Capacitance grading self-checking method and device for photovoltaic energy storage battery string

Abstract

The invention relates to the technical field of photovoltaic power generation, and provides a capacity grading self-checking method and device for a photovoltaic energy storage battery string. The battery string is charged according to the preset control strategy; in the charging process of the battery string, the current sampling value of each single battery in the battery string is collected according to the sampling interval time; determining the integral value of the current sampling value of each single battery in the self-charging process, and determining the integral value as the total charging amount of the single battery in the current charging process; after the single battery completes multiple charging and discharging processes, determining the maximum battery capacity of the single battery according to the total charging amount and the charging and discharging times of each charging process; according to the method, the maximum battery capacity of the single battery is determined by collecting the current sampling value, and the problems that in the prior art, a method for detecting the maximum battery capacity of the single battery in the battery string is large in error and poor in practicability are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a method and device for self-testing the capacity distribution of a photovoltaic energy storage battery string. Background Art

[0002] Battery testing technology is a crucial tool for ensuring the performance, safety, and reliability of individual cells. In photovoltaic power generation scenarios, photovoltaic panels are used to charge a battery string. A battery string consists of multiple individual cells connected in series, each storing energy independently. To ensure that the capacity of photovoltaic power generation batteries remains stable, the capacity of each individual cell in the string must be tested.

[0003] For a single cell, if the battery capacity of the single cell cannot be accurately known, the equipment connected to the single cell will suddenly lose power, causing damage to subsequent devices connected to the single cell and increasing the risk of thermal runaway; and if the charge and discharge management of the single cell is improper (for example, frequent overcharging), it will accelerate the aging of the single cell and shorten its lifespan.

[0004] In existing technologies, the capacity and related parameters of each battery cell in a battery string are often collected manually. This is a complex operation that inevitably wastes a lot of manpower and resources. Furthermore, existing methods for measuring the capacity of individual batteries in a battery string are subject to large errors and are not practical.

[0005] In view of this, overcoming the defects of the prior art is an urgent problem to be solved in this technical field. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a photovoltaic energy storage battery string capacity self-test method and device, the purpose of which is to collect the current sampling value of each single battery during the charging process of the battery string; determine the maximum battery capacity of the single battery based on the integral value of the current sampling value of the single battery during its own charging process, thereby solving the problem of large error and poor practicality of the existing method of detecting the maximum battery capacity of single batteries in the battery string.

[0007] The present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a photovoltaic energy storage battery string capacity self-test method, comprising:

[0009] Charging the battery string according to a preset control strategy;

[0010] During the charging process of the battery string, a current sampling value of each single battery in the battery string is collected according to a sampling interval; an integral value of the current sampling value of each single battery during its own charging process is determined, and the integral value is determined as the total charge capacity of the single battery in this charging process;

[0011] After the single battery completes multiple charge and discharge processes, the maximum battery capacity of the single battery is determined according to the total charge capacity and the number of charge and discharge times of each charging process.

[0012] Furthermore, during the charging process of the battery string, collecting a current sampling value of each single battery in the battery string according to a sampling interval; determining an integral value of the current sampling value of each single battery during its own charging process, and determining the integral value as the total charge capacity of the single battery in this charging process includes:

[0013] Obtaining a charging start time for the battery string;

[0014] At each sampling interval, a current sampling value of each single battery in the battery string is collected;

[0015] A time series feature set is constructed using each collected current sampling value; each time a current sampling value is collected, a set of collected data is added to the time series feature set until the battery is fully charged, and all current sampling values are obtained from the time series feature set;

[0016] Obtaining the charging end time of the single battery; determining the time interval from the charging start time to the charging end time as the charging period of the single battery;

[0017] All the acquired current sampling values are integrated over the charging period to obtain an integral value; and the integral value is determined as the total charge amount.

[0018] Furthermore, after constructing the time series feature set using the collected current sampling values, the method further includes:

[0019] Determine the time series feature set of the single battery at a specified time point as a real-time power feature set; and obtain all current sampling values from the real-time power feature set;

[0020] Determining the time interval from the charging start time to the specified time point as the collection period of the single battery;

[0021] Integrate all the current sampling values obtained over the acquisition period to obtain a real-time power value;

[0022] The ratio of the real-time power value to the maximum available capacity of the single battery is determined as the charge of the single battery.

[0023] Furthermore, an energy storage module is provided between each first switch and the positive electrode of the corresponding single battery, and each energy storage module is equipped with a corresponding control switch. The method further includes:

[0024] When the charge and discharge module for controlling the charge and discharge of the battery string cannot support charging of the remaining single cells that are not fully charged, the charge and discharge module is turned off, and the charge of each single cell is obtained according to the sampled voltage and the sampled current at both ends of the single cell;

[0025] Comparing the charge amounts of two adjacent single cells, and controlling the conduction states of the first switch, the second switch, and the control switches of the corresponding energy storage modules so that the single cell with the larger charge amount charges the corresponding energy storage unit;

[0026] After the energy storage unit is charged for a preset time, the first switch, the second switch and the corresponding control switch of the energy storage unit are controlled to be on, so that the charged energy storage unit charges the single battery with a smaller charge.

[0027] Furthermore, it also includes:

[0028] When the single cell enters a constant voltage charging mode, monitoring the charging current of the single cell;

[0029] When the charging current is lower than the charging threshold, it is determined that the battery is fully charged.

[0030] Furthermore, the method further comprises:

[0031] Obtain the sampled voltage across each single battery and the sampled current in the battery string charge and discharge circuit;

[0032] The conduction states of the first switch and the second switch corresponding to the corresponding single battery are controlled respectively according to the sampled voltage and the sampled current, so as to select and charge and discharge the single batteries that meet the charge and discharge requirements respectively.

[0033] Furthermore, the control of the conduction states of the first switch and the second switch corresponding to the corresponding single battery according to the sampled voltage and the sampled current, so as to select and charge and discharge the single battery that meets the charge and discharge requirements, further includes:

[0034] In the charging state, judging whether the charge state of each single battery is in a fully charged state or in an undercharged state according to the sampled voltage and the sampled current;

[0035] Disconnecting a first switch and a second switch at both ends of a first single battery in a fully charged state;

[0036] Turning on the first switch and the second switch at both ends of the second single battery in the undercharged state, and controlling the charge and discharge module to charge the second single battery until it is detected that the charge state of the second single battery reaches the fully charged state; or obtaining the connection relationship of the second single batteries in the undercharged state, if there are at least two second single batteries connected in series, forming a series battery group with the at least two second single batteries, and turning on the first switch corresponding to the series battery group and the second switch corresponding to the series battery group.

[0037] Furthermore, it also includes:

[0038] Obtaining the maximum battery capacity and the rated capacity of each of the single cells; and determining whether the maximum battery capacity meets the rated capacity;

[0039] Identify, from the battery string, single cells whose maximum battery capacity does not meet the corresponding rated capacity;

[0040] When the battery string is in the initial installation state, replacing the single battery that has been checked;

[0041] When the battery string is in a long-term operation state, determine whether the maximum battery capacity of the detected single battery is lower than the capacity life value; wherein the capacity life value is: the product of the rated capacity of the detected single battery and a preset ratio value; when the maximum battery capacity of the detected single battery is lower than the capacity life value, replace the detected single battery.

[0042] In a second aspect, the present invention further provides a photovoltaic energy storage battery string capacity self-test device, comprising:

[0043] At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the processor to perform the photovoltaic energy storage battery string capacity self-test method described in the first aspect.

[0044] In a third aspect, the present invention further provides a non-volatile computer storage medium storing computer-executable instructions, which are executed by one or more processors to complete the photovoltaic energy storage battery string capacity self-test method described in the first aspect.

[0045] In a fourth aspect, a computer program product comprising instructions is provided, which, when executed on a computer or processor, causes the computer or processor to execute the photovoltaic energy storage battery string capacity self-test method according to the first aspect.

[0046] In a fifth aspect, the present invention further provides a photovoltaic energy storage battery string capacity division self-test system, comprising the photovoltaic energy storage battery string capacity division self-test device as described in the second aspect, and using the photovoltaic energy storage battery string capacity division self-test method as described in the first aspect to complete the interaction of the photovoltaic energy storage battery string capacity division self-test device as described in the second aspect.

[0047] Different from the prior art, the present invention has at least the following beneficial effects:

[0048] During the charging process of a battery string, the present invention collects current sampling values from each single cell in the battery string and determines the maximum battery capacity of each single cell based on the integral of the current sampling values during the charging process. The current sampling value collection process is convenient and simple, requiring no special plug-ins or other hardware installation, and can be performed while the battery string is operating normally. Because the current sampling value collection is achieved through real-time monitoring of the charging current of each single cell, and the maximum battery capacity is estimated using the total charge capacity of multiple charge and discharge processes, the error is small, achieving the purpose of monitoring the maximum battery capacity and accurately determining the maximum battery capacity, thereby avoiding malfunction or even damage to subsequent components in the battery string. This solves the problem of large errors and poor practicality in existing methods for detecting the maximum battery capacity of single cells in a battery string. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0050] Figure 1 This is a schematic structural diagram of a battery string assembly structure provided by an embodiment of the present invention;

[0051] Figure 2 1 is a schematic structural diagram of a battery string assembly structure provided by an embodiment of the present invention;

[0052] Figure 3 This is a schematic structural diagram of connecting conductive components in a battery string assembly structure provided by an embodiment of the present invention;

[0053] Figure 4 This is a schematic structural diagram of connecting conductive components in a battery string assembly structure provided by an embodiment of the present invention;

[0054] Figure 5 This is a structural diagram of a connection component in a battery string assembly structure provided by an embodiment of the present invention;

[0055] Figure 6This is a schematic structural diagram of a connecting piece in a battery string assembly structure provided by an embodiment of the present invention;

[0056] Figure 7 This is a schematic structural diagram of a connecting piece in a battery string assembly structure provided by an embodiment of the present invention;

[0057] Figure 8 This is a partial structural diagram of a battery string assembly structure provided by an embodiment of the present invention;

[0058] Figure 9 This is a schematic structural diagram of a fixing ring in a battery string assembly structure provided by an embodiment of the present invention;

[0059] Figure 10 This is a schematic structural diagram of a fixing ring in a battery string assembly structure provided by an embodiment of the present invention;

[0060] Figure 11 This is a schematic structural diagram of a battery conductive structure and an external guide point structure in a battery string assembly structure provided by an embodiment of the present invention;

[0061] Figure 12 This is a schematic structural diagram of a connecting piece in a battery string assembly structure provided by an embodiment of the present invention;

[0062] Figure 13 This is a schematic structural diagram of a connecting piece in a battery string assembly structure provided by an embodiment of the present invention;

[0063] Figure 14 This is a schematic structural diagram of a battery conductive structure and an external guide point structure in a battery string assembly structure provided by an embodiment of the present invention;

[0064] Figure 15 This is a structural diagram of a connection component in a battery string assembly structure provided by an embodiment of the present invention;

[0065] Figure 16 This is a schematic structural diagram of connecting conductive components in a battery string assembly structure provided by an embodiment of the present invention;

[0066] Figure 17 This is a structural diagram of a connection component in a battery string assembly structure provided by an embodiment of the present invention;

[0067] Figure 18 This is a schematic structural diagram of a battery conductive structure and an external guide point structure in a battery string assembly structure provided by an embodiment of the present invention;

[0068] Figure 19 This is a schematic structural diagram of a battery conductive structure and an external guide point structure in a battery string assembly structure provided by an embodiment of the present invention;

[0069] Figure 20 This is a schematic structural diagram of a fixing ring in a battery string assembly structure provided by an embodiment of the present invention;

[0070] Figure 21 This is a schematic structural diagram of a connecting piece in a battery string assembly structure provided by an embodiment of the present invention;

[0071] Figure 22 This is a structural diagram of a connection component in a battery string assembly structure provided by an embodiment of the present invention;

