Inverter, energy storage converter system and thermal management method therefor

Abstract

An inverter, an energy storage converter system, and a thermal management method therefor. An inverter (2) is connected between an energy storage battery (1) and a power grid (3), and the energy storage battery (1) comprises a battery module (11) and a preheating module (12) thermally conductively connected to the battery module (11). The inverter (2) is configured to: when the power grid (3) is powered and the ambient temperature of the battery module (11) is lower than a first threshold, enable the power grid (3) to provide electric energy to the preheating module (12), and control the preheating module (12) to preheat the battery module (11).

Description

Inverter, energy storage converter system and thermal management method thereof

[0001] The present disclosure claims priority to the Chinese patent application No. 202411390490.0, filed on September 30, 2024, and entitled “Inverter, energy storage converter system and thermal management method thereof”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate to an inverter, an energy storage converter system and a thermal management method thereof. BACKGROUND

[0003] With the rapid development of new energy technology, energy storage systems capable of effectively storing energy are also increasingly important.

[0004] When the ambient temperature is low (e.g., below 0°C), at least one of the capacity and output characteristics of the energy storage battery decreases, resulting in difficulty in fully charging under cold conditions, which damages the service life and performance of the energy storage battery. SUMMARY

[0005] The following is a summary of the detailed description of the present disclosure. This summary is not intended to limit the scope of protection of the claims. The present disclosure provides an inverter, an energy storage converter system and a thermal management method thereof, and the present disclosure adopts the following technical solutions:

[0006] In a first aspect, embodiments of the present disclosure provide an inverter connected between an energy storage battery and a power grid, the energy storage battery comprising a battery module and a preheating module in thermal conductive connection with the battery module; the inverter is configured to, in a case where the power grid is powered and the ambient temperature of the battery module is lower than a first threshold, cause the power grid to provide power to the preheating module and control the preheating module to preheat the battery module.

[0007] According to some embodiments, the inverter comprises a first sensing circuit, a second sensing circuit, a power conversion circuit, and a controller connected with the first sensing circuit, the second sensing circuit, and the power conversion circuit, respectively. The first sensing circuit is configured to sample an electrical signal of the power grid. The second sensing circuit is configured 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, in a case where the electrical signal of the power grid indicates that the power grid is powered and the ambient temperature of the battery module is lower than the first threshold, control the power conversion circuit to be turned on, cause the power grid to provide power to the preheating module, and control the preheating module to preheat the battery module.

[0008] According to some embodiments, the power conversion circuit comprises a bidirectional inverter circuit.

[0009] According to some embodiments, the inverter further comprises: an inverter circuit connected between the preheating module and the power grid; wherein the electric energy conversion circuit is connected in parallel with the inverter circuit; and the electric energy conversion circuit comprises a rectifier circuit.

[0010] According to some embodiments, the inverter further comprises: a charge-discharge circuit connected between the bus and the battery module. The preheating module is connected to the charge-discharge circuit; and the electric energy conversion circuit is connected between the bus and the power grid. The controller is further connected to the charge-discharge circuit and configured to: before controlling the preheating module to preheat the battery module, turn on the preheating module and the charge-discharge circuit, and control the charge-discharge circuit to work in a constant voltage mode; and when the ambient temperature is higher than or equal to the first threshold value, turn on the battery module and the charge-discharge circuit, and control the charge-discharge circuit to charge and discharge.

[0011] According to some embodiments, the inverter further comprises: a third sensing circuit, a fourth sensing circuit, and a controller connected to the third sensing circuit and the fourth sensing circuit respectively. The third sensing circuit is configured to sample the voltage of the battery module. The fourth sensing circuit is configured 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, in the case that the difference between the voltage of the battery module and the port voltage of the charge-discharge circuit is less than a second threshold value, control the preheating module to preheat the battery module, and in the case that the difference between the voltage of the battery module and the port voltage of the charge-discharge circuit is greater than or equal to the second threshold value, adjust the port voltage of the charge-discharge circuit.

[0012] According to some embodiments, the inverter further comprises: an acquisition module configured to acquire a fault code of the battery module. The controller is connected to the acquisition module and configured to: according to the fault code, control the preheating module to stop preheating the battery module.

[0013] According to some embodiments, the inverter further comprises: a fifth sensing circuit configured to sample the temperature of the energy storage battery. The controller is connected to the fifth sensing circuit and configured to: in the case that the temperature of the energy storage battery is higher than or equal to a third threshold value, control the preheating module to stop preheating the battery module, and in the case that the temperature of the energy storage battery is less than the third threshold value, control the preheating module to continue preheating the battery module.

[0014] In a second aspect, the embodiments of the present disclosure further provide an energy storage conversion system, comprising the inverter as above, the inverter being connected between the energy storage battery and the power grid.

[0015] The energy storage battery comprises the battery module and the preheating module in thermal conductive connection with the battery module, and the inverter is configured to: in the case that the power grid has power and the ambient temperature of the battery module is lower than the first threshold value, enable the power grid to provide electric energy to the preheating module, and control the preheating module to preheat the battery module.

