Battery assembly and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a battery assembly and a photovoltaic system, the battery assembly comprises a plurality of three-terminal laminated batteries arranged in sequence, the three-terminal laminated batteries comprise a top battery and a bottom battery arranged below the top battery, the top battery is provided with a first electrode, and the bottom battery is provided with a second electrode; a second electrode and a third electrode are respectively arranged on the bottom battery, the first electrode and the second electrode have the same polarity, and the first electrode and the third electrode have different polarities; the first welding strips are connected with the first electrode of one three-end laminated battery and the third electrode of the other three-end laminated battery; and the second welding strips are connected with the second electrode of one three-end laminated battery and the third electrode of the other three-end laminated battery. Electrical series connection between the top batteries of different three-end lamination layers is achieved, electric energy of different batteries is integrated, the performance of the battery assembly is further optimized, and the output power is improved.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, and particularly relates to a battery module and a photovoltaic system. Background Technology

[0002] There are certain technical challenges in the traditional three-terminal stacked battery connection, which affect its application effect and power generation efficiency.

[0003] From the perspective of output power, these drawbacks are particularly evident. With partial connection methods, the voltage and current output cannot reach ideal levels. Because the top and bottom cells of a three-terminal tandem battery have different voltages, voltage mismatch occurs with partial connections, preventing the module voltage from being effectively increased when multiple cells are connected. Simultaneously, due to differences in manufacturing processes and material properties, the output current of the top and bottom cells in a three-terminal tandem battery is not the same, and some connection methods cause the current of the entire circuit to be determined by the cell with the lowest output current. This inability to increase voltage or current limitation directly results in the battery module's output power failing to reach a high level.

[0004] Furthermore, existing connection methods suffer from insufficient electrode utilization. Three-terminal tandem batteries inherently have three electrodes, but current connection methods only utilize two, failing to fully utilize the third. This not only wastes battery resources but also prevents the battery from achieving its potential for higher output power, further hindering the efficient application and development of three-terminal tandem batteries. Summary of the Invention

[0005] This invention provides a battery module and photovoltaic system, which aims to solve the problem of limited output power in traditional three-terminal stacked battery connections.

[0006] This invention is implemented as follows: a battery assembly includes: A plurality of three-terminal stacked batteries arranged in sequence, the three-terminal stacked batteries including a top battery and a bottom battery disposed below the top battery, the top battery being provided with a first electrode, the bottom battery being provided with a second electrode and a third electrode respectively, the first electrode and the second electrode having the same polarity, and the first electrode and the third electrode having different polarities; A plurality of first solder strips, the first solder strips connecting the first electrode of one of the three-terminal stacked cells to the third electrode of another of the three-terminal stacked cells; Several second solder strips connect the second electrode of one of the three-terminal stacked cells to the third electrode of another of the three-terminal stacked cells.

[0007] Optionally, the first solder strip includes at least a first sub-solder strip and a second sub-solder strip; The top battery of the first sub-welded strip is connected in series to form a first sequence string; The second sub-strip is connected in series with at least a portion of the remaining top cells to form a second sequence string; At least the first sequence string and the second sequence string are connected in parallel.

[0008] Optionally, the open-circuit voltages of the first sequence string and the second sequence string are equal.

[0009] Optionally, the second solder strip includes at least a third sub-strip; The third sub-welding strip is connected in series with at least part of the bottom battery to form a third sequence string; The third sequence string is connected in parallel with the first sequence string.

[0010] Optionally, the open-circuit voltage of the third sequence string is equal to that of the first sequence string.

[0011] Optionally, the second solder strip further includes at least a fourth sub-strip; The fourth sub-welding strip is connected in series with at least a portion of the remaining bottom batteries to form a fourth sequence string; The fourth sequence string and the third sequence string are connected in parallel.

[0012] Optionally, the open-circuit voltages of the fourth sequence string and the third sequence string are equal or differ by a range of ±0.2V.

[0013] Optionally, the open-circuit voltage of the top battery is greater than the open-circuit voltage of the bottom battery.

[0014] Optionally, the ratio of the open-circuit voltage of the top battery to the open-circuit voltage of the bottom battery is 1 to 3.

[0015] Optionally, the ratio of the open-circuit voltage of the top battery to the open-circuit voltage of the bottom battery is 1.5 to 2.

[0016] Optionally, the top cell and the bottom cell in a single three-terminal stacked battery have a common electrode.

[0017] Optionally, at least a portion of the top battery is a terminal loss battery.

[0018] Optionally, at least a portion of the bottom battery is a terminal loss battery.

[0019] Optionally, the first welding strip has a bend, while the second welding strip does not have a bend.

[0020] Optionally, the number of the first solder strips is equal to the number of the second solder strips.