[0072] Figure 23 1 is a schematic structural diagram of a battery string assembly structure provided by an embodiment of the present invention;

[0073] Figure 24 This is a partial structural diagram of a battery string assembly structure provided by an embodiment of the present invention;

[0074] Figure 25 1 is a schematic structural diagram of a locking assembly in a battery string assembly structure provided by an embodiment of the present invention;

[0075] Figure 26 This is a partial structural diagram of a battery string assembly structure provided by an embodiment of the present invention;

[0076] Figure 27 1 is a schematic structural diagram of a locking assembly in a battery string assembly structure provided by an embodiment of the present invention;

[0077] Figure 28 This is a schematic structural diagram of a housing in a battery string assembly structure provided by an embodiment of the present invention;

[0078] Figure 29 This is a schematic structural diagram of a housing in a battery string assembly structure provided by an embodiment of the present invention;

[0079] Figure 30 This is a schematic structural diagram of a main wiring cover of a battery string assembly structure provided by an embodiment of the present invention;

[0080] Figure 31 This is a schematic structural diagram of a battery string provided by an embodiment of the present invention;

[0081] Figure 32 This is a flow chart of a photovoltaic energy storage battery string capacity self-test method provided by an embodiment of the present invention;

[0082] Figure 33 20 is a flow chart of step 20 of a photovoltaic energy storage battery string capacity self-test method provided by an embodiment of the present invention;

[0083] Figure 34 This is a schematic diagram of a specific example of a charging curve provided by an embodiment of the present invention;

[0084] Figure 35 is a schematic diagram of a specific example of a discharge curve provided by an embodiment of the present invention;

[0085] Figure 36 202 is a flow chart of step 202 of a photovoltaic energy storage battery string capacity self-test method provided by an embodiment of the present invention;

[0086] Figure 37 This is a flow chart of another photovoltaic energy storage battery string capacity self-test method provided by an embodiment of the present invention;

[0087] Figure 38 1 is a flow chart of a method for controlling balanced charging and discharging of a battery string provided by an embodiment of the present invention;

[0088] Figure 39 1 is a flow chart of a method for balancing charging a battery string during a charging process provided by an embodiment of the present invention;

[0089] Figure 40 This is a schematic diagram of the relationship between battery cell temperature and battery charge provided by an embodiment of the present invention;

[0090] Figure 41 1 is a flow chart of a method for balanced discharge of a battery string during a discharge process provided by an embodiment of the present invention;

[0091] Figure 42 This is another schematic diagram of the relationship between battery cell temperature and battery charge provided by an embodiment of the present invention;

[0092] Figure 43 This is a schematic diagram of a process for performing battery mutual charging for balancing battery power, provided by an embodiment of the present invention;

[0093] Figure 44 This is a schematic diagram of a circuit structure for battery mutual charging provided by an embodiment of the present invention;

[0094] Figure 45 This is a schematic diagram of a process for real-time charge detection provided by an embodiment of the present invention;

[0095] Figure 46 1 is another structural diagram of a circuit for controlling balanced charging and discharging of a battery string provided by an embodiment of the present invention;

[0096] Figure 47 1 is another structural diagram of a circuit for controlling balanced charging and discharging of a battery string provided by an embodiment of the present invention;

[0097] Figure 48 This is a schematic structural diagram of an energy storage module provided by an embodiment of the present invention;

[0098] Figure 49 This is a schematic diagram of a structure in which a single battery is used to charge an energy storage unit according to an embodiment of the present invention;

[0099] Figure 50 This is a schematic diagram of a structure for charging a single battery through an energy storage unit provided by an embodiment of the present invention;

[0100] Figure 51 This is a schematic diagram of a specific example of a string distributed energy storage provided by an embodiment of the present invention;

[0101] Figure 52 The present invention provides a schematic diagram of the structure of a photovoltaic energy storage battery string capacity self-test device.

[0102] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0103] 1. Connecting rod; 11. First connecting rod; 12. Second connecting rod; 2. Connecting conductive component; 21. Connecting component; 211. Connecting piece; 2110. Inserting piece; 21101. First through hole; 2111. Placement slot; 2112. Opening; 2113. First spring piece; 2114. Second spring piece; 212. Fixing ring; 2120. Slot; 2121. Protrusion; 21211. First sub-protrusion; 21212. Second sub-protrusion; 21213. First protrusion; 21214. Second protrusion; 21210. Channel; 212101. First sub-channel; 212102. Second sub-channel; 2122. Buckle; 2 1221. First groove; 21222. Second groove; 2123. Notch; 22. Battery conductive structure; 221. First conductive sheet; 222. Second conductive sheet; 223. First connecting portion; 224. Second connecting portion; 225. Extension portion; 23. External conductive structure; 3. Battery; 4. External circuit; 5. Locking assembly; 51. Connecting rod; 511. Second through hole; 512. Third through hole; 513. Abutment block; 52. First screw; 53. Second screw; 54. Third screw; 55. Fourth screw; 6. Outer shell; 61. Cylindrical shell; 62. Bottom cover; 63. Wiring cover; 631. Wiring cap; 632. Pressure relief cap; 7. Wiring harness. DETAILED DESCRIPTION

[0104] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0105] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as meaning open inclusion, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that the specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner, that is, although they may be carried in the embodiments or examples of the above terms due to reasons such as the order and position of appearance, it is not limited to that they can be carried in combination by one embodiment or example.

[0106] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0107] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "multiple" means two or more. In addition, for example, the description may also use the method of adding "A" and "B" at the end to describe the same type of nouns as two independent individuals. In this case, the corresponding features defined as "A" and "B" are only used to distinguish the description purposes of the same type of individuals, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0108] When describing some embodiments, the expressions "coupling", "coupling" and "connection" and their derivatives may be used. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical or electrical contact with each other. For another example, when describing some embodiments, the term "coupling" may be used to indicate that two or more components are in direct physical or electrical contact. However, the term "connection" or "coupling" may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other, such as "optical coupling", "wireless connection", etc. The embodiments disclosed herein are not necessarily limited to the contents of the present invention.

[0109] In the description of the present invention, the expression "A and / or B" (where A and B are used to formally represent specific characteristic contents) will be involved, and the corresponding expressions include the following three combinations: only A, only B, and a combination of A and B.

[0110] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0111] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0112] Embodiment 1:

[0113] This embodiment provides a battery string assembly structure and a battery string. The photovoltaic energy storage battery string capacity self-test method according to the embodiment of the present invention is applied to the battery string assembly structure and the battery string.

[0114] Specifically, a battery string assembly structure is provided, such as Figure 1 and Figure 2 As shown, it includes at least one serial rod 1 and multiple connecting conductive components 2; each connecting conductive component 2 is connected in series on the serial rod 1; and a reserved space is set between every two connecting conductive components 2 for accommodating a battery 3 and directly contacting the positive or negative pole of the battery 3; each connecting conductive component 2 is also used to connect to an external circuit 4 to achieve coupling between the battery 3 and the external circuit 4.

[0115] In actual use, the serial rod 1 can be one; in order to ensure stability, the number of the serial rods 1 can be two, and a relatively stable bracket is formed by two serial rods 1, such as Figure 1 and Figure 2 As shown, 7 connecting conductive components 2 can be connected in series on a bracket to accommodate 6 batteries 3. Figure 1This is a schematic diagram without battery installed. Figure 2 This is a schematic diagram of the battery installed.

[0116] In this embodiment, a connecting rod 1 is used to form a connecting bracket, and each connecting conductive component 2 is used to form a connecting piece for coupling the battery 3 and the external circuit 4. Therefore, the battery 3 and the external circuit 4 can be coupled without welding them. Under the implementation method of this embodiment, when a problem occurs with the corresponding battery, the battery can be directly removed and replaced without disassembling the connecting rod 1, other batteries in the battery string, and the connecting conductive component 2, thereby saving manpower and material resources.

[0117] In an optional embodiment, as Figure 3 and Figure 4 As shown, the connecting conductive component 2 includes a connecting component 21, a battery conductive structure 22 and an external conductive structure 23 formed by extending the battery conductive structure 22; the battery conductive structure 22 is installed on the connecting component 21, and the connecting component 21 is connected in series to the serial rod 1; the battery conductive structure 22 is in direct contact with the positive or negative pole of the battery 3; the external conductive structure 23 is used to connect the external line 4 to achieve coupling between the battery 3 and the external line 4.

[0118] in, Figure 3 and Figure 4 They are respectively the front view and the back view of the connecting conductive component 2. The connecting component 21 can be connected in series to the connecting rod 1 by through holes, channels or other fixing structures (such as buckles, etc.).

[0119] In a preferred embodiment, Figure 5 As shown, the connecting assembly 21 includes a connecting piece 211 and a fixing ring 212; Figure 6 As shown, at least one end of the connecting piece 211 is provided with an insert 2110; Figure 9 As shown, the ring wall of the fixing ring 212 is provided with at least one slot 2120, and the slot 2120 matches the insert 2110; the insert 2110 is inserted into the slot 2120 to install the connecting piece 211 in the ring of the fixing ring 212, and the connecting piece 211 is perpendicular to the axial direction of the fixing ring 212 (i.e., the direction of the serial rod 1); Figure 10 As shown, the outer wall of the fixing ring 212 is provided with at least one protrusion 2121, and the protrusion 2121 is provided with a channel 21210 axially parallel to the fixing ring 212. The connecting rod 1 is inserted into the channel 21210 to connect the connecting assembly 21 in series; the connecting piece 211 is used to provide an installation position for the battery conductive structure 22.

[0120] It should be noted that the fixing ring 212 may not be a full ring in actual use, so as to leave an opening for the connecting piece 211 to be installed in the ring. The number of the inserting pieces 2110 can be multiple, and the number of the slots 2120 can be multiple, such as Figure 6 In the embodiment, there are two inserting tabs 2110, one at each end of the inserting tab 2110. Correspondingly, there are also two slots 2120 on the fixing ring 212. This allows the fixing ring 212 to form a stable structure after the connecting tab 211 is installed on it. In actual use, the fixing ring 212 may have a certain degree of elasticity to allow the fixing ring 212 to be opened, allowing the connecting tab 211 to enter the ring, and the inserting tabs 2110 to be inserted into the corresponding slots 2120.

[0121] Furthermore, the width of the insert 2110 (i.e. Figure 7 W1 in the figure) is smaller than the width of the connecting piece 211 body (i.e. Figure 7 W2 in Figure 7 As shown, W1<W2, the size of the slot 2120 is adapted to the width of the inserting piece 2110, so that after the inserting piece 2110 is inserted into the slot 2120, the connecting piece 211 body is stuck in the ring.

[0122] In a preferred embodiment, Figure 8 As shown, the number of the serial rods 1 can be two, namely the first serial rod 11 and the second serial rod 12, and the number of the protrusions 2121 is also two, namely the first protrusion 21213 and the second protrusion 21214, and the two protrusions 2121 are arranged opposite to each other, the first protrusion 21213 and the second protrusion 21214 are respectively arranged on both sides of the fixing ring 212, the first serial rod 11 passes through the hole 21210 on the first protrusion 21213, and the second serial rod 12 passes through the hole 21210 on the second protrusion 21214, so that the first serial rod 11, the second serial rod 12 and the multiple connected conductive components 2 in series together constitute a stable, non-rotating bracket structure.

[0123] In a specific application scenario, such as Figure 11 As shown, the battery conductive structure 22 includes a first conductive sheet 221 and a second conductive sheet 222 that are arranged opposite to each other, and a first connecting portion 223 connecting the first conductive sheet 221 and the second conductive sheet 222; Figure 12As shown, the connecting piece 211 is provided with a placement groove 2111 that matches the first connecting part 223; an opening 2112 is provided on one side of the placement groove 2111, and the opening 2112 extends to the edge of the connecting piece 211, so that the first connecting part 223 can be placed in the placement groove 2111 through the opening 2112, and the first conductive piece 221 is located on the first connecting surface of the connecting piece 211, and the second conductive piece 222 is located on the second connecting surface of the connecting piece 211; wherein, the first connecting surface and the second connecting surface are two opposite connecting surfaces of the connecting piece 211; the first conductive piece 221 is in direct contact with the battery 3 on the side where the first connecting surface is located; and the second conductive piece 222 is in direct contact with the battery 3 on the side where the second connecting surface is located.

