Battery management system based on wireless network

Abstract

The invention discloses a battery management system based on a wireless network, which comprises a main control device, a plurality of wireless access points (AP) and a plurality of clusters of battery nodes, and each cluster of battery nodes comprises a plurality of battery nodes (BP); a main control device and a plurality of wireless access points (AP) are connected through a bus to form a first-layer bus-type network, and each wireless access point (AP) and a cluster of battery nodes (BP) bound with the wireless access point (AP) are wirelessly connected to form a second-layer star-shaped network; one wireless access point AP and one cluster of battery nodes BP bound with the wireless access point AP form a cluster, and the nodes in the same cluster work at the same group of frequency points and share one broadcast channel to perform wireless communication in the cluster; the invention provides a wireless battery management system scheme which is simple and reasonable, can realize rapid networking, and has high reliability and high service timeliness.

Description

Technical Field

[0001] The present invention relates to the fields of wireless communication and new energy battery management, and more specifically, to a battery management system based on a wireless network. Background Art

[0002] The battery management system is a system that monitors, controls and protects batteries. It is used to manage the charging and discharging process of the battery to extend the battery life and provide safety performance. The traditional battery management system uses a sensor harness to connect a group of batteries and collect battery status information through the harness. In large-scale battery packs, the installation of a large number of complex sensor harnesses causes a lot of labor costs; the sensor harnesses and connectors themselves have reliability risks such as aging, short circuits, and looseness; and the harness connection scheme also makes the scalability and maintainability of the battery pack worse.

[0003] Each battery is equipped with an intelligent wireless sensor module as a wireless battery node, and a large number of wireless battery nodes are organized into a network to form a battery management system based on a wireless network. The battery management system based on a wireless network replaces the traditional wiring harness solution, which can significantly reduce the complexity of the design, production and maintenance process, reduce system costs, and improve system reliability and scalability. Summary of the invention

[0004] The working environment of the battery nodes of the battery management system is closed and dense, and the wireless channels are complex and diverse. At the same time, the battery management system has very high requirements for the timeliness and reliability of sensing battery information. Therefore, the networking of wireless battery nodes in the battery management system is relatively difficult and requires targeted design and development.

[0005] In view of the shortcomings of the existing battery management system based on the sensor harness, the present invention provides a simple and reasonable wireless battery management system solution that can realize rapid networking and has high reliability and high service timeliness.

[0006] The technical solution of the present invention is as follows: A battery management system based on a wireless network comprises a main control device, several wireless access points AP and several cluster battery nodes, each cluster battery node contains multiple battery nodes BP; a main control device and several wireless access points AP are connected via a bus to form a first-layer bus network, each wireless access point AP and a cluster battery node BP bound thereto form a second-layer star network via a wireless connection; a wireless access point AP and a cluster battery node BP bound thereto form a cluster, the nodes in the same cluster work at the same frequency group, share a broadcast channel, and perform wireless communication within the cluster.

[0007] Furthermore, the specific network binding method includes the following steps: 1.1) Pre-processing step: During the battery assembly phase, a unique identity ID is burned into each battery node BP; after the battery assembly is completed, the operator uses a dedicated device to connect to the wireless access point AP and informs the information of all battery nodes BP in the cluster; 1.2) Frequency binding step: After the assembly is completed, the battery works at N default frequencies. The wireless access point AP selects one of the default frequencies as the binding frequency and continuously broadcasts the binding beacon information at the frequency. At this time, the battery node BP continuously switches and listens between the N default frequency points until it hears the TOD frame in the binding beacon information, and then confirms that the current frequency point is the binding frequency point; 1.3) Battery node BP binding steps: After the wireless access point AP broadcasts the binding beacon information for a period of time, it will send the binding frame sequence of the corresponding battery node BP in sequence. Each binding frame is used to bind a battery node BP. After the battery node BP hears its own binding frame at the binding frequency, it returns the binding feedback frame to complete the binding. 1.4) Binding step: The wireless access point AP decides whether to complete the binding based on the reception of the binding feedback frame in step 1.3); if the binding is not completed, another default frequency is selected as the binding frequency, and returns to step 1.2) to make another binding judgment until the binding of all battery nodes BP is completed.