[0021] The present invention also provides a photovoltaic system including the above-described battery module.

[0022] The beneficial effects achieved by this invention are due to the separate placement of a first solder strip and a second solder strip. The first solder strip connects the first electrode of one three-terminal tandem battery to the third electrode of another three-terminal tandem battery. This connection method achieves electrical series connection between the top cells of different three-terminal tandem batteries, integrating the electrical energy of different batteries. The second solder strip connects the second electrode of one three-terminal tandem battery to the third electrode of another three-terminal tandem battery. Similarly, this connection method achieves electrical connection between the bottom cells of the three-terminal tandem batteries, further optimizing the performance of the battery assembly and increasing output power. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the first type of three-terminal stacked battery; Figure 2 This is a schematic diagram of the structure of the first type of three-terminal stacked battery; Figure 3 This is a schematic diagram of the structure of the first type of three-terminal stacked battery; Figure 4 This is a schematic diagram of the structure of the first type of three-terminal stacked battery; Figure 5 A schematic diagram of the equivalent diode connection of the first type of battery assembly; Figure 6 A schematic diagram of the equivalent diode connection of the second type of battery assembly; Figure 7 A schematic diagram of the equivalent diode connection for the third type of battery assembly.

[0024] Explanation of reference numerals in the attached figures: 10. Battery module; 100. Three-terminal stacked battery; 110. Top battery; 120. Bottom battery; 130. First solder strip; 131. First sub-solder strip; 132. Second sub-solder strip; 133. Fifth sub-solder strip; 140. Second solder strip; 141. Third sub-solder strip; 142. Fourth sub-solder strip. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0031] This invention utilizes a first solder strip and a second solder strip. The first solder strip connects the first electrode of one three-terminal tandem battery to the third electrode of another three-terminal tandem battery. This connection method achieves electrical series connection between the top cells of different three-terminal tandem batteries, integrating the electrical energy of different batteries. The second solder strip connects the second electrode of one three-terminal tandem battery to the third electrode of another three-terminal tandem battery. Similarly, this connection method achieves electrical connection between the bottom cells of the three-terminal tandem batteries, further optimizing the performance of the battery assembly and increasing output power.

[0032] Example 1 like Figures 1 to 7 As shown, this embodiment provides a battery assembly 10, including: A plurality of three-terminal stacked batteries 100 are arranged in sequence. Each three-terminal stacked battery 100 includes a top battery 110 and a bottom battery 120 disposed below the top battery 110. A first electrode is disposed on the top battery 110, and a second electrode and a third electrode are disposed on the bottom battery 120 respectively. The first electrode and the second electrode have the same polarity, and the first electrode and the third electrode have different polarities. Several first solder strips 130, the first solder strips 130 connecting the first electrode of one three-terminal stacked battery 100 and the third electrode of another three-terminal stacked battery 100; Several second solder strips 140 connect the second electrode of one three-terminal stacked cell 100 to the third electrode of another three-terminal stacked cell.

[0033] like Figures 1 to 4As shown, the three-terminal stacked battery 100 includes a top battery 110 and a bottom battery 120 disposed below the top battery 110. The "three terminals" of the three-terminal stacked battery 100 mean it has three electrodes. The top battery 110 has a first electrode, and the bottom battery 120 has a second electrode and a third electrode with opposite polarities. Specifically, the bottom battery 120 has one positive electrode and one negative electrode. The first electrode on the top battery 110 can be either a positive or negative electrode. When the first electrode is positive, the second electrode is positive and the third electrode is negative; when the first electrode is negative, the second electrode is negative and the third electrode is positive.

[0034] First solder ribbon 130 and second solder ribbon 140 connect several three-terminal stacked cells 100. First solder ribbon 130 connects the first electrode of one three-terminal stacked cell 100 to the third electrode of another three-terminal stacked cell 100. This connection method achieves electrical series connection between the top cells 110 of different three-terminal stacked cells, integrating the electrical energy of different cells. Second solder ribbon 140 connects the second electrode of one three-terminal stacked cell 100 to the third electrode of another three-terminal stacked cell 100. Similarly, this connection method achieves electrical connection between the bottom cells 120 of the three-terminal stacked cells 100, further optimizing the performance of the battery assembly 10.

