Reconfigurable battery topology design method based on graph theory

Abstract

The invention discloses a reconfigurable battery topology design method based on a graph theory, and the method comprises the steps: carrying out the modeling based on a battery and a switch, and defining the series connection of the reconfigurable battery, and three sub-structures of a positive electrode switch and a negative electrode switch; defining a modular building rule of the three sub-structures and building a candidate topology directed graph; defining effective path judgment conditions and positive and negative output endpoint constraint conditions based on a graph theory, screening effective topologies based on the candidate topology directed graph, and mapping the effective topologies into physical topologies; according to the invention, based on the three sub-structures of the reconfigurable battery topology directed graph defined based on the characteristics of different connection modes of the reconfigurable battery topology and the modular construction rule thereof, the structured derivation and systematic generation of the reconfigurable battery topology are realized, and the universality and normalization of the design of the reconfigurable battery topology are significantly improved; the effective path judgment condition and positive and negative electrode output endpoint constraints defined by the graph theory and the basic requirements of the reconfigurable battery topology are utilized, so that wrong endpoint selection is avoided, and the correctness and reliability of the generated topology are ensured.

Description

Technical Field

[0001] This invention belongs to the field of energy storage system technology, specifically relating to a graph-based method for reconfigurable battery topology design. Background Technology

[0002] With the rapid popularization and continuous expansion of the application scale of new energy vehicles, a large number of power batteries are entering the retirement stage after the end of their service life. How to efficiently and economically realize the tiered utilization of retired batteries has become an important research direction in the field of energy storage. However, retired batteries generally have differences in capacity, internal resistance, etc., and the direct parallel or series connection of traditional energy storage systems can easily lead to performance degradation and safety problems when the differences between retired batteries are large.

[0003] To address the aforementioned issues, reconfigurable battery technology has gradually gained attention. This technology introduces power electronic switches between individual battery cells, allowing for flexible switching of connection methods between batteries, thereby mitigating the adverse effects of battery variations on system performance to some extent. Especially in energy storage systems with poor battery consistency, reconfigurable battery topologies can achieve functions such as bypassing faulty batteries, state-of-charge balancing, and multi-level output through flexible reconfiguration methods, providing a new technical approach for the efficient utilization of retired batteries.

[0004] However, existing research mostly focuses on the functional implementation of specific topologies, lacking a systematic derivation method for reconfigurable battery topologies. This leads to the construction process of novel topologies often relying on experience or specific scenarios, making it difficult to guarantee the universality and scalability of the design methods, thus limiting the promotion and application of reconfigurable battery networks in complex application scenarios. Summary of the Invention

[0005] The purpose of this invention is to provide a graph theory-based reconfigurable battery topology design method, which solves the problems of traditional topology design relying on experience and lacking a general design method.

[0006] The technical solution adopted in this invention is a graph-based reconfigurable battery topology design method, comprising the following steps: Step 1: Based on battery and switch modeling, define three substructures: reconfigurable battery series structure, reconfigurable positive switch structure, and reconfigurable negative switch structure. Step 2: Define the modular construction rules for the three substructures obtained in Step 1, and construct the candidate topology directed graph; Step 3: Define the valid path judgment conditions and positive and negative output endpoint constraints based on graph theory, and filter the valid topologies based on the candidate topology directed graph obtained in Step 2 and map them to the physical topology.

[0007] The invention is further characterized in that, Step 1 specifically includes the following steps: Step 1.1: Abstract a single battery cell as a unidirectional edge, a power electronic switch as a bidirectional edge, and the connection nodes between the battery and the switch, and between switches, as vertices. Step 1.2: Based on series, parallel, and bypass connection methods, define three substructures of the reconfigurable battery topology directed graph: reconfigurable battery series structure, reconfigurable positive switch structure, and reconfigurable negative switch structure. Among them, the reconfigurable battery series structure is formed by alternating connection of batteries and switches to form a series path; the reconfigurable positive switch structure consists of switches connecting all battery positive nodes, or switches connecting battery positive nodes and the topology negative output terminal; the reconfigurable negative switch structure consists of switches connecting all battery negative nodes, or switches connecting battery negative nodes and the topology positive output terminal.