[0008] Furthermore, the binding beacon information and the binding frame both include a PN frame for assisting synchronization and a TOD frame for providing control information; the TOD frame includes a frame type, an AP identity ID, a synchronization time slot, and a designated time slot information; The frame type is a field that distinguishes different frame types; AP ID is the unique physical address of the wireless access point AP; The synchronization time slot is the time slot number for the wireless access point AP to send frames; The designated time slot is a designated time slot for the battery node BP to reply the binding feedback frame.

[0009] Further, the binding feedback frame includes a frame type, an AP identity ID, a battery node BP number, a battery node BP identity ID, and a binding success flag; The frame type is a field that distinguishes different frame types; AP ID is the unique physical address of the wireless access point AP; The battery node BP number is the unique number in the cluster assigned by the AP to the BP, which is the time slot number of the instant access guaranteed time slot; The battery node BP identity ID is the unique identity physical address of the battery node BP; The successful binding mark is used to record the successful binding information.

[0010] Furthermore, the master device networks the wireless access point AP in the following specific steps: 2.1) Frequency point set step: The master device or a wireless access point AP detects the current available frequency points to form an available frequency point set; 2.2) Allocation step: The master device counts the number of online wireless access points AP, and allocates a frequency to each online wireless access point AP according to the available frequency set and the number of online wireless access points AP; if the number of wireless access points AP is greater than the number of available frequencies, 2 or 3 wireless access points AP are required to form a reuse group, and the reuse group uses the same frequency. After the reuse group is determined, the idle frequency is allocated to the reuse group first; 2.3) Cluster networking steps: The master device traverses the online wireless access points AP and networks the clusters where each wireless access point AP is located in turn; if a wireless access point AP fails to network, it is allowed to retry once immediately. If the network still fails after the retry, the wireless access point AP is skipped and added to the networking failure list; 2.4) Networking judgment steps: After the master device traverses the online wireless access point AP, it traverses the networking failure list, and retries the networking for each wireless access point AP that failed to network; if there are still wireless access points AP that cannot be networked, repeat step 2.1) to re-network; in step 2.2), frequency points are allocated to failed wireless access points AP first; if there are still wireless access points AP that cannot be networked after the second networking, exit the networking and report the error information.

[0011] Furthermore, in step 2.2), when the available frequency set and the number of online wireless access points AP allocate frequencies to each online wireless access point AP, the allocated frequencies include one main frequency and three backup frequencies.

[0012] Furthermore, the networking process of the battery node BP during networking is as follows: 3.1) Listening step: When the battery node BP is networked for the first time after binding, it will traverse all default frequencies in turn and listen to the networking beacon; the listening time of each frequency is not less than 2 times the networking beacon time length, until the battery node BP hears the networking beacon broadcast by the bound wireless access point AP; 3.2) Time slot synchronization step: According to the time slot information carried in the TOD frame of the networking beacon, the time slot synchronization between the battery node BP and the wireless access point AP is completed; 3.3) Networking feedback step: add the TOD end time carried in the networking beacon TOD frame and the time slot number of the time-division access guarantee time slot obtained in the battery node BP binding process to obtain a networking feedback frame return time; when the slot count value increases to the return time, the battery node BP sends a networking feedback frame to the wireless access point AP; 3.4) Judgment step: After the networking feedback frame is sent, the battery node BP starts to listen to the networking result feedback NE frame returned by the wireless access point AP; if the NE frame indicates that the networking is successful, the battery node BP networking is completed; if the NE frame indicates that the networking fails or the NE frame is not received due to timeout, it returns to 3.1) listening step.

[0013] Furthermore, if the wireless access point AP and the battery node BP have successfully completed a networking, the networking configuration information is stored in the non-volatile memory of the system; when the system is restarted, the configuration information is directly read from the non-volatile memory and the networking is completed according to the configuration information.

