Integrated pv energy storage module

Abstract

The present invention belongs to the field of solar photovoltaic power generation, relates to an integrated photovoltaic energy storage assembly, and aims to solve the problems of complex structures, complex mounting, high costs, low efficiency and high safety risks of existing photovoltaic energy storage products. The integrated photovoltaic energy storage assembly comprises a solar panel, an AC / DC multi-directional conversion device and an energy storage battery. The AC / DC multi-directional conversion device and the energy storage battery are mounted on the back surface of the solar panel and each have an extension height not exceeding an end face of a back side of a solar panel frame. The AC / DC multi-directional conversion device comprises three groups of connection terminals, which are respectively electrically connected to the solar panel, the energy storage battery and an AC power grid, a plurality of voltage converters, a plurality of switching elements, and a control chip, wherein the control chip is configured to selectively turn on at least one switching element in different operating modes of the integrated photovoltaic energy storage assembly, so as to establish a voltage conversion path between two corresponding groups of connection terminals by means of at least one voltage converter.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of PV power generation, and more specifically to an integrated PV energy storage module in which PV power generation, energy storage and power conversion equipment (or called “converter equipment”) are integrated together. BACKGROUND

[0002] With the increase of global energy demand and the focus on environmental protection, photovoltaic (abbreviated as “PV”) power generation, as a renewable clean energy technology, has been increasingly widely developed and applied. PV power generation technology uses PV cell array to convert PV energy into electricity and supply it to the grid or loads. To solve the problems of intermittency and fluctuation of PV energy, itis generally combined with energy storage system to form two systems: PV power generation and energy storage system (“ESS”).

[0003] However, conventional PV power generation and energy storage system operate independently, that is, the DC power generated by PV cell array or PV panel is first converted into AC power by an inverter and then combined with battery banks through a converter, so that the efficiency is greatly reduced after multiple conversions of the electrical energy.

[0004] The string inverter equipped for each photovoltaic string is currently a widely used type, which has Maximum Power Point Tracking (referred to as “MPPT”) at the DC end and is connected in parallel to the grid at the AC end. However, string inverters - do not have panel-level MPPT capability, leading to the "bucket effect" and resulting in relatively low efficiency. Additionally, the string inverter operates under high DC voltage and faces issues with long-distance high DC voltage transmission. After long-term use and aging, it is prone to inducing DC arcing, potentially causing fire safety hazards. Although optimizers and rapid shutdown device can now be added to improve MPPT performance and cut off high DC voltage after a fire occurs, which helps eliminate the risk of electric shock for firefighters during rescue operations, the root cause of long-distance high DC voltage transmission remains unresolved. Consequently, the possibility of fire occurrence remains high, and adding rapid shutdown device and optimizers drive up the system cost.

[0005] Compared with string inverters, traditional microinverters (micro-inverters) resolve the issue of long-distance high-voltage DC transmission, which could easily induce DC arcing and cause fire hazards. It could also achieve panel level MPPT regulation and avoid the bucket effect in string inverters. However, the cost per watt is high, and installation is complex—firstly microinverters must be mounted one by one on rails, then PV panels are mounted, and finally the PV panels and microinverters are connected. This significantly increases installation costs, especially in harsh outdoor high-altitude installation environments. In addition, integration with energy storage systems requires separate configuration of additional power conversion equipment, leading to a complex system and a significant increase in cost. It also results in low efficiency due to multiple power conversions.

[0006] Furthermore, in the current configurations of PV power generation and energy storage products, PV modules, inverters, and batteries each exist as independent products. Customers can only purchase these products individually and then rely on professional installers to integrate them into a combined system. This not only significantly increases customer acquisition costs but also greatly reduces product accessibility. Customers can only obtain non-standard customized product combinations from qualified distributors, resulting in a lack of universality and ease of use. The costs occurred from sales, transportation, installation, and maintenance are very high, and there are significant construction risks and safety hazards during use. SUMMARY OF THE INVENTION

[0007] The purpose of the present disclosure is to solve at least one of the aforementioned problems and / or other deficiencies existing in the prior art.

[0008] The present disclosure provides an integrated PV energy storage module, comprising a PV panel, an AC / DC multi-directional conversion device, and a battery. The PV panel is equipped with a frame extending toward its rear side. The AC / DC multi-directional conversion device and the battery are mounted on the rear side of the PV panel and do not protrude beyond the rear end face of the frame. The AC / DC multi-directional conversion device comprises three sets of connection terminals, multiple voltage converters, multiple switching elements, and a control chip. The three sets of connection terminals are electrically connected to the PV panel, the battery, and the AC grid, respectively. Each switching element is configured to electrically connect a corresponding converter among the multiple voltage converters to another converter therein, or to a corresponding set among the three sets of connection terminals. The control chip is configured to: in different working modes of the integrated PV energy storage module, selectively turn on at least one of the multiple switching elements, thereby establishing a voltage conversion pathway between two respective sets of connection terminals among the three sets using at least one of the multiple voltage converters.

[0009] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module, the AC / DC multi-directional conversion device and the battery can be mounted on the rear side of the PV panel by a one-piece grid-shaped bracket fixed in the frame.

[0010] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the battery may comprise a battery module having multiple blade batteries, multiple pouch batteries, or multiple solid-state batteries.

[0011] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the integrated PV energy storage module may also comprise a battery management system integrated within the AC / DC multi-directional conversion device or separately arranged from the latter.

[0012] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the multiple voltage converters comprise a first DC / DC converter, a second DC / DC converter, and a bidirectional AC / DC converter, wherein the input side of the first DC / DC converter is electrically connected to the PV panel, the input side of the second DC / DC converter is electrically connected to the battery, the AC side of the bidirectional AC / DC converter is electrically connected to the AC grid, the multiple switching elements comprise a first, a second, and a third switching element, wherein the first switching element is assigned to the first DC / DC converter, the second switching element is assigned to the second DC / DC converter, the third switching element is assigned to the bidirectional AC / DC converter. The control chip is further configured to selectively turn on two corresponding switching elements among the first, the second, and the third switching element, so as to achieve different working modes of the integrated PV energy storage module using two corresponding converters selected from the first DC / DC converter, the second DC / DC converter, and the bidirectional AC / DC converter.

[0013] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the working modes of the integrated PV energy storage module may comprise a PV power supply mode, a DC charging mode, an AC charging mode, and a battery power supply mode, wherein the control chip may be further configured to: in the PV power supply mode, turn on the first and third switching elements and operate the bidirectional AC / DC converter in an inverting state, so as to convert the first DC power from the PV panel into a first AC power to be supplied to the AC grid via the first DC / DC converter and the bidirectional AC / DC converter. In the DC charging mode, turn on the first and second switching elements to convert the first DC power from the PV panel into second DC power, and charge the battery via the first DC / DC converter and the second DC / DC converter. In the AC charging mode, turn on the second and third switching elements, the bidirectional AC / DC converter is switched to rectifying mode, converting the first AC power from the AC grid into second DC power to charge the battery via the bidirectional AC / DC converter and the second DC / DC converter. And in the battery power supply mode, turn on the second and third switching elements, the bidirectional AC / DC converter is switched to inverting mode, converting the second DC power from the battery into first AC power to be supplied to the AC grid via the second DC / DC converter and the bidirectional AC / DC converter.

[0014] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the first and second DC / DC converters may each be implemented as any one of a Boost circuit, a Buck circuit, or a Boost-Buck circuit.