[0016] In a third aspect, the embodiments of the present disclosure further provide a thermal management method for an energy storage and conversion system, the energy storage and conversion system comprising: an inverter connected between an energy storage battery and a power grid; the energy storage battery comprising a battery module and a preheating module in thermal conductive connection with the battery module;

[0017] The thermal management method comprises:

[0018] In a case where the power grid has power and an ambient temperature of the battery module is lower than a first threshold, the power grid is caused to provide power to the preheating module, and the preheating module is controlled to preheat the battery module.

[0019] According to some embodiments, the inverter comprises: an electric energy conversion circuit. The electric energy conversion circuit is connected between the preheating module and the power grid. In this case, causing the power grid to provide power to the preheating module comprises: controlling the electric energy conversion circuit to be turned on, so that the power grid provides power to the preheating module.

[0020] According to some embodiments, the inverter further comprises: a charge and discharge circuit connected between a bus and the battery module. The preheating module is connected to the charge and discharge circuit. The electric energy conversion circuit is connected between the bus and the power grid. In this case, the thermal management method further comprises the following steps:

[0021] Before the preheating module is controlled to preheat the battery module, the preheating module and the charge and discharge circuit are turned on, and the charge and discharge circuit is controlled to work in a constant voltage mode;

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

[0023] According to some embodiments, the thermal management method further comprises the following steps:

[0024] Before the preheating module is controlled to preheat the battery module, in a case where a difference between a voltage of the battery module and a port voltage of the charge and discharge circuit is less than a second threshold, the preheating module is controlled to preheat the battery module;

[0025] In a case where the difference between the voltage of the battery module and the port voltage of the charge and discharge circuit is greater than or equal to the second threshold, the port voltage of the charge and discharge circuit is adjusted.

[0026] According to some embodiments, the thermal management method further comprises the following steps:

[0027] A fault code of the battery module is acquired;

[0028] According to the fault code, the preheating module is controlled to stop preheating the battery module.

[0029] According to some embodiments, the thermal management method further comprises the following steps:

[0030] in the case where the temperature of the energy storage battery is higher than or equal to the third threshold value, controlling the preheating module to stop preheating the battery module;

[0031] in the case where the temperature of the energy storage battery is lower than the third threshold value, controlling the preheating module to continue preheating the battery module.

[0032] Other aspects can become apparent from the following description, which, when taken in conjunction with the drawings, describe the preferred embodiments.

[0033] BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this disclosure, are intended to provide further understanding of the disclosure and are incorporated herein in conjunction with the description of the preferred embodiments. The description and illustrations of the preferred embodiments are intended to explain the disclosure, and are not intended to limit the disclosure.

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0036] FIG. 1 is a structural schematic diagram of a power storage converter system in some embodiments;

[0037] FIG. 2 is a structural schematic diagram of another power storage converter system in some embodiments;

[0038] FIG. 3 is a structural schematic diagram of another power storage converter system in some embodiments;

[0039] FIG. 4 is a structural schematic diagram of another power storage converter system in some embodiments;

[0040] FIG. 5 is a structural schematic diagram of another power storage converter system in some embodiments;

[0041] FIG. 6 is a structural schematic diagram of an energy storage battery in some embodiments;

[0042] FIG. 7 is a flowchart of a thermal management method in some embodiments;

[0043] FIG. 8 is a flowchart of another thermal management method in some embodiments;

[0044] FIG. 9 is a flowchart of another thermal management method in some embodiments;

[0045] FIG. 10 is a flowchart of another thermal management method in some embodiments;

[0046] FIG. 11 is a flowchart of another thermal management method in some embodiments;

[0047] FIG. 12 is a flow diagram of another thermal management method in some embodiments;

[0048] FIG. 13 is a flow diagram of another thermal management method in some embodiments.

[0049] BRIEF DESCRIPTION OF DRAWINGS: 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 - electric energy conversion circuit, 24 - controller, 201 - charge and discharge circuit, 202 - balancing bridge circuit, 203 - bidirectional inverter circuit, 203' - inverter circuit, 204 - inverter gating circuit, 3 - power grid, 31 - grid-connection gating circuit, 4 - load, 5 - display device. DETAILED DESCRIPTION

[0050] Embodiments of the present disclosure will be described in detail below with specific reference to particular examples. The advantages and benefits of the present disclosure will become apparent to those skilled in the art upon consideration of the disclosure. The present disclosure can be implemented or applied in other different specific embodiments and with various modifications as appropriate, and the details can be modified or changed in various ways based on different views and applications without departing from the spirit of the present disclosure. It should be noted that the following examples and features in the examples can be combined with each other without conflict.

[0051] Some example embodiments of the present disclosure are described for illustrative purposes, and the present disclosure can be implemented in other ways not specifically shown in the drawings.

[0052] The energy storage battery in the energy storage inverter system is usually a lithium ion battery. However, the physical properties of the lithium ion battery itself are easily affected by the external environment. For example, in high-latitude areas, once the environmental temperature is too low (for example, below 0°C), the capacity and output characteristics of the energy storage battery will decrease, resulting in not only easy to charge not full under cold conditions, but also affecting the service life and performance of the energy storage battery.