[0014] The advantages of the present invention are: The wireless battery management system network of the present invention is a star-bus hybrid topology network, which has the advantages of being simple and easy to maintain, strong in scalability, and having a wide coverage range. Because it adopts a mixture of the two simplest topological structures, the star topology and the bus topology, the technology is mature and easy to maintain. The bus topology has the advantage of good scalability. If a new subnet needs to be added, it is only necessary to connect the new wireless access point AP to the bus; if a new battery needs to be added, it is only necessary to place the new battery node BP within the communication range of the wireless access point AP. Since the wireless access point AP and the application center are connected by wire, the network can cover a wider range by reasonably arranging the position of the wireless access point AP. The networking method of the present invention adopts a schedulable networking method, which has the advantages of being simple and easy to implement, fast networking, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the network topology of a wireless battery management system according to an embodiment of the present application; Figure 2 This is a flow chart of the binding process of an embodiment of the present application; Figure 3 This is a schematic diagram of the binding beacon frame structure of an embodiment of the present application; Figure 4 A schematic diagram of sending and listening to binding beacons and binding frames according to an embodiment of the present application; Figure 5 This is a schematic diagram of the binding frame structure of an embodiment of the present application; Figure 6 This is a schematic diagram of the binding feedback frame structure of an embodiment of the present application; Figure 7 This is a flow chart of the application center networking of an embodiment of the present application; Figure 8 This is a wireless access point AP networking flow chart of an embodiment of the present application; Fig. 9 This is a flow chart of the battery node BP networking of an embodiment of the present application; Fig.10Schematic diagram of the networking process between a wireless access point AP and a battery node BP according to an embodiment of the present application. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Any design description not clearly specified in the present solution is implemented using conventional designs.

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on the above drawings without creative work.

[0018] Specific as Figures 1 to 10 As shown, a battery management system based on a wireless network includes a main control device, several wireless access points AP and several clusters of battery nodes BP, each cluster of battery nodes BP contains multiple battery nodes BP; a main control device and several wireless access points AP are connected through a bus to form a first-layer bus network, and each wireless access point AP and a corresponding cluster of battery nodes BP bound thereto form a second-layer star network through a wireless connection; that is, several clusters of battery nodes BP and several wireless access points AP generally have corresponding numbers, and one wireless access point AP accesses a corresponding cluster of battery nodes BP.

[0019] A wireless access point AP and all the battery nodes BP bound to it form a cluster. Nodes in the same cluster work at the same frequency, share a broadcast channel, and conduct wireless communication within the cluster; nodes in different clusters work at different frequencies, use different channels, and do not conduct wireless communication. That is, the cluster head nodes (i.e., several wireless access points AP) of each cluster are connected to the same bus network, and wired communication is carried out between cluster heads (i.e., wireless access points AP).

[0020] The network architecture of this solution has the following advantages when used in wireless battery management systems: (1) Simple and easy to maintain: It adopts a hybrid of the two simplest topologies, star topology and bus topology, with mature technology and easy maintenance.

[0021] (2) Strong scalability: The bus topology has the advantage of good scalability. If you need to add a new subnet, you only need to connect the new wireless access point AP to the bus. If you need to add a new battery, you only need to place the new battery node BP within the communication range of the wireless access point AP.

[0022] (3) Wide coverage: Since wireless access points (APs) and application centers are connected via wired connections, the network can cover a wider area by properly distributing the locations of wireless access points (APs).

[0023] The specific network binding method is as follows: 1.1) Pre-processing step: During the battery assembly phase, a unique identity ID is burned into each battery node BP; after the battery assembly is completed, the operator uses a dedicated device to connect to the wireless access point AP and inform the wireless access point AP of the information of all battery nodes BP in its cluster; 1.2) Frequency binding step: After assembly, the battery works at N default frequencies. The number of N frequencies is greater than or equal to the number of wireless access points (APs). In practice, it is usually sufficient to set three default frequencies. The wireless access point (AP) selects one of the default frequencies as the binding frequency and continuously broadcasts the binding beacon at the frequency. At this time, the battery node BP continuously switches and listens between the N default frequency points until it hears the TOD frame in the binding beacon, and then confirms that the current frequency point is the binding frequency point; 1.3) Battery node BP binding steps: After the wireless access point AP sends a broadcast binding beacon for a period of time, it will send the binding frames of the corresponding battery node BP in sequence. Each binding frame is used to bind a battery node BP. After the battery node BP hears its own binding frame at the binding frequency, it returns a binding feedback frame to complete the binding. That is, according to the actual situation, the process of broadcasting the binding beacon and the binding frame can be repeated multiple times, which can reserve enough to ensure that the battery node BP completes the binding.