[0015] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the Boost-Buck circuit may comprise a first switching transistor disposed at the input side of the corresponding DC / DC converter, a second switching transistor disposed at the output side of the corresponding DC / DC converter, and an energy storage inductor disposed between the first and second switching transistors, wherein the control chip may be configured to control the duty cycles of the first and second switching transistors based on the output voltage of the PV panel and the charging voltage of the battery, thereby operating the corresponding DC / DC converter in a Boost mode or Buck mode.

[0016] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the first and second DC / DC converters may each comprise a first capacitor array having at least one electrolytic capacitor and at least one surface-mount capacitor.

[0017] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, each electrolytic capacitor has a capacitance of 800^F-3000gF, each surface-mount capacitor has a capacitance of 1-10gF, and the diameter of each electrolytic capacitor is less than 17mm.

[0018] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the bidirectional AC / DC converter may comprise an inductor, an isolation transformer, a first switching circuit, and a second switching circuit, wherein the input side of the first switching circuit is electrically connected to the DC side of the bidirectional AC / DC converter, the inductor is disposed between the secondary side of the isolation transformer and the input side of the second switching circuit, the output side of the second switching circuit is electrically connected to the AC side of the bidirectional AC / DC converter, wherein the first and second switching circuits each adopt a full-bridge topology structure, the four arms of the first switching circuit each composed of a single switching transistor, the first upper arm and the first lower arm of the second switching circuit are each composed of two switching transistors connected in a back-to-back series connection, and the second upper arm and the second lower arm of the second switching circuit are each composed of a single capacitor.

[0019] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, when the isolation transformer is within a frequency range of 8KHz to 300KHz, the primary winding turns of the isolation transformer are set to 3 to 6, the secondary winding turns are set to 9 to 18, and the turns ratio is set to between 2 to 4, the primary inductance is between 50pH to 1.5mH, the secondary leakage inductance is between 5gH to 200gH, and the height of the isolation transformer is set to less than 17mm.

[0020] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the bidirectional AC / DC converter may also comprise a second capacitor array disposed between the second switching circuit and the AC grid, the second capacitor array comprises 1 to 3 safety capacitors each having a height less than 17mm.

[0021] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the bidirectional AC / DC converter may comprise a bidirectional full-bridge converter composed of four switching transistors and an LC resonant converter, the DC side of the bidirectional full-bridge converter is electrically connected to the second terminal of the third switching element, the LC resonant converter is disposed between the AC side of the bidirectional full-bridge converter and the AC grid.

[0022] According to an exemplary configuration of the present disclosure, in the integrated PV energy storage module as described in any of the preceding items, the bidirectional AC / DC converter may also comprise a third capacitor array disposed between the LC resonant converter and the AC grid, the third capacitor array comprises 1 to 3 safety capacitors each having a height less than 17mm.

[0023] The integrated PV energy storage module of the present disclosure has at least the following advantages: I. The integrated PV energy storage module integrates PV power generation, energy storage, and power conversion equipment into an organic unit, achieving functional and structural integration. This simplifies the implementation of PV energy storage products. Unlike traditional configurations where PV equipment, inverters, and energy storage units are separate to each other, users no longer need to purchase these devices individually or hire specialized personnel for matching and installation. Complex custom design configurations are replaced by simple component selection, significantly lowering purchase and usage barriers. This approach greatly facilitates transportation, installation, and maintenance while substantially reducing labor costs associated with transporting, installing, and maintaining PV energy storage products. The integrated PV energy storage module adds no volume or dimension change to a single PV panel, further facilitating storage, transportation, and installation of the PV energy storage products.

[0024] II. In the integrated PV energy storage module, an individual PV panel achieves conversion, energy storage, and grid connection directly through its DC end, and during its DC stage, the module always operates at a low voltage below 80V, completely eliminating the risk of DC arcing in the circuit that arises from prolonged operation and aging associated with DC high voltage in string inverters and traditional energy storage power stations. This significantly reduces the probability of fires occurring in PV energy storage power stations, and offers vastly superior safety compared to traditional power conversion, energy storage, and grid connection solutions.

[0025] III. The AC / DC multi-directional conversion device in the integrated PV energy storage module directly charges the battery via the DC converter. Compared with the traditional PV energy storage system that first converts DC into AC and then rectifies AC into DC to charge the battery, it eliminates dual conversion processes from DC to AC and then from AC back to DC, significantly improves the conversion efficiency.

[0026] IV. The AC / DC multi-directional conversion device in the integrated PV energy storage module integrates multiple different power conversion functions, including DC boost and buck operations and AC / DC conversion, into a single unit. It can automatically switch and adapt to different working modes based on varying power demands, irradiance conditions, and grid sates across different time periods: (1) PV-generated power for feeding back to the grid, energy storage, and power supply for loads; (2) energy storage battery power supply for feeding back to the grid, power supply for loads; (3) charging of battery by grid power generation equipment, etc. Compared to traditional PV power plants and energy storage facilities, which require multiple authorizations from grid operators and owners, long-distance transmission, and consideration of complex cross-grid benefit negotiations for power dispatch and distribution switching, the present disclosure offers distinct advantages in terms of dispatch efficiency, convenience, and transmission losses. DESCRIPTION OF THE DRAWINGS

[0027] The features and advantages of the present disclosure will be clearly understood through the following detailed description with reference to the accompanied drawings. It should be understood that the drawings are merely schematic and not necessarily drawn to scale, and thus should not be construed as a limitation of the present disclosure. Among them: Figure 1 shows an overall schematic diagram of the integrated PV energy storage module connected to the grid according to the present disclosure.

[0028] Fig. 2-1 shows a rear view of the integrated PV energy storage module according to a first exemplary embodiment of the present disclosure.

[0029] Fig. 2-2 shows a sectional view of the integrated PV energy storage module according to the first exemplary embodiment of the present disclosure.

[0030] Fig. 3-1 shows a rear view of the integrated PV energy storage module according to a second exemplary embodiment of the present disclosure.

[0031] Fig. 3-2 shows a sectional view of the integrated PV energy storage module according to the second exemplary embodiment of the present disclosure.

[0032] Fig. 4 shows an internal structure diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to an exemplary embodiment of the present disclosure.

[0033] Fig. 5-1 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure under the PV power supply mode.

[0034] Fig. 5-2 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure under DC charging mode.

[0035] Fig. 5-3 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure under AC charging mode.

[0036] Fig. 5-4 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure under battery power supply mode.

[0037] Fig. 6 shows a schematic diagram of the output voltage waveform of the PV panel in the integrated PV energy storage module according to the present disclosure.

[0038] Fig. 7-1 shows an internal circuit diagram of the first or second DC / DC converter implemented as a Boost circuit.

[0039] Fig. 7-2 shows an internal circuit diagram of the first or second DC / DC converter implemented as a Buck circuit.

[0040] Fig. 7-3 shows an internal circuit diagram of the first or second DC / DC converter implemented as a Boost-Buck circuit.

[0041] Fig. 8-1 shows a schematic diagram of the internal circuit structure of the bidirectional AC / DC converter using an isolation transformer structure.

