Inverter, energy storage conversion system and thermal management method thereof

Abstract

The invention relates to an inverter, an energy storage conversion system and a thermal management method of the energy storage conversion system. The inverter is connected between the energy storage battery and the power grid, and the energy storage battery comprises a battery module and a preheating module in heat conduction connection with the battery module. The inverter is configured to judge whether the power grid is electrified or not, so as to judge whether the environment temperature of the battery module is lower than a first threshold value or not when the power grid is electrified; and when the environment temperature is lower than the first threshold value, the power grid provides electric energy for the preheating module, and the preheating module is controlled to preheat the battery module. The method is used for improving the safety of stable operation of the energy storage converter system.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to an inverter, an energy storage converter system and its thermal management method. Background Technology

[0002] With the rapid development of new energy technologies, energy storage systems that can effectively store energy are becoming increasingly important.

[0003] Currently, at least one of the following problems exists: when the ambient temperature is low (e.g., below 0°C), the capacity and / or output characteristics of the energy storage battery decrease, making it easy to not fully charge under cold conditions, which damages the life and performance of the energy storage battery. Summary of the Invention

[0004] In view of this, this application provides an inverter, an energy storage converter system, and a thermal management method thereof.

[0005] In a first aspect, this application provides an inverter connected between an energy storage battery and a power grid. The energy storage battery includes a battery module and a preheating module thermally connected to the battery module. The inverter is configured to: determine whether there is power in the power grid; if there is power in the power grid, determine whether the ambient temperature of the battery module is below a first threshold; and, if the ambient temperature is below the first threshold, cause the power grid to supply power to the preheating module and control the preheating module to preheat the battery module.

[0006] According to some embodiments, the inverter includes: a first sensing circuit, a second sensing circuit, a power conversion circuit, and a controller respectively connected to the first sensing circuit, the second sensing circuit, and the power conversion circuit. The first sensing circuit is used to sample electrical signals from the power grid. The second sensing circuit is used to sample the ambient temperature of the battery module. The power conversion circuit is connected between the preheating module and the power grid. The controller is configured to: determine whether there is power in the power grid based on the electrical signals from the power grid; determine whether the ambient temperature of the battery module is below a first threshold when there is power in the power grid; and, when the ambient temperature is below the first threshold, control the power conversion circuit to conduct, so that the power grid provides power to the preheating module, and control the preheating module to preheat the battery module.

[0007] According to some embodiments, the power conversion circuit includes a bidirectional inverter circuit.

[0008] According to some embodiments, the inverter further includes: an inverter circuit connected between the preheating module and the power grid; wherein the power conversion circuit is connected in parallel with the inverter circuit; the power conversion circuit includes a rectifier circuit.

[0009] According to some embodiments, the inverter further includes a charging and discharging circuit connected between the bus and the battery module. A preheating module is connected to the charging and discharging circuit; a power conversion circuit is connected between the bus and the power grid. A controller is also connected to the charging and discharging circuit and configured to: before controlling the preheating module to preheat the battery module, turn on the preheating module and the charging and discharging circuit, and control the charging and discharging circuit to operate in a constant voltage mode; and when the ambient temperature is higher than or equal to a first threshold, turn on the battery module and the charging and discharging circuit, and control the charging and discharging circuit to perform charging and discharging.

[0010] According to some embodiments, the inverter further includes a third sensing circuit, a fourth sensing circuit, and a controller connected to the third and fourth sensing circuits respectively. The third sensing circuit is used to sample the voltage of the battery module. The fourth sensing circuit is used to sample the port voltage of the charge / discharge circuit. The controller is configured to: before controlling the preheating module to preheat the battery module, determine whether the difference between the voltage of the battery module and the port voltage of the charge / discharge circuit is less than a second threshold, so that if the difference is less than the second threshold, the preheating module is controlled to preheat the battery module, and if the difference is greater than or equal to the second threshold, the port voltage of the charge / discharge circuit is adjusted.

[0011] According to some embodiments, the inverter further includes an acquisition module for acquiring fault codes of the battery module. A controller connected to the acquisition module is configured to, based on the fault codes, control the preheating module to stop preheating the battery module.

[0012] According to some embodiments, the inverter further includes a fifth sensing circuit for sampling the temperature of the energy storage battery. The controller is connected to the fifth sensing circuit and configured to: determine whether the temperature of the energy storage battery is higher than or equal to a third threshold; control the preheating module to stop preheating the battery module when the temperature of the energy storage battery is higher than or equal to the third threshold; and control the preheating module to continue preheating the battery module when the temperature of the energy storage battery is lower than the third threshold.

[0013] Secondly, this application also provides an energy storage converter system, including the inverter described above. The inverter is connected between the energy storage battery and the power grid.

[0014] Thirdly, this application also provides a thermal management method for an energy storage converter system, the energy storage converter system including: an inverter connected between an energy storage battery and the power grid; the energy storage battery including a battery module and a preheating module thermally connected to the battery module.

[0015] Thermal management methods include the following steps:

[0016] Determine if the power grid has electricity;

[0017] When the power grid is available, determine whether the ambient temperature of the battery module is lower than the first threshold.

[0018] When the ambient temperature is below the first threshold, the power grid supplies power to the preheating module and controls the preheating module to preheat the battery module.