[0035] Understandably, in this embodiment, the polarity of the electrode refers to whether the electrode is positive or negative. Assume there are three sequentially arranged three-terminal stacked batteries 100, namely battery A, battery B, and battery C. Battery A has a top battery 110 with a first positive electrode, a bottom battery 120 with a second positive electrode, and a third negative electrode. Battery B has a top battery 110 with a first positive electrode, a bottom battery 120 with a second positive electrode, and a third negative electrode. Battery C has a top battery 110 with a first positive electrode, a bottom battery 120 with a second positive electrode, and a third negative electrode. Specifically, the connection method can be: using a first solder strip 130 to connect the first electrode (positive) of battery A to the third electrode (negative) of battery B, and then using another first solder strip 130 to connect the first electrode (positive) of battery B to the third electrode (negative) of battery C. Use the second solder ribbon 140 to connect the second electrode (positive) of battery A to the third electrode (negative) of battery B, and then use another second solder ribbon 140 to connect the second electrode (positive) of battery B to the third electrode (negative) of battery C.

[0036] Through this connection, three three-terminal stacked batteries 100 form a battery module 10, realizing the effective integration and output of electrical energy.

[0037] Due to the special structure of the three-terminal tandem battery 100 and the connection method of the solder strips, it can utilize energy sources such as solar energy more effectively. The connection method between electrodes of different polarities enables the battery module 10 to generate more current under conditions such as sunlight, thereby improving the output power of the entire battery module 10.

[0038] In a traditional battery module 10, if one battery fails, it may affect the performance of the entire module. However, in this type of battery module 10, due to the use of three-terminal stacked batteries 100 and a special connection method, when one battery experiences a partial failure, the other batteries can still continue to operate through different connection paths, thereby enhancing the stability and reliability of the battery module 10.

[0039] In this embodiment, a first solder ribbon 130 and a second solder ribbon 140 are respectively provided. The first solder ribbon 130 connects the first electrode of one three-terminal stacked battery 100 and the third electrode of another three-terminal stacked battery 100. This connection method achieves electrical series connection between the top batteries 110 of different three-terminal stacked batteries, integrating the electrical energy of different batteries. The second solder ribbon 140 connects the second electrode of one three-terminal stacked battery 100 and the third electrode of another three-terminal stacked battery 100. Similarly, this connection method achieves electrical connection between the bottom batteries 120 of the three-terminal stacked batteries 100, further optimizing the performance of the battery assembly 10 and improving the output power.

[0040] In some embodiments, the first solder strip 130 has a bend, while the second solder strip 140 does not. Typically, several three-terminal stacked cells 100 are arranged sequentially with the same orientation; that is, the first electrodes of the several three-terminal stacked cells 100 face the same direction. The second and third electrodes of the three-terminal stacked cells 100 also face the same direction, opposite to the first electrode.

[0041] The first solder strip 130 connects the first electrode and the third electrode. The first electrode is located on the side of the top battery 110 facing away from the bottom battery 120, and the third electrode is located on the side of the bottom battery 120 facing away from the top battery 110. The first electrode and the third electrode are arranged opposite to each other, connecting two electrodes arranged in opposite directions. The first solder strip 130 has a bend, which facilitates the adjustment of the direction of the first solder strip 130.

[0042] The second welding strip 140 connects the second electrode and the third electrode. Both the second electrode and the third electrode are located on the side of the bottom battery 120 facing away from the top battery 110. The second electrode connects the two electrodes located on the same side, and can be directly connected without bending.

[0043] In some embodiments, the first solder strip 130 includes at least a first sub-solder strip 131 and a second sub-solder strip 132; The first sub-welding strip 131 is connected in series with the top battery 110 to form a first sequence string; The second sub-welding strip 132 is connected in series with at least a portion of the remaining top battery 110 to form a second sequence string; The first sequence string and the second sequence string are connected in parallel.

[0044] The first solder ribbon 130 includes at least a first sub-solder ribbon 131 and a second sub-solder ribbon 132. The first and second sequence strings are formed by connecting the first sub-solder ribbon 131 and the second sub-solder ribbon 132, respectively. A sequence string is a battery string formed by connecting a plurality of top batteries 110 or a plurality of bottom batteries 120 in series. The first sequence string includes a plurality of top batteries 110. Specifically, in the first sequence string, the plurality of top batteries 110 are connected in series through the first sub-solder ribbon 131, meaning that the current flow direction of the top batteries 110 in the first sequence string is the same. The second sequence string includes a plurality of top batteries 110 (excluding the top batteries 110 in the first sequence string). The plurality of top batteries 110 are connected in series through the second sub-solder ribbon 132, meaning that the current flow direction of the top batteries 110 in the second sequence string is the same. The top batteries 110 in the first sequence string and the top batteries 110 in the second sequence string cannot have the same top battery 110; that is, a top battery 110 cannot be in both the second and first sequence strings.

[0045] The first and second sequence strings are connected in parallel, therefore, their actual voltages are the same or similar. Understandably, if the open-circuit voltages of the first and second sequence strings differ significantly, their actual voltages will be the smaller of the two, resulting in a larger voltage drop. Therefore, the open-circuit voltages of the first and second sequence strings are similar or equal.