[0053] For example, the preheating methods that can be used by the energy storage battery mainly rely on the heat conduction of external media such as gas, liquid or inherent material, but the aforementioned preheating methods are prone to uneven heating, high cost, low safety and other shortcomings. In some examples, a photovoltaic module (PV) is provided in the energy storage inverter system, which can supplement the heating energy of the energy storage battery through the photovoltaic module, control the start of the energy storage inverter, etc. However, for the energy storage inverter system without a photovoltaic module and corresponding external hardware, there is still no effective battery preheating solution.

[0054] Based on this, the disclosure embodiment provides an inverter, an energy storage converter system and a heat management method thereof, without setting a photovoltaic module, the preheating requirement of the energy storage battery can be realized, which is conducive to ensuring and improving the service life and performance of the energy storage battery, and further conducive to improving the safety of stable operation of the energy storage converter system.

[0055] Please refer to FIG. 1, the energy storage converter system provided by the disclosure embodiment includes an inverter 2 connected between an energy storage battery 1 and a power grid 3. Among them, the energy storage battery 1 includes a battery module 11 and a preheating module 12 in thermal conduction connection with the battery module 11.

[0056] 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 is arranged on at least one side (including one side, multiple sides or surrounding the circumferential side, etc.) of the battery module 11, the preheating module 12 is in contact or not in contact with the battery module 11, etc.; that is, the preheating module 12 can provide a thermal environment to the battery module 11 to conduct heat to the battery module 11. The relative position and connection between the preheating module 12 and the battery module 11 are not limited in the disclosure.

[0057] Correspondingly, the inverter 2 is configured to: in the case that the power grid 3 has power and the ambient temperature of the battery module 11 is lower than the first threshold value, the power grid 3 provides power to the preheating module 12, and controls the preheating module 12 to preheat the battery module 11.

[0058] In the disclosure embodiment, by setting the inverter 2 between the energy storage battery 1 and the power grid 3, in the case that the power grid 3 has power and the ambient temperature of the battery module 11 of the energy storage battery 1 is lower than the first threshold value, the power grid 3 provides power to the preheating module 12 of the energy storage battery 1, and controls the preheating module 12 to preheat the battery module 11 of the energy storage battery 1. In this way, the disclosure embodiment does not need to increase the photovoltaic module in the energy storage converter system, and the preheating requirement of the energy storage battery 1 in the energy storage converter system can be realized, which is conducive to ensuring and improving the service life and performance of the energy storage battery, and further conducive to improving the safety of stable operation of the energy storage converter system.

[0059] In some embodiments, please refer to FIG. 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 with the first sensing circuit 21, the second sensing circuit 22 and the power conversion circuit 23 respectively.

[0060] The first sensing circuit 21 is configured to sample the electrical signal of the power grid 3, for example, it can be connected to the power grid 3.

[0061] The second sensing circuit 22 is configured to sample the ambient temperature of the battery module 11, for example, it can be a temperature sensing circuit arranged beside the battery module 11.

[0062] The electric energy conversion circuit 23 is connected between the preheating module 12 and the power grid 3.

[0063] The controller 24 is configured to: in a case that the electric signal of the power grid 3 indicates that the power grid 3 is powered and the ambient temperature of the battery module 11 is lower than the first threshold value, control the electric energy conversion circuit 23 to be turned on, so that the power grid 3 provides electric energy to the preheating module 12, and control the preheating module 12 to preheat the battery module 11.

[0064] The electric energy conversion circuit 23 described above is configured to realize electric energy conversion transmission between the power grid 3 and the energy storage battery 1, and the electric energy conversion circuit 23 can be matched with the demand selection setting.

[0065] In some embodiments, the electric energy conversion circuit 23 includes a bidirectional inverter circuit 203, that is, the bidirectional inverter circuit 203 in the inverter 2 can be multiplexed as the electric energy conversion circuit 23. In this way, the preheating requirement of the energy storage battery 1 can be realized without adding photovoltaic components and external hardware in the energy storage and conversion system, which is conducive to simplifying the circuit structure and reducing the cost.

[0066] In other embodiments, the inverter 2 further includes an inverter circuit 203' connected between the preheating module 12 and the power grid 3, and the electric energy conversion circuit 23 is connected in parallel with the inverter circuit 203', that is, the electric energy conversion circuit 23 can be set as a bypass of the inverter circuit 203'. The electric energy conversion circuit 23 can be, for example, a rectifier circuit. In this way, in the embodiments of the present disclosure, the rectifier circuit can be added as the electric energy conversion circuit 23 between the power grid 3 and the energy storage battery 1 without changing the existing circuit structure of the energy storage and conversion system. The structure of the rectifier circuit is not limited in the embodiments of the present disclosure, which is limited to the rectifier circuit capable of realizing electric energy transmission from the power grid 3 to the energy storage battery 1.

[0067] For the convenience of description, the structure of the energy storage and conversion system and the energy storage battery 1 is described by taking the electric energy conversion circuit 23 as the bidirectional inverter circuit 203 in some embodiments.