[0124] It should be noted that this embodiment is for the connecting conductive component 2 located in the middle. When the connecting conductive component 2 is located at both ends, there may be no battery on one side. At this time, the first conductive sheet 221 or the second conductive sheet 222 is not in contact with the battery.

[0125] The inner wall of the placement groove 2111 is designed to be arc-shaped to prevent the first connection part 223 and the placement groove 2111 from being damaged when the first connection part 223 shakes in the placement groove 2111 .

[0126] The opening 2112 may be perpendicular to the placement groove 2111, and the position of the opening 2112 may be on the side where the vertical distance between the placement groove 2111 and the edge of the connecting piece 211 is greater than the preset distance, so that the depth of the opening 2112 reaches the preset distance, such as in Figure 13 In the embodiment, the depth W3 of the opening 2112 is greater than a predetermined distance, which is determined by those skilled in the art based on an analysis of the structural characteristics of the battery conductive structure 22. This allows the first conductive sheet 221 to have a larger area located on the first connection surface, and the second conductive sheet 222 to have a larger area located on the second connection surface after the first connecting portion 223 is placed in the placement groove 2111. This is to provide sufficient contact surface for the battery 3 and to ensure the stability of the battery conductive structure 22 after it is installed on the connecting sheet 211. In actual use, the placement groove 2111 can be positioned near an edge of the connecting sheet 211, with the other edge of the connecting sheet 211 being farther from the placement groove 2111. Thus, the opening 2112 is provided on one side of the placement groove 2111 near the other edge.

[0127] The battery conductive structure 22 may be a U-shaped piece that can be bent from the first connection portion 223, and the direction opposite to the first connection portion 223 is an opening; in another embodiment, as Figure 14As shown, the battery conductive structure 22 further includes a second connecting portion 224, that is, the two ends of the first conductive sheet 221 and the two ends of the second conductive sheet 222 are respectively connected, one end is connected by the first connecting portion 223, and the other end is connected by the second connecting portion 224, thereby forming a ring with a hollow groove. This implementation is more stable than the U-shaped sheet. Corresponding to this embodiment, the connecting sheet 211 is made of elastic material so that two springs are formed on both sides of the opening 2112, namely the first spring sheet 2113 and the second spring sheet 2114, as shown in FIG. Figure 13 As shown, when the battery conductive structure 22 needs to be installed on the connecting piece 211, the first elastic piece 2113 and the second elastic piece 2114 are respectively opened forward and backward, as shown in FIG. Figure 15 As shown, the hollow groove of the battery conductive structure 22 is then slid into the first elastic piece 2113 and the second elastic piece 2114, and the first connecting portion 223 is placed in the placement groove 2111. In this embodiment, in order to facilitate the installation of the battery conductive structure 22, this embodiment also provides a preferred embodiment, specifically: the width of the second elastic piece 2114 (i.e. Figure 13 d4 in (i.e., the distance between the opening 2112 and the first end of the placement slot 2111) is less than a first preset value, which is obtained by a person skilled in the art based on the elasticity of the connecting piece 211 and the structural characteristics of the battery conductive structure 22. The width of the second elastic piece 2114 is less than the first preset value to ensure that after the hollow slot of the battery conductive structure 22 slides into the first elastic piece 2113, the second elastic piece 2114 and the elasticity of the first elastic piece 2113 can enable the second elastic piece 2114 to slide into the hollow slot. In addition, the width of the second elastic piece 2114 can also be greater than the second preset value, which is also obtained by a person skilled in the art based on the elasticity of the connecting piece 211 and the structural characteristics of the battery conductive structure 22, thereby ensuring that the battery conductive structure 22 can be clamped by the second elastic piece 2114 without tilting or sliding after installation. Similarly, the width of the first elastic piece 2113 (i.e. Figure 13 d2 in ) and the width of the opening 2112 (ie Figure 13 The value d3) in the figure is also determined by those skilled in the art based on the elasticity of the connecting piece 211 and the structural characteristics of the battery conductive structure 22. In actual use, the connecting piece 211 and the fixing ring 212 can be made of plastic.

[0128] In actual use, the width of the placement slot 2111 (i.e. Figure 13d1) is greater than a preset width, which is obtained by a technician in this field based on the structural characteristics of the battery conductive structure 22 to ensure that the first connecting portion 223 of the battery conductive structure 22 can be smoothly installed in the placement groove 2111, and the first connecting portion 223 does not move a large distance in the placement groove 2111.

[0129] This embodiment also provides a preferred implementation method. Figure 14 As shown, the external conductive structure 23 is a connecting tube; the connecting tube is used to insert the external line 4 therein to achieve connection with the external line 4.

[0130] The dimensions of the connecting tube can be designed by a person skilled in the art based on the dimensions of the external circuit 4. Alternatively, the connecting tube can be provided with an opening, and after the external circuit 4 is inserted into the connecting tube, the opening is clamped to achieve connection with the external circuit 4. The opening of the connecting tube can be oriented in the direction of the connecting rod 1, so that after the external circuit 4 is connected, the external circuit 4 extends from both ends or either end of the connecting rod 1.

[0131] In an optional embodiment, as Figure 16 As shown, the outer wall of the fixing ring 212 is provided with a buckle 2122; the connecting pipe is inserted into the buckle 2122 to achieve the fixation of the connecting pipe.

[0132] Furthermore, in order to ensure that the first connecting portion 223 is placed in the placement groove 2111, the connecting tube can be inserted into the buckle 2122, as shown in FIG. Figure 17 As shown, the fixing ring 212 is provided with a notch 2123 at the location of the buckle 2122 for accommodating the extension portion 225 of the battery conductive structure 22. The extension portion 225 is the portion of the battery conductive structure 22 extending until it is connected to the external conductive structure 23. Figure 18 As shown, in order to prevent the gap 2123 from affecting the stability of the fixing ring 212, the width of the extension portion 225 is relatively small. Figure 19 As shown, the width W5 of the extension portion 225 is smaller than the width W4 of the first conductive sheet 221 and the second conductive sheet 222. Correspondingly, the width of the main body of the battery conductive structure 22 (i.e., the first conductive sheet 221 and the second conductive sheet 222) gradually decreases at the connection portion with the extension portion 225. Figure 19 The width of the second connecting portion 224 gradually decreases. The buckle 2122 can be a closed full-ring buckle or a partial-ring buckle with an opening.

[0133] In a preferred embodiment, Figure 17As shown, the inner wall of the buckle 2122 is provided with a first groove 21221 and a second groove 21222. The first groove 21221 and the second groove 21222 are relatively arranged on both sides of the inner wall of the buckle (such as being arranged on the left and right sides of the buckle, as shown in Figure 17), and the first groove 21221 and the second groove 21222 are smoothly connected with other parts of the inner wall. The depth of the first groove 21221 and the depth of the second groove 21222 are determined by those skilled in the art based on demand analysis. The first groove 21221 and the second groove 21222 facilitate the insertion of the external circuit on the one hand, and reduce the stress on both sides of the buckle on the other hand, thereby reducing the probability of the buckle being broken by force and extending the service life of the buckle. In actual use, the inner ring diameter r of the buckle is slightly smaller than the outer diameter R of the external circuit. The depth of the first groove 21221 and the depth of the second groove 21222 are D, then r+2D≥R, and usually r+2D is slightly larger than R.

[0134] This embodiment also provides a preferred implementation method. Figure 20 As shown, the protrusion 2121 includes a first sub-protrusion 21211 and a second sub-protrusion 21212; the channel 21210 includes a first sub-channel 212101 provided on the first sub-protrusion 21211 and a second sub-channel 212102 provided on the second sub-protrusion 21212; the first sub-protrusion 21211 and the second sub-protrusion 21212 are arranged opposite to each other, and the first sub-channel 212101 and the second sub-channel 212102 are arranged opposite to each other; a gap is provided between the first sub-protrusion 21211 and the second sub-protrusion 21212 to form the slot 2120; Figure 21 As shown, the insert 2110 is provided with a first through hole 21101 at a position aligned with the first sub-channel 212101 and the second sub-channel 212102 , so that the connecting rod 1 passes through the first through hole 21101 when inserted into the channel 21210 .

[0135] In actual application scenarios, there are two inserts 2110, and a first through hole 21101 is provided on each insert 2110, so that the serial rod 1, the connecting piece 211 and the fixing ring 212 together form a stable structure, and the two inserts 2110 are arranged relative to each other. Since errors may occur during the device manufacturing process, and the fixing ring 212 needs to be pried apart when the connecting piece 211 is installed in the fixing ring 212, and the fixing ring 212 may also have slight deformation after elastic recovery, this embodiment also provides a preferred implementation method, that is, the first through hole 21101 is a waist-shaped hole (that is, a hole with arcs at both ends), and the two ends of the waist-shaped hole are in the direction of the connection line of the two inserts 2110 (that is, Figure 21In the horizontal direction), when the inserting piece 2110 is inserted into the slot 2120, even if there is an error between the connecting piece 211 and the fixing ring 212, the first through hole 21101 and the channel 21210 can be aligned in the horizontal direction. In addition, the length of the slot 2120 is slightly larger than the width of the inserting piece 2110 (i.e. Figure 13 W3), as described in the figure, the length of the slot 2120 may be the width of the insert 2110 plus a third preset value, and the third preset value is obtained by a person skilled in the art based on empirical analysis, so that after the insert 2110 is inserted into the slot 2120, it can be aligned with the channel 21210 in the vertical direction by a small amount of up and down movement.

[0136] In practical application scenarios, the radial length of the fixing ring 212 (that is, the thickness of the fixing ring 212, i.e. Figure 22 d5) is greater than a preset length, and the inner wall of the fixing ring 212 matches the side wall of the battery 3 to accommodate and hold the battery 3 and align the positive or negative electrode of the battery 3 with the corresponding battery conductive structure 22. The preset length is determined by those skilled in the art based on empirical analysis to ensure that the inner wall of the fixing ring 212 can hold the battery 3.

[0137] In an optional embodiment, as Figure 23 As shown, the number of the serial rods 1 is two, namely the first serial rod 11 and the second serial rod 12; and also includes a locking assembly 5; Figure 24 and Figure 25 As shown, the locking assembly 5 includes a connecting rod 51, a first screw 52 and a second screw 53; the locking assembly 5 is arranged at both ends of the serial rod 1; in actual use, it is manifested as having two locking assemblies 5, one locking assembly 5 is arranged at one end of the serial rod 1, and the other is arranged at the other end of the serial rod 1, so as to realize the locking of the serial rod 1, each battery 3 and each connecting conductive assembly 2.

[0138] The rod bodies of the first series rod 11 and the second series rod 12 are provided with threads; the connecting rod 51 is provided with a second through hole 511 and a third through hole 512; the first series rod 11 passes through the second through hole 511, and the second series rod 12 passes through the third through hole 512, so as to limit and fix the relative position between the first series rod 11 and the second series rod 12; the first screw 52 is screwed into the first series rod 11, and the second screw 53 is screwed into the second series rod 12, so as to keep the connecting rod 51, the first series rod 11, the second series rod 12, the connecting conductive component 2 and each battery 3 fixed in position by tightening the first screw 52 and the second screw 53.

[0139] In a preferred embodiment, in order to accommodate errors and deformations, the second through hole 511 and the third through hole 512 are both waist-shaped holes.