[0046] Understandably, in this application, the open-circuit voltages are similar, that is, the difference between the open-circuit voltages is within a small range, specifically, the difference range can be ±0.2V.

[0047] Furthermore, the open-circuit voltage difference between each sequence can be ±0.1V.

[0048] Understandably, the first solder strip 130 may also include other sub-solder strips, which are connected to form other sequence strings. For example, it may include a fifth sub-solder strip 133, which is connected in series with at least a portion of the remaining top batteries 110 (excluding the top batteries 110 in the second and first sequence strings) to form a fifth sequence string. The fifth sequence string is connected in parallel with the first sequence string. The top batteries 110 connected in series in any two sequence strings cannot be repeated. When more other sequence strings are connected in parallel, the open-circuit voltage of the other parallel sequence strings is equal to or close to the open-circuit voltage of both the first and second sequence strings.

[0049] Furthermore, the open-circuit voltages of the first and second sequence strings are equal or differ by a range of ±0.2V.

[0050] This means that the voltages of the first and second series of batteries are matched. In battery assembly 10, the first and second series of batteries are connected in parallel. According to circuit principles, when the open-circuit voltages of each branch connected in parallel are equal, no inrush current caused by voltage difference will be generated between the branches at the instant of parallel connection. Inrush current may damage the battery, affect its lifespan, and may even lead to safety problems such as overheating and short circuits. Equal open-circuit voltages ensure the electrical compatibility of each series of batteries when connected in parallel, making battery assembly 10 more stable and reliable during connection.

[0051] Because the open-circuit voltage of each battery string is equal, it ensures that each string operates close to its optimal state when connected in parallel, fully utilizing the power generation capacity of each string. This avoids energy loss and power loss caused by voltage differences, thereby improving the overall power generation efficiency of the battery module 10. Over long-term use, this efficiency improvement can bring significant economic benefits, reduce energy waste, and enhance the cost-effectiveness of the battery module 10.

[0052] In some embodiments, the second solder strip 140 includes at least a third sub-solder strip 141; The third sub-welding strip 141 is connected in series with at least a portion of the bottom battery 120 to form a third sequence string; The third sequence string and the first sequence string are connected in parallel.

[0053] The second solder strip 140 includes at least a third sub-solder strip 141, and the third sequence is formed by connecting the third sub-solder strips 141. The third sequence includes a plurality of bottom batteries 120. Specifically, in the third sequence, the plurality of bottom batteries 120 are connected in series through the third sub-solder strips 141, that is, the current flows in the same direction in the bottom batteries 120 in the third sequence.

[0054] The third sequence string and the first sequence string are connected in parallel. Therefore, the actual voltages of the third sequence string and the first sequence string are the same or similar. Understandably, if the open-circuit voltages of the third sequence string and the first sequence string have a large difference, then their actual voltages will be the voltage of the smaller of the two, resulting in a large voltage drop. Therefore, the open-circuit voltages of the third sequence string and the second sequence string are similar or equal. Usually, if the open-circuit voltages of the first sequence string and the second sequence string are similar or equal, then the open-circuit voltages of the first sequence string, the second sequence string, and the third sequence string are similar or equal.

[0055] Understandably, the second solder ribbon 140 may also include other sub-strips, which are connected to form other sequence strings. For example, the second solder ribbon 140 may also include at least a fourth sub-strip 142, which is connected in series with at least a portion of the remaining (excluding the bottom battery 120 of the third sequence string) bottom batteries 120 to form a fourth sequence string. The fourth sequence string is connected in parallel with the third sequence string. The top batteries 110 connected in series in any two sequence strings cannot be repeated. When more other sequence strings are connected in parallel, the open-circuit voltage of the other parallel sequence strings is equal to or close to the open-circuit voltage of both the first and second sequence strings.

[0056] Furthermore, the open-circuit voltages of the first sequence string and the second sequence string are equal.

[0057] This means that the voltages of the first and second series of batteries are matched. In battery assembly 10, the first and second series of batteries are connected in parallel. According to circuit principles, when the open-circuit voltages of each branch connected in parallel are equal, no inrush current caused by voltage difference will be generated between the branches at the instant of parallel connection. Inrush current may damage the battery, affect its lifespan, and may even lead to safety problems such as overheating and short circuits. Equal open-circuit voltages ensure the electrical compatibility of each series of batteries when connected in parallel, making battery assembly 10 more stable and reliable during connection.

[0058] Because the open-circuit voltages of each battery string are equal or similar, it ensures that each string operates close to its optimal state when connected in parallel, fully utilizing the power generation capacity of each string. This avoids energy loss and power loss caused by voltage differences, thereby improving the overall power generation efficiency of the battery module 10. Over long-term use, this efficiency improvement can bring significant economic benefits, reduce energy waste, and enhance the cost-effectiveness of the battery module 10.