[0068] In some embodiments, as shown in FIGS. 2, 3 and 4, the inverter 2 further comprises a charge-discharge circuit 201 connected between the bus (BUS+ and BUS-) and the battery module 11. The preheating module 12 is connected to the charge-discharge circuit 201. The power conversion circuit 23 is connected between the bus (BUS+ and BUS-) and the power grid 3. The controller 24 is further connected to the charge-discharge circuit 201 and configured to: turn on the preheating module 12 and the charge-discharge circuit 201 before controlling the preheating module 12 to preheat the battery module 11, and control the charge-discharge circuit 201 to work in a constant voltage mode; and when the ambient temperature is greater than or equal to the first threshold, turn on the battery module 11 and the charge-discharge circuit 201, and control the charge-discharge circuit 201 to charge and discharge.

[0069] In the embodiments of the present disclosure, without adding photovoltaic components and external hardware in the energy storage and conversion system, the selection control between the preheating demand and the charge-discharge demand of the energy storage battery 1 in the energy storage and conversion system can be realized, which is conducive to ensuring and improving the service life and performance of the energy storage battery 1, and further improving the safety of stable operation of the energy storage and conversion system.

[0070] For example, the first threshold includes but is not limited to 0℃.

[0071] In some embodiments, as shown in FIGS. 2, 3 and 4, the inverter 2 is connected to the power grid 3 through the grid gating circuit 31, and the controller 24 of the inverter 2 is also connected to the grid gating circuit 31. When the power grid 3 has power, the controller 24 can control the grid gating circuit 31 to be in a conductive state, so as to connect the power grid 3 and the power conversion circuit 23, and supply power to the bus (BUS+ and BUS-) through the power conversion circuit 23, so as to establish the bus (BUS+ and BUS-) voltage.

[0072] For the energy storage and conversion system without photovoltaic components, 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 normally charge and discharge. If the ambient temperature is lower than the first threshold and the controller 24 of the inverter 2 charges the energy storage battery 1, the preheating module 12 of the energy storage battery 1 can be started to preheat first, and then the energy storage battery 1 is charged after the ambient temperature is greater than or equal to the first threshold. That is, in the case that the energy storage battery 1 is not suitable to work (for example, in a low temperature case), the present disclosure can rely on the self-starting logic to realize the establishment of the bus (BUS+ and BUS-) voltage by the power grid 3, and in the case that the energy storage and conversion system does not have photovoltaic components and does not add external hardware, the preheating module 12 heats the battery module 11, thereby enriching the application scenarios of the energy storage and conversion system without photovoltaic components.

[0073] In some embodiments, referring to FIG. 3, the inverter 2 can include, in sequence, a charge-discharge circuit 201, a balance bridge circuit 202, a bidirectional inverter circuit 203, and an inverter gating circuit 204. The inverter gating circuit 204 is connected to the grid gating circuit 31. Accordingly, the controller 24 is further configured to control the inverter gating circuit 204 to be in a conductive state when the grid gating circuit 31 is in a conductive state, so that the grid 3 can supply power to the bus (BUS+ and BUS-) through the bidirectional inverter circuit 203 (i.e., the power conversion circuit 23).

[0074] In some embodiments, the inverter gating circuit 204 of the inverter 2 is further configured to be connected to the load 4.

[0075] The specific structures of the constituent circuits in the inverter 2 and the connection relationship therebetween are not limited in the embodiments of the present disclosure, but are limited to the corresponding functions.

[0076] For example, the charge-discharge circuit 201 can be a bidirectional DC-DC converter (BDC).

[0077] For example, the balance bridge circuit 202 can be connected by capacitors, inductors, thyristors, and the like, as shown in FIG. 3, including thyristor T1, thyristor T2, capacitor C1, capacitor C2, and inductor L1. The first end of the capacitor C1 is connected to the positive bus BUS+, the first end of the capacitor C2 is connected to the negative bus BUS-, the second end of the capacitor C1 and the second end of the capacitor C2 are connected to the neutral point N, the first pole of the thyristor T1 is connected to the positive bus BUS+, the second pole of the thyristor T2 is connected to the negative bus BUS-, and the second pole of the thyristor T1 and the second pole of the thyristor T2 are connected to the neutral point N through the inductor L1.

[0078] For example, the bidirectional inverter circuit 203 is a three-phase inverter circuit. The phase line in the bidirectional inverter circuit 203 that is not connected to the bus neutral point N has an inductor in series, such as the inductors L2 and L3 shown in FIG. 3. The phase line in the bidirectional inverter circuit 203 that is connected to the bus neutral point N and the adjacent phase line have a capacitor in series, such as the capacitors C4 and C5 shown in FIG. 3. In addition, the equivalent capacitor C3 of the bus neutral point N to ground PE is also shown in FIG. 3.