[0140] like Figure 26 and Figure 27 As shown, the locking assembly 5 also includes a third screw 54 and a fourth screw 55. The third screw 54 and the fourth screw 55 are arranged on the inner side of the connecting conductive assembly 2 located at both ends of the serial rod 1, that is, on the side close to the middle of the serial rod 1, so that the third screw 54 and the first screw 52 clamp the connecting conductive assembly 2, and the fourth screw 55 and the second screw 53 clamp the connecting conductive assembly 2, thereby achieving structural reinforcement. The connecting rod 51 is also designed with an abutment block 513. The abutment block 513 is arranged at a position opposite to the center of the connecting conductive assembly 2 (such as a position opposite to the battery conductive structure 22). This is because the presence of the fixing ring 212 makes it possible for the locking assembly 5 to only abut against the protrusion on the fixing ring 212 when the locking assembly 5 is locked, and cannot apply abutment pressure to the center of the connecting conductive assembly 2. In order to further enhance the stability of the structure, the abutment block 513 is provided to fill the gap between the connecting rod 51 and the center of the connecting conductive assembly 2, thereby abutting and fixing the center of the connecting conductive assembly 2. The thickness of the abutment block 513 is greater than or equal to the distance between the connecting rod 51 and the center of the connected conductive component 2 .

[0141] In some embodiments, the radial length of the protrusion 2121 (ie, the thickness of the protrusion 2121, i.e. Figure 22 d6) is smaller than the radial length of the fixing ring 212 (ie Figure 22 d5 in the .

[0142] In actual use, such as Figure 28 and Figure 29 As shown, the structure of this embodiment further includes a housing 6, which includes a cylindrical shell 61, a bottom cover 62, and a wiring cover 63. The cylindrical shell 61 surrounds the serial rod 1, multiple connecting conductive components 2, and the battery 3. The bottom cover 62 and the wiring cover 63 are respectively disposed at both ends of the cylindrical shell 61. Both ends of the cylindrical shell 61 are provided with first threads, and the inner walls of the bottom cover 62 and the wiring cover 63 are provided with second threads that match the first threads to enable the bottom cover 62 and the cylindrical shell 61 to be tightened, and the wiring cover 63 and the cylindrical shell 61 to be tightened. The outer walls of the wiring cover 63 and the bottom cover 62 are also provided with textures to increase friction when tightened by hand.

[0143] Furthermore, the wiring cover 63 is provided with a wiring hole (not shown in the figure) and a pressure relief hole (not shown in the figure). The external line 4 passes through the wiring hole to connect to the connecting conductive component 2 inside the housing 6. The pressure relief hole is used to relieve pressure when opened to ensure that the air pressure inside and outside the housing 6 is consistent.

[0144] The wiring hole is provided with a wiring cap 631 for closing the wiring hole when not in use, and the pressure relief hole is provided with a pressure relief cap 632 for closing the pressure relief hole. Figure 30 It should be noted that since the pressure relief hole is closed by the pressure relief cap 632 and the wiring hole is closed by the wiring cap 631, Figure 30 Although not shown, it does not mean that the pressure relief holes and wiring holes do not exist.

[0145] Furthermore, it should be emphasized that, for the sake of clarity of the drawings, in this embodiment, for some drawings with many identical objects, one or several of them are often marked, but not all identical objects are marked. It can be understood that this embodiment does not limit the number of such objects.

[0146] This embodiment also provides a battery string, such as Figure 31 As shown, it includes a plurality of batteries 3 and the battery string assembly structure described in Example 1; the plurality of batteries 3 are arranged in the battery string assembly structure.

[0147] In an optional embodiment, the external circuit 4 corresponding to each battery 3 is routed to one end of the battery string assembly structure and bundled to form a wiring harness 7. In actual use, the wiring harness 7 is located at the end where the wiring cover 63 is located, so that wiring can be easily connected through the wiring holes of the wiring cover 63.

[0148] in, Figure 31 is a schematic diagram of the battery string after the shell 6 is removed, and the schematic diagram after the shell 6 is installed is as follows Figure 28 shown.

[0149] Example 2:

[0150] In order to solve the above problems, Figure 32 As shown, an embodiment of the present invention provides a photovoltaic energy storage battery string capacity self-test method, comprising:

[0151] Step 10: Charge the battery string according to the preset control strategy.

[0152] Among them, the preset control strategy is selected by those skilled in the art according to the specific usage scenario, which will be explained below.

[0153] It should be noted that the charging process of the battery string in the embodiment of the present invention refers to: when the power level of each single cell in the battery string is equal to the lower power limit value, each single cell is charged until the corresponding single cell is fully charged; wherein the lower power limit value refers to the power level when the single cell is discharged, and the lower power limit value is selected by those skilled in the art based on the specific usage scenario; in one embodiment, the lower power limit value can be 20% of the rated capacity of the single cell.

[0154] In an optional embodiment, a high-precision voltage sensor can be used to detect the voltage on both sides of each single cell in the battery string during the charging process of the battery string, and then determine the charge amount charged into each single cell to accurately obtain the real-time power value of the single cell and determine whether the power of the single cell is equal to the lower limit of the power.

[0155] Step 20: During the charging process of the battery string, current sampling values of each single battery in the battery string are collected according to sampling intervals; an integral value of the current sampling values of each single battery during its own charging process is determined, and the integral value is determined as the total charge capacity of the single battery in this charging process.

[0156] The sampling interval is the time interval for sampling the current sample value of a single battery cell. The sampling interval is selected by those skilled in the art based on the specific usage scenario. In one embodiment, the sampling interval may be 10 milliseconds. The current sampling accuracy of the charging current of a single battery cell may be 0.01 amperes. The current sampling accuracy refers to the minimum unit of the current sampling value. The current sampling value represents the magnitude of the charging current for the single battery cell in the battery string.

[0157] The embodiment of the present invention collects the charging current of each single battery as a current sampling value; and calculates the integral value of all current sampling values collected for the single battery during this charging process to obtain the total charge capacity of the single battery during this charging process.

[0158] Step 30: After the single battery completes multiple charge and discharge processes, the maximum battery capacity of the single battery is determined according to the total charge capacity and the number of charge and discharge times of each charging process.

[0159] The charge and discharge process is as follows: after the power of a single battery is discharged to a lower power limit, the single battery is charged until the power of the single battery is fully charged.

[0160] Among them, when determining the maximum battery capacity, the number of selected charging and discharging processes is selected by technical personnel in this field according to the specific usage scenario; in an optional embodiment, after the single cell completes three charging and discharging processes, the total charging amount corresponding to the three charging and discharging processes can be averaged, and the average value is the maximum battery capacity of the single cell.

[0161] It should be noted that the embodiment of the present invention detects the maximum battery capacity of the single cell during the multiple charge and discharge processes based on the total charge capacity of the single cell during the multiple charge and discharge processes. The maximum battery capacity is likely to differ from the rated capacity of the single cell. By detecting the maximum battery capacity, the status of the single cells in the battery string can be monitored.

[0162] During the charging process of a battery string, the present invention collects current sampling values from each single cell in the battery string and determines the maximum battery capacity of each single cell based on the integral of the current sampling values during the charging process. The current sampling value collection process is convenient and simple, requiring no special plug-ins or other hardware installation, and can be performed while the battery string is operating normally. Because the current sampling value collection is achieved through real-time monitoring of the charging current of each single cell, and the maximum battery capacity is estimated using the total charge capacity of multiple charge and discharge processes, the error is small, achieving the purpose of monitoring the maximum battery capacity and accurately determining the maximum battery capacity, thereby avoiding malfunction or even damage to subsequent components in the battery string. This solves the problem of large errors and poor practicality in existing methods for detecting the maximum battery capacity of single cells in a battery string.

[0163] Example 3:

[0164] This embodiment, based on the first embodiment, specifically describes the photovoltaic energy storage battery string capacity self-test method according to the embodiment of the present invention:

[0165] To illustrate the process of determining the total charge capacity, Figure 33 As shown, the step 20 includes:

[0166] Step 201: Obtain the charging start time of the battery string.

[0167] Since all batteries in the battery string start charging at the same time when charging starts, when performing battery capacity detection on each battery, it is only necessary to record the charging start time of the battery string.

[0168] Step 202: collecting a current sampling value of each single battery in the battery string at each sampling interval.

[0169] For example, during the charging process of the battery string, the current sampling value of each single battery in the battery string is collected every 10 milliseconds; and each collected current sampling value is collected as a time series feature set.

[0170] Step 203: construct a time series feature set using the collected current sampling values; each time a current sampling value is collected, a set of collected data is added to the time series feature set until the battery is fully charged, and all current sampling values are obtained from the time series feature set.

[0171] The embodiment of the present invention determines the maximum battery capacity of a single cell by counting the amount of electricity charged into the single cell during the process of being discharged to being fully charged. Therefore, it is necessary to collect all current sampling values collected during the process of being discharged to being fully charged.

[0172] Step 204: Obtain the charging end time of the single battery; and determine the time interval from the charging start time to the charging end time as the charging period of the single battery.

[0173] The charging end time of a single battery is the time point when the single battery is fully charged.

[0174] Step 205: Integrate all the acquired current sampling values over the charging period to obtain an integral value; and determine the integral value as the total charge capacity.

[0175] All current sampling values in the time series feature set are integrated over the charging period. The result of the integration is the integration value, which is determined as the total charge capacity of the single battery.

[0176] In one embodiment, the integral value is expressed as:

[0177]

[0178] Where Q is the integral value, t a is the charging start time, t b is the charging end time, and I(t) is the current sampling value.

[0179] The embodiment of the present invention provides a specific example of an embodiment: for a single battery with a rated capacity of 50 ampere hours (ie, AH), the total amount of charging is actually about 52 ampere hours, and the total amount of discharging is actually about 50 ampere hours; Figure 34 The figure shows a charging curve of the single battery, in which the relatively stable curve represents the voltage, and the curve with a sharp drop represents the current. Figure 35 The figure shows a discharge curve of the single battery; Figure 35 The upper curve represents the current, located at Figure 35 The upper curve represents voltage.

[0180] To illustrate the process of detecting whether a single battery is fully charged, the following first describes the charging process of a battery string:

[0181] During the charging process of the battery string, all the cells in the battery string will not be fully charged at the same time. Figure 44The "cell A", "cell B", and "cell C" in the battery pack are connected in series, so all the cells are charged simultaneously first.

[0182] For each single cell, the charging process is divided into three stages: trickle charging, constant current charging, and constant voltage charging. Trickle charging is a low-current charging method used in the pre-charging stage or maintenance charging stage of the single cell; if the voltage of the single cell reaches the preset voltage threshold of the trickle stage (for example, 3.0V), the single cell is switched from the trickle charging stage to the constant current charging stage. Constant current charging is a fixed-current charging method used in the main charging stage of the single cell; if the voltage of the single cell reaches the preset threshold (for example, 4.2V), the single cell is switched from the constant current charging stage to the constant voltage charging stage. Constant voltage charging is a fixed-voltage charging method used to ensure that the single cell is fully charged. After the constant voltage charging stage ends, the single cell is fully charged.

[0183] In step 202, it is necessary to determine whether the charging process is completed based on whether the single battery is fully charged. Figure 36 As shown, it also includes:

[0184] Step 2021: After the single cell enters the constant voltage charging mode, the charging current of the single cell is monitored.

[0185] During constant-voltage charging, the charging current gradually decreases until the battery is fully charged. For example, after the battery enters the constant-voltage charging stage, if the voltage of a single battery exceeds 3.65 volts, the charging current is reduced. At the same time, the voltage of the single battery will also decrease as the current decreases. If a single battery that has reached 3.65 volts is found to be below 3.65 volts due to the reduced current, the charging current is increased to maintain it at 3.65 volts. By adjusting the charging current, the voltage of the single battery is always maintained at 3.65 volts. As the single battery gradually becomes full, the charging current for the single battery is gradually reduced. When the charging current drops to 2.5 amps, the single battery is fully charged. After the single battery is fully charged, charging stops.