[0059] In some embodiments, the number of first solder strips 130 is equal to the number of second solder strips 140.

[0060] like Figures 5-7As shown, in this embodiment, one solder ribbon connects a positive electrode and a negative electrode at both ends. Specifically, one end of the solder ribbon can be connected to the positive electrode of one battery and the other end to the negative electrode of another battery; alternatively, one end of the solder ribbon can be connected to the positive electrode of a circuit and the other end to the negative electrode of a battery; or one end of the solder ribbon can be connected to the negative electrode of a circuit and the other end to the positive electrode of a battery. The first solder ribbon 130 includes several solder ribbons, such as a first sub-solder ribbon 131 and a second sub-solder ribbon 132. The number of first solder ribbons 130 is also the total number of first solder ribbons 130. The second solder ribbon 140 also includes several solder ribbons, such as a third sub-solder ribbon 141. The number of second solder ribbons 140 is also the total number of second solder ribbons 140. The first solder ribbon 130 connects the first electrode of one three-terminal stacked battery 100 and the third electrode of another three-terminal stacked battery 100. The second solder ribbon 140 connects the second electrode of one three-terminal stacked battery 100 and the third electrode of another three-terminal stacked battery 100. When the two quantities are equal, the current distribution within the battery module 10 becomes more uniform. This avoids situations where the current in some areas is too high or too low due to uneven connection methods, reduces resistance loss, improves the overall energy conversion efficiency of the battery module 10, and thus increases the output power of the battery module 10.

[0061] Example 2 In some embodiments, the open-circuit voltage of the top battery 110 is greater than the open-circuit voltage of the bottom battery 120.

[0062] The solar spectrum encompasses a wide wavelength range, from ultraviolet to infrared. The top cell 110 has a larger open-circuit voltage and typically employs a wide bandgap material, enabling it to absorb and convert high-energy, short-wavelength photons from the solar spectrum. The bottom cell 120, on the other hand, has a smaller open-circuit voltage and uses a narrow bandgap material, absorbing long-wavelength photons that the top cell 110 does not absorb. This difference allows the three-terminal tandem solar cell 100 to utilize the solar spectrum more comprehensively and efficiently, converting photons of varying energies into electrical energy, thereby improving the overall photoelectric conversion efficiency of the cell.

[0063] The top cell 110 has a larger band gap, resulting in a higher open-circuit voltage. During cell operation, a higher voltage can more effectively overcome various internal resistances, reducing energy loss during transmission and conversion. In contrast, if the open-circuit voltages of the top and bottom cells 120 were similar or opposite, some photon energy might not be fully utilized, leading to energy waste.

[0064] In some embodiments, the ratio of the open-circuit voltage of the top battery 110 to the open-circuit voltage of the bottom battery 120 is 1 to 3. Specifically, the ratio of the open-circuit voltage of the top battery 110 to the open-circuit voltage of the bottom battery 120 can be 1.1, 1.3, 1.5, 1.7, 1.9, 2, 2.2, 2.4, 2.6, 2.8, or 3, or other values ​​within the range of 1 to 3, which are not limited here.

[0065] This ratio range makes the three-terminal stacked battery 100 easier to integrate with other electronic devices or battery systems. Different application scenarios have different voltage and power requirements for batteries, and the three-terminal stacked battery 100 with a ratio between 1 and 3 can more easily meet the voltage and power requirements of various applications by adjusting the series or parallel connection method.

[0066] In some embodiments, the ratio of the open-circuit voltage of the top battery 110 to the open-circuit voltage of the bottom battery 120 is 1.5 to 2.

[0067] When the ratio of the open-circuit voltage of the top cell 110 to that of the bottom cell 120 is between 1.5 and 2, a more ideal voltage match can be achieved between the top and bottom cells 120. At this ratio, the top cell 110, with its wider bandgap, generates a higher open-circuit voltage and can absorb high-energy, short-wavelength photons. Conversely, the bottom cell 120, with its narrower bandgap, generates a lower open-circuit voltage and can absorb low-energy, long-wavelength photons. This synergistic effect between the absorption of short-wavelength photons by the top cell 110 and the absorption of long-wavelength photons by the bottom cell 120 broadens the spectral response, enabling the entire battery system to convert solar energy into electrical energy more efficiently. This voltage matching reduces energy loss within the battery and improves the overall photoelectric conversion efficiency, thus allowing for the output of more electrical energy under the same illumination conditions.