[0079] For example, the inverter gating circuit 204 can be configured by gating switches, such as the relays Rly1, Rly2 and Rly3 shown in FIG. 3, connected in parallel on each phase line of the bidirectional inverter circuit 23. The grid gating circuit 31 can be configured by gating switches, such as the relays Rly4, Rly5 and Rly6 shown in FIG. 3, connected in parallel corresponding to the gating switches, such as the relays Rly1, Rly2 and Rly3, of the inverter gating circuit 204.

[0080] For example, please continue to refer to FIG. 3, the line connected to the grid 3 relay Rly5 and the line connected to the grid 3 relay Rly4 are connected in series with the capacitor C6, and the line connected to the grid 3 relay Rly5 and the line connected to the grid 3 relay Rly6 are connected in series with the capacitor C7.

[0081] For example, please continue to refer to FIG. 3, the line connected to the load 4 ground PE can also be connected to the bus neutral point N through a switch, such as the relay Rly7. The line connected to the load 4 relay Rly2 and the line connected to the load 4 relay Rly1 are connected in series with the capacitor C8, and the line connected to the load 4 relay Rly2 and the line connected to the load 4 relay Rly3 are connected in series with the capacitor C9.

[0082] In some embodiments, please refer to FIG. 5, the energy storage battery 1 further comprises a gating 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 charge-discharge circuit 201, or turn on the battery module 11 and the charge-discharge circuit 201 through the gating module 13.

[0083] Please continue to refer to FIG. 5, in some embodiments, the gating module 13 comprises a first gating circuit 131 and a second gating circuit 132. The control end of the first gating circuit 131 is connected to the controller 24, the first end of the first gating circuit 131 is connected to the preheating module 12, and the second end of the first gating circuit 131 is connected to the charge-discharge circuit 201. The control end of the second gating circuit 132 is connected to the controller 24, the first end of the second gating circuit 132 is connected to the battery module 11, and the second end of the second gating circuit 132 is connected to the charge-discharge circuit 201. Wherein, the first gating circuit 131 can be in a conductive state in response to a first control instruction of the controller 24, and in a disconnected state in response to a second control instruction of the controller 24. The second gating circuit 132 is in a disconnected state in response to a first control instruction of the controller 24, and in a conductive state in response to a second control instruction of the controller 24. Wherein, the first control instruction of the controller 24 can be generated when the ambient temperature of the battery module 11 is lower than a first threshold, and the second control instruction of the controller 24 can be generated when the ambient temperature of the battery module 11 is higher than or equal to the first threshold.

[0084] In the embodiments of the present disclosure, the preheating circuit based on the first gating circuit 131 and the charging and discharging circuit based on the second gating circuit 132 in the energy storage battery 1 can share the same circuit formed by the charging and discharging circuit 201 connecting the bus (BUS+ and BUS-), but the preheating circuit and the charging and discharging circuit cannot work at the same time.

[0085] In some embodiments, please understand in combination with FIG. 5 and FIG. 6 that the bus includes a positive bus BUS+ and a negative bus BUS-.

[0086] Correspondingly, 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.

[0087] As shown in FIG. 6, the first end of the first relay M1 is connected to the positive transmission end of the preheating module 12, and the second end of the first relay M1 is connected to the positive transmission end of the charging and discharging circuit 201, which can be, for example, the positive transmission end (P+) of the charging and discharging circuit 201 connecting the preheating module 12. The first end of the second relay M2 is connected to the negative transmission end of the preheating module 12 through the first switch K1, and the second end of the second relay M2 is connected to the negative transmission end of the charging and discharging circuit 201, which can be, for example, the negative transmission end (P-) of the charging and discharging circuit 201 connecting the preheating module 12. The control end of the first relay M1 and the control end of the second relay M1 are both connected to the controller 24.

[0088] As shown in FIG. 6, the first end of the first battery contactor N1 is connected to the positive electrode of the battery module 11, and the second end of the first battery contactor N1 is connected to the positive transmission end of the charging and discharging circuit 201, which can be, for example, the positive transmission end (P+) of the charging and discharging circuit 201 connecting the preheating module 12. The first end of the second battery contactor N2 is connected to the negative electrode of the battery module 11, and the second end of the second battery contactor N2 is connected to the negative transmission end B- of the charging and discharging circuit 201 and the negative transmission end of the charging and discharging circuit 201 through the second switch K2, which can be, for example, the negative transmission end (P-) of the charging and discharging circuit 201 connecting the preheating module 12. The control end of the first battery contactor N1 and the control end of the second battery contactor N2 are both connected to the controller 24.

[0089] In some embodiments, please continue to refer to FIG. 6, a fuse F is connected in series between the second end of the second battery contactor N2 and the second switch K2.

[0090] In some embodiments, please refer to FIG. 2, FIG. 3, FIG. 4 and FIG. 6, the inverter 2 further comprises an acquisition module configured to acquire the fault code of the battery module 11. The controller 24 is connected with the acquisition module and configured to control the preheating module 12 to stop preheating the battery module 11 according to the fault code.

[0091] For example, please refer to FIG. 6, the battery module 11 comprises a plurality of battery cells U connected in series, and a single battery management unit BMU connected with each battery cell U. The single 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 with each single battery management unit BMU to determine whether the battery module 11 is in a fault state according to the performance parameters of each battery cell U, and acquire the fault code when the battery module 11 is in a fault state, so as to prevent or stop preheating the battery module 11.