[0019] According to some embodiments, the inverter includes: a power conversion circuit and a controller connected to the power conversion circuit. The power conversion circuit is connected between a preheating module and the power grid. The function of supplying power from the power grid to the preheating module when the ambient temperature is below a first threshold includes: controlling the power conversion circuit to conduct when the ambient temperature is below the first threshold, thereby supplying power from the power grid to the preheating module.

[0020] According to some embodiments, the inverter further includes: a charging and discharging circuit connected between the bus and the battery module. A preheating module is connected to the charging and discharging circuit. A power conversion circuit is connected between the bus and the power grid. The thermal management method further includes the following steps.

[0021] Before the preheating module preheats the battery module, the preheating module and the charging / discharging circuit are connected, and the charging / discharging circuit is controlled to operate in constant voltage mode.

[0022] When the ambient temperature is higher than or equal to the first threshold, the battery module and the charging and discharging circuit are turned on, and the charging and discharging circuit is controlled to charge and discharge.

[0023] According to some embodiments, the thermal management method further includes the following steps.

[0024] Before controlling the preheating module to preheat the battery module, it is determined whether the difference between the voltage of the battery module and the port voltage of the charging and discharging circuit is less than a second threshold.

[0025] If the difference is less than the second threshold, the preheating module is controlled to preheat the battery module.

[0026] If the difference is greater than or equal to the second threshold, the port voltage of the charging and discharging circuit is adjusted.

[0027] According to some embodiments, the thermal management method further includes the following steps.

[0028] Obtain the fault codes for the battery module;

[0029] Based on the fault code, control the preheating module to stop preheating the battery module.

[0030] According to some embodiments, the thermal management method further includes the following steps.

[0031] Determine whether the temperature of the energy storage battery is higher than or equal to the third threshold.

[0032] If the temperature of the energy storage battery is higher than or equal to the third threshold, the preheating module will stop preheating the battery module.

[0033] If the temperature of the energy storage battery is lower than the third threshold, the preheating module is controlled to continue preheating the battery module.

[0034] The various embodiments of this application have at least one of the following advantages:

[0035] This application utilizes an inverter installed between the energy storage battery and the power grid to determine whether the power grid is operational. When the power grid is operational, it determines whether the ambient temperature of the battery module is below a first threshold. Furthermore, when the ambient temperature is below the first threshold, the power grid supplies power to the preheating module of the energy storage battery, and the preheating module preheats the battery module. Thus, this application eliminates the need for additional photovoltaic modules to meet the preheating requirements of the energy storage battery, which helps ensure and improve the battery's lifespan and performance, thereby enhancing the safety and stability of the energy storage converter system. Attached Figure Description

[0036] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0037] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of an energy storage converter system in some embodiments;

[0039] Figure 2 This is a schematic diagram of another energy storage converter system in some embodiments;

[0040] Figure 3 This is a schematic diagram of the structure of another energy storage converter system in some embodiments;

[0041] Figure 4 This is a schematic diagram of the structure of another energy storage converter system in some embodiments;

[0042] Figure 5 This is a schematic diagram of the structure of another energy storage converter system in some embodiments;

[0043] Figure 6 This is a schematic diagram of the structure of an energy storage battery in some embodiments;

[0044] Figure 7 This is a flowchart illustrating a thermal management method in some embodiments;

[0045] Figure 8 This is a flowchart illustrating another thermal management method in some embodiments;

[0046] Figure 9 This is a flowchart illustrating another thermal management method in some embodiments;

[0047] Figure 10 This is a flowchart illustrating yet another thermal management method in some embodiments;

[0048] Figure 11 This is a flowchart illustrating yet another thermal management method in some embodiments;

[0049] Figure 12 This is a flowchart illustrating yet another thermal management method in some embodiments;

[0050] Figure 13 This is a flowchart illustrating another thermal management method in some embodiments.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1-Energy storage battery, 11-Battery module, 12-Preheating module, 13-Gating module, 131-First gating circuit, 132-Second gating circuit, 2-Inverter, 21-First sensing circuit, 22-Second sensing circuit, 23-Energy conversion circuit, 24-Controller, 201-Charging and discharging circuit, 202-Balance bridge circuit, 203-Bidirectional inverter circuit, 203'-Inverter circuit, 204-Inverter gating circuit, 3-Grid, 31-Grid connection gating circuit, 4-Load, 5-Display device. Detailed Implementation

[0053] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0054] Some exemplary embodiments of this application have been described for illustrative purposes. It should be understood that this application may be implemented in other ways not specifically shown in the accompanying drawings.

[0055] Currently, most energy storage batteries in energy storage converter systems are lithium-ion batteries. However, the physical characteristics of lithium-ion batteries are easily affected by the external environment. For example, in high-latitude regions, if the ambient temperature is too low (e.g., below 0°C), the capacity and output characteristics of the energy storage battery will decrease. This can lead to problems such as incomplete charging under cold conditions, and will also affect the battery's lifespan and performance.

[0056] For example, the preheating methods available for energy storage batteries mainly rely on heat conduction from external media such as gases, liquids, or inherent materials. However, these methods are prone to uneven heating, high costs, and low safety. Furthermore, in some examples, the energy storage converter system incorporates photovoltaic (PV) modules, which can supplement the energy storage battery's heating energy and control the startup of the energy storage converter. However, for energy storage converter systems without PV modules and corresponding external hardware, there is currently no effective battery preheating solution.