[0042] Fig. 8-2 shows a schematic diagram of the internal circuit structure of the bidirectional AC / DC converter using a non-isolation transformer structure. DETAILED DESCRIPTION OF EMBODIMENTS

[0043] Embodiments of the present disclosure are described below with reference to the accompanied drawings. In the following description, numerous specific details are set forth to provide a more thorough understanding and enable implementation of the present disclosure by those skilled in the art. However, it will be apparent to those skilled in the art that the present disclosure may be implemented without some of these specific details. Furthermore, it should be understood that the present disclosure is not limited to the specific embodiments introduced. Rather, any combination of the features and elements described below may be considered for implementing the present disclosure, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims, unless explicitly stated in the claims.

[0044] Terms such as "first", "second", etc., are used herein to describe elements of 7 the present application. These terms are used only to distinguish the elements and are not intended to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusive meaning and mean that there may be additional elements / components besides the listed elements / components.

[0045] Fig. 1 schematically shows a line connection diagram of the integrated PV energy storage module according to the present disclosure. The integrated PV energy storage module comprises a PV cell array as a basic element. The PV cell array specifically refers to a single PV panel 1 in the present application, which may have a relatively low open-circuit voltage of less than 80V. In addition, the integrated PV energy storage module also comprises an AC / DC multi-directional conversion device 2 and a battery 3. As shown in Fig. 1, the AC / DC multi-directional conversion device 2 connects the PV panel 1, the battery 3, and the AC grid 4 to each other, and is configured to perform desired power conversion between any two of these three as needed. For example, the AC / DC multi-directional conversion device 2 performs DC Boost and Buck conversion between the PV panel 1 and the battery 3, or the AC / DC multi-directional conversion device 2 performs AC / DC conversion between each of the PV panel 1 and the battery 3 and the AC grid 4. In other words, the AC / DC multi-directional conversion device 2 is a multi-purpose power conversion unit that integrates various different power conversion functions. In this application, the AC grid 4 comprises not only the general large grid but also a micro-grid or other electrical equipment capable of receiving or providing power.

[0046] The integrated PV energy storage module according to the present disclosure is an integrated structure that, in terms of hardware, integrates the PV panel 1, the AC / DC multi-directional conversion device 2, and the battery 3 together. Fig. 2-1 and Fig. 2-2 respectively show a rear view and a sectional view of the first exemplary configuration of this integrated structure, where the sectional view of Fig. 2-2 is taken along line A-A in Fig. 2-1. The integrated PV energy storage module shown in Fig. 2-1 and Fig. 2-2 comprises the PV panel 1, the AC / DC multi-directional conversion device 2, and the battery 3 mounted together. More specifically, both the AC / DC multi-directional conversion device 2 and the battery 3 are mounted on the rear side of the single PV panel 1. As described above, the AC / DC multi-directional conversion device 2 is a multi-purpose power conversion unit, which is advantageously encapsulated in a single casing. The battery 3 may be a battery module having multiple battery cells, and may adopt battery types such as blade batteries, pouch batteries, or solid-state batteries.

[0047] The PV panel 1 is equipped with a frame 11 (e.g., but not limited to the illustrated rectangular frame) made of, for example, aluminum, which protrudes toward its rear side (i.e., the direction pointing out of the page in the rear view of Fig. 2-1, or the direction toward the right side in the sectional view of Fig. 2-2). The AC / DC multi-directional conversion device 2 and the battery 3, after being mounted in place on the rear side of the PV panel 1, shall have their protrusion height (defined as the maximum height reached by any part of them in the direction perpendicular to the rear side of the PV panel 1) not exceeding the rear end face of the frame 11 (shown as a rectangular frame located at the peripheral end face of the PV panel 1 in Fig. 2-1).

[0048] Apart from the PV panel 1, the AC / DC multi-directional conversion device 2 and the battery 3 are the components that occupy the most space in the thickness direction (the direction perpendicular to the page in Fig. 2-1, or the left-right direction in Fig. 2-2) within the entire PV energy storage module. However, their protrusion height on the rear side of the PV panel 1 does not extend beyond the rear end face of the frame 11 of the PV panel. Therefore, the overall thickness of the entire PV energy storage module is equal to the original thickness of the PV panel 1 (including its frame 11), thereby maintaining the regular profile of the single PV panel 1. This is particularly convenient for the stacking of multiple integrated PV energy storage modules according to the present disclosure, thus facilitating storage, transportation, installation, etc., of PV energy storage module products in a space-saving and cost-effective manner. In the integrated PV energy storage module according to the present disclosure, as described in more detail below, the structure and / or arrangement of the AC / DC multi-directional conversion device 2 and the battery 3 can be designed in such a way that even after integrating the AC / DC multi-directional conversion device 2 and the battery 3 onto a conventional PV panel 1, the thickness of the single PV panel 1 will not be increased and the dimensions thereof will not be altered. Advantageously, the integrated PV energy storage module according to the present disclosure can be realized without increasing the dimensions (specifically, the thickness) of existing mainstream PV modules (the overall thickness of the mainstream PV modules is not greater than 36mm; the backside void height is not greater than 28mm, where the backside void height refers to the distance between the rear side of the PV panel in the PV module and the rear end face of its frame).

[0049] As shown in Fig. 2-1 and Fig. 2-2, the AC / DC multi-directional conversion device 2 and the battery 3 can be mounted on the rear side of the PV panel 1 via a bracket 12. The bracket 12 may be fixed, for example, onto the frame 11 with the frame 11, and may be formed into various appropriate configurations that facilitate the installation of the AC / DC multi-directional conversion device 2 and the battery 3, such as, but not limited to, the illustrated one-piece grid-shaped bracket, which defines multiple grids so that the AC / DC multi-directional conversion device 2 and the battery 3 can be assembled into different grids respectively. In the first embodiment shown in Fig. 2-1 and Fig. 2-2, the AC / DC multi-directional conversion device 2 is mounted at the central position of the bracket 12, while the multiple battery cells (such as the illustrated blade batteries) of the battery 3 are placed on both sides of the AC / DC multi-directional conversion device 2. Compared with the AC / DC multi-directional conversion device 2 and the battery 3, the bracket 12, which is much simpler in structure and function, also has a more compact size. Consequently, after being fixed in place on the frame 11, the height of the bracket 12 will certainly not extend beyond the rear end face of the frame 11. The bracket 12 may be fixed onto the frame 11 by various appropriate ways, such as, but not limited to, screw fastening, riveting fastening, or screw clamp fastening.

[0050] To reduce the thickness, the battery 3 may be a battery module having multiple blade batteries, multiple pouch batteries, or multiple solid-state batteries. To minimize the thickness of the battery 3 to prevent it from extending beyond the rear end face of the frame 11 of the PV panel, the multiple battery cells (e.g., multiple blade batteries, multiple pouch batteries, or multiple solid-state batteries) constituting the battery 3 may be arranged in a single-layer flat configuration. However, provided the thickness requirement is met, at least a portion of the multiple battery cells could also be stacked (e.g., for blade batteries that inherently have a small cell thickness). The individual battery cells within the battery 3 can be flexibly arranged, split into different modules according to the configuration of the bracket 12 and the spatial layout within the frame 11. The number of modules, their arrangement positions, as well as the number and arrangement of battery cells within each module can be flexibly adjusted, thereby forming batteries 3 of different capacities and consequently PV energy storage module products of different specifications.