[0092] For example, the battery cell U can be composed of one or a plurality of battery cells Cell connected in series. Each battery cell U in the battery module 11 is connected in series, and the positive electrode of the first battery cell U is the positive electrode of the battery module 11, and the negative electrode of the last battery cell U is the negative electrode of the battery module 11.

[0093] For example, the battery cell U and the single battery management unit BMU are set one-to-one, and the performance parameters of the battery cell U that the single battery management unit BMU can monitor include but are not limited to voltage V and temperature T; and the single battery management unit BMU can also perform voltage management on the battery cell U, such as voltage balancing.

[0094] For example, the single battery management unit BMU can be composed of one or more management chips AFE, for example: the management chip AFE in the single battery management unit BMU is set one-to-one with the battery cell Cell in the battery cell U.

[0095] For example, the preheating module 12 comprises a plurality of heating units Hot set one-to-one with each battery cell Cell, and the plurality of heating units Hot are connected in parallel. The heating unit Hot can be a heating circuit or a heating device, and the specific structure of the heating unit Hot is not limited in the embodiments of the present disclosure, as long as it can heat the battery cell Cell. In addition, the preheating module 12 is arranged beside the battery module 11, including being arranged outside or inside the corresponding battery cell Cell.

[0096] In some embodiments, a separate control module can be provided in the energy storage battery 1, and the controller 24 of the inverter 2 is connected with the control module of the energy storage battery 1 through a Can bus (CAN BUS) to realize communication through the Can bus and realize the relay control of each component in the energy storage battery 1 through the control module of the energy storage battery 1.

[0097] The controller 24 of the inverter 2 and the control modules in the energy storage battery 1 can be implemented by software, hardware, or a combination thereof, in whole or in part, for example, in the form of hardware embedded in or independent of a processor in a computer device, or in the form of software stored in a memory in a computer device, so as to be called and executed by the processor to perform the corresponding operations of the controller 24 and the control modules in the energy storage battery 1.

[0098] In some embodiments, at least one of the controller 24 of the inverter 2 and the control modules of the energy storage battery 1 is connected to the display device 5, which can visually display the performance parameters of the battery unit U, the fault codes of the battery module 11, and the information required for at least part of the control instructions and function implementation of the controller 24.

[0099] In some embodiments, the inverter 2 further comprises 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 configured to sample the voltage of the battery module 11. The fourth sensing circuit is configured 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, control the preheating module 12 to preheat the battery module 11 when 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, and adjust the port voltage of the charge-discharge circuit 201 when the difference between the voltage of the battery module 11 and the port voltage of the charge-discharge circuit 201 is greater than or equal to the second threshold.

[0100] In some embodiments, the inverter 2 further comprises a fifth sensing circuit configured to sample the temperature of the energy storage battery 1. The controller 24 is connected to the fifth sensing circuit and is configured to control the preheating module 12 to stop preheating the battery module 11 when the temperature of the energy storage battery 1 is greater than or equal to a 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 less than the third threshold.

[0101] The embodiments of the present disclosure also provide an energy storage and conversion system, which comprises the inverter in any of the above embodiments. The structure of the inverter can refer to the related description in the above embodiments, which will not be repeated here.

[0102] The embodiments of the present disclosure also provide a thermal management method of an energy storage and conversion system.

[0103] Referring to FIG. 7, the thermal management method comprises the following steps S100-S300.

[0104] S100, whether the power grid has power.

[0105] S200, whether the ambient temperature of the battery module is lower than a first threshold value.

[0106] Here, if the grid is not powered, the subsequent process cannot be started.

[0107] For example, the first threshold value includes but is not limited to 0°C.

[0108] S300, in the case where the ambient temperature is lower than the first threshold value, the grid is enabled to provide power to the preheating module, and the preheating module is controlled to preheat the battery module.

[0109] 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 grid. Accordingly, in step S300, when the ambient temperature is lower than the first threshold value, the grid is enabled to provide power to the preheating module, including: when the ambient temperature is lower than the first threshold value, the power conversion circuit is controlled to be turned on, and the grid is enabled to provide power to the preheating module.

[0110] Here, taking the bidirectional inverter circuit in the inverter as an example. Accordingly, after the ambient temperature is lower than the first threshold value, the energy storage battery does not work, the inverter executes the self-starting program and the self-checking program, and the bus voltage can be established through the grid.

[0111] In this way, in step S300, the power conversion circuit is controlled to be turned on, and the grid is enabled to provide power to the preheating module, which can be manifested as: the grid is enabled to connect the bidirectional inverter circuit of the inverter by controlling the grid connection gating circuit to be in a conductive state.