[0057] Based on this, embodiments of this application provide an inverter, an energy storage converter system, and a thermal management method thereof, thereby eliminating the need for photovoltaic modules to meet the preheating requirements of the energy storage battery. This helps to ensure and improve the lifespan and performance of the energy storage battery, and further enhances the safety of the stable operation of the energy storage converter system.

[0058] Please see Figure 1 The energy storage converter system provided in this application includes an inverter 2, which is connected between the energy storage battery 1 and the power grid 3. The energy storage battery 1 includes a battery module 11 and a preheating module 12 that is thermally connected to the battery module 11.

[0059] For example, the thermal conduction connection between the preheating module 12 and the battery module 11 includes, but is not limited to: the preheating module 12 being disposed on at least one side of the battery module 11 (including one side, multiple sides, or surrounding the periphery, etc.), and the preheating module 12 being in contact with or not in contact with the battery module 11; that is, the preheating module 12 only needs to be able to provide a thermal environment to the battery module 11 for heat conduction. This application does not specifically limit the relative position and connection between the preheating module 12 and the battery module 11.

[0060] Accordingly, the inverter 2 is configured to: determine whether the grid 3 has power, and when the grid 3 has power, determine whether the ambient temperature of the battery module 11 is lower than a first threshold; and when the ambient temperature is lower than the first threshold, cause the grid 3 to provide power to the preheating module 12, and control the preheating module 12 to preheat the battery module 11.

[0061] In this embodiment, the inverter 2, located between the energy storage battery 1 and the power grid 3, can determine whether the power grid 3 has power. When the power grid 3 has power, it can determine whether the ambient temperature of the battery module 11 of the energy storage battery 1 is below a first threshold. Furthermore, when the ambient temperature is below the first threshold, the power grid 3 supplies power to the preheating module 12 of the energy storage battery 1, and the preheating module 12 preheats the battery module 11 of the energy storage battery 1. Thus, this embodiment achieves the preheating requirement of the energy storage battery 1 in the energy storage converter system without adding photovoltaic modules, which helps ensure and improve the lifespan and performance of the energy storage battery, thereby enhancing the safety of the stable operation of the energy storage converter system.

[0062] In some embodiments, please refer to Figure 2 The inverter 2 includes: a first sensing circuit 21, a second sensing circuit 22, a power conversion circuit 23, and a controller 24 connected to the first sensing circuit 21, the second sensing circuit 22, and the power conversion circuit 23 respectively.

[0063] The first sensing circuit 21 is used to sample the electrical signal of the power grid 3, for example, it can be connected to the power grid 3.

[0064] The second sensing circuit 22 is used to sample the ambient temperature of the battery module 11, for example, it can be a temperature sensing circuit located next to the battery module 11.

[0065] The power conversion circuit 23 is connected between the preheating module 12 and the power grid 3.

[0066] The controller 24 is configured to: determine whether the power grid 3 has power based on the electrical signal of the power grid 3; determine whether the ambient temperature of the battery module 11 is lower than a first threshold when the power grid 3 has power; and control the power conversion circuit 23 to turn on when the ambient temperature is lower than the first threshold, so that the power grid 3 provides power to the preheating module 12, and control the preheating module 12 to preheat the battery module 11.

[0067] It is understood that the above-mentioned power conversion circuit 23 is used to realize the power conversion and transmission between the power grid 3 and the energy storage battery 1. The power conversion circuit 23 can be selected and set according to the needs.

[0068] In some embodiments, please combine Figure 3 It is understood that the power conversion circuit 23 includes a bidirectional inverter circuit 203, that is, the bidirectional inverter circuit 203 in the inverter 2 can be reused as the power conversion circuit 23. Thus, in this embodiment of the application, the preheating requirements of the energy storage battery 1 can be met without adding photovoltaic modules and external hardware to the energy storage converter system, which is beneficial to simplifying the circuit structure and reducing costs.

[0069] In other embodiments, please refer to Figure 4It is understood that the inverter 2 also includes an inverter circuit 203' connected between the preheating module 12 and the power grid 13; wherein, the power conversion circuit 23 is connected in parallel with the inverter circuit 203', that is, the power conversion circuit 23 can be set as a bypass of the inverter circuit 203'. The power conversion circuit 23 can be, for example, a rectifier circuit. Thus, in this embodiment, a rectifier circuit can be added as the power conversion circuit 23 between the power grid 3 and the energy storage battery 11 without changing the existing circuit structure of the energy storage converter system. This embodiment does not limit the structure of the rectifier circuit, as long as the rectifier circuit can realize the power transmission from the power grid 3 to the energy storage battery 1.

[0070] For ease of description, the following embodiments use the power conversion circuit 23 as an example of a bidirectional inverter circuit 203 to illustrate the structure of the energy storage converter system and the energy storage battery 1.