[0186] The embodiment of the present invention realizes monitoring of the charging current through software control.

[0187] Step 2022: When the charging current is lower than the charging threshold, it is determined that the battery is fully charged.

[0188] The charging threshold is selected by those skilled in the art based on the specific usage scenario. In one embodiment, the charging threshold may be 2.5A.

[0189] For example, after entering the constant voltage mode, the voltage needs to be maintained at 3.65 volts. When the charging current is monitored to drop to 2.5 amps, it indicates that the battery cell is fully charged.

[0190] For example, the number of charge and discharge times of the single battery is obtained. When the number of charge and discharge times is 3, after the single battery is repeatedly discharged and fully charged 3 times, the average value of the total charge capacity of the 3 times is calculated to obtain the maximum battery capacity of the single battery.

[0191] By detecting the maximum battery capacity in the above manner, the quality stability of the single battery in the battery string can be quantitatively monitored, and then the quality of the single battery can be determined and processed according to the detected maximum battery capacity. Figure 37 As shown, it also includes:

[0192] Step 401: Obtain the maximum battery capacity and rated capacity of each single battery; and determine whether the maximum battery capacity meets the rated capacity.

[0193] Step 402: Detecting, from the battery string, single cells whose maximum battery capacity does not meet the corresponding rated capacity.

[0194] Step 403: When the battery string is in the initial installation state, replace the detected single battery.

[0195] If, during the initial installation of the battery string, it is detected that the maximum battery capacity of a single battery is lower than the rated capacity of the single battery, the single battery needs to be replaced in a timely manner.

[0196] Step 404: When the battery string is in a long-term operation state, determine whether the maximum battery capacity of the detected single cell is lower than the capacity life value; wherein the capacity life value is: the product of the rated capacity of the detected single cell and a preset ratio value; when the maximum battery capacity of the detected single cell is lower than the capacity life value, replace the detected single cell.

[0197] If the battery string has been in operation for a long time, the capacity life value of the single cell is calculated and compared with the detected maximum battery capacity to confirm whether the single cell has reached its service life. The preset ratio value is selected by a person skilled in the art based on the specific usage scenario; in one embodiment, the preset ratio value can be 70%. That is, if the detected maximum battery capacity drops to 70% of the rated capacity, the single cell is deemed to have reached its service life. In one embodiment, the battery capacity is calculated based on the number of cycles after long-term operation. For example, after 4,000 to 6,000 charging cycles, the remaining battery capacity reaches 70%, meeting the scrap standard; the battery capacity changes linearly with the number of cycles. After the battery capacity drops below 70%, the battery capacity may drop sharply if continued use occurs. When the single cell has reached the end of its service life, it should be replaced in a timely manner.

[0198] Because the charging current of a single cell is not constant when charging according to trickle current, constant current, and constant voltage processes, the embodiment of the present invention integrates the total charge amount charged to the single cell by sampling over time, thereby determining the maximum battery capacity of the single cell. Subsequently, the individual cells in the battery string can be managed, checked, and maintained based on the detected maximum battery capacity.

[0199] Embodiment 4:

[0200] In a photovoltaic system, photovoltaic modules convert light energy into electrical energy and store it in the corresponding battery string (i.e., the charging and discharging module in this embodiment charges the battery string). In an external environment with insufficient light energy on a cloudy day or at night, the electrical energy transmitted by the photovoltaic modules cannot fully charge each single cell in the battery string.

[0201] In actual application scenarios, there is a situation where when one of the cells is fully charged, the charging and discharging module stops charging and discharging. At this time, only one or very few cells are fully charged, resulting in the current charge level of each cell being different. Even if the charge level is the same, after multiple charge and discharge cycles, the charge levels of multiple cells in the same battery string will vary, resulting in incomplete charging and discharging of each cell, affecting the lifespan and performance of the cell. For cells in the battery string that are already fully charged, continuing to charge them after they are fully charged is considered overcharging, which can damage the cell's service life. For example, a cell that can be charged 6,000 times can only be charged 4,000 times. If a cell is fully charged and continues to assist other cells in charging, the voltage of the fully charged cell will increase, and adverse chemical reactions will occur inside the fully charged cell, which may cause damage to the cell or thermal runaway.

[0202] To address the aforementioned issues, embodiments of the present invention provide a pre-set control strategy for charging a battery string. Switches are provided within the charging circuit to control the conduction state of the branches containing individual cells, selectively charging or discharging cells that meet the charging or discharging requirements. When a cell in the string is fully charged, the switch disconnects the fully charged cell, allowing only the remaining cells to continue charging. This process continues in this manner until all cells are fully charged.

[0203] The following describes the preset control strategy:

[0204] In one embodiment, a preset control strategy is used to control the charging and discharging of each single cell. This embodiment provides a method for controlling the balanced charging and discharging of a battery string, which is implemented in a battery string charging and discharging circuit, wherein a first switch is respectively provided between the positive electrode of a charging and discharging module for controlling the charging and discharging of the battery string and the positive electrode of each single cell in the battery string, and a second switch is respectively provided between the negative electrode of the charging and discharging module and the negative electrode of each single cell in the battery string. Figure 38 As shown, the method includes:

[0205] Step 501: Obtain the sampled voltage across each single battery cell and the sampled current in the battery string charge and discharge circuit.

[0206] To obtain the sampled voltage across each cell, sampling points must be set at the positive and negative electrodes of each cell. Since a battery string is composed of multiple cells connected in series, sampling points must be set at the connection point between two adjacent cells, the positive electrode of the first cell, and the negative electrode of the last cell. By calculating the voltage difference between adjacent sampling points, the sampled voltage across each cell can be obtained. The specific sampling method is described below. In one embodiment, current sampling points can be set within the charge and discharge circuit, such as using a current sensor to obtain the sampled current.

[0207] Step 502: Controlling the conduction states of the first switch and the second switch corresponding to the corresponding single battery cells according to the sampled voltage and the sampled current, so as to select and charge and discharge the single battery cells that meet the charge and discharge requirements.

[0208] Among them, the single cells meeting the charge and discharge requirements refer to, after obtaining the state of charge of each single cell based on the sampled voltage and sampled current, during the charging process, judging the fully charged single cells and the uncharged single cells according to the corresponding state of charge, and controlling the corresponding first switch and second switch to select the uncharged single cells to continue charging; during the discharging process, judging the fully discharged single cells and the not fully discharged single cells according to the corresponding state of charge, and controlling the corresponding first switch and second switch to select the not fully discharged single cells to continue discharging.

[0209] In a battery string, due to their own characteristics (such as internal resistance differences, initial charge differences, etc.), the voltages of different single cells may be different. In one embodiment, in order to determine whether a single cell needs to be charged or discharged, a charging threshold voltage V_ch and a discharging threshold voltage V_dis can be preset in advance. If the sampled voltage V_i of a certain single cell is lower than the charging threshold voltage V_ch (i.e., V_i < V_ch), it means that the charge of this single cell is low and a charging operation is still required; if the sampled voltage V_i of a certain single cell is higher than the discharging threshold voltage V_dis (i.e., V_i > V_dis), it means that the charge of this single cell is high and a discharging operation is required.

[0210] For the single cells that need to be charged, control the corresponding first switch and second switch to conduct, so that the current output by the charge and discharge module can flow into this single cell and charge it.

[0211] For the single cells that need to be discharged, also control the corresponding first switch and second switch to conduct. At this time, the charge and discharge module can control this single cell to discharge and release its excess charge.

[0212] In addition, when the entire battery string is in the charging state, if the sampled voltage of a certain single cell has reached the charging threshold voltage, even if the entire battery string is still charging, it is necessary to control the corresponding first switch and second switch of this single cell to disconnect and stop charging it to avoid overcharging. Similarly, when the entire battery string is in the discharging state, if the sampled voltage of a certain single cell has reached the discharging threshold voltage, it is also necessary to control its corresponding switch to disconnect to prevent over-discharging.

[0213] In one embodiment, the voltage of a single cell constantly changes during the charge and discharge process. Therefore, it is necessary to monitor the sampled voltage and current in real time and dynamically adjust the conduction state of the first and second switches corresponding to each single cell. For example, when charging a single cell, the sampled voltage gradually rises as the charge level increases. When the sampled voltage reaches the charging threshold voltage, the first and second switches corresponding to that single cell are promptly disconnected, terminating charging. Conversely, during discharge, when the sampled voltage drops to the discharge threshold voltage, the switches are disconnected, terminating discharge.

[0214] In one embodiment, the conduction states of the first switch and the second switch are comprehensively controlled based on the sampled voltage and the sampled current, thereby achieving separate charging and discharging of the single cells in the battery string that meet the charging and discharging requirements, thereby solving the problem of incomplete charging and discharging of each single cell in the battery string and achieving the purpose of balanced charging and discharging of the battery string.

[0215] In one embodiment, Figure 39 As shown, the control of the conduction states of the first switch and the second switch corresponding to the corresponding single battery according to the sampled voltage and the sampled current, so as to select and charge and discharge the single battery that meets the charge and discharge requirements, specifically includes:

[0216] Step 601: In a charging state, determine whether the state of charge of each single battery is in a fully charged state or in an undercharged state according to the sampled voltage and the sampled current.

[0217] During the charging process, the system continuously samples the voltage and current of each cell. To determine whether the battery is fully charged, a clear standard is required. Generally, battery manufacturers provide a reference value, which is usually related to the battery's design capacity. For common lithium-ion batteries, a fully charged state is considered when the charge reaches 95%-100% of the design capacity. However, this standard is not absolute and is affected by factors such as battery age and temperature.

[0218] In one embodiment, when a single cell enters the constant voltage charging mode, the charging current is adjusted to keep the voltage at Va. As the single cell is gradually filled, the current used to maintain the single cell is gradually reduced. When the corresponding sampling current drops to Ia, it means that the single cell is fully charged, otherwise it is not fully charged. When the battery reaches the maximum charging voltage (the current maximum charging voltage of the battery is 3.65V), the single cell enters the constant voltage charging mode. The constant voltage charging mode is controlled by controlling the charging current. In one embodiment, Figure 40As shown in the figure, when the temperature is 10°C and the battery capacity is between 0% and 80%, the maximum charging current is 0.5C. For example, if the current battery capacity is 50AH, a charging current of 0.5C means 50AH * 0.5C = 25A, that is, the maximum charging current of this battery can be 25A. Similarly, the maximum charging current of each battery can be obtained.

[0219] When the maximum charging current is determined according to the above method and charging is performed using this maximum charging current, if the voltage of a single cell is found to be greater than 3.65V, the charging current is reduced. At the same time, the sampling voltage of the single cell will also decrease as the charging current decreases. If it is found that the sampling voltage of a single cell that has reached 3.65V is lower than 3.65V due to the reduction in charging current, the charging current is increased to maintain it at 3.65V. During the process of dynamically adjusting the current, the maximum charging current does not exceed the maximum charging current determined above. The time granularity of sampling and control in the constant voltage stage is 1 second (dynamically configurable), and the step value of each increase or decrease in the charging current is 0.1A. Through the above process, the system can also evaluate the maximum charging current of each single cell individually and select the minimum value as the charging current for charging. This can ensure that the single cell is not damaged while maximizing the charging speed.

[0220] In one embodiment, the system determines the battery's state of charge based on sampled voltage and current, combined with battery characteristics, to determine whether the battery is fully charged. For example, if a battery's sampled voltage continues to rise while its current gradually decreases, this may indicate that the battery is approaching a fully charged state. When the voltage reaches a preset upper limit and the current decreases to a very low value, the battery is considered fully charged. Conversely, if the voltage remains relatively low and the current is relatively high, the battery is not fully charged.

[0221] Step 602: Disconnect the first switch and the second switch at both ends of the first single cell in the fully charged state, connect the first switch and the second switch at both ends of the second single cell in the partially charged state, and control the charge and discharge module to charge the second single cell until it is detected that the charge state of the second single cell reaches the fully charged state.