[0008] Step 2 specifically includes the following steps: Step 2.1: Based on the matching relationship between the output voltage and the rated voltage of the battery, determine the required number of batteries, and then construct a directed graph of the reconfigurable battery series structure, the reconfigurable positive switch structure, and the reconfigurable negative switch structure in sequence. Step 2.2: Define modular construction rules: Take the reconfigurable battery series structure as the main path, and determine the connection order of the battery and the switch in sequence; on the basis of the main path, select the positive and negative terminal nodes of the battery or the corresponding switch nodes as connection points, and connect the reconfigurable positive switch structure or the reconfigurable negative switch structure to the corresponding node, keeping the internal connection relationship of the substructure unchanged; after completing the connection, check the node correspondence to ensure that the substructure is correctly coupled with the main path, and obtain the candidate topology directed graph.

[0009] Step 3 specifically includes the following steps: Step 3.1: Convert the candidate topology directed graph into an adjacency matrix, preset the positive and negative output endpoints as the starting and ending points of the path search, define the valid path judgment conditions and the positive and negative output endpoint constraints, and perform path search and filtering. Step 3.2: Map the adjusted topological directed graph to the physical topology.

[0010] Step 3.1 specifically includes the following steps: Step 3.1.1: Transform the candidate topological directed graph into an adjacency matrix: The nodes of the candidate topological directed graph are numbered sequentially to obtain the node set. V = {1,2,…, n},in n The adjacency matrix W is the number of nodes in the candidate topological directed graph.

[0011]

[0012] In the formula, where [ w ij ] n×n yes n × n The matrix, w ij Represents a matrix [ w ij ] n×n The Middle i Line number j The values ​​of the column elements; Step 3.1.2: Pre-select the positive and negative output endpoints as the starting nodes for path search. startNode and end node endNode ; Step 3.1.3: Perform path search based on the adjacency matrix W, enumerating all paths from... startNode arrive endNode The paths are used to form a candidate path set. P :

[0013]

[0014] In the formula, m It is the total number of candidate paths. Indicates starting point = startNode To the finish line = endNode One of the candidate paths; Define valid path judgment conditions and based on Filter out candidate path set P Invalid paths are identified, resulting in a set of valid paths. P *:

[0015] In the formula, Indicate candidate path The validity, if If it is 1 Effective, if If it is 0, then invalid; Step 3.1.4: Define constraints and determine whether the pre-selected positive and negative output endpoints are reasonable based on the constraints. Adjust the candidate topology directed graph to obtain a topology directed graph with reasonable positive and negative output endpoints.

[0016] The valid path determination condition defined in step 3.1.3 is as follows:

[0017]

[0018]

[0019]

[0020]

[0021] In the formula, This represents the set of unidirectional edges in a candidate topological directed graph; Representation of candidate paths The set of intersecting one-way edges, express The starting node is Termination node is The edge; Indicate candidate path The edges in Indicate candidate path point; Indicate candidate path The total number of nodes in; This represents the set of one-way edges contained in the candidate path.

[0022] The constraints defined in step 3.1.4 include constraint 1 and constraint 2: Constraint 1: Let the number of batteries in the candidate topological directed graph be... There are candidate paths So that the number of unidirectional edges of the battery contained therein satisfies ; Constraint 2: Let the set of batteries in the candidate topological directed graph be... In the set P * In the context, for any given battery There must be a path , making .

[0023] The mapping method in step 3.2 is as follows: unidirectional edges are mapped to batteries, bidirectional edges are mapped to switches, and nodes are mapped to the positive and negative terminals of batteries or the connection points between batteries and switches, generating a series of reconfigurable battery topologies.

[0024] The beneficial effects of this invention are: 1) Based on the characteristics of different connection methods of reconfigurable battery topology, three substructures of the directed graph of reconfigurable battery topology (reconfigurable battery series structure, reconfigurable battery positive electrode switch structure and reconfigurable battery negative electrode switch structure) and their modular construction rules are defined, realizing the structured derivation and systematic generation of reconfigurable battery topology, which significantly improves the universality and standardization of reconfigurable battery topology design.