[0051] As an example, the battery 3 can also be equipped with a battery management system (BMS). The BMS is used to monitor and manage the charging and discharging processes of the individual battery cells within the battery, thereby ensuring the safe operation of the battery, preventing overcharging or over-discharging, and simultaneously achieving balanced control inside the battery. The BMS can communicate with the battery 3 and its battery cells via wired or wireless communication. In the embodiment shown in Fig. 2-1 and Fig. 2-2, the battery management system may be integrated within the AC / DC multi-directional conversion device 2, thus not occupying additional space, and the height of the AC / DC multi-directional conversion device 2, which includes the battery management system, on the rear side of the PV panel 1 does not extend beyond the rear end face of the frame 11.

[0052] Fig. 3-1 and Fig. 3-2 respectively show a rear view of an integrated PV energy storage module according to a second exemplary embodiment of the present disclosure. The sectional view of Fig. 3-2 is taken along line A-A in Fig. 3-1. In the second embodiment shown in Fig. 3-1 and Fig. 3-2, the battery management system 31 can also be separately arranged from the AC / DC multi-directional conversion device 2. As shown in Fig. 3-1 and Fig. 3-2, the battery management system 31 is also mounted on the rear side of the PV panel 1 via the bracket 12. For this purpose, compared with the first embodiment shown in Fig. 2-1 and Fig. 2-2, the one-piece grid-shaped bracket 12 is slightly adjusted in structure to also provide an assembly grid for the battery management system 31. Here, the independent battery management system 31 is smaller in size than the AC / DC multi-directional conversion device 2, and after being mounted on the rear side of the PV panel 1 via the bracket 12, could also maintain an overall height that does not extend beyond the rear end face of the frame 11.

[0053] Provided the overall size requirements of the PV energy storage module of the present disclosure are met, various settings for the battery management system, including the embodiments shown in Fig. 2-1, Fig. 2-2, Fig. 3-1, and Fig. 3-2, are feasible and will not affect the overall performance of the PV energy storage module.

[0054] After various components of the aforementioned integrated PV energy storage module, including the AC / DC multi-directional conversion device 2, the battery 3 and its battery management system, the bracket 12, and various connecting wires and fixing structures, etc., are mounted, the overall heights on the rear side of the PV panel 1 does not extend beyond the rear end face of the frame 11. This design results in the overall profile of the entire PV energy storage module being virtually identical to that of a single PV panel 1. Such an integrated PV energy storage module can also be conveniently fitted with a protective film or protective shell to protect the various components from damage during transportation and installation, and it can also be used for waterproofing, dust prevention, etc., to resist the influences of the external environment conditions.

[0055] The AC / DC multi-directional conversion device in the integrated PV energy storage module according to an exemplary embodiment of the present disclosure, which is the core of the PV energy storage module, is described in detail below. Fig. 4 shows an internal structure diagram of the AC / DC multi-directional conversion device.

[0056] As shown in Fig. 4, the AC / DC multi-directional conversion device comprises three sets of connection terminals, multiple voltage converters, multiple switching elements, and a control chip. The three sets of connection terminals are respectively a first set of connection terminals electrically connected to the positive and negative electrodes PV+, PV- of the PV panel 1, a second set of connection terminals electrically connected to the positive and negative electrodes BAT+, BAT- of the battery 3, and a third set of connection terminals electrically connected to the live and neutral wires L, N of the AC grid.

[0057] The multiple voltage converters may comprise a DC Boost-Buck converter (i.e., a DC / DC device) and a bidirectional AC / DC converter (i.e., a bidirectional AC / DC device). Among them, the DC / DC device may be composed of one or more of a Boost circuit, a Buck circuit, and a Boost-Buck circuit. The bidirectional AC / DC device may comprise a rectifier circuit and an inverter circuit. The rectifier circuit and the inverter circuit can be the same hardware circuit or different hardware circuits.

[0058] Each switching element plays a key role in internally connecting various modules within the AC / DC multi-directional conversion device. Specifically, under the control of the control chip 7, depending on the different working modes of the integrated PV energy storage module, each switching element can electrically connect a respective voltage converter to another voltage converter or to the corresponding connection terminal, thereby establishing the required voltage conversion pathway between the two respective sets of connection terminals. For example, when it is necessary to transmit electrical energy from the PV panel to the battery, by controlling the corresponding switching elements, the output side of the PV panel is connected to the DC / DC converter, and then through another switching element, the output of the DC / DC converter is connected to the input side of the battery, thereby achieving the transmission of electrical energy from the PV panel to the battery.

[0059] The control chip 7 is the "brain" of the entire conversion device. It can monitor the circuit states of the conversion device in real time, selectively control the ON / OFF states of each switching element and the working state of each conversion module to achieve various voltage conversion functions of the bidirectional AC / DC conversion device. By controlling the switching elements and different switching transistor combinations in the AC / DC multi-directional conversion device, the control chip can enable the bidirectional AC / DC conversion device to perform multi-directional voltage conversion functions from AC to DC, from DC to AC, or from DC to DC. Furthermore, using this AC / DC multi-directional conversion device enables the integrated PV energy storage module to operate in at least four working modes, including a PV power supply mode, a DC charging mode, an AC charging mode, and a battery power supply mode.

[0060] Here, the "PV power supply mode" refers to using the PV panel to feed power into the AC grid or supply power to a microgrid. In this mode, the DC power output from the PV panel is converted into AC power using the DC / DC converter and the bidirectional AC / DC converter, and finally transmitted to the AC grid. The "DC charging mode" refers to using the PV panel to charge the battery. In this mode, the DC power output from the PV panel undergoes Boost or Buck operations using the DC / DC converter and finally be fed to the battery. The "AC charging mode" refers to using the AC grid to charge the battery. In this mode, the AC power from the AC grid is converted into DC power using the bidirectional AC / DC converter and the DC / DC converter, then undergo Boost-Buck operations, and finally be fed to the battery. The "battery power supply mode" refers to using the battery to supply power to the AC grid (or a microgrid). In this mode, the DC power output from the battery undergoes Boost-Buck operations using the DC / DC converter and then is converted into AC power using the bidirectional AC / DC converter, and finally is transmitted to the AC grid.

[0061] Optionally, the control chip 7 can also monitor the output current and output voltage generated by the PV panel in real time, and thereby calculate the MPPT (Maximum Power Point Tracking) to achieve maximum power point tracking, so that the PV panel 1 operates at the highest efficiency when feeding power into the grid or charging the battery. The power supply (PS) circuit of the control chip 7 can automatically match the power output from the PV panel or the battery.

[0062] Figs. 5-1 to 5-4 respectively show schematic diagrams of different circuit states of the AC / DC multi-directional conversion device under different working modes of the integrated PV energy storage module according to the present disclosure. The circuit states and working principles of this AC / DC multi-directional conversion device under different working modes are elaborated in detail below with reference to Figs. 5-1 to 5-4.

[0063] Fig. 5-1 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure in the PV power supply mode. Fig. 5-2 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure in the DC charging mode. Fig. 5-3 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure in the AC charging mode. Fig. 5-4 shows a circuit state diagram of the AC / DC multi-directional conversion device in the integrated PV energy storage module according to the present disclosure in the battery power supply mode.

[0064] As shown in Figs. 5-1 to 5-4, the AC / DC multi-directional conversion device has three sets of connection terminals, respectively connected to the positive and negative electrodes PV+, PV- of the PV panel, the positive and negative electrodes BAT+, BAT- of the battery, and the live and neutral wires L, N of the AC grid (or microgrid).