[0071] In some embodiments, please combine Figure 2 , Figure 3 and Figure 4 It is understood that the inverter 2 also includes a charging and discharging circuit 201 connected between the bus (BUS+ and BUS-) and the battery module 11. A preheating module 12 is connected to the charging and discharging circuit 201. A power conversion circuit 23 is connected between the bus (BUS+ and BUS-) and the power grid 3. A controller 24 is also connected to the charging and discharging circuit 201 and configured to: before controlling the preheating module 12 to preheat the battery module 11, turn on the preheating module 11 and the charging and discharging circuit 201, and control the charging and discharging circuit 201 to operate in a constant voltage mode; and when the ambient temperature is higher than or equal to a first threshold, turn on the battery module 11 and the charging and discharging circuit 201, and control the charging and discharging circuit 201 to perform charging and discharging.

[0072] In this embodiment, without adding photovoltaic modules and external hardware to the energy storage converter system, the energy storage battery 1 in the energy storage converter system can be selectively controlled between preheating requirements and charging / discharging requirements. This helps to ensure and improve the lifespan and performance of the energy storage battery 1, thereby improving the safety of the stable operation of the energy storage converter system.

[0073] For example, the first threshold includes, but is not limited to, 0°C.

[0074] In some embodiments, please combine Figure 2 , Figure 3 and Figure 4It is understood that the inverter 2 is connected to the grid 3 through the grid connection selection circuit 31, and its controller 24 is also connected to the grid connection selection circuit 31. When the grid 3 is powered, the controller can control the grid connection selection circuit 31 to be in a conducting state, thereby connecting the grid 3 and the power conversion circuit 23, and supplying power to the bus (BUS+ and BUS-) through the power conversion circuit 23 to establish the bus (BUS+ and BUS-) voltage.

[0075] It should be added that for energy storage converter systems without photovoltaic modules, if the ambient temperature is greater than or equal to the first threshold, the preheating module 12 of the energy storage battery 1 does not need to work, and the energy storage battery 1 can charge and discharge normally. However, if the ambient temperature is lower than the first threshold, and the controller 24 of the inverter 2 determines that the energy storage battery 1 needs to be charged, the preheating module 12 of the energy storage battery 1 needs to be activated first for preheating, so that the energy storage battery 1 can be charged after the ambient temperature is greater than or equal to the first threshold. That is, the embodiments of this application can establish the voltage of the grid 3 to the bus (BUS+ and BUS-) by relying on the self-starting logic when the energy storage battery 1 is not suitable for operation (e.g., low temperature conditions), and enable the preheating module 12 to heat the battery module 11 in the absence of photovoltaic modules and without the addition of external hardware in the energy storage converter system, thereby enriching the application scenarios of energy storage converter systems without photovoltaic modules.

[0076] In some embodiments, please refer to Figure 3 Inverter 2 may include, in sequence, a charging / discharging circuit 201, a balancing bridge circuit 202, a bidirectional inverter circuit 203, and an inverter gating circuit 204. The inverter gating circuit 204 is connected to the grid-connected gating circuit 31. Correspondingly, controller 24 is also configured to, when controlling the grid-connected gating circuit 31 to be in a conducting state, control the inverter gating circuit 204 to be in a conducting state, enabling the power grid 3 to supply power to the buses (BUS+ and BUS-) through the bidirectional inverter circuit 203 (i.e., the power conversion circuit 23).

[0077] In some embodiments, the inverter gating circuit 24 of the inverter 2 is also used to connect the load 4.

[0078] The embodiments disclosed herein do not limit the specific structure of each component circuit in inverter 2 or the connection relationship between them, but are limited to the ability to achieve the corresponding functions.

[0079] For example, the charging and discharging circuit 201 can be a bidirectional DC-DC converter (BDC).

[0080] For example, the balanced bridge circuit 202 can be constructed using components such as capacitors, inductors, and thyristors, for example... Figure 3As shown, the system includes thyristors T1 and T2, capacitors C1 and C2, and inductor L1. The first terminal of capacitor C1 is connected to the positive bus BUS+, the first terminal of capacitor C2 is connected to the negative bus BUS-, the second terminals of capacitors C1 and C2 are connected to the neutral point N, the first terminal of thyristor T1 is connected to the positive bus BUS+, the second terminal of thyristor T2 is connected to the negative bus BUS-, and the second terminals of thyristors T1 and T2 are connected and connected to the neutral point N through inductor L1.

[0081] For example, the bidirectional inverter circuit 203 is a three-phase inverter circuit. In the bidirectional inverter circuit 203, an inductor is connected in series in the phase lines not connected to the neutral point N of the bus, for example... Figure 3 The inductors L2 and L3 are shown in the diagram. In the bidirectional inverter circuit 203, a capacitor is connected in series between the phase line connecting to the neutral point N of the bus and the adjacent phase line, for example... Figure 3 The capacitors C4 and C5 are shown in the diagram. Furthermore, Figure 3 The equivalent capacitance C3 of the bus neutral point N to ground PE is also shown.

[0082] For example, the inverter gating circuit 204 can be constructed using gating switches connected in parallel on each phase line of the bidirectional inverter circuit 23. The gating switches are, for example, [missing information - likely a specific type of switch]. Figure 3 The relays Rly1, Rly2, and Rly3 shown are illustrated. The grid-connected selection circuit 31 can be constructed using multiple selection switches corresponding to the selection switches in the inverter selection circuit 204 (e.g., relays Rly1, Rly2, and Rly3), for example... Figure 3 The relays Rly4, Rly5, and Rly6 are shown in the diagram.