[0068] A suitable open-circuit voltage ratio also helps reduce carrier recombination. When the ratio is between 1.5 and 2, the carrier generation and collection processes of the top and bottom cells 120 are more coordinated. The carriers generated by the top cell 110 and the bottom cell 120 can be transported and collected better along the designed paths of the cell, reducing the probability of carrier recombination inside the cell, improving carrier collection efficiency, and further enhancing the performance of the cell.

[0069] In specific examples, such as Figure 6 As shown, the battery assembly 10 contains a total of 10 three-terminal stacked batteries 100 connected in series. The open-circuit voltage ratio of the top battery 110 and the bottom battery 120 in the connected three-terminal stacked batteries 100 is 2:1. The third sequence of the battery assembly 10 (i.e., Figure 6The battery string connected in series by the solid orange line in the middle contains 9 batteries (including 9 fully connected batteries) connected in series at the bottom. The second sequence string (i.e. Figure 6 The battery string connected in series by the red dashed line consists of five top batteries 110 (including four fully connected batteries and one voltage-loss battery, whose open-circuit voltage is equal to or close to the open-circuit voltage of the 4.5 fully connected bottom batteries 120). The first sequence string (i.e. Figure 6 The top battery string (connected by the blue dashed line) has a total of 5 batteries 110 connected in series (including 4 fully connected batteries and 1 voltage-loss battery, whose open-circuit voltage is equal to or close to the open-circuit voltage of the 4.5 fully connected bottom batteries 120). This makes the open-circuit voltages of the first, second, and third battery strings equal.

[0070] It should be noted that the "voltage loss battery" in this embodiment refers to the battery whose open-circuit voltage has a certain loss, as detailed in the following embodiment three.

[0071] like Figure 7 As shown, the battery assembly 10 contains a total of 14 three-terminal stacked batteries 100 connected in series. The open-circuit voltage ratio of the top battery 110 and the bottom battery 120 in the connected three-terminal stacked batteries 100 is 3:2. The battery assembly 10 also has a fourth sequence string and a fifth sequence string. The fourth sequence string can connect in series with at least some of the remaining bottom batteries 120 (excluding the bottom batteries 120 in the first sequence string); the fifth sequence string can connect in series with at least some of the remaining top batteries 110 (excluding the top batteries 110 in the second and third sequence strings). The fourth sequence string of the battery assembly 10 (i.e., Figure 7 The battery string connected in series with green dots and dashes consists of 6 batteries (including 6 fully connected batteries) connected in series at the bottom. The third sequence string (i.e. Figure 7 The battery string connected in series by the solid orange line contains 7 batteries (including 5 fully connected batteries and 2 voltage-loss batteries, whose open-circuit voltage is equal to or close to the open-circuit voltage of the 6 fully connected bottom batteries 120). The first sequence string (i.e. Figure 7 The battery string connected in series by the blue dotted line in the middle) has a total of 4 batteries (including 4 fully connected batteries) connected in series at the top, and the second sequence string (that is... Figure 7 The battery string connected in series by the red dashed line consists of five top batteries 110 (including three fully connected batteries and two voltage-loss batteries, whose open-circuit voltage is equal to or close to the open-circuit voltage of the four fully connected top batteries 110). The fifth sequence string (i.e. Figure 7The series of batteries connected in series (with black double-dotted lines) consists of five top batteries 110 (including three fully connected batteries and two voltage-loss batteries, whose open-circuit voltage is equal to or close to the open-circuit voltage of the four fully connected top batteries 110). This ensures that the open-circuit voltages of the first, second, third, fourth, and fifth series of batteries are equal.

[0072] Example 3 In some embodiments, at least a portion of the top battery 110 is a terminal loss battery.

[0073] Terminal loss batteries include voltage loss batteries and unconnected batteries. Voltage loss batteries are those with a loss of open-circuit voltage, typically ranging from 20% to 80%. The terminal loss battery can be either the top battery 110 or the bottom battery 120; no limitation is made here. An unconnected battery means that the battery is not connected in series with any sequence string and cannot form a loop, such as... Figures 5-7 As shown, it cannot output electrical energy. A voltage loss battery, also known as a voltage-loss battery, is one where, when connected in a sequence, a circuit can be formed, allowing it to output electrical energy, but with some loss. Typically, the open-circuit voltage of a voltage loss battery will have a loss of 20% to 80%.

[0074] The specific connection method between the voltage loss battery and the battery module 10 is related. Figure 5 As shown, the battery assembly 10 consists of ten three-terminal stacked batteries 100 connected in series. The open-circuit voltage ratio between the top battery 110 and the bottom battery 120 in the connected three-terminal stacked batteries 100 is 2:1. The wiring connection in a battery assembly 10 includes large loops and small loops. The large loop is a complete sequence connected to the positive and negative terminals. Figure 5 It has three large circuits. The small circuit is formed by a top battery 110 and a bottom battery 120 connected to its two ends. The large circuit and the small circuit are voltage matched respectively.