[0065] The core part of the AC / DC multi-directional conversion device consists of multiple voltage converters and multiple switching elements. Depending on the working mode to be achieved by the integrated PV energy storage module, by using the control chip 7 to selectively turn on the corresponding switching elements and control the working states of the voltage converters, a respective voltage conversion pathway can be established between the two respective sets of connection terminals.

[0066] The AC / DC multi-directional conversion device has a first DC / DC converter 8, a second DC / DC converter 9, and a bidirectional AC / DC converter 10, as well as a first, a second, and a third switching element S1, S2, S3. Each switching element is assigned to a respective one of the switching elements in the AC / DC multi-directional conversion device. For example, the first switching element S1 is assigned to the first DC / DC converter 8, the second switching element S2 is assigned to the second DC / DC converter 9, and the third switching element S3 is assigned to the bidirectional AC / DC converter 10.

[0067] Herein, the expression "assigned to" describes a specific association configuration / assignment relationship between the switching element and the converter, i.e., the switching element is allocated or designated to operate in coordination with a specific converter. This "assignment" relationship indicates that although the specific location of the switching element may be flexibly set in the circuit, its main function is to serve the voltage converter it is "assigned to", by controlling the current flow pathway related to that converter to achieve different working modes of the PV energy storage module. Therefore, the expression "assigned to" herein is not intended to limit the physical location of the switching element but to emphasize its control relationship for activating a specific voltage converter in the system control logic.

[0068] In the circuit diagrams shown in Figs. 5-1 to 5-4, an exemplary connection relationship between each switching element and each converter is shown. Among them, the input side of the first DC / DC converter 8 is electrically connected to the positive and negative electrodes PV+, PV- of the PV panel. The input side of the second DC / DC converter 9 is electrically connected to the positive and negative electrodes BAT+, BAT- of the battery. The first switching element S1 connects the output side of the first DC / DC converter 8 to the first terminal of the third switching element S3. The second switching element S2 connects the output side of the second DC / DC converter 9 to the first terminal of the third switching element S3. The DC side of the bidirectional AC / DC converter 10 is connected to the second terminal of the third switching element S3, and its AC side is connected to the AC grid (or microgrid). The ON / OFF states of these switching elements, the working states (Boost or Buck) of the DC / DC converters, and the working states (inversion or rectification) of the AC / DC converter are collectively controlled by the control chip to ultimately achieve different working modes of the PV energy storage module.

[0069] In Fig. 5-1, the PV energy storage module operates in the PV power supply mode. The control chip 7 turns on the first and third switching elements S1, S3, so that the first DC power generated by the PV panel undergoes voltage regulation (Boost or Buck) through the first DC / DC converter 8, is then converted into first AC power through the bidirectional AC / DC converter 10 in a inversing way, and ultimately supplied to the AC grid. In this PV power supply mode, the switching elements S1 and S3 are closed, S2 is open, and the bidirectional AC / DC converter 10 is in the inversion state, and the electrical energy from the PV panel can be fed back to the grid or supplied to the microgrid.

[0070] In Fig. 5-2, the PV energy storage module operates in the DC charging mode. The control chip 7 turns on the first and second switching elements S1, S2, so that the first DC power generated by the PV panel is converted into an intermediate DC power through the first DC / DC converter 8, and then converted into a second DC power suitable for charging the battery via the second DC / DC converter 9. At this time, the first and second DC / DC converters are in the DC Boost or Buck state, depending on the output voltage of the PV panel and the charging requirement voltage of the battery. In this DC charging mode, the switching elements S1 and S2 are closed, S3 is open, and the bidirectional AC / DC converter 10 does not operate, enabling efficient charging of the battery using the electrical energy from the PV panel.

[0071] In Fig. 5-3, the PV energy storage module operates in the AC charging mode. The control chip 7 turns on the second and third switching elements S2, S3 and operates the bidirectional AC / DC converter 10 in the rectification state. At this time, the first AC power from the AC grid is rectified by the bidirectional AC / DC converter 10 and converted into DC power. This DC power is then voltage-regulated by the second DC / DC converter 9 and converted into second DC power suitable for charging the battery. In this AC charging mode, the bidirectional AC / DC converter 10 is in the rectification state, S2 and S3 are closed, S1 is open, enabling charging of the battery using the AC power from the AC grid.

[0072] In Fig. 5-4, the PV energy storage module operates in the battery power supply mode. The control chip 7 turns on the second and third switching elements S2, S3 and operates the bidirectional AC / DC converter 10 in the inversion state. At this time, the DC power generated by the battery undergoes voltage regulation (Boost or Buck) through the second DC / DC converter 9, is then inverted and converted into first AC power through the bidirectional AC / DC converter 10, and ultimately supplied power to the AC grid. In this battery power supply mode, the bidirectional AC / DC converter 10 is in the inversion state, S2 and S3 are closed, S1 is open, enabling the supply of power to the AC grid using the DC power from the battery.

[0073] By flexibly switching between the four working modes shown in Figs. 5-1 to 5-4, the integrated PV energy storage module of the present disclosure can achieve efficient utilization of the PV panel, flexible charging and discharging of the battery, and stable interaction with the AC grid, enabling adaptation to different operating scenarios.

[0074] Although Figs. 5-1 to 5-4 show the switching elements S1-S3 being respectively disposed between various voltage converters, this arrangement is only schematic and not the only feasible implementation. In fact, the positions of these switching elements may be flexibly adjusted. For example, they can also be set on the side of the connection terminals of the AC / DC multi-directional conversion device to directly control the connection and disconnection of the connection terminals. This arrangement can also achieve effective control of the voltage conversion pathway, thereby achieving flexible switching of the current flow pathway for the PV energy storage module in different working modes. Therefore, even if the setting positions of the switching elements change, as long as they can selectively connect or disconnect the relevant conversion pathways according to the instructions of the control chip 7, the expected working modes of the PV energy storage module can be achieved.

[0075] Importantly, regardless of the position where the switching elements are set, they can be implemented using various types of switching devices, including but not limited to Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs), BJTs, relays, or Insulated Gate Bipolar Transistors (IGBTs). These switching devices, due to their different characteristics and applicable scenarios, can be selected according to the specific needs of the AC / DC multi-directional conversion device to ensure efficient, safe, and reliable operation of the converters. Furthermore, the switching elements S1-S3 can be independently set switches or switching transistors shared with the DC / DC converter or the bidirectional AC / DC converter. Said switching transistors may be selected, for example, from the group consisting of diodes, BJTs, thyristors, MOSFETs, and IGBTs.

[0076] In the AC / DC multi-directional conversion device, the first and second DC / DC converters can adopt a highly flexible circuit design to adapt to different voltage conversion requirements. The first and second DC / DC converters can each be implemented as any one of a Boost circuit, a Buck circuit, or a Boost-Buck circuit.

[0077] Fig. 6 shows a schematic diagram of the output voltage waveform of a PV panel in the integrated PV energy storage module according to the present disclosure. As shown in Fig. 6, the output voltage of the PV panel is not a stable DC voltage but contains high-frequency / HF or low-frequency / LF noise signals. Therefore, before performing Boost or Buck operations on the output voltage of the PV panel, it is necessary to filter it using a filtering module, which may be integrated, for example, inside the first DC / DC converter.