[0024] 1.4) Binding step: The wireless access point AP decides whether to complete the binding based on the reception of the binding feedback frame in step 1.3). If the binding is not completed, another default frequency point is selected as the binding frequency point, and the process returns to step 1.2) to make another binding decision. The process continues until the binding is completed or the number of cycles is reached and an error is reported.

[0025] Among them, the binding beacon and the binding frame both include a PN frame for auxiliary synchronization and a TOD frame for providing control information; the TOD frame includes a frame type, an AP identity ID, a synchronization time slot, and a designated time slot information; The frame type is a field that distinguishes different frame types; AP ID is the unique physical address of the wireless access point AP; The synchronization time slot is the time slot number when the wireless access point AP sends this frame; The designated time slot is the battery node. If BP receives this frame, it should reply with a binding feedback frame in the designated time slot.

[0026] The binding feedback frame includes the frame type, AP identity ID, battery node BP number, battery node BP identity ID and binding success flag; The frame type is a field that distinguishes different frame types; AP ID is the unique physical address of the wireless access point AP; The battery node BP number is the unique number in the cluster assigned by the AP to the BP, which is the time slot number of the instant access guaranteed time slot; The battery node BP identity ID is the unique identity physical address of the battery node BP; The successful binding mark is used to record the successful binding information.

[0027] After binding, networking is performed. In the networking method, the master device networks the wireless access point AP. The specific steps are as follows: 2.1) Frequency point set step: The master device or a wireless access point AP detects the current available frequency points to form an available frequency point set; 2.2) Allocation step: The master device counts the number of online wireless access points AP, and allocates a frequency to each online wireless access point AP according to the available frequency set and the number of online wireless access points AP (the allocated frequency may include one main frequency and three backup frequencies); if the number of wireless access points AP is greater than the number of available frequencies, 2 or 3 wireless access points AP are required to form a reuse group, and the reuse group uses the same frequency. After the reuse group is determined, the idle frequency is allocated to the reuse group first; 2.3) Cluster networking steps: The master device traverses the online wireless access points AP and networks the clusters where each wireless access point AP is located in turn; if a wireless access point AP fails to network, it is allowed to retry once immediately. If the network still fails after the retry, the wireless access point AP is skipped and added to the networking failure list; 2.4) Networking judgment steps: After the master device traverses the online wireless access point AP, it traverses the networking failure list, and retries the networking for each wireless access point AP that failed to network; if there are still wireless access points AP that cannot be networked, repeat step 2.1) to re-network; in step 2.2), frequency points are allocated to failed wireless access points AP first; if there are still wireless access points AP that cannot be networked after the second networking, exit the networking and report the error information.

[0028] After receiving the networking request from the master device, the wireless access point AP listens on the frequency specified in the request to determine whether the frequency is valid; if the frequency is invalid, the networking fails; if the frequency is valid, the wireless access point AP continues to broadcast the networking beacon at the frequency for a period of time; After a period of time, the wireless access point AP will switch to the listening mode to listen to the networking feedback confirmation returned by the battery node BP; if the networking feedback frame returned by all battery nodes BP in the cluster is heard, it means that the networking is successful, and the wireless access point AP will broadcast a networking initialization identification broadcast frame, namely the NE frame, as the networking result feedback; if the networking feedback confirmation returned by all battery nodes BP is not received, the networking fails. The specific steps are as follows: Step 1: After receiving the networking request from the master device, the wireless access point AP listens on the frequency specified in the request to determine whether the frequency is valid. If the frequency is invalid, the networking fails.

[0029] Step 2: If the frequency is valid, the wireless access point AP broadcasts the networking beacon at the frequency for a period of time. A networking beacon contains a PN frame and a TOD frame.

[0030] Step 3: The wireless access point AP switches to the listening mode and listens for the networking feedback confirmation returned by the battery node BP. If the networking feedback confirmation returned by all battery nodes BP in the cluster is heard, it means that the networking is successful, and the wireless access point AP needs to broadcast another NE frame as the networking result feedback. If the networking feedback confirmation returned by all battery nodes BP is not received, the networking fails.

