery module as the second control signal; The first end of the grounding resistor R2 is connected between the contact switch S41 and the contact switch S51, and the second end of the grounding resistor R2 is connected to the ground end; the first end of the switch relay J5 is connected between the contact switch S41 and the contact switch S51, and the second end of the switch relay J5 is connected to the ground end; The switch relay J1 is used to control the on and off of the first scheduling switch S1, the switch relay J2 is used to control the on and off of the second scheduling switch S2, the contact switch S21 and the contact switch S22, the switch relay J3 is used to control the on and off of the third scheduling switch S3, the switch relay J4 is used to control the on and off of the fourth scheduling switch S4 and the contact switch S41, and the switch relay J5 is used to control the on and off of the fifth scheduling switch S5 and the contact switch S51.

3. The multi-voltage mode integrated lithium battery energy storage system according to claim 2, characterized in that: The second dispatching switch S2, the contact switch S21, the contact switch S22, the contact switch S41 and the contact switch S51 are all normally closed switches; the first dispatching switch S1, the third dispatching switch S3, the fourth dispatching switch S4 and the fifth dispatching switch S5 are all normally open switches.

4. The multi-voltage mode integrated lithium battery energy storage system according to claim 2, characterized in that: The switch relay J1 and the switch relay J2 are triggered when the first control signal is higher than the upper limit value of the predetermined power generation power of the photovoltaic power generation group; the switch relay J4 is triggered when the first control signal is between the upper limit value and the lower limit value of the predetermined power generation power; the switch relay J3 is triggered when the second control signal is lower than the lower limit value of the predetermined output power of the cascade utilization battery module; the switch relay J5 is triggered when the second control signal is higher than the upper limit value of the predetermined output power of the cascade utilization battery module.

5. The multi-voltage mode integrated lithium battery energy storage system according to claim 1, characterized in that: The power demand end control module includes a switch relay J6, a switch relay J7, a switch relay J8, a contact switch S71, a contact switch S72, a contact switch S81 and a grounding resistor R3, wherein: The input end of the power demand end control module is connected to the power grid to receive the power grid demand power signal from the power grid as the third control signal, and the contact switch S71, the contact switch S81 and the switch relay J6 are connected in series between the input end of the power demand end control module and the ground end; The switch relay J7 is connected between the input end of the power demand end control module and the ground end, the grounding resistor R3 is connected between the input end of the power demand end control module and the ground end, and the contact switch S72 and the switch relay J8 are connected in series between the input end of the power demand end control module and the ground end; The switch relay J6 is used to control the on and off of the sixth scheduling switch S6, the switch relay J7 is used to control the on and off of the seventh scheduling switch S7, the contact switch S71 and the contact switch S72, and the switch relay J8 is used to control the on and off of the eighth scheduling switch S8 and the contact switch S81.

6. The multi-voltage mode integrated lithium battery energy storage system according to claim 5, characterized in that: The sixth dispatching switch S6, the seventh dispatching switch S7 and the eighth dispatching switch S8 are all normally open switches; the contact switch S71, the contact switch S72 and the contact switch S81 are all normally closed switches.

7. The multi-voltage mode integrated lithium battery energy storage system according to claim 5, characterized in that: When the third control signal is higher than the predetermined upper limit value of the normal power grid demand power, the seventh dispatching switch S7 is triggered; when the third control signal is between the predetermined upper limit value and the lower limit value of the normal power grid demand power, the eighth dispatching switch S8 is triggered; when the third control signal is lower than the predetermined lower limit value of the normal power grid demand power, the sixth dispatching switch S6 is triggered.

8. The multi-voltage mode integrated lithium battery energy storage system according to claim 1, characterized in that: The second-use battery module includes a low-voltage battery exchange unit and a plurality of lithium battery packs with an output voltage of 100V and a plurality of lithium battery packs with an output voltage of 200V, wherein the plurality of lithium battery packs with an output voltage of 100V and the plurality of lithium battery packs with an output voltage of 200V are retired lithium battery packs, and the low-voltage battery exchange unit is a detachable battery slot, and the lithium battery pack can be installed on the low-voltage battery exchange unit in a detachable manner.

9. The multi-voltage mode integrated lithium battery energy storage system according to any one of claims 1 to 8, characterized in that: The energy-type lithium battery module includes a plurality of 300V energy-type lithium batteries connected in sequence, and the power-type lithium battery module includes a plurality of 500V power-type lithium batteries connected in sequence.

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