[0222] Alternatively, the connection relationship of the second single cells in the uncharged state is obtained. If there are at least two second single cells connected in series, the at least two second single cells are formed into a series battery group, and the first switch corresponding to the series battery group and the second switch corresponding to the series battery group are turned on.

[0223] Overcharging can damage individual cells and shorten their service life. For a first cell determined to be fully charged, the system immediately issues a command to disconnect the first and second switches at its terminals. Disconnecting the corresponding switches prevents the charge-discharge module from delivering current to the first cell, preventing overcharging. In one embodiment, during the charging process, if multiple cells are determined to be fully charged, the corresponding first and second switches are disconnected.

[0224] For a second battery cell that is not fully charged, the original charging circuit is no longer conductive due to the presence of fully charged batteries in the battery string. Therefore, the system controls the first and second switches at both ends of the battery cell to conduct. After the corresponding switches are turned on, the charge-discharge module and these partially charged batteries form a complete charging circuit, allowing current to flow from the charge-discharge module to one or more second batteries, and further charging of the second batteries begins. While charging one or more second batteries, the system continuously monitors the voltage and current changes of each second battery cell. As charging progresses, the sampled voltage of the second battery cell gradually increases, and the corresponding sampled current gradually decreases. When the system detects that the battery has reached the fully charged state, it immediately issues a command to control the first and second switches at both ends of the corresponding second battery cell to disconnect, or directly shuts down the charge-discharge module to stop charging. This ensures that each battery cell is charged to the appropriate level, ensuring neither undercharging nor overcharging.

[0225] During the charging process, the system dynamically adjusts the charging current based on the battery's state. In the initial stages of charging, when the battery's charge level is low, a higher charging current (i.e., the minimum of the maximum charging current corresponding to each battery) can be used for fast charging. As the battery's charge level increases, the charging current gradually decreases to prevent overheating and overcharging. When a battery is detected to be nearly fully charged, a lower current is used for trickle charging, ensuring safe and stable charging and extending the battery's lifespan.

[0226] In one embodiment, Figure 41 As shown, the control of the conduction states of the first switch and the second switch corresponding to the corresponding single battery according to the sampled voltage and the sampled current, so as to select and charge and discharge the single battery that meets the charge and discharge requirements, further includes:

[0227] Step 701 : In a discharge state, determine whether the state of charge of each single battery is in a fully discharged state or an incompletely discharged state according to the sampled voltage and the sampled current.

[0228] Among them, when the battery string is in the discharge state, the system will continuously obtain the sampled voltage and sampled current information of each single cell. This information changes in real time and reflects the current discharge state of the single cell. For different types of batteries, there are different definition standards for the fully discharged state. Generally speaking, it is based on factors such as the rated voltage, design capacity, and safe use range of the battery. For example, for common lithium-ion batteries, when the voltage of a single cell drops to a specific lower limit (such as 2.5V-3.0V), the battery is generally considered to be in a fully discharged state. Because if excessive discharge continues, it will cause irreversible damage to the internal structure of the battery, reducing the performance and life of the battery.

[0229] If the sampling voltage of a single battery has dropped to the lower limit mentioned above, or if the current analysis shows that the single battery can no longer provide effective power output, then the single battery is determined to be in a fully discharged state. Conversely, if the sampling voltage is still higher than the lower limit and the current is still flowing within the normal range, it means that the single battery still has residual power and is not fully discharged.

[0230] Step 702: Disconnect the first switch and the second switch at both ends of the third single cell battery that is in a fully discharged state, connect the first switch and the second switch at both ends of the fourth single cell battery that is in a partially discharged state, and control the charge and discharge module to discharge the fourth single cell battery until it is detected that the state of charge of the fourth single cell battery reaches a fully discharged state.

[0231] Alternatively, the connection relationship of the second single cells in the partially discharged state is obtained. If there are at least two second single cells connected in series, the at least two second single cells are formed into a series battery group, and the first switch corresponding to the series battery group and the second switch corresponding to the series battery group are turned on.

[0232] In one embodiment, when it is determined that a third single cell is in a fully discharged state, the system will quickly send a control signal to disconnect the first switch and the second switch at both ends of the third single cell, preventing current from continuing to flow from the corresponding third single cell, thereby avoiding over-discharge.

[0233] For a partially discharged fourth battery, the system turns on its corresponding first and second switches. This creates a closed discharge loop between the charge-discharge module and the corresponding fourth battery or batteries. The energy in the corresponding fourth battery can be output through the charge-discharge module to power external devices. During this process, the charge-discharge module adjusts the discharge current appropriately based on the external device's needs.

[0234] It's worth noting that during the discharge of the fourth cell, the system continuously monitors changes in its sampled voltage and current. As discharge progresses, the sampled voltage gradually decreases, and the sampled current also changes based on changes in the external load. When the system detects that the sampled voltage of the corresponding fourth cell has dropped to the standard value for full discharge, or when it determines based on current changes that the battery can no longer discharge effectively, it controls the first and second switches at both ends of the fourth cell to disconnect, halting discharge. This ensures that each cell discharges within a safe range, preventing damage to the battery caused by excessive discharge.

[0235] In summary, throughout the discharge process, the system manages all individual cells uniformly, monitoring each cell's status in real time and dynamically adjusting the on and off states of the corresponding first and second switches to ensure the battery string can stably and efficiently power external devices. This approach also ensures that the discharge of each cell is as uniform as possible, improving the overall performance and service life of the battery string.

[0236] The state of charge (SOC) of a single cell significantly affects its maximum discharge current. When the SOC is high, the cell can typically withstand relatively high discharge currents. However, when the SOC is low, the internal resistance of the battery increases. Discharging at high currents at this point generates excessive heat and may damage the battery. For example, when the SOC (State of Charge) of a single cell is 80%, it can be safely discharged at a current of 3C. However, when the SOC drops to 20%, the maximum safe discharge current may need to be reduced to 1C. Temperature is also a significant factor affecting the maximum discharge current of a battery. At low temperatures, the chemical reaction rate within the cell slows down, reducing ion conductivity, which limits the cell's maximum discharge current. For example, at -20°C, a cell's maximum discharge current of 3C may need to be reduced to 1C or even lower to prevent lithium deposition, which can affect battery performance and safety. As batteries age, the electrode materials within the cell gradually age, increasing internal resistance and reducing the maximum discharge current. For example, the maximum discharge current of a new battery is 5A. After 500 charge and discharge cycles, the maximum discharge current may drop to 3A due to aging of the electrode material. During the discharge process of the battery string, the method for controlling the balanced charge and discharge of the battery string further includes: evaluating the maximum discharge current that each single cell can accept during the discharge process of the battery string, and controlling the charge and discharge module to perform series discharge according to the minimum value of the maximum amplified current.

[0237] In one embodiment, Figure 42As shown, each battery is provided with a detailed specification sheet by the manufacturer before it leaves the factory, which clearly indicates the maximum discharge current that the battery can withstand. In one embodiment, sensors in the battery management system can be used to monitor battery voltage, current, temperature, and other parameters in real time, and combined with a preset algorithm to dynamically estimate the maximum discharge current of each battery. For example, by monitoring the battery voltage change rate under different operating conditions and combining it with the battery's equivalent circuit model, the maximum discharge current that the battery can withstand under the current state can be calculated.

[0238] After evaluating the maximum discharge current of each single cell, the minimum value is selected from the maximum discharge current values of all single cells. Figure 42 , the maximum discharge current of single battery A is 50AH*0.5C=25A, and the maximum amplified current of single battery B is 50AH*1C=50A, so the discharge current finally decided by the series circuit of A and B is set to min(25,50)=25A.

[0239] As discharge progresses, the state of charge and temperature of each cell continuously change, and the maximum discharge current of each cell may also change. For example, if the temperature of a cell rises during discharge, its maximum discharge current may decrease. In this case, the maximum discharge current of each cell needs to be reassessed, a new minimum value determined, and the discharge current of the charge and discharge modules adjusted accordingly to ensure that the entire battery string always operates under safe conditions.

[0240] Example 5:

[0241] In a photovoltaic system, the photovoltaic modules convert light energy into electrical energy and store it in the corresponding battery strings (i.e., the charging and discharging modules in this embodiment charge the battery strings). Under the premise that the electrical energy transmitted by the photovoltaic modules cannot fully charge each single cell in the battery string under the external environment of cloudy days or dark nights with insufficient light energy, the method of controlling the balanced charging and discharging of the battery strings further includes: when the charging and discharging modules can only support charging of the remaining single cells, the single cell with the lowest voltage is selected for charging according to a preset cycle, so as to continuously increase the power of the single cell with the lowest voltage, so as to reduce the voltage difference between the single cells.

[0242] Taking a photovoltaic system as an example, during the day, PV panels convert sunlight into electricity to charge the battery string. However, on cloudy days with low sunlight intensity, or at night when there is no sunlight, the electricity generated by the PV panels is significantly reduced, making it difficult to fully charge every single cell in the battery string. During these times, the system monitors the output power of the charge and discharge modules and the charging requirements of the battery string in real time. If the power output of the charge and discharge modules is found to be only sufficient to charge the remaining single cells, the subsequent balancing charging strategy is triggered. For example, if a PV system is equipped with a charge and discharge module with a rated power of 100W and on a cloudy day, the output power of the PV panels drops to 20W, and there are multiple uncharged cells in the battery string, if the power required to fully charge each cell exceeds 20W, the charge and discharge module is deemed to be only capable of charging a single cell.

[0243] To reduce voltage differences between individual cells, the system periodically selects the cell with the lowest voltage based on the collected voltage data for each cell. The preset period can be set based on actual conditions, for example, screening every 30 minutes. During each screening, the system iterates through the voltage values of all partially charged cells and compares them to identify the cell with the lowest voltage. For example, if there are five partially charged cells in a battery string with voltages of 3.2V, 3.3V, 3.1V, 3.4V, and 3.25V, the cell with a voltage of 3.1V will be selected.

[0244] After determining the single cell with the lowest voltage, the system will control the first switch and the second switch corresponding to the single cell, so that the charge and discharge module will only charge this single cell. During the charging process, the system will continuously monitor the voltage changes of the single cell. When the charging reaches a certain time, or the voltage of the single cell rises to the set threshold, charging will be suspended. Then, entering the next preset cycle, the system will again select the single cell with the lowest voltage for charging. For example, the initial voltage of the selected single cell is 3.1V, and the charging threshold is set to 3.5V. When the voltage of the single cell reaches 3.5V, charging will be suspended. In the next 30-minute cycle, the single cell with the lowest voltage will be selected again. It is possible that another single cell has the lowest voltage at this time, so it will be charged.

[0245] By continuously charging the battery with the lowest voltage according to a preset cycle, each charge increases the battery's charge level, thereby increasing its voltage. Over time, the voltage difference between the individual batteries will gradually decrease, improving the overall performance of the battery string.

[0246] In a series battery string, if the voltage of some cells is too high and the voltage of some cells is too low, the performance of each cell will be inconsistent, thereby affecting the use of the entire battery string. When the charging and discharging module completely stops generating electricity, that is, when the photovoltaic module fails, it is impossible to continue charging the battery string. In order to ensure that the battery maintains a minimum voltage difference between each cell when the photovoltaic module fails and maintain the stability of the battery string, in one embodiment, an energy storage module is provided between each first switch and the positive electrode of the corresponding cell, and each energy storage module is equipped with a corresponding control switch. The method further includes:

[0247] like Figure 43 As shown, the method for controlling balanced charging and discharging of a battery string further includes:

[0248] Step 801: When the charge and discharge module for controlling the charge and discharge of the battery string cannot support charging of the remaining cells that are not fully charged, the charge and discharge module is turned off, and the charge of each cell is obtained based on the sampled voltage and the sampled current at both ends of the cell.