[0025] 2) By utilizing graph theory and the basic requirements of reconfigurable battery topology to define the effective path judgment conditions and positive and negative output endpoint constraints, incorrect endpoint selection is avoided, ensuring the correctness and reliability of the generated topology. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the reconfigurable battery topology design method based on graph theory of the present invention. Figure 2 This is a schematic diagram of directed graph modeling of the battery and switch in an embodiment of the present invention; Figure 3 This is a schematic diagram of five reconfigurable positive electrode switch structures, two reconfigurable battery series structures, and five reconfigurable negative electrode switch structures constructed using the three substructures proposed in this invention. Figure 4 This is a schematic diagram of the modular construction rules based on three substructures proposed in this invention; Figure 5 This is a schematic diagram of some candidate topological directed graphs obtained by the modular construction rules proposed in this invention; Figure 6 This is a schematic diagram of the invalid path proposed in this invention; Figure 7 This is a schematic diagram of the preset invalid positive and negative output endpoints of the candidate topology directed graph in this invention; Figure 8 This is a schematic diagram of the preset effective positive and negative output endpoints of the candidate topology directed graph in this invention; Figure 9 This is a schematic diagram of the reconfigurable battery topology finally generated in an embodiment of the present invention. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0028] Example 1 This invention provides a graph theory-based method for reconfigurable battery topology design. Based on the characteristics of different connection methods in reconfigurable battery topologies, and combined with graph theory, a systematic derivation method for reconfigurable battery topologies is proposed. This effectively improves the standardization and scalability of topology design, solving the problems of traditional topology design relying on experience and lacking universal design methods, thus enhancing the reliability and universality of reconfigurable battery topology design. First, a directed graph model of the reconfigurable battery topology is constructed based on graph theory. Considering the characteristics of different connection methods in reconfigurable battery topologies, three substructures of the directed graph are defined: a reconfigurable battery series structure, a reconfigurable positive electrode switch structure, and a reconfigurable negative electrode switch structure. Second, modular construction rules based on the three substructures are defined, and candidate topology directed graphs are generated under the constraints of these rules. Finally, based on the basic requirements of reconfigurable battery topologies, effective path judgment conditions and positive and negative electrode output endpoint constraints are defined. The candidate topology directed graphs, after constraint adjustment, are mapped to physical topologies, ultimately yielding a series of reconfigurable battery topologies.

[0029] Example 2 This invention provides a graph-based method for reconfigurable battery topology design, such as... Figure 1 As shown, please follow these steps: Step 1: Construct a directed graph model of the reconfigurable battery topology based on graph theory. Considering the characteristics of different connection methods of the reconfigurable battery topology, three substructures of the directed graph of the reconfigurable battery topology are defined, namely the reconfigurable battery series structure, the reconfigurable positive electrode switch structure, and the reconfigurable negative electrode switch structure.

[0030] Step 2: Define modular construction rules based on three substructures, and generate candidate topology directed graphs under the constraints of these rules.

[0031] Step 3: Based on the basic requirements of reconfigurable battery topology, valid path judgment conditions and positive and negative output endpoint constraints are defined. The candidate topology directed graph after constraint adjustment is mapped to the physical topology, and finally a series of reconfigurable battery topologies are obtained.

[0032] Example 3 This invention provides a graph-based method for reconfigurable battery topology design. Based on Example 2, the preferred specific process of step 1 is as follows: Step 1.1: Based on graph theory, the battery cells and power electronic switches are abstracted as edges. Specifically, the battery is modeled as a unidirectional edge and the switch as a bidirectional edge according to the power flow direction of the battery charging and discharging. The connection nodes between the battery and the switch, and between switches, are abstracted as vertices.

[0033] Step 1.2: Considering the characteristics of the three connection methods of battery topology—series, parallel, and bypass—three substructures of the reconfigurable battery topology directed graph are defined: reconfigurable battery series structure, reconfigurable positive switch structure, and reconfigurable negative switch structure, as specifically defined below: Reconfigurable battery series structure: a series path formed by alternating connections of batteries and switches; Reconfigurable positive switch structure: 1) Consists of several switches connecting all battery positive nodes (applicable condition: the positive output terminal of the battery topology coincides with the positive node of a certain battery); 2) Consists of several switches connecting the battery positive node and the negative output terminal of the battery topology (applicable condition: the positive output terminal of the battery topology does not coincide with the positive nodes of any battery). Reconfigurable negative switch structure: 1) Consists of several switches connecting all battery negative terminals (applicable condition: the negative output terminal of the battery topology coincides with the negative terminal of a certain battery); 2) Consists of several switches connecting the battery negative terminal and the positive output terminal of the battery topology (applicable condition: the positive output terminal of the battery topology does not coincide with the negative terminals of any battery).

[0034] Example 4 This invention provides a graph-based reconfigurable battery topology design method. Based on Example 2, the preferred specific process of step 2 is as follows: Step 2.1: Determine the number of batteries required for the battery topology based on the matching relationship between the output voltage of the reconfigurable battery topology and the rated voltage of the battery. Then, based on the three substructures defined in Step 1.2, construct directed graphs of the reconfigurable battery series structure, the reconfigurable positive switch structure, and the reconfigurable negative switch structure in sequence.