[0078] Fig. 7-1 shows an internal circuit diagram of a first or second DC / DC converter implemented as a Boost circuit. This Boost circuit is suitable for situations where the output voltage of the PV panel is lower than the charging voltage of the battery. First, to filter out noise signals in the output voltage of the PV panel, the Boost circuit comprises a first capacitor array on the input side. This capacitor array comprises electrolytic capacitors C1-C4 and surface-mount (SMD) capacitors C6-C9 connected in parallel. Among them, the electrolytic capacitors C1-C4 have a diameter of less than 17mm and a capacitance of 800pF-3000pF, quantity: 4-8; the surface-mount capacitors C6-C9 have a capacitance of 1-10pF, quantity: 4-14.

[0079] Through the combination of electrolytic capacitors C1-C4 and surface-mount capacitors C6-C9, the ripple and high-order harmonic interference in the input signal of the Boost circuit may be better suppressed. Among them, the electrolytic capacitors can effectively suppress the low-frequency filtering part, and the surface-mount capacitors can compensate for the deficiency of electrolytic capacitors in filtering the high-frequency part, reducing the diameter of the electrolytic capacitors and extending their lifespan. In summary, the design of this capacitor array ensures its compact layout within a limited space and also ensures the stability of the output voltage of the DC / DC converter.

[0080] In the downstream of this capacitor array, a conventional Boost circuit is disposed, which comprises an energy storage inductor L, two switching transistors Q1 and Q2, and an energy storage capacitor C5. The control terminals of switching transistors Q1 and Q2 are respectively P1 and P2. Control terminals P1 and P2 are each connected to the control chip 7, so that the switching transistors Q1 and Q2 are turned on / off alternately under the control of the control chip 7, thereby realizing the Boost function of the circuit. Here, the switching transistor Q2 may be a MOSFET or a diode; if it is a MOSFET, it can reuse the same switch with the switching element S1 or S2 in the AC / DC multi-directional conversion device.

[0081] Fig. 7-2 shows an internal circuit diagram of the first or second DC / DC converter implemented as a Buck circuit. This Buck circuit is suitable for situations where the output voltage of the PV panel is higher than the charging voltage of the battery. Similarly, to filter out noise signals in the output voltage of the PV panel, the Buck circuit comprises a capacitor array on the input side. This capacitor array comprises electrolytic capacitors C1-C4 and surface-mount capacitors C6-C9 connected in parallel. Among them, the electrolytic capacitors C1-C4 have a diameter of less than 17mm and a capacitance of 800pF-3000pF, quantity: 4-8; the surface-mount capacitors C6-C9 have a capacitance of 1-10pF, quantity: 4-14.

[0082] Through the combined filtering of electrolytic capacitors C1-C4 and surface-mount capacitors C6-C9, the ripple and high-order harmonic interference in the input signal of this Buck circuit may be better suppressed. Among them, electrolytic capacitors can effectively suppress the low-frequency filtering part, and surface-mount capacitors can compensate for the deficiency of electrolytic capacitors in filtering the high-frequency part, reducing the diameter of the electrolytic capacitors and extending their lifespan.

[0083] In the downstream of this capacitor array, a conventional Buck circuit is disposed, which comprises an energy storage inductor L, two switching transistors Q1 and Q2, and an energy storage capacitor C5. The control terminals of switching transistors Q1 and Q2 are respectively P1 and P2. Control terminals P1 and P2 are each connected to the control chip, so that the switching transistors Q1 and Q2 are turned on / off alternately under the control of the control chip, thereby realizing the Buck function of the circuit. Here, the switching transistor Q2 may be a MOSFET or a diode.

[0084] Fig. 7-3 shows an internal circuit diagram of the first or second DC / DC converter implemented as a Boost-Buck circuit. This Boost-Buck converter circuit is suitable for situations where the output voltage of the PV panel is sometimes higher than, and at other times lower than, the charging voltage of the battery. To filter out noise signals in the output voltage of the PV panel, this Boost-Buck circuit comprises a capacitor array on the input side. This capacitor array comprises electrolytic capacitors C1-C4 and surface-mount capacitors C6-C9 connected in parallel. Among them, the electrolytic capacitors C1-C4 have a diameter of less than 17mm and a capacitance of 800pF-3000pF, quantity: 4-8; the surface-mount capacitors C6-C9 have a capacitance of 1-10pF, quantity: 4-14.

[0085] Through the combined filtering of electrolytic capacitors C1-C4 and surface-mount capacitors C6-C9, the ripple and high-order harmonic interference in the input signal of this Boost-Buck circuit can be better suppressed. Among them, the electrolytic capacitors can effectively suppress the low-frequency filtering part, and surface-mount capacitors can compensate for the deficiency of electrolytic capacitors in filtering the high-frequency part, reducing the diameter of the electrolytic capacitors and extending their lifespan.

[0086] In the downstream of this capacitor array, a conventional Boost-Buck circuit is disposed, which comprises an energy storage inductor L, two switching transistors Q1 and Q2, and an energy storage capacitor C5. Among them, the switching transistor Q1 is set on the input side of this Boost-Buck circuit, the switching transistor Q2 is set on the output side of this Boost-Buck circuit, and the energy storage inductor L is disposed between the switching transistors Q1 and Q2. Here, the switching transistor Q2 may be a MOSFET or a diode; if it is a MOSFET, it can reuse the same switch with the switching element S1 or S2 in the AC / DC multi-directional conversion device.

[0087] The control terminals of the switching transistors Q1 and Q2 are respectively P1 and P2. Control terminals P1 and P2 are each connected to the control chip 7. According to the output voltage of the PV panel and the charging voltage of the battery, the control chip can dynamically adjust the duty cycles of Q1 and Q2, thereby enabling this Boost-Buck circuit to switch freely between Boost mode and Buck mode. For example, when the output voltage of the PV panel is lower than the charging voltage of the battery, the Boost-Buck circuit is made to operate in Boost mode; when the output voltage of the PV panel is higher than the charging voltage of the battery, the Boost-Buck circuit is made to operate in Buck mode.

[0088] In this AC / DC multi-directional conversion device, depending on the specific application scenario of the integrated PV energy storage module (e.g., the operating voltage of the connected AC grid), the bidirectional AC / DC converter can adopt two forms: an isolation transformer structure and a non-isolation transformer structure.

[0089] Fig. 8-1 shows a schematic diagram of the internal circuit structure of the bidirectional AC / DC converter using an isolation transformer structure. In Fig. 8-1, the circuit design of the bidirectional AC / DC converter adopts an isolation transformer to meet the electrical isolation requirements for specific occasions (such as the United States). This bidirectional AC / DC converter is based on a variation of a dual active bridge (DAB) circuit to achieve efficient bidirectional conversion between DC power and AC power.

[0090] The core structure of this variant dual active bridge circuit comprises an isolation transformer T, a first switching circuit, a second switching circuit, and an inductor Ls. The input side of the first switching circuit is connected to the DC side of the bidirectional AC / DC converter. The inductor Ls is disposed between the secondary side of the isolation transformer T and the input side of the second switching circuit. The output side of the second switching circuit is electrically connected to the AC side of the bidirectional AC / DC converter. Here, the leakage inductance of the secondary side of the isolation transformer T can also be used to replace the inductor Ls, thereby omitting additional setting of secondary side inductor.

[0091] As an optional example, on the primary side of the isolation transformer T, especially between the output side of the first switching circuit and the primary side of the isolation transformer T, one or more capacitors can also be separately set to filter out the DC component in the electrical signal received by the primary side of the isolation transformer. As another optional example, on the primary side of the isolation transformer T, another resonant circuit comprising a primary side inductor and a primary side capacitor can also be set.