[0249] During the charging process, the system monitors the output capacity of the charge and discharge modules in real time. If a module is unable to provide sufficient charging current to the remaining partially charged cells due to power limitations, a fault, or insufficient power, the system will determine and shut down the module. For example, a 100W designed power module may, after prolonged operation, reduce its actual output power to 30W due to internal component heating. At this point, the remaining partially charged cells require 50W of power to charge properly. In this case, the module is deemed unable to support charging and shut down.

[0250] After the charge and discharge module is turned off, the system calculates the charge of each battery based on the sampled voltage and current of each battery. The process of determining the charge is described below.

[0251] Step 802: Compare the charges of two adjacent single cells, and control the conduction states of the first switch, the second switch, and the control switches of the corresponding energy storage modules so that the single cell with the larger charge charges the corresponding energy storage unit.

[0252] After obtaining the charge of each battery, the system compares the charges of two adjacent batteries one by one. For example, in a battery string consisting of 10 batteries connected in series, the charges of the first and second batteries, the second and third batteries, and so on, and finally the ninth and tenth batteries will be compared.

[0253] When it is found that the charge of one cell (with a larger charge) is significantly higher than that of the other (with a smaller charge) between two adjacent cells, the system will control the corresponding switch to turn on. Figure 44 As shown, through the above detection process, at a certain detection node, the charge of single cell A is greater than the charge of single cell B. Therefore, the first switch Sa1 corresponding to single cell A, the first switch Sb1 corresponding to single cell B, the control switch Ka2, and the control switch Kb1 of the corresponding energy storage unit LB are turned on, and the second switch Sa2 of single cell A is turned off, so that single cell A and the corresponding energy storage unit LB form a charging circuit, allowing single cell A to charge the energy storage unit LB.

[0254] Step 803: After charging the energy storage unit for a preset time, the first switch, the second switch and the corresponding control switch of the energy storage unit are controlled to enable the charged energy storage unit to charge the single battery with a smaller charge.

[0255] Among them, still taking the above example, the system will pre-set a charging time to allow single battery A to charge the energy storage unit LB. The preset time can be determined based on a combination of factors such as the capacity of the energy storage unit, the remaining power of the single battery with a larger charge, and the charging current.

[0256] In one embodiment, referring to Figure 44 When battery A charges energy storage unit LB for a preset time, the system re-controls the switch states. At this point, the first switch Sa1 is disconnected, the second switch Sb2 corresponding to battery B is disconnected, and the first switch Sb1 corresponding to battery B, the first switch Sc1 corresponding to battery C, and the control switch Kc2 on energy storage unit LC are turned on. This allows the charged energy storage unit LB to form a charging circuit with battery B, allowing the energy storage unit LB to charge battery B.

[0257] The following describes the process of determining the charge of each single battery:

[0258] Since the time series feature set needs to be collected during the charging process, the time series feature set is used to realize the real-time monitoring of the charge of the single battery, such as Figure 45 As shown, after step 601, the method further includes:

[0259] Step 6011: Determine the time series feature set of the single battery at a specified time point as a real-time power feature set; and obtain all current sampling values from the real-time power feature set.

[0260] The designated time point is the time point at which the charge of the single battery needs to be detected.

[0261] Step 6012: Determine the time interval from the charging start time to the designated time point as the collection period of the single battery.

[0262] Similar to the process of obtaining the integral value, when the real-time power value needs to be determined, the embodiment of the present invention integrates all current sampling values in the real-time power feature set over the acquisition period, and the result of the integration is the real-time power value.

[0263] Step 6013: Integrate all the acquired current sampling values over the acquisition period to obtain a real-time power value.

[0264] Step 6014: Determine the ratio of the real-time power value to the maximum available capacity of the single battery as the charge of the single battery.

[0265] Through the above steps, the energy storage module is used to achieve power balance between adjacent single cells when the charge and discharge module cannot support charging, thereby improving the overall performance and service life of the battery string.

[0266] In summary, this embodiment obtains the sampled voltage across each single cell and the sampled current in the battery string charge and discharge circuit; then controls the conduction states of the first switch and the second switch corresponding to the corresponding single cell according to the sampled voltage and the sampled current, so as to select and charge and discharge the single cells that meet the charge and discharge requirements; it is possible to charge and discharge a single single cell individually, and ultimately achieve full charge and discharge of each single cell; it solves the limitation of the energy storage battery system that a single or very few single cells can be fully utilized; it can charge and discharge a single single cell, or multiple single cells can be charged and discharged together; it solves the problem of unbalanced charge and discharge of the battery system, thereby maximizing the utilization of battery resources.

[0267] Example 6:

[0268] In order to further illustrate the above embodiment, this embodiment proposes a circuit for controlling the balanced charging and discharging of a battery string, such as Figure 44As shown, it includes: a control module, a charge and discharge module, a voltage sampling module, a current sampling module and a switch module. The positive electrode of the charge and discharge module is connected to the positive electrode of the battery string, and the negative electrode of the charge and discharge module is connected to the negative electrode of the battery string; the switch module includes a first switch arranged between the positive electrode of each single battery and the positive electrode of the charge and discharge module, and a second switch arranged between the negative electrode of each single switch and the negative electrode of the charge and discharge module; the sampling point of the voltage sampling module is respectively connected to the positive electrode and negative electrode of each single battery; the current sampling module is connected in series in the main circuit of the charge and discharge module; the control module is respectively connected to the control end of each switch in the charge and discharge module, the voltage sampling module, the current sampling module and the switch module.

[0269] The charge and discharge module is used to charge or discharge the battery string according to the instructions of the control module; the voltage sampling module is used to respectively obtain the sampled voltage across each single cell, and the current sampling module is used to obtain the sampled current in the main charge and discharge circuit of the battery string; the control module is used to respectively control the conduction state of the first switch and the second switch corresponding to the corresponding single cell according to the sampled voltage and the sampled current, so as to select the single cells that meet the charge and discharge requirements for charge and discharge, so as to achieve charge and discharge balance of each single cell in the battery string under the charge and discharge state.

[0270] Among them, the entire circuit is built with the goal of controlling the battery string to achieve balanced charging and discharging, and includes a control module, a charging and discharging module, a voltage sampling module, a current sampling module, and a switch module. The positive pole of the charging and discharging module is connected to the positive pole of the battery string, and the negative pole is connected to the negative pole of the battery string. It is responsible for delivering charging current to the battery string or guiding the battery string to discharge. The first switch in the switch module is distributed between the positive pole of each single cell and the positive pole of the charging and discharging module, and the second switch is distributed between the negative pole of each single cell and the negative pole of the charging and discharging module. By controlling the on and off of the corresponding first switch and the second switch, it is determined whether the single cell is connected to the charging and discharging circuit for charging or discharging. In one embodiment, both the first switch and the second switch can be MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) tubes controlled by the corresponding pulse width modulation (PWM) signals (such as PWM1 to PWM8) output by the control module.

[0271] The voltage sampling module is used to obtain real-time voltage information across the battery cells. The current sampling module, connected in series with the main circuit of the charge and discharge module, monitors the current during the charge and discharge process. The control module collects and analyzes feedback from each module and then issues instructions for the operation of the entire circuit.

[0272] For the charge-discharge module, when the control module issues a charge command, the module draws power from the external power source and transmits it to the battery string to charge the batteries. When the control module issues a discharge command, the module directs the battery string to release power to supply external loads. For example, in a photovoltaic energy storage system, during the day, when the photovoltaic panels generate electricity, the control module instructs the charge-discharge module to store the energy in the battery string. At night, when electricity is needed, the control module instructs the charge-discharge module to discharge the battery string to provide power for household electrical appliances.

[0273] During the charging phase, the control module comprehensively analyzes the sampled voltages of each cell. For cells with low sampled voltages and insufficient state of charge, the control module controls the corresponding first and second switches to conduct, allowing the charge and discharge module to charge them. As charging progresses, the voltage sampling module continuously monitors changes in the cell voltages. When the voltage of a cell reaches the preset full charge threshold, the control module controls the corresponding first and second switches to disconnect, stopping charging for that cell.

[0274] In one embodiment, Figure 46 As shown, taking four single cells as an example, when it is detected that single cell 1 is fully charged and single cell 2, single cell 3 and single cell 4 are not fully charged (the specific detection method is referred to Example 1 and is not repeated here), switch Q1 (i.e., the first switch corresponding to single cell 1) and switch Q5 (i.e., the second switch corresponding to single cell 1) are disconnected, and switch Q2 (i.e., the first switch corresponding to single cell 2) and switch Q8 (i.e., the second switch corresponding to single cell 4) are turned on, so that the sub-battery string consisting of single cell 2, single cell 3 and single cell 4 can continue to be charged.

[0275] In one embodiment, Figure 47 As shown, taking four single cells as an example, when it is detected that single cells 2 and 3 are fully charged, and single cells 1 and 4 are not fully charged, switches Q2 (i.e., the first switch corresponding to single cell 2), switch Q6 (i.e., the second switch corresponding to single cell 2), switch Q3 (i.e., the first switch corresponding to single cell 3), and switch Q7 (i.e., the second switch corresponding to single cell 3) are turned off, and switches Q1, Q5, Q4 (i.e., the first switch corresponding to single cell 4), and Q8 (i.e., the second switch corresponding to single cell 4) are turned on. When charging the entire battery string, switches Q1 and Q8 need to be turned on. Therefore, in the above process, it is sufficient to check whether switches Q1 and Q8 are in the on or off state, and repeated control is unnecessary.

[0276] In one embodiment, referring to Figure 46 and Figure 47When only single cell 1 is detected to be fully charged (or discharged), the sub-battery string consisting of single cells 2, 3, and 4 needs to continue charging (or discharging). At this time, it is only necessary to turn on the first switch between the positive electrode of the sub-battery string and the positive electrode of the charge and discharge module, and the second switch between the negative electrode of the sub-battery string and the negative electrode of the charge and discharge module to realize the charging or discharging of the sub-battery string.

[0277] The conduction conditions of the switches under other charging and discharging conditions can be obtained based on the above principles and the accompanying drawings, and will not be described in detail in this embodiment.

[0278] In one embodiment, the discharge phase operates similarly to the charging phase. The control module prioritizes discharge by focusing on cells with higher charge levels and controlling their corresponding switches. Simultaneously, the current sampling module monitors the discharge current to ensure a safe and stable discharge process. As discharge continues, if the cell's state of charge drops to a certain level, the control module controls the corresponding first and second switches to disconnect to prevent over-discharge.

[0279] Through the above method, during the entire charging and discharging process, it is ensured that each single battery can be charged and discharged at the appropriate time, achieving balanced charging and discharging of the battery string, effectively extending the service life of the battery string and improving the overall performance of the battery system.

[0280] Referring to the above embodiment, in a battery string connected in series, if the voltage of some cells is too high and the voltage of some cells is too low, the performance of each cell will be inconsistent, thereby affecting the use of the entire battery string. When the charge and discharge module completely stops generating electricity, in a photovoltaic system, if the photovoltaic module fails or stops generating electricity, it is impossible to continue charging the battery string. In order to ensure that the voltage difference between each cell of the battery string is minimized when the photovoltaic module fails, so as to maintain the stability of the battery string, in one embodiment, as Figure 48 As shown, the circuit for controlling the balanced charge and discharge of the battery string also includes an energy storage module arranged in the charge and discharge circuit where each single cell is located. The energy storage module includes an energy storage unit, a first control switch, and a second control switch; one end of the first control switch and the second control switch are respectively connected to one end of the first switch, and the other end of the first control switch is connected to one end of the energy storage unit, and the other end of the energy storage unit and the other end of the second control switch are respectively connected to the positive electrode of each single cell. It is worth noting that an energy storage module may or may not be arranged between the positive electrode of the first single cell and the last single cell and the corresponding first switch. The energy storage unit can be an inductor or a capacitor. In this embodiment, an inductor is used as an example. The first control switch and the second control switch are both MOS tubes controlled by the PWM signal output by the control module.