[0083] For example, please continue reading Figure 3 A capacitor C6 is connected in series between the line connecting relay Rly5 and the line connecting relay Rly4 of power grid 3, and a capacitor C7 is connected in series between the line connecting relay Rly5 and the line connecting relay Rly6 of power grid 3.

[0084] For example, please continue reading Figure 3 The line connecting load 4 to ground PE can also be connected to the bus neutral point N via a switch (e.g., relay Rly7). A capacitor C8 is connected in series between the line connecting load 4 to relay Rly2 and the line connecting load 4 to relay Rly1, and a capacitor C9 is connected in series between the line connecting load 4 to relay Rly2 and the line connecting load 4 to relay Rly3.

[0085] In some embodiments, please refer to Figure 5The energy storage battery 1 also includes a selection module 13 connected to the preheating module 12 and the battery module 11. The controller 24 of the inverter 2 can select to turn on the preheating module 12 and the charging / discharging circuit 201, or turn on the battery module 11 and the charging / discharging circuit 201, through the selection module 13.

[0086] Please continue reading. Figure 5 In some embodiments, the gating module 13 includes a first gating circuit 131 and a second gating circuit 132. The control terminal of the first gating circuit 131 is connected to the controller 24, its first terminal is connected to the preheating module 12, and its second terminal is connected to the charging / discharging circuit 21. The control terminal of the second gating circuit 132 is connected to the controller 24, its first terminal is connected to the battery module 11, and its second terminal is connected to the charging / discharging circuit 21. The first gating circuit 131 can be in a conducting state in response to a first control command from the controller 24, and in a de-energized state in response to a second control command from the controller 24. The second gating circuit 132 can be in a de-energized state in response to a first control command from the controller 24, and in a conducting state in response to a second control command from the controller 24. The first control command from the controller 24 can be generated when the ambient temperature of the battery module 11 is below a first threshold, and the second control command from the controller 24 can be generated when the ambient temperature of the battery module 11 is above or equal to the first threshold.

[0087] In this embodiment of the application, although the preheating circuit built on the first gate circuit 131 and the charging and discharging circuit built on the second gate circuit 132 in the energy storage battery 1 can share the corresponding circuit formed by the charging and discharging circuit 201 connecting bus (BUS+ and BUS-), the preheating circuit and the charging and discharging circuit cannot work at the same time.

[0088] In some embodiments, please combine Figure 5 and Figure 6 Understand, the busbar includes the positive busbar BUS+ and the negative busbar BUS-.

[0089] Accordingly, the first gating circuit 131 includes, for example, a first switch K1, a first relay M1, and a second relay M2. The second gating circuit 132 includes, for example, a second switch K2, a first battery contactor N1, and a second battery contactor N2.

[0090] like Figure 6As shown, the first terminal of the first relay M1 is connected to the positive transmission terminal of the preheating module 12, and the second terminal of the first relay M1 is connected to the positive transmission terminal of the charging and discharging circuit 201. For example, the charging and discharging circuit 201 can be connected to the positive transmission terminal (P+) of the preheating module 12. The first terminal of the second relay M2 is connected to the negative transmission terminal of the preheating module 12 through the first switch K1, and the second terminal of the second relay M2 is connected to the negative transmission terminal of the charging and discharging circuit 201. For example, the charging and discharging circuit 201 can be connected to the negative transmission terminal (P-) of the preheating module 12. The control terminals of both the first and second relays M1 are connected to the controller 24.

[0091] like Figure 6 As shown, the first end of the first battery contactor N1 is connected to the positive terminal of the battery module 11, and the second end of the first battery contactor N1 is connected to the positive transmission terminal of the charging / discharging circuit 201, for example, the charging / discharging circuit 201 can be connected to the positive transmission terminal (P+) of the preheating module 12. The first end of the second battery contactor N2 is connected to the negative terminal of the battery module 11, and the second end of the second battery contactor N2 is connected to the negative transmission terminal B- of the charging / discharging circuit 201 and connected to the negative transmission terminal of the charging / discharging circuit 201 through the second switch K2, for example, the charging / discharging circuit 201 can be connected to the negative transmission terminal (P-) of the preheating module 12. The control terminals of the first battery contactor N1 and the second battery contactor N2 are both connected to the controller 24.

[0092] In some embodiments, please continue reading Figure 6 A fuse F is connected in series between the second terminal of the second battery contactor N2 and the second switch K2.

[0093] In some embodiments, please combine Figure 2 , Figure 3 , Figure 4 and Figure 6 It is understood that the inverter 2 also includes an acquisition module for acquiring fault codes of the battery module 11. The controller 24 is connected to the acquisition module and is configured to control the preheating module 12 to stop preheating the battery module 11 based on the fault codes.

[0094] For example, please refer to Figure 6 The battery module 11 includes multiple battery cells U connected in series, and a single-cell battery management unit (BMU) connected to each battery cell U. The single-cell battery management unit (BMU) is configured to monitor the performance parameters of the corresponding battery cell U. The acquisition module of the inverter 2 can be connected to each single-cell battery management unit (BMU) to determine whether the battery module 11 is in a fault state based on the performance parameters of each battery cell U, and to acquire a fault code when the battery module 11 is in a fault state, thereby preventing or stopping preheating of the battery module 11.