[0035] Step 2.2: Based on the three substructures constructed in Step 1, define the following modular construction rules: 1) First, the reconfigurable battery series structure is used as the main path of the topology, and the connection order of each battery and switch is determined in sequence to form a continuous path. 2) Based on the main path, select the positive and negative terminal nodes of the battery or the corresponding switch nodes as connection points, and connect the reconfigurable positive switch structure or the reconfigurable negative switch structure to the corresponding node, while keeping the connection relationship inside each switch structure unchanged. 3) After completing the connection of the directed graph of each substructure, check the correspondence of the nodes to ensure that all substructures are correctly coupled to the main path.

[0036] By coupling the three substructures according to the modular construction rules, some candidate topological directed graphs are obtained.

[0037] Example 5 This invention provides a graph-based reconfigurable battery topology design method. Based on Example 2, the preferred specific process of step 3 is as follows: Step 3.1: Transform the candidate topological directed graph obtained in Step 2.2 into an adjacency matrix. The specific process is as follows: Number the nodes in the candidate topology directed graph sequentially to obtain the node set. V = {1,2,…, n},in n It represents the number of nodes in the candidate topological directed graph. The adjacency matrix W is defined as follows:

[0038]

[0039] in[ w ij ] n×n yes n × n The matrix, w ij Represents a matrix [ w ij ] n×n The Middle i Line number j The value of the column element.

[0040] Select the positive and negative output endpoints of the pre-selected candidate topology directed graph and set them as the starting nodes for subsequent path searches, respectively. startNode and end node endNode For each pair ( startNode , endNode The algorithm performs path search based on graph theory and evaluates the search results to determine whether the pre-selected positive and negative output endpoints are reasonable. The specific process is as follows: 1) with startNode Starting from the adjacency matrix W, recursively search layer by layer along the connected edges until the destination is reached. endNode Or there are no scalable nodes; 2) During the search process, record the sequence of visited nodes and store it as a candidate path; 3) When the search reaches a dead end, backtrack to the previous node and continue exploring untraversed branches until all branches have been explored. startNode arrive endNode All paths are enumerated; 4) Summarize all candidate paths obtained from the traversal to form a path set. P They are then screened and categorized, and the specific process is as follows: Candidate path set P The definition is as follows:

[0041]

[0042] in m It is the total number of candidate paths. Indicates starting point = startNode To the finish line = endNode One of the candidate paths.

[0043] Considering that although there are no closed loops in the candidate paths, the unidirectional edges representing batteries outside the paths may form closed loops with some edges in the candidate paths (corresponding to the battery short-circuit case), thus creating invalid paths, a valid path judgment condition is defined for the set. P The paths in the list are filtered one by one to remove invalid paths. The criteria for judging a valid path are defined as follows:

[0044]

[0045]

[0046]

[0047]

[0048] in Let represent the set of unidirectional edges in a candidate topological directed graph. Representation of candidate paths The set of intersecting one-way edges, express The starting node is Termination node is The edge, Indicate candidate path The edges in Indicate candidate path point, Indicate candidate path The total number of nodes in This represents the set of one-way edges contained in the candidate path. Indicate candidate path The validity, if If it is 1 Effective, if If it is 0, then invalid.

[0049] based on Filter out candidate path set P Invalid paths in the set, and define the updated set as P* The definition is as follows:

[0050] 5) Considering that the reconfigurable battery topology needs to have the ability to output all batteries in series and bypass any faulty battery, constraints 1 and 2 are defined to determine whether the preset positive and negative output terminals are reasonable. The definitions of constraints 1 and 2 are as follows: Constraint 1: Let the number of batteries in the candidate topological directed graph be . There are candidate paths The number of unidirectional edges of the battery contained therein satisfies .

[0051] Constraint 2: Let the set of batteries in the candidate topological directed graph be... In the set P * In the context, for any given battery There must be a path , making .

[0052] After adjusting the above constraints on the candidate topological directed graph, a topological directed graph with reasonable positive and negative output endpoints is obtained.

[0053] Step 3.2: Map the adjusted directed topology graph from Step 3.1 to a physical topology, i.e., map unidirectional edges to batteries, bidirectional edges to switches, and nodes to the positive and negative terminals of batteries or the connection points between batteries and switches, thereby generating a series of reconfigurable battery topologies.