[0075] Figure 5 As shown, in this battery assembly 10, the large-loop voltage matching, that is, the voltage matching of the first sequence string, the second sequence string, and the third sequence string, and the third sequence string (i.e. Figure 5 The battery string connected in series by the solid orange line in the middle contains 9 batteries, 120 in total, connected in series at the bottom. The second sequence string (i.e., Figure 5 The battery string connected in series by the red dotted line in the middle is connected to the top battery 110, a total of 5 batteries. The first sequence string (that is...) Figure 5 The top battery 110 is connected in series with five batteries in the series (connected by solid blue lines). The actual open-circuit voltage ratio of the top battery 110 to the bottom battery 120 is 2:1. In order to achieve voltage matching, there are batteries with voltage loss in the second and third series.

[0076] Specific settings for voltage loss batteries, such as... Figure 5 The first top battery 110 from the right, together with the first and second bottom batteries 120 from the right, form a small loop. The voltage in this small loop is matched (the open-circuit voltage of the top battery 110 is equal to the open-circuit voltage of the bottom battery 120), and there are no batteries with voltage loss in this small loop. For example... Figure 5 The second top battery 110 from the right and the first bottom battery 120 from the right form a small loop. Since the open-circuit voltage ratio of the top battery 110 and the bottom battery 120 is 2:1, the top battery 110 in this small loop is a voltage-loss battery, and its voltage loss is 50%. The voltage loss of the voltage-loss battery varies depending on the connection method. Therefore, a suitable connection method for the battery assembly 10 can be selected based on the actual situation, and the number and voltage loss of the voltage-loss batteries can be set reasonably; no restrictions are imposed here.

[0077] In some embodiments, at least a portion of the bottom battery 120 is a terminal loss battery.

[0078] Example 4 In some embodiments, one end of the battery assembly 10 is provided with a positive terminal connected to the positive electrode, and the other end is provided with a negative terminal connected to the negative electrode, with at least one end of the positive terminal and the negative terminal connected to a common electrode.

[0079] Understandably, the battery assembly 10 includes several three-terminal stacked batteries 100 interconnected in a series. The positive and negative terminals of the battery assembly 10 are respectively located at both ends of the battery assembly 10, that is, the positive and negative terminals are connected to three-terminal stacked batteries 100 at different locations. Current flows from the positive terminal to the negative terminal, that is, the current within the battery assembly 10 flows from the positive terminal to the negative terminal. Specifically, it can be that only the positive terminal is connected to the common electrode, only the negative terminal is connected to the common electrode, or both the positive and negative terminals are connected to the common electrode.

[0080] In some embodiments, one end of the battery assembly 10 is provided with a positive terminal connected to the positive electrode, and the other end is provided with a negative terminal connected to the negative electrode. At least one end of the positive terminal and the negative terminal is connected to the electrode of the top battery 110.

[0081] Understandably, the battery assembly 10 includes several three-terminal stacked batteries 100 interconnected in a series. The positive and negative terminals of the battery assembly 10 are respectively located at both ends of the battery assembly 10, that is, the positive and negative terminals are connected to three-terminal stacked batteries 100 at different positions. Specifically, it can be that only the positive terminal is connected to the electrode of the top battery 110, it can be that only the negative terminal is connected to the electrode of the top battery 110, or it can be that both the positive and negative terminals are connected to the electrode of the top battery 110.

[0082] In some embodiments, one end of the battery assembly 10 is provided with a positive terminal connected to the positive electrode, and the other end is provided with a negative terminal connected to the negative electrode. At least one end of the positive terminal and the negative terminal is connected to the electrode of the bottom battery 120.

[0083] Understandably, the battery assembly 10 includes several three-terminal stacked batteries 100 interconnected in a series. The positive and negative terminals of the battery assembly 10 are respectively located at both ends of the battery assembly 10, that is, the positive and negative terminals are connected to three-terminal stacked batteries 100 at different locations. Specifically, it can be that only the positive terminal is connected to the electrode of the bottom battery 120, it can be that only the negative terminal is connected to the electrode of the bottom battery 120, or it can be that both the positive and negative terminals are connected to the electrode of the bottom battery 120.