[0095] For example, a battery cell U can be composed of one or multiple cells connected in series. The battery cells U in the battery module 11 are connected in series, and according to their series connection order, the positive terminal of the first battery cell U is the positive terminal of the battery module 11, and the negative terminal of the last battery cell U is the negative terminal of the battery module 11.

[0096] For example, battery cells U are configured in a one-to-one correspondence with individual battery management units (BMUs). The performance parameters of battery cells U that can be monitored by the individual battery management units (BMUs) include, but are not limited to, voltage V and temperature T. Furthermore, the individual battery management units (BMUs) can also perform voltage management on battery cells U, such as voltage equalization.

[0097] For example, a single-cell battery management unit (BMU) can be composed of one or more management chips (AFE). For instance, the management chips (AFE) in the single-cell battery management unit (BMU) are configured to correspond one-to-one with the cells in the battery cell (U).

[0098] For example, the preheating module 12 includes multiple heating units (Hot) corresponding to each battery cell, and the multiple heating units (Hot) are connected in parallel. The heating unit (Hot) can be a heating circuit or a heating device; the specific structure is not limited in this embodiment, as long as it can heat the battery cell. Furthermore, the preheating module 12 is disposed beside the battery module 11, including on the outer or inner side of the corresponding battery cell.

[0099] In some embodiments, the energy storage battery 1 may be equipped with an independent control module. The controller 24 of the inverter 2 is connected to the control module of the energy storage battery 1 through a CAN bus to achieve communication and to realize the relay control of each component in the energy storage battery 1 through the control module of the energy storage battery 1.

[0100] The controller 24 of the inverter 2 and the control module in the energy storage battery 1 can be implemented entirely or partially through software, hardware and their combination. For example, they can be embedded in the processor of the computer device in hardware form or independent of the processor, or stored in the memory of the computer device in software form, so that the processor can call and execute the corresponding operations of the control module in the aforementioned controller 24 and energy storage battery 1.

[0101] In some embodiments, the controller 24 of the inverter 2 and / or the control module of the energy storage battery 1 are connected to the display device 5. The display device 5 can visually display the performance parameters of the battery unit U, the fault codes of the battery module 11, and at least some of the control commands of the controller 24 and the information required for the function implementation.

[0102] It should be added that, in some embodiments, the inverter 2 further includes a third sensing circuit and a fourth sensing circuit. The controller 23 is connected to the third sensing circuit and the fourth sensing circuit respectively. The third sensing circuit is used to sample the voltage of the battery module 11. The fourth sensing circuit is used to sample the port voltage of the charge / discharge circuit 201. The controller 24 is configured to: before controlling the preheating module 12 to preheat the battery module 11, determine whether the difference between the voltage of the battery module 11 and the port voltage of the charge / discharge circuit 201 is less than a second threshold, so that when the difference is less than the second threshold, the preheating module 12 is controlled to preheat the battery module 11, and when the difference is greater than or equal to the second threshold, the port voltage of the charge / discharge circuit 201 is adjusted.

[0103] In some embodiments, the inverter 2 further includes a fifth sensing circuit for sampling the temperature of the energy storage battery 1. The controller 24 is connected to the fifth sensing circuit and is configured to: determine whether the temperature of the energy storage battery 1 is higher than or equal to a third threshold; control the preheating module 12 to stop preheating the battery module 11 when the temperature of the energy storage battery 1 is higher than or equal to the third threshold; and control the preheating module 12 to continue preheating the battery module 11 when the temperature of the energy storage battery 1 is lower than the third threshold.

[0104] This application also provides an energy storage converter system, including the inverter as described in some of the preceding embodiments. The structure of the inverter can be referred to the relevant descriptions in the foregoing embodiments, and will not be repeated here.

[0105] This application also provides a thermal management method for an energy storage converter system.

[0106] Please see Figure 7 The thermal management method includes the following steps S100~S300.

[0107] S100 determines whether there is electricity in the power grid.

[0108] S200 determines whether the ambient temperature of the battery module is lower than a first threshold when the power grid is available.

[0109] Here, it can be understood that if it is determined that there is no power in the grid, the subsequent processes cannot be initiated.

[0110] For example, the first threshold includes, but is not limited to, 0°C.

[0111] S300, when the ambient temperature is below the first threshold, enables the power grid to supply power to the preheating module and controls the preheating module to preheat the battery module.

[0112] In some embodiments, the inverter includes a power conversion circuit and a controller connected to the power conversion circuit. The power conversion circuit is connected between the preheating module and the power grid. Accordingly, in step S300, supplying power to the preheating module from the power grid when the ambient temperature is below a first threshold includes: controlling the power conversion circuit to turn on when the ambient temperature is below the first threshold, thereby supplying power to the preheating module from the power grid.

[0113] Here, we can understand it as taking the bidirectional inverter circuit in the inverter as an example of the power conversion circuit. Accordingly, after the ambient temperature drops below the first threshold, the energy storage battery stops working, and the inverter executes the self-starting program and self-test program, which can establish the bus voltage through the power grid.

[0114] Therefore, it should be added that in step S300, controlling the power conversion circuit to conduct so that the power grid provides power to the preheating module can be manifested as: controlling the grid connection selection circuit to be in a conducting state so that the power grid connects to the bidirectional inverter circuit of the inverter.