[0112] For example, please understand in combination with FIG. 3, the grid connection gating circuit 31 is in a conductive state, which can be manifested as: each gating switch in the grid connection gating circuit 31 is in a closed state; for example, the relay Rly4, the relay Rly5 and the relay Rly6 are controlled to be attracted. Accordingly, the grid is enabled to connect the bidirectional inverter circuit of the inverter, which can be manifested as: at the same time or after the grid connection gating circuit 31 is controlled to be in a conductive state, each gating switch in the inverter gating circuit 204 is controlled to be in a closed state; for example, the relay Rly1, the relay Rly2 and the relay Rly3 are controlled to be attracted.

[0113] In some embodiments, the inverter further includes: a charge-discharge circuit connected between the bus and the battery module. The preheating module is connected to the charge-discharge circuit. The power conversion circuit is connected between the bus and the grid.

[0114] Accordingly, please refer to FIG. 8, the thermal management method further includes steps S210 and S310.

[0115] S210, before controlling the pre-heating module to pre-heat the battery module, turn on the pre-heating module and the charge-discharge circuit, and control the charge-discharge circuit to work in a constant voltage mode.

[0116] S310, when the ambient temperature is higher than or equal to the first threshold value, turn on the battery module and the charge-discharge circuit, and control the charge-discharge circuit to charge and discharge.

[0117] For example, in step S300, the pre-heating module can pre-heat the battery module by taking power from the bus through the charge-discharge circuit after the charge-discharge circuit works in the constant voltage mode.

[0118] Here, the voltage stability of the bus refers to that the voltage between the positive bus BUS+ and the negative bus BUS- can be maintained within a target threshold value or a target voltage range.

[0119] In some embodiments, referring to FIG. 9, before controlling the pre-heating module to pre-heat the battery module, the thermal management method further includes steps S220 and S230.

[0120] S220, 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 value. In the case that the difference is less than the second threshold value, the pre-heating module is controlled to pre-heat the battery module. In the case that the difference is greater than or equal to the second threshold value, the port voltage of the charge-discharge circuit is adjusted, i.e., S230 is performed.

[0121] For example, the second threshold value is greater than or equal to 20V.

[0122] For example, the way of adjusting the port voltage of the charge-discharge circuit can be that the port of the charge-discharge circuit is controlled to emit waves to perform voltage modulation; for example, the floating voltage can be effectively eliminated.

[0123] The embodiments of the present disclosure can effectively prevent the difference between the voltage of the energy storage battery and the port voltage of the charge-discharge circuit in the inverter from being too large.

[0124] In some embodiments, referring to FIG. 10, the thermal management method further includes steps S410 and S420.

[0125] S410, obtaining a fault code of the battery module.

[0126] S420, according to the fault code, controlling the pre-heating module to stop pre-heating the battery module.

[0127] Here, if it is determined that the battery module is not faulty, the energy storage battery can be controlled to close the heating relay, issue a heating power to the inverter, and control the charge-discharge circuit in the inverter to work in a constant voltage mode.

[0128] The fault code of the battery module obtainable in step S410 can not include the fault code of the over-temperature fault. And, in the case that the fault code is obtained in step S410, the specific operation of preventing the pre-heating module from pre-heating the battery module based on the fault code is performed in step S410, which is derived from the fact that step S300 has not been performed.

[0129] Correspondingly, in some other embodiments, step S410 can also be performed (as shown in FIG. 11) or re-performed (as shown in FIG. 12) after step S300. In this way, the fault code of the battery module obtainable in step S410 can be the fault code of the over-temperature fault, i.e., step S410 performed after step S300 can be: obtaining the over-temperature fault code of the battery module.

[0130] Based on this, in some embodiments, referring to FIG. 13, the thermal management method can further include the following step S500.

[0131] S500, whether the temperature of the energy storage battery is higher than or equal to a third threshold value. If the temperature of the energy storage battery is higher than or equal to the third threshold value, the pre-heating module is controlled to stop pre-heating the battery module. If the temperature of the energy storage battery is lower than the third threshold value, the pre-heating module is controlled to continue pre-heating the battery module.

[0132] For example, the third threshold value is the same as or different from the first threshold value.

[0133] For example, the third threshold value includes but is not limited to 0℃.

[0134] After the pre-heating module is controlled to stop pre-heating the battery module, the charging and discharging circuit exits the heating state and can perform charging and discharging on the battery module.

[0135] Although each step in the flowchart involved in the above embodiments is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps has no strict sequence limitation, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in the above embodiments can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps.

[0136] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described above, however, as long as the combinations of technical features do not have contradictions, they shall be considered within the scope of the present disclosure.

[0137] The above embodiments only express several implementation manners of the present disclosure, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present disclosure. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, and these shall be within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the appended claims.

Claims

1. An inverter connected between an energy storage battery and a power grid, the energy storage battery comprising a battery module and a preheating module in thermal conductive connection with the battery module; the inverter being configured to, in a case that the power grid is powered and an ambient temperature of the battery module is lower than a first threshold, cause the power grid to provide electric energy to the preheating module and control the preheating module to preheat the battery module. 2.The inverter of claim 1, the inverter comprising: a first sensing circuit configured to sample an electric signal of the power grid; a second sensing circuit configured to sample the ambient temperature of the battery module; an electric energy conversion circuit connected between the preheating module and the power grid; a controller connected with the first sensing circuit, the second sensing circuit and the electric energy conversion circuit respectively, the controller being configured to, in a case that the electric signal of the power grid indicates that the power grid is powered and the ambient temperature of the battery module is lower than the first threshold, control the electric energy conversion circuit to be turned on, cause the power grid to provide electric energy to the preheating module and control the preheating module to preheat the battery module.