[0092] Both the first and second switching circuits adopt a full-bridge topology structure. Among them, the four arms of the first switching circuit are each composed of switching transistors Q1-Q4. The corresponding control terminals P1-P4 of these four switching transistors Q1-Q4 are each connected to the control chip 7.

[0093] In the second switching circuit, the first upper arm and the first lower arm forming the first half-bridge are each composed of two switching transistors (MOSFETs Q5, Q6 and MOSFETs Q7, Q8, respectively) connected in a back-to-back series connection. The second upper arm and the second lower arm forming the second half-bridge are composed of a single capacitor (C1 and C2 respectively). That is to say, on the AC side of this bidirectional AC / DC converter, one terminal of the secondary side of the isolation transformer T is connected in series to two sets of parallel circuits: one set is formed by the series connection of switching transistors Q5, Q6 and capacitor C1, and the other set is formed by the series connection of switching transistors Q7, Q8 and capacitor C2. The source terminals of switching transistors Q5 and Q6 are connected to each other, and the source terminals of switching transistors Q7 and Q8 are connected to each other, finally returning to the other terminal of the secondary side of the isolation transformer T. The control terminals P1-P8 of the switching transistors Q1-Q8 are turned on sequentially by the control chip 7 according to the requirements for bidirectional rectification or inversion mode, AC power frequency (phase) synchronization, etc.

[0094] On the secondary side of the isolation transformer T, based on the topology structure of the second switching circuit and the inductor Ls (or the transformer's leakage inductance) as shown in Fig. 8-1, the control chip 7 can selectively control the ON / OFF states of the four switching transistors Q5, Q6, Q7, Q8, thereby forming a first resonant loop through the inductor Ls and the capacitor C1, or forming a second resonant loop through the inductor Ls and the capacitor C2, and ultimately achieving the required voltage / current waveform on the secondary side of the transformer.

[0095] Specifically, as shown in Fig. 8-1, when the bidirectional AC / DC converter operates in rectification mode, for example, when it is necessary to use the AC power from the AC grid to charge the battery, the AC side of the bidirectional AC / DC converter receives the AC signal L-N from the AC grid. During the positive half-cycle of this AC signal L-N, with the help of the control chip 7, the switching transistors Q6 and Q8 in the second switching circuit are kept constantly on, and the switching transistors Q5 and Q7 alternately perform high-frequency switching operations (i.e., when Q5 is on, Q7 is off, and vice versa). Conversely, during the negative half-cycle of L-N, with the help of the control chip 7, the switching transistors Q5 and Q7 are kept constantly on, and the switching transistors Q6 and Q8 alternately perform high-frequency switching operations. At the same time, on the DC side of this bidirectional AC / DC converter, the switching transistors Q1, Q4 and switching transistors Q2, Q3 in the first switching circuit are turned on alternately to coordinate with the actions of the switching transistors on the AC side (i.e., when switching transistors Q1, Q4 are turned on synchronously, switching transistors Q2, Q3 are turned off synchronously, and vice versa), thereby achieving power transmission from the second switching circuit on the AC side to the first switching circuit on the DC side.

[0096] When the bidirectional AC / DC converter operates in inversion mode, for example, when it is necessary to use the PV panel or the battery to supply power to the AC grid, on the DC side, switching transistors Q1, Q4 and switching transistors Q2, Q3 are made to alternately perform high-frequency switching operations, thereby converting the DC power received on the DC side into high-frequency AC power. At the same time, on the AC side, the control chip 7 controls the switching transistors Q5~Q8 to operate synchronously with the high-frequency signal on the DC side. For example, during the positive half-cycle, Q5 and Q7 are kept constantly on, and Q6 and Q8 are switched on and off alternately; during the negative half-cycle, Q6 and Q8 are kept constantly on, and Q5 and Q7 are switched on and off alternately, thereby achieving power transmission from the first switching circuit on the DC side to the second switching circuit on the AC side.

[0097] In the above conversion process, the switching frequency of the DC side switching transistors is the same as that of the AC side switching transistors that perform high-frequency switching operations, and a phase shift angle is formed between the control signals of the AC side switching transistors that perform high-frequency switching operations and the signals of the DC side switching transistors. By adjusting the size of this phase shift angle, for example, by making the AC side switching transistor signals lead or lag behind the DC side switching transistor signals, the current direction on the inductor Ls can be regulated, thereby making the entire converter operate in rectification or inversion mode.

[0098] To meet the overall size requirements of the PV energy storage module, the design parameters of the isolation transformer are optimized. According to E=4.44fNQm, where E is the electromotive force, f is the frequency, N is the turns, and Qm is the magnetic flux, when the thickness of the isolation transformer becomes thinner, N decreases and Qm also decreases. By increasing the frequency f, the effects caused by the decrease of N and Qm may be compensated.

[0099] Testing has shown that when the operating frequency is within the range of 8KHz to 300KHz, the primary winding turns of the isolation transformer are set to 3 to 6, the secondary winding turns are set to 9 to 18, and the turns ratio is set to between 2 to 4. The primary inductance is between 50pH and 1.5mH, and the secondary leakage inductance is between 5uH and 200pH. When the thickness of the transformer becomes thinner, and the turns and magnetic flux decrease, the impact of these changes can be compensated by increasing the frequency f, while maintaining the height of the isolation transformer less than 17mm.

[0100] In addition, the bidirectional AC / DC converter also comprises a second capacitor array, which is disposed between the second switching circuit and the AC grid. This capacitor array consists of 1 to 3 safety capacitors Cx2 each having a height of less than 17mm, used for filtering on the AC side of the bidirectional AC / DC converter. Due to the high-frequency operation, the height requirement for the safety capacitors is reduced, so its height is also less than 17mm. Through this isolation transformer structure design of the bidirectional AC / DC converter, not only is the efficient conversion between DC and AC achieved, but also the compact space and high-performance requirements of the PV energy storage module are met, while also fulfilling the safety requirements for electrical isolation.

[0101] Fig. 8-2 shows a schematic diagram of the internal circuit structure of the bidirectional AC / DC converter using a non-isolation transformer structure. In Fig. 8-2, the circuit design of the bidirectional AC / DC converter adopts a non-isolation transformer structure, which is suitable for scenarios where electrical isolation is not required.

[0102] The bidirectional AC / DC converter comprises a bidirectional full-bridge converter composed of four switching transistors Q1-Q4 and an LC resonator. The DC side of the bidirectional full-bridge converter is electrically connected to the second terminal of the third switching element S3. The LC resonator is disposed between the AC side of the bidirectional full-bridge converter and the AC grid.

[0103] The switching transistors Q1-Q4 may be MOSFETs, thyristors, etc. They are controlled by the control chip 7 to operate in rectification or inversion states. Similarly, by increasing the switching frequency of the switching transistors, the quality of the output side waveform can be improved, and the height requirement for the safety capacitor Cx2 (used for AC side filtering) can be reduced, making its height less than 17mm. The number of such safety capacitors used is 1-3.

[0104] As described above, many of the aforementioned designs of the internal circuit structure of the AC / DC multi-directional conversion device are conducive to achieving a compact size for the AC / DC multi-directional conversion device, particularly reducing its size in the thickness direction of the integrated PV energy storage module. This ensures that the height of the AC / DC multi-directional conversion device on the rear side of the PV panel does not extend beyond the rear end face of its frame. Consequently, the entire PV energy storage module can be implemented without increasing the overall dimensions (specifically, the thickness) of existing mainstream PV modules (the overall thickness of mainstream PV module is not greater than 36mm, and the backside void height is not greater than 28mm).