[0281] Among them, when the charging and discharging module fails or stops generating electricity, the charge of two adjacent single cells is determined by detecting the charge of each battery (refer to the above-mentioned embodiment for the specific detection method). The single cell with a larger charge is used to charge the single cell with a lower charge to balance the charge between the single cells and maintain the stability of the battery system.

[0282] In one embodiment, Figure 49 As shown, when it is detected that the charge of single cell 1 is greater than the charge of single cell 2, the switch Q1, the switch Q2 and the control switch K1 are turned on to form a charging circuit including the energy storage unit L1, the control switch K1, the switch Q2, the switch Q1 and the single cell 1, so as to charge the energy storage unit L1 through the single cell 1.

[0283] In one embodiment, Figure 50 As shown, after the energy storage unit L1 is charged for a preset time, the switch Q1 is turned off, and the switch Q3 and the control switch K22 are turned on to form a charging circuit including the energy storage unit L1, the control switch K1, the switch Q2, the switch Q3, the control switch K22, and the single battery 2. The single battery 2 is charged by the energy storage unit L1, thereby transferring part of the power in the single battery 1 to the single battery 2. When the charge and discharge module cannot support charging, the energy storage unit L1 is used to achieve power balance between adjacent single batteries 1 and 2, thereby improving the overall performance and service life of the battery string.

[0284] Similarly, in other embodiments, the electricity in multiple single cells can be transferred to one single cell. Specifically, each switch can be controlled by referring to the above method to obtain a corresponding charging circuit, which will not be explained in detail in this embodiment.

[0285] Example 7:

[0286] This embodiment provides a specific example of detecting the real-time power value and the maximum battery capacity.

[0287] like Figure 51 As shown, the battery strings of the present invention are used to charge photovoltaic panels. The photovoltaic panels are connected in parallel to a set of battery strings, which store and transport electrical energy through charging and discharging. Each photovoltaic panel is equipped with a Maximum Power Point Tracking (MPPT) module, which is connected in parallel to the corresponding battery string.

[0288] Among them, the MPPT module is used to monitor the voltage and current of the battery string in real time, and adjust the operating voltage or current of the battery string according to the monitoring results to ensure that each photovoltaic panel can operate at its maximum power point, thereby maximizing energy output.

[0289] Each battery is connected in series and in parallel to a sampling and integration monitoring module, which detects the maximum battery capacity and obtains current sampling values from the MPPT module. In an optional embodiment, the sampling and integration monitoring module can be used as part of a single battery management system (BMS), ensuring that the BMS can respond in real time and enabling remote access to data monitoring.

[0290] During the charging process of the battery string, the MPPT module uses a high-precision sensor to collect the current sampling value of each single battery in the battery string every 10 milliseconds, with a current sampling accuracy of 0.01A.

[0291] While the MPPT module collects the current sampling value of a single battery, the sampling integration monitoring module continuously uses the newly collected current sampling value and the corresponding charging period to update the real-time power characteristic set of the single battery.

[0292] When the real-time power value of a single battery needs to be obtained, the sampling and integration monitoring module obtains the real-time power feature set of the single battery, integrates all current sampling values in the obtained real-time power feature set over the acquisition period, and obtains the real-time power value.

[0293] When any single battery is fully charged, the sampling and integration monitoring module obtains the battery's time series feature set and integrates all current sampling values within the acquired time series feature set over the charging period to obtain the integral value for the single battery. This integral value is then used as the total charge capacity of the single battery. After the single battery is repeatedly discharged and fully charged three times, the average total charge capacity of these three times is calculated to obtain the maximum battery capacity of the single battery.

[0294] The embodiment of the present invention performs an integral operation on the current sampling value, fully reuses the time advantage, and realizes real-time updating of the maximum battery capacity to monitor the maximum battery capacity of the photovoltaic panel, thereby ensuring the safe operation of the entire BMS; it can efficiently utilize the output of the battery string, maximize the energy conversion efficiency, and manage the maximum battery capacity of the battery string in real time.

[0295] Example 8:

[0296] like Figure 52 The figure is a schematic diagram of the structure of the photovoltaic energy storage battery string capacity self-test device according to an embodiment of the present invention. The photovoltaic energy storage battery string capacity self-test device according to this embodiment includes one or more processors 21 and a memory 22. Figure 52 A processor 21 is taken as an example.

[0297] The processor 21 and the memory 22 may be connected via a bus or other means. Figure 52 The bus connection is taken as an example.

[0298] Memory 22, as a nonvolatile computer-readable storage medium, can be used to store nonvolatile software programs and nonvolatile computer-executable programs, such as the photovoltaic energy storage battery string capacity self-test method in this embodiment. Processor 21 executes the photovoltaic energy storage battery string capacity self-test method by running the nonvolatile software program and instructions stored in memory 22.

[0299] The memory 22 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state memory device. In some embodiments, the memory 22 may optionally include a memory remotely located relative to the processor 21, and such remote memory may be connected to the processor 21 via a network. Examples of such networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0300] The program instructions / modules are stored in the memory 22. When executed by the one or more processors 21, the photovoltaic energy storage battery string capacity self-test method in the above embodiment is executed, for example, each step of the photovoltaic energy storage battery string capacity self-test method in the embodiment of the present invention described above is executed.

[0301] An embodiment of the present invention further provides a non-volatile computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are executed by one or more processors, for example Figure 52 A processor 21 can enable the above one or more processors to execute the photovoltaic energy storage battery string capacity self-test method in the specific embodiment of the present invention, for example, to execute the various steps of the photovoltaic energy storage battery string capacity self-test method described above in the embodiment of the present invention; it can also realize Figure 52 The modules and units described above; or executing the photovoltaic energy storage battery string capacity self-test method in the specific embodiment of the present invention, for example, executing the various steps of the photovoltaic energy storage battery string capacity self-test method of the embodiment of the present invention described above; it can also be realized Figure 52 The various modules and units described.

[0302] It is worth noting that the information interaction, execution process, etc. between the modules and units within the above-mentioned devices and systems are based on the same concept as the processing method embodiment of the present invention. The specific content can be found in the description of the method embodiment of the present invention and will not be repeated here.

[0303] Those skilled in the art will understand that all or part of the steps in the various methods of the embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), a disk or an optical disk, etc.

[0304] The above description is only a preferred embodiment of the present invention and is 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 in the scope of protection of the present invention.

Claims

1. A photovoltaic energy storage battery string capacity self-test method, characterized in that: include: Charging the battery string according to a preset control strategy; During the charging process of the battery string, a current sampling value of each single battery in the battery string is collected according to a sampling interval; Determine the integral value of the current sampling value of each single battery during its own charging process, and determine the integral value as the total charge capacity of the single battery in this charging process; After the single battery completes multiple charge and discharge processes, the maximum battery capacity of the single battery is determined according to the total charge capacity and the number of charge and discharge times of each charging process.

2. The photovoltaic energy storage battery string capacity self-test method according to claim 1, characterized in that: include: Obtaining a charging start time for the battery string; At each sampling interval, a current sampling value of each single battery in the battery string is collected; Use the collected current sampling values to construct a time series feature set; Each time a current sampling value is collected, a set of collected data is added to the time series feature set until the battery is fully charged, and all current sampling values are obtained from the time series feature set; Obtaining the charging end time of the single battery; determining the time interval from the charging start time to the charging end time as the charging period of the single battery; Integrating all the acquired current sampling values over the charging period to obtain an integral value; The integrated value is determined as the total charge amount.

3. The photovoltaic energy storage battery string capacity self-test method according to claim 2, characterized in that: Also includes: Determine the time series feature set of the single battery at a specified time point as a real-time power feature set; Obtaining all current sampling values from the real-time power characteristic set; Determining the time interval from the charging start time to the specified time point as the collection period of the single battery; Integrate all the current sampling values obtained over the acquisition period to obtain a real-time power value; The ratio of the real-time power value to the maximum available capacity of the single battery is determined as the charge of the single battery.

4. The photovoltaic energy storage battery string capacity self-test method according to claim 3, characterized in that: An energy storage module is provided between each first switch and the positive electrode of the corresponding single battery, and each energy storage module is equipped with a corresponding control switch. The method further includes: When the charge and discharge module for controlling the charge and discharge of the battery string cannot support charging of the remaining single cells that are not fully charged, the charge and discharge module is turned off, and the charge of each single cell is obtained according to the sampled voltage and the sampled current at both ends of the single cell; Comparing the charge amounts of two adjacent single cells, and controlling the conduction states of the first switch, the second switch, and the control switches of the corresponding energy storage modules so that the single cell with the larger charge amount charges the corresponding energy storage unit; After the energy storage unit is charged for a preset time, the first switch, the second switch and the corresponding control switch of the energy storage unit are controlled to be on, so that the charged energy storage unit charges the single battery with a smaller charge.

5. The photovoltaic energy storage battery string capacity self-test method according to claim 2, characterized in that: include: When the single cell enters a constant voltage charging mode, monitoring the charging current of the single cell; When the charging current is lower than the charging threshold, it is determined that the battery is fully charged.

6. The photovoltaic energy storage battery string capacity self-test method according to claim 1, characterized in that: The method is implemented in a battery string charge and discharge circuit, wherein a first switch is respectively provided between the positive electrode of a charge and discharge module for controlling the charge and discharge of the battery string and the positive electrode of each single cell in the battery string, and a second switch is respectively provided between the negative electrode of the charge and discharge module and the negative electrode of each single cell in the battery string. The method further comprises: Obtain the sampled voltage across each single battery and the sampled current in the battery string charge and discharge circuit; The conduction states of the first switch and the second switch corresponding to the corresponding single battery are controlled respectively according to the sampled voltage and the sampled current, so as to select and charge and discharge the single batteries that meet the charge and discharge requirements respectively.

7. The photovoltaic energy storage battery string capacity self-test method according to claim 6, characterized in that: Also includes: In the charging state, judging whether the charge state of each single battery is in a fully charged state or in an undercharged state according to the sampled voltage and the sampled current; Disconnecting a first switch and a second switch at both ends of a first single battery in a fully charged state; Turning on the first switch and the second switch at both ends of the second single battery in the undercharged state, and controlling the charge and discharge module to charge the second single battery until it is detected that the charge state of the second single battery reaches the fully charged state; or obtaining the connection relationship of the second single batteries in the undercharged state, if there are at least two second single batteries connected in series, forming a series battery group with the at least two second single batteries, and turning on the first switch corresponding to the series battery group and the second switch corresponding to the series battery group.

8. The photovoltaic energy storage battery string capacity self-test method according to any one of claims 1 to 7, characterized in that: Also includes: Obtaining the maximum battery capacity and rated capacity of each of the single batteries; determining whether the maximum battery capacity meets the rated capacity; Identify, from the battery string, single cells whose maximum battery capacity does not meet the corresponding rated capacity; When the battery string is in the initial installation state, replacing the single battery that has been checked; When the battery string is in a long-term operation state, determine whether the maximum battery capacity of the detected single battery is lower than the capacity life value; wherein the capacity life value is: the product of the rated capacity of the detected single battery and a preset ratio value; when the maximum battery capacity of the detected single battery is lower than the capacity life value, replace the detected single battery.

9. A photovoltaic energy storage battery string capacity self-test device, characterized in that: The photovoltaic energy storage battery string capacity division self-test device includes at least one processor and a memory, wherein the at least one processor and the memory are connected via a data bus, and the memory stores instructions executable by the at least one processor. After being executed by the processor, the instructions are used to implement the photovoltaic energy storage battery string capacity division self-test method according to any one of claims 1 to 8.

10. A non-volatile computer storage medium, characterized in that The computer storage medium stores computer-executable instructions, which are executed by one or more processors to implement the photovoltaic energy storage battery string capacity self-test method according to any one of claims 1 to 8.

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