[0115] For example, please combine Figure 3 To understand, controlling the grid connection selection circuit 31 to be in a conducting state can be manifested by controlling each selection switch in the grid connection selection circuit 31 to be in a closed state; for example, controlling relays Rly4, Rly5, and Rly6 to be energized. Correspondingly, enabling the grid to connect the inverter to the bidirectional inverter circuit can be manifested by controlling each selection switch in the inverter selection circuit 204 to be in a closed state at the same time or after controlling the grid connection selection circuit 31 to be in a conducting state; for example, controlling relays Rly1, Rly2, and Rly3 to be energized.

[0116] In some embodiments, the inverter further includes a charging and discharging circuit connected between the bus and the battery module. A preheating module is connected to the charging and discharging circuit. An energy conversion circuit is connected between the bus and the power grid.

[0117] Accordingly, please refer to Figure 8 The thermal management method further includes the following steps S210 and S310.

[0118] S210 connects the preheating module and the charging / discharging circuit before controlling the preheating module to preheat the battery module, and controls the charging / discharging circuit to work in constant voltage mode.

[0119] S310, when the ambient temperature is higher than or equal to the first threshold, connects the battery module and the charging and discharging circuit, and controls the charging and discharging circuit to charge and discharge.

[0120] For example, in step S300, the preheating module can preheat the battery module by drawing power from the bus through the charging and discharging circuit after the charging and discharging circuit operates in constant voltage mode.

[0121] Here, bus voltage stability means that the voltage between the positive bus BUS+ and the negative bus BUS- can be maintained within the target threshold or target voltage range.

[0122] In some embodiments, please refer to Figure 9 The thermal management method further includes the following steps S220 and S230.

[0123] S220: Before controlling the preheating module to preheat the battery module, determine whether the difference between the battery module voltage and the port voltage of the charging / discharging circuit is less than a second threshold. If the difference is less than the second threshold, control the preheating module to preheat the battery module. If the difference is greater than or equal to the second threshold, adjust the port voltage of the charging / discharging circuit, i.e., execute S230.

[0124] For example, the second threshold is greater than or equal to 20V.

[0125] For example, adjusting the port voltage of the charging and discharging circuit can be achieved by controlling the port ripple of the charging and discharging circuit to perform voltage modulation; for example, floating voltage can be effectively eliminated.

[0126] The embodiments of this application can effectively prevent the voltage difference between the energy storage battery and the port voltage of the charging and discharging circuit in the inverter from being too large, thereby avoiding current surges or overcurrent problems after the battery module of the energy storage battery is preheated.

[0127] In some embodiments, please refer to Figure 10 The thermal management method further includes the following steps S410 and S420.

[0128] S410, retrieve the fault code for the battery module.

[0129] S420, based on the fault code, controls the preheating module to stop preheating the battery module.

[0130] Here, it can be understood that if the battery module is confirmed to be fault-free, the energy storage battery can be controlled to close the heating relay, send heating power to the inverter, and control the charging and discharging circuit in the inverter to operate in constant voltage mode.

[0131] It is understood that the fault codes of the battery module that can be obtained in step S410 may not include over-temperature fault codes. Furthermore, if a fault code is obtained in step S410, since step S300 has not yet been executed, step S410 specifically executes the function of preventing the preheating module from preheating the battery module based on the fault code.

[0132] Accordingly, in some other embodiments, step S410 may also be performed after step S300 (e.g., Figure 11 (as shown) or repeat (e.g.) Figure 12 (As shown in the diagram). Thus, the fault code of the battery module that can be obtained in step S410 can be an over-temperature fault code, that is: step S410, which is executed after step S300, can be: obtaining the over-temperature fault code of the battery module.

[0133] Based on this, in some embodiments, please refer to Figure 13 The thermal management method may further include the following step S500.

[0134] S500 determines whether the temperature of the energy storage battery is higher than or equal to a third threshold. If the temperature of the energy storage battery is higher than or equal to the third threshold, the preheating module is controlled to stop preheating the battery module. If the temperature of the energy storage battery is lower than the third threshold, the preheating module is controlled to continue preheating the battery module.

[0135] For example, the third threshold may be the same as or different from the first threshold.

[0136] For example, the third threshold includes, but is not limited to, 0°C.

[0137] It is understandable that after the preheating module stops preheating the battery module, the charging and discharging circuit exits the heating state and can charge and discharge the battery module.

[0138] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0139] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An inverter, characterized in that, include: The inverter is connected between the energy storage battery and the power grid; The energy storage battery includes a battery module and a preheating module that is thermally connected to the battery module; The inverter is configured to: determine whether the power grid has power, and when the power grid has power, determine whether the ambient temperature of the battery module is lower than a first threshold; and when the ambient temperature is lower than the first threshold, cause the power grid to provide power to the preheating module and control the preheating module to preheat the battery module.

2. The inverter according to claim 1, characterized in that, The inverter includes: A first sensing circuit is used to sample the electrical signals of the power grid; The second sensing circuit is used to sample the ambient temperature of the battery module; An energy conversion circuit is connected between the preheating module and the power grid; The controller, connected to the first sensing circuit, the second sensing circuit, and the power conversion circuit respectively, is configured to: determine whether the power grid has power based on the electrical signal of the power grid; when the power grid has power, determine whether the ambient temperature of the battery module is lower than a first threshold; and when the ambient temperature is lower than the first threshold, control the power conversion circuit to conduct, so that the power grid provides power to the preheating module, and control the preheating module to preheat the battery module.