3. The inverter of claim 2, wherein, the electric energy conversion circuit comprising a bidirectional inverter circuit.

4. The inverter of claim 2, further comprising: an inverter circuit connected between the preheating module and the power grid; wherein the electric energy conversion circuit is connected in parallel with the inverter circuit; and the electric energy conversion circuit comprises a rectifier circuit.

5. The inverter of claim 2, further comprising: a charge-discharge circuit connected between a bus and the battery module; wherein the preheating module is connected with the charge-discharge circuit; and the electric energy conversion circuit is connected between the bus and the power grid; the controller is further connected with the charge-discharge circuit and is configured to, before controlling the preheating module to preheat the battery module, turn on the preheating module and the charge-discharge circuit and control the charge-discharge circuit to work in a constant voltage mode; and when the ambient temperature is higher than or equal to the first threshold, turn on the battery module and the charge-discharge circuit and control the charge-discharge circuit to charge and discharge. 6.The inverter of claim 5, the inverter further comprising: a third sensing circuit configured to sample a voltage of the battery module; a fourth sensing circuit configured to sample a port voltage of the charge-discharge circuit; wherein the controller is connected with the third sensing circuit and the fourth sensing circuit respectively, and the controller is configured to, before controlling the preheating module to preheat the battery module, control the preheating module to preheat the battery module in a case that a difference between the voltage of the battery module and the port voltage of the charge-discharge circuit is less than a second threshold, and adjust the port voltage of the charge-discharge circuit when the difference is greater than or equal to the second threshold. 7.The inverter of claim 2, the inverter further comprising: an acquisition module configured to acquire a fault code of the battery module; wherein the controller is connected with the acquisition module and is configured to, according to the fault code, control the preheating module to stop preheating the battery module.

8. The inverter of any one of claims 2-7, further comprising: a fifth sensing circuit configured to sample a temperature of the energy storage battery; wherein the controller is connected with the fifth sensing circuit and configured to: control the pre-heating module to stop pre-heating the battery module when the temperature of the energy storage battery is higher than or equal to a third threshold, and control the pre-heating module to continue pre-heating the battery module when the temperature of the energy storage battery is less than the third threshold.

9. An energy storage conversion system comprising the inverter of any one of claims 1-8, the inverter being connected between an energy storage battery and a power grid; the energy storage battery comprising a battery module and a pre-heating module in thermal conductive connection with the battery module, the inverter being configured to: cause the power grid to provide power to the pre-heating module and control the pre-heating module to pre-heat the battery module when the power grid is powered and an ambient temperature of the battery module is lower than a first threshold.

10. A method of thermal management of an energy storage inverter system, the energy storage inverter system comprising: an inverter connected between an energy storage battery and a power grid; the energy storage battery comprising a battery module and a pre-heating module in thermal conductive connection with the battery module; the thermal management method comprising: causing the power grid to provide power to the pre-heating module and controlling the pre-heating module to pre-heat the battery module when the power grid is powered and an ambient temperature of the battery module is lower than a first threshold.

11. The thermal management method of claim 10, the inverter comprising: an energy conversion circuit connected between the pre-heating module and the power grid; wherein the causing the power grid to provide power to the pre-heating module comprises: controlling the energy conversion circuit to be conductive, so that the power grid provides power to the pre-heating module.

12. The thermal management method of claim 10, the inverter further comprising: a charge-discharge circuit connected between a bus and the battery module; the pre-heating module being connected to the charge-discharge circuit; the energy conversion circuit being connected between the bus and the power grid; wherein the thermal management method further comprises: before controlling the pre-heating module to pre-heat the battery module, turning on the pre-heating module and the charge-discharge circuit, and controlling the charge-discharge circuit to work in a constant voltage mode; when the ambient temperature is higher than or equal to the first threshold, turning on the battery module and the charge-discharge circuit, and controlling the charge-discharge circuit to charge and discharge.

13. The thermal management method of claim 12, further comprising: before controlling the pre-heating module to pre-heat the battery module, controlling the pre-heating module to pre-heat the battery module when a difference between a voltage of the battery module and a port voltage of the charge-discharge circuit is less than a second threshold; when the difference is greater than or equal to the second threshold, adjusting the port voltage of the charge-discharge circuit.

14. The thermal management method of claim 10, further comprising: obtaining a fault code of the battery module; controlling the pre-heating module to stop pre-heating the battery module according to the fault code.

15. The thermal management method of any one of claims 10-14, further comprising: controlling the pre-heating module to stop pre-heating the battery module if the temperature of the energy storage battery is higher than or equal to a third threshold value; controlling the pre-heating module to continue pre-heating the battery module if the temperature of the energy storage battery is less than the third threshold value.

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