[0054] Example 6 This invention provides a graph-based method for reconfigurable battery topology design, taking a topology containing four batteries as an example, combined with... Figures 2-9 The implementation process of this invention will be described as follows: First, such as Figure 2 As shown, a directed graph is used to abstractly model the battery and switch, where the battery is represented by a unidirectional edge and the switch by a bidirectional edge. The positive and negative terminals of the battery, or the connection points between the battery and the switch, are defined as nodes. Based on this, and according to the definition of three substructures, two reconfigurable battery series structures, five reconfigurable positive switch structures, and five reconfigurable negative switch structures are constructed, as follows: Figure 3 As shown.

[0055] Furthermore, following the modular construction rules, Figure 3 Neutron structure directed graph coupling yields a topological directed graph. Figure 4The coupling process is given, where the reconfigurable battery series structure is used as the main path. Then, nodes 5, 6, 7, 8, 17, 18, 19, and 20 are connected to nodes 9, 10, 11, 12, 13, 14, 15, and 16 respectively to form a candidate topology directed graph. Following the above process, a series of candidate topology directed graphs are obtained. Due to the large number of these graphs, this embodiment only provides a portion of the candidate topology directed graphs, such as... Figure 5 The nine candidate topological directed graphs are shown.

[0056] Subsequently, positive and negative output endpoints are preset, and the defined valid path judgment conditions and positive and negative output endpoint constraints are used in conjunction with computer verification to ensure the rationality of the endpoint selection. To explain the defined valid path judgment conditions in detail... Figure 6 An invalid path is given. Although the candidate path {10, 8, 5, 4, 7, 3, 6, 2, 1} does not form a closed loop, the unidirectional edge (8, 4) forms a closed loop with it, causing battery B3 to be in a short-circuit state. Therefore, the candidate path {10, 8, 5, 4, 7, 3, 6, 2, 1} is invalid. Figure 7 and Figure 8 This further clarifies the constraints on positive and negative extreme points. Figure 7 In the preset candidate topology directed graph, if node 1 is the positive output endpoint and node 7 is the negative output endpoint, the path search shows that there are only 3 possible output paths for the three batteries in series and no complete battery series output path, which does not satisfy constraints 1 and 2. Therefore, it is impossible to bypass any battery and impossible to achieve a complete battery series output. Thus, the preset positive and negative output endpoints 1 and 7 are invalid. Figure 8 If node 1 of the preset candidate topology directed graph is the positive output endpoint and node 10 is the negative output endpoint, the path search finds that there are 5 output paths for the three batteries in series, and among these 5 paths, there is a bypass B1 or B2 or B3 or B4, which satisfies constraint 2. At the same time, the entire battery can be connected in series for output, which satisfies constraint 1. Therefore, the preset positive and negative output endpoints 1 and 10 are valid.

[0057] Subsequently, the candidate topological directed graph with appropriate positive and negative output endpoints is transformed into a physical topology, resulting in the final reconfigurable battery topology, such as... Figure 9 As shown, topologies (1), (2) and (3) can dynamically adjust the switching state to achieve flexible switching between series, parallel and series-parallel hybrid connection, meeting the needs of diverse voltage and current output under normal operating conditions; topologies (4), (5) and (6) can not only meet the needs under normal operating conditions, but also have the balancing ability within and between modules, which is suitable for scenarios with high requirements for energy utilization efficiency and balancing performance; topologies (7), (8) and (9) have the fault tolerance capability of switching faults, which can maintain the stability and reliability of the system under complex or harsh operating environments.

Claims

1. A graph-based method for reconfigurable battery topology design, characterized in that, Includes the following steps: Step 1: Based on battery and switch modeling, define three substructures: reconfigurable battery series structure, reconfigurable positive switch structure, and reconfigurable negative switch structure. Step 2: Define the modular construction rules for the three substructures obtained in Step 1, and construct the candidate topology directed graph; Step 3: Define the valid path judgment conditions and positive and negative output endpoint constraints based on graph theory, and filter the valid topologies based on the candidate topology directed graph obtained in Step 2 and map them to the physical topology.