[0084] It should be noted that since the battery assembly 10 includes several sequences, the electrodes connecting the positive and negative terminals in each sequence may be different. For example, in one sequence, the positive terminal may be connected to the electrode of the top battery 110 of the three-terminal stacked battery 100 in that sequence, and the negative terminal may be connected to the common electrode of the three-terminal stacked battery 100 in that sequence; in another sequence, the positive terminal may be connected to the electrode of the bottom battery 120 of the three-terminal stacked battery 100 in that sequence, and the negative terminal may be connected to the electrode of the top battery 110 of the three-terminal stacked battery 100 in that sequence. Therefore, for a battery assembly 10, the positive terminal may be connected to different electrodes of the three-terminal stacked battery 100 in different sequences simultaneously. For example, the positive terminal of the battery assembly 10 may be connected to the electrode of the top battery 110 of one sequence and the common electrode of another sequence simultaneously. The negative terminal can also be connected to different electrodes of the three-terminal stacked battery 100 in different sequences at the same time. For example, the negative terminal of the battery assembly 10 can be connected to the common electrode of one sequence and the electrode of the bottom battery 120 of another sequence at the same time.

[0085] Example 5 This embodiment provides a photovoltaic system, including the aforementioned battery module 10.

[0086] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. They can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it's understandable that the application scenarios of photovoltaic systems are not limited to these; that is, photovoltaic systems can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system grid as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. The photovoltaic array can be an array combination of multiple battery modules 10. For example, multiple battery modules 10 can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which can collect the current generated by the photovoltaic arrays. The collected current flows through an inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0087] The beneficial effects of the photovoltaic system in this embodiment are equivalent to the beneficial effects of the battery module 10 described above, and will not be repeated here.

[0088] It is understood that those skilled in the art can combine various implementation methods in the above embodiments under the guidance of the above examples to obtain technical solutions with multiple implementation methods.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A battery assembly, characterized in that, include: A plurality of three-terminal stacked batteries arranged in sequence, the three-terminal stacked batteries including a top battery and a bottom battery disposed below the top battery, the top battery being provided with a first electrode, the bottom battery being provided with a second electrode and a third electrode respectively, the first electrode and the second electrode having the same polarity, and the first electrode and the third electrode having different polarities; A plurality of first solder strips, the first solder strips connecting the first electrode of one of the three-terminal stacked cells to the third electrode of another of the three-terminal stacked cells; A plurality of second solder strips, the second solder strips connecting the second electrode of one of the three-terminal stacked cells to the third electrode of another of the three-terminal stacked cells; and It has one input terminal and one output terminal for connecting to the circuit.

2. The battery assembly as claimed in claim 1, characterized in that, The first solder strip includes at least a first sub-solder strip and a second sub-solder strip; The top battery of the first sub-welded strip is connected in series to form a first sequence string; The second sub-strip is connected in series with at least a portion of the remaining top cells to form a second sequence string; The first sequence string and the second sequence string are connected in parallel.

3. The battery assembly as described in claim 2, characterized in that, The open-circuit voltages of the first sequence string and the second sequence string are equal or differ by a range of ±0.2V.

4. The battery assembly as described in claim 2, characterized in that, The second solder strip includes at least a third sub-strip; The third sub-welding strip is connected in series with at least part of the bottom battery to form a third sequence string; The third sequence string is connected in parallel with the first sequence string.

5. The battery assembly as claimed in claim 4, characterized in that, The open-circuit voltages of the third sequence string and the first sequence string are equal or differ by a range of ±0.2V.

6. The battery assembly as claimed in claim 4, characterized in that, The second solder strip also includes at least a fourth sub-strip; The fourth sub-welding strip is connected in series with at least a portion of the remaining bottom batteries to form a fourth sequence string; The fourth sequence string and the third sequence string are connected in parallel.

7. The battery assembly as claimed in claim 6, characterized in that... The open-circuit voltages of the fourth sequence string and the third sequence string are equal or differ by a range of ±0.2V.

8. The battery assembly as claimed in claim 1, characterized in that, The open-circuit voltage of the top battery is greater than the open-circuit voltage of the bottom battery.

9. The battery assembly as claimed in claim 1, characterized in that, The ratio of the open-circuit voltage of the top battery to the open-circuit voltage of the bottom battery is 1 to 3.

10. The battery assembly as claimed in claim 9, characterized in that, The ratio of the open-circuit voltage of the top battery to the open-circuit voltage of the bottom battery is 1.5 to 2.

11. The battery assembly as claimed in claim 1, characterized in that, The top and bottom cells in a single three-terminal stacked battery have a common electrode.

12. The battery assembly as claimed in claim 1, characterized in that, At least part of the top battery is a terminal loss battery.

13. The battery assembly as claimed in claim 1, characterized in that, At least part of the bottom battery is a terminal loss battery.

14. The battery assembly as claimed in claim 1, characterized in that, The number of the first solder strips is equal to the number of the second solder strips.

15. A photovoltaic system, characterized in that, Includes the battery assembly as described in any one of claims 1-14.

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