[0105] For those skilled in the art, various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of the present disclosure. Other embodiments of the present disclosure will be apparent to those skilled in the art from the practice of the present disclosure as disclosed in this specification. The specification and its disclosed examples should be considered merely illustrative, with the true scope of the present disclosure being specified by the appended claims and their equivalents.

Claims

1. An integrated PV energy storage module, comprising a PV panel, an AC / DC multi-directional conversion device, and a battery,wherein the PV panel is equipped with a frame protruding toward its rear side, the AC / DC multi-directional conversion device and the battery are mounted on the rear side of the PV panel, with their protrusion height not extending beyond the rear end face of the frame,the AC / DC multi-directional conversion device comprises three sets of connection terminals, multiple voltage converters, multiple switching elements, and a control chip, the three sets of connection terminals are electrically connected to the PV panel, the battery, and an AC grid respectively, each switching element is configured to electrically connect a respective one of the multiple voltage converters to another converter thereof, or to a corresponding set of the three sets of connection terminals, and the control chip is configured to: in different working modes of the integrated PV energy storage module, selectively turn on at least one of the multiple switching elements to establish a voltage conversion pathway between two corresponding sets of the three sets of connection terminals by means of at least one of the multiple voltage converters,wherein the AC / DC multi-directional conversion device and the battery are mounted on the rear side of the PV panel via a one-piece grid-shaped bracket fixed to the frame within the frame, the battery comprises multiple battery cells, with at least a portion of these cells arranged in a single-layer flat configuration,wherein the multiple voltage converters comprise a first DC / DC converter, a second DC / DC converter, and a bidirectional AC / DC converter, wherein the input side of the first DC / DC converter is electrically connected to the PV panel, the input side of the second DC / DC converter is electrically connected to the battery, and the AC side of the bidirectional AC / DC converter is electrically connected to the AC grid, the multiple switching elements comprise a first, a second, and a third switching element, wherein the first switching element is assigned to the first DC / DC converter, the second switching element is assigned to the second DC / DC converter, and the third switching element is assigned to the bidirectional AC / DC converter,wherein the control chip is further configured to selectively turn on corresponding two of the first, the second, and the third switching element to realize different working modes of the integrated PV energy storage module by means of corresponding two converters selected from the first DC / DC converter, the second DC / DC converter, and the bidirectional AC / DC converter,the bidirectional AC / DC converter comprises an inductor, an isolation transformer, a first switching circuit, and a second switching circuit, wherein the input side of the first switching circuit is electrically connected to the DC side of the bidirectional AC / DC converter, the inductor is disposed between the secondary side of the isolation2025338179   23 Sep 2026transformer and the input side of the second switching circuit, the output side of the second switching circuit is electrically connected to the AC side of the bidirectional AC / DC converter, wherein the first and second switching circuits adopt a full-bridge topology structure respectively, the four arms of the first switching circuit are each composed of a single switching transistor, a first upper arm and a first lower arm of the second switching circuit are each composed of two switching transistors connected in a back-to-back series connection, and a second upper arm and a second lower arm of the second switching circuit are each composed of a single capacitor,when the isolation transformer operates within a frequency range of 8KHz to 300KHz, the primary winding turns of the isolation transformer are set to 3 to 6, the secondary winding turns are set to 9 to 18, the turns ratio is set to between 2 to 4, the primary inductance is between 50p.H and 1.5mH, the secondary leakage inductance is between 5nH and 200gH, and the height of the isolation transformer is set to less than 17mm.2.The integrated PV energy storage module according to claim 1, wherein the battery comprises a battery module formed by a combination of multiple blade batteries, or multiple pouch batteries, or multiple solid-state batteries.3.The integrated PV energy storage module according to claim 1 or 2, wherein the integrated PV energy storage module further comprises a battery management system integrated within the AC / DC multi-directional conversion device or separately arranged from the AC / DC multi-directional conversion device.4.The integrated PV energy storage module according to any of claims 1 to 3, wherein the working modes of the integrated PV energy storage module comprise a PV power supply mode, a DC charging mode, an AC charging mode, and a battery power supply mode, wherein the control chip is further configured to:in the PV power supply mode, turn on the first and third switching elements and operate the bidirectional AC / DC converter in an inversion state, so as to convert, by means of the first DC / DC converter and the bidirectional AC / DC converter, a first DC power from the PV panel into a first AC power to be supplied to the AC grid;in the DC charging mode, turn on the first and second switching elements, so as to convert, by means of the first DC / DC converter and the second DC / DC converter, the first DC power from the PV panel into a second DC power for charging the battery;in the AC charging mode, turn on the second and third switching elements and operate the bidirectional AC / DC converter in a rectification state, so as to convert, by means of the bidirectional AC / DC converter and the second DC / DC converter, a first AC power from the AC grid into a second DC power for charging the battery; andin the battery power supply mode, turn on the second and third switching elements and operate the bidirectional AC / DC converter in the inversion state, so as to convert, by means of the second DC / DC converter and the bidirectional AC / DC converter, a second DC power from the battery into the first AC power to be supplied to the AC grid.2025338179   23 Sep 20265.The integrated PV energy storage module according to any of claims 1 to 4, wherein the first and second DC / DC converters are each implemented as any one of a Boost circuit, a Buck circuit, and a Boost-Buck circuit.6.The integrated PV energy storage module according to claim 5, wherein the Boost-Buck circuit comprises a first switching transistor disposed at the input side of the corresponding DC / DC converter, a second switching transistor disposed at the output side of the corresponding DC / DC converter, and an energy storage inductor disposed between the first switching transistor and the second switching transistor, wherein the control chip is configured to control the duty cycle of the first and second switching transistors based on the output voltage of the PV panel and the charging voltage of the battery, thereby causing the corresponding DC / DC converter to operate in the Boost mode or the Buck mode.7.The integrated PV energy storage module according to any one of claims 1 to 6, wherein the first and second DC / DC converters each comprise a first capacitor array, the first capacitor array being constituted by at least one electrolytic capacitor and at least one surface-mount capacitor.8.The integrated PV energy storage module according to claim 7, wherein each electrolytic capacitor has a capacitance of 800pF-3000pF, each surface-mount capacitor has a capacitance of 1-10pF, and the diameter of each electrolytic capacitor is less than 17mm.9.The integrated PV energy storage module according to any of claims 1 to 8, wherein the bidirectional AC / DC converter further comprises a second capacitor array disposed between the second switching circuit and the AC grid, the second capacitor array comprises 1 to 3 safety capacitors each having a height less than 17mm.10.The integrated PV energy storage module according to any one of claims 1 to 9, wherein the bidirectional AC / DC converter comprises a bidirectional full-bridge converter composed of four switching transistors and an LC resonator, the DC side of the bidirectional full-bridge converter is electrically connected to the second terminal of the third switching element, and the LC resonator is disposed between the AC side of the bidirectional full-bridge converter and the AC grid.11.The integrated PV energy storage module according to claim 10, wherein the bidirectional AC / DC converter further comprises a third capacitor array disposed between the LC resonator and the AC grid, the third capacitor array comprises 1 to 3 safety capacitors each having a height less than 17mm.

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