2. The graph-based reconfigurable battery topology design method as described in claim 1, characterized in that, Step 1 specifically includes the following steps: Step 1.1: Abstract a single battery cell as a unidirectional edge, a power electronic switch as a bidirectional edge, and the connection nodes between the battery and the switch, and between switches, as vertices. Step 1.2: Based on series, parallel, and bypass connection methods, define three substructures of the reconfigurable battery topology directed graph: reconfigurable battery series structure, reconfigurable positive switch structure, and reconfigurable negative switch structure. Among them, the reconfigurable battery series structure is formed by alternating connection of batteries and switches to form a series path; the reconfigurable positive switch structure consists of switches connecting all battery positive nodes, or switches connecting battery positive nodes and the topology negative output terminal; the reconfigurable negative switch structure consists of switches connecting all battery negative nodes, or switches connecting battery negative nodes and the topology positive output terminal.

3. The graph-based reconfigurable battery topology design method as described in claim 1, characterized in that, Step 2 specifically includes the following steps: Step 2.1: Based on the matching relationship between the output voltage and the rated voltage of the battery, determine the required number of batteries, and then construct a directed graph of the reconfigurable battery series structure, the reconfigurable positive switch structure, and the reconfigurable negative switch structure in sequence. Step 2.2: Define modular construction rules: Take the reconfigurable battery series structure as the main path, and determine the connection order of the battery and the switch in sequence; on the basis of the main path, select the positive and negative terminal nodes of the battery or the corresponding switch nodes as connection points, and connect the reconfigurable positive switch structure or the reconfigurable negative switch structure to the corresponding node, keeping the internal connection relationship of the substructure unchanged; after completing the connection, check the node correspondence to ensure that the substructure is correctly coupled with the main path, and obtain the candidate topology directed graph.

4. The graph-based reconfigurable battery topology design method as described in claim 1, characterized in that, Step 3 specifically includes the following steps: Step 3.1: Convert the candidate topology directed graph into an adjacency matrix, preset the positive and negative output endpoints as the starting and ending points of the path search, define the valid path judgment conditions and the positive and negative output endpoint constraints, and perform path search and filtering. Step 3.2: Map the adjusted topological directed graph to the physical topology.

5. The graph-based reconfigurable battery topology design method as described in claim 4, characterized in that, Step 3.1 specifically includes the following steps: Step 3.1.1: Transform the candidate topological directed graph into an adjacency matrix: The nodes of the candidate topological directed graph are numbered sequentially to obtain the node set. V = {1,2,…, n },in n The adjacency matrix W is the number of nodes in the candidate topological directed graph. In the formula, where [ w ij ] n×n yes n × n The matrix, w ij Represents a matrix [ w ij ] n×n The Middle i Line number j The values ​​of the column elements; Step 3.1.2: Pre-select the positive and negative output endpoints as the starting nodes for path search. startNode and end node endNode ; Step 3.1.3: Perform path search based on the adjacency matrix W, enumerating all paths from... startNode arrive endNode The paths are used to form a candidate path set. P : In the formula, m It is the total number of candidate paths. Indicates starting point = startNode To the finish line = endNode One of the candidate paths; Define valid path judgment conditions and based on Filter out candidate path set P Invalid paths are identified, resulting in a set of valid paths. P *: In the formula, Indicate candidate path The validity, if If it is 1 Effective, if If it is 0, then invalid; Step 3.1.4: Define constraints and determine whether the pre-selected positive and negative output endpoints are reasonable based on the constraints. Adjust the candidate topology directed graph to obtain a topology directed graph with reasonable positive and negative output endpoints.

6. The graph-based reconfigurable battery topology design method as described in claim 5, characterized in that, The valid path determination condition defined in step 3.1.3 is as follows: In the formula, This represents the set of unidirectional edges in a candidate topological directed graph; Representation of candidate paths The set of intersecting one-way edges, express The starting node is Termination node is The edge; Indicate candidate path The edges in Indicate candidate path point; Indicate candidate path The total number of nodes in; This represents the set of one-way edges contained in the candidate path.

7. The graph-based reconfigurable battery topology design method as described in claim 5, characterized in that, The constraints defined in step 3.1.4 include constraint 1 and constraint 2: Constraint 1: Let the number of batteries in the candidate topological directed graph be... There are candidate paths So that the number of unidirectional edges of the battery contained therein satisfies ; Constraint 2: Let the set of batteries in the candidate topological directed graph be... In the set P * In the context, for any given battery There must be a path , making .

8. The graph-based reconfigurable battery topology design method as described in claim 4, characterized in that, The mapping method in step 3.2 is as follows: unidirectional edges are mapped to batteries, bidirectional edges are mapped to switches, and nodes are mapped to the positive and negative terminals of the battery or the connection point between the battery and the switch, generating a series of reconfigurable battery topologies.

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