3. The inverter according to claim 2, characterized in that, The power conversion circuit includes a bidirectional inverter circuit.

4. The inverter according to claim 2, characterized in that, The inverter further includes an inverter circuit connected between the preheating module and the power grid; The power conversion circuit is connected in parallel with the inverter circuit; the power conversion circuit includes a rectifier circuit.

5. The inverter according to claim 2, characterized in that, The inverter further includes a charging and discharging circuit connected between the bus and the battery module; The preheating module is connected to the charging and discharging circuit; the power conversion circuit is connected between the busbar and the power grid. The controller is also connected to the charging and discharging circuit and is configured to: before controlling the preheating module to preheat the battery module, turn on the preheating module and the charging and discharging circuit, and control the charging and discharging circuit to operate in constant voltage mode; and when the ambient temperature is higher than or equal to the first threshold, turn on the battery module and the charging and discharging circuit, and control the charging and discharging circuit to charge and discharge.

6. The inverter according to claim 5, characterized in that, The inverter also includes: The third sensing circuit is used to sample the voltage of the battery module; The fourth sensing circuit is used to sample the port voltage of the charging and discharging circuit; The controller is connected to the third sensing circuit and the fourth sensing circuit respectively, and is configured to: before controlling the preheating module to preheat the battery module, determine whether the difference between the voltage of the battery module and the port voltage of the charging and discharging circuit is less than a second threshold, so that when the difference is less than the second threshold, the preheating module is controlled to preheat the battery module, and when the difference is greater than or equal to the second threshold, the port voltage of the charging and discharging circuit is adjusted.

7. The inverter according to claim 2, characterized in that, The inverter also includes: An acquisition module is used to acquire the fault codes of the battery module; The controller is connected to the acquisition module and is configured to: control the preheating module to stop preheating the battery module according to the fault code.

8. The inverter according to any one of claims 2 to 7, characterized in that, The inverter also includes: The fifth sensing circuit is used to sample the temperature of the energy storage battery; The controller is connected to the fifth sensing circuit and is configured to: determine whether the temperature of the energy storage battery is higher than or equal to a third threshold, so that when the temperature of the energy storage battery is higher than or equal to the third threshold, the preheating module is controlled to stop preheating the battery module, and when the temperature of the energy storage battery is lower than the third threshold, the preheating module is controlled to continue preheating the battery module.

9. An energy storage converter system, characterized in that, Includes an inverter as described in any one of claims 1 to 8, wherein the inverter is connected between an energy storage battery and the power grid; The energy storage battery includes a battery module and a preheating module that is thermally connected to the battery module.

10. A thermal management method for an energy storage converter system, characterized in that, The energy storage converter system includes: an inverter connected between the energy storage battery and the power grid; the energy storage battery includes a battery module and a preheating module thermally connected to the battery module; The thermal management method includes: Determine whether the power grid has power; When the power grid is energized, determine whether the ambient temperature of the battery module is lower than a first threshold. When the ambient temperature is lower than the first threshold, the power grid supplies electrical energy to the preheating module and controls the preheating module to preheat the battery module.

11. The thermal management method according to claim 10, characterized in that, The inverter includes: a power conversion circuit and a controller connected to the power conversion circuit; the power conversion circuit is connected between the preheating module and the power grid; The step of supplying power from the power grid to the preheating module when the ambient temperature is lower than the first threshold includes: controlling the power conversion circuit to conduct when the ambient temperature is lower than the first threshold, so that the power grid supplies power to the preheating module.

12. The thermal management method according to claim 10, characterized in that, The inverter further includes: a charging and discharging circuit connected between the bus and the battery module; a preheating module connected to the charging and discharging circuit; and an energy conversion circuit connected between the bus and the power grid. The thermal management method further includes: Before controlling the preheating module to preheat the battery module, the preheating module and the charging and discharging circuit are turned on, and the charging and discharging circuit is controlled to work in constant voltage mode; When the ambient temperature is higher than or equal to the first threshold, the battery module and the charging / discharging circuit are switched on, and the charging / discharging circuit is controlled to charge and discharge.

13. The thermal management method according to claim 12, characterized in that, The thermal management method further includes: Before controlling the preheating module to preheat the battery module, it is determined whether the difference between the voltage of the battery module and the port voltage of the charging and discharging circuit is less than a second threshold. If the difference is less than the second threshold, then the preheating module is controlled to preheat the battery module; If the difference is greater than or equal to the second threshold, then the port voltage of the charging and discharging circuit is adjusted.

14. The thermal management method according to claim 10, characterized in that, The thermal management method further includes: Obtain the fault code of the battery module; Based on the fault code, control the preheating module to stop preheating the battery module.

15. The thermal management method according to any one of claims 10 to 14, characterized in that, The thermal management method further includes: Determine whether the temperature of the energy storage battery is higher than or equal to the third threshold; If the temperature of the energy storage battery is higher than or equal to the third threshold, then the preheating module is controlled to stop preheating the battery module; If the temperature of the energy storage battery is less than the third threshold, the preheating module is controlled to continue preheating the battery module.

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