[0031] The networking process of the battery node BP is as follows: 3.1) Listening step: When the battery node BP is networked for the first time after binding, it will traverse all frequency points in turn and listen to the networking beacon; the listening time of each frequency point shall not be less than 2 times the networking beacon time length until the battery node BP hears the networking beacon broadcast by the bound wireless access point AP; 3.2) Time slot synchronization step: According to the time slot information carried in the TOD frame of the networking beacon, the time slot synchronization between the battery node BP and the wireless access point AP is completed; the specific method of time slot synchronization is as follows: the TOD frame carries the time slot count value when the wireless access point AP sends the TOD frame. There is an end-to-end delay composed of propagation delay and transmission delay between the wireless access point AP and the battery node BP. The time slot count value in the TOD frame and the end-to-end delay are added to obtain a new local time slot count value, and the local time slot counter of the battery node BP is updated with this value; the time slot count value increases by 1 in each time slot.

[0032] 3.3) Networking feedback step: add the TOD end time carried in the networking beacon TOD frame and the time slot number of the time-division access guarantee time slot obtained in the battery node BP binding process to obtain a networking feedback frame return time; when the time slot counter increases to the return time, the battery node BP sends a networking feedback frame to the wireless access point AP; 3.4) Judgment step: After the networking feedback frame is sent, the battery node BP starts to listen to the networking result feedback NE frame returned by the wireless access point AP; if the NE frame indicates that the networking is successful, the battery node BP networking is completed; if the NE frame indicates that the networking fails or the NE frame is not received due to timeout, it returns to 3.1) listening step.

[0033] As a preference, if the wireless access point AP and the battery node BP have successfully completed a networking, the networking configuration information is stored in the non-volatile memory of the system; when the system is restarted, the configuration information is directly read from the non-volatile memory, and the networking is completed according to the configuration information. The frame exchange of the networking process between the wireless access point AP and the battery node BP can be as follows: Fig.10 shown.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the concept of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A battery management system based on a wireless network, characterized in that: It includes a main control device, several wireless access points AP and several cluster battery nodes, each cluster battery node contains multiple battery nodes BP; a main control device and several wireless access points AP are connected through a bus to form a first-layer bus network, and each wireless access point AP and a cluster battery node BP bound to it form a second-layer star network through wireless connection; a wireless access point AP and a cluster battery node BP bound to it form a cluster, and the nodes in the same cluster work at the same set of frequencies, share a broadcast channel, and conduct wireless communication within the cluster.

2. A wireless network-based battery management system according to claim 1, characterized in that: The specific network binding method includes the following steps: 1.1) Pre-processing step: During the battery assembly phase, a unique identity ID is burned into each battery node BP; after the battery assembly is completed, the operator uses a dedicated device to connect to the wireless access point AP and informs the information of all battery nodes BP in the cluster; 1.2) Frequency binding step: After the assembly is completed, the battery works at N default frequencies. The wireless access point AP selects one of the default frequencies as the binding frequency and continuously broadcasts the binding beacon information at the frequency. At this time, the battery node BP continuously switches and listens between the N default frequency points until it hears the TOD frame in the binding beacon information, and then confirms that the current frequency point is the binding frequency point; 1.3) Battery node BP binding steps: After the wireless access point AP broadcasts the binding beacon information for a period of time, it will send the binding frame sequence of the corresponding battery node BP in sequence. Each binding frame is used to bind a battery node BP. After the battery node BP hears its own binding frame at the binding frequency, it returns the binding feedback frame to complete the binding. 1.4) Binding step: The wireless access point AP decides whether to complete the binding based on the reception of the binding feedback frame in step 1.3); if the binding is not completed, another default frequency is selected as the binding frequency, and returns to step 1.2) to make another binding judgment until the binding of all battery nodes BP is completed.

3. A wireless network-based battery management system according to claim 2, characterized in that: Both the binding beacon information and the binding frame include a PN frame for auxiliary synchronization and a TOD frame for providing control information; the TOD frame includes the frame type, AP identity ID, synchronization time slot and designated time slot information; The frame type is a field that distinguishes different frame types; AP ID is the unique physical address of the wireless access point AP; The synchronization time slot is the time slot number for the wireless access point AP to send frames; The designated time slot is a designated time slot for the battery node BP to reply the binding feedback frame.

4. A wireless network-based battery management system according to claim 3, characterized in that: The binding feedback frame includes the frame type, AP identity ID, battery node BP number, battery node BP identity ID and binding success flag; The frame type is a field that distinguishes different frame types; AP ID is the unique physical address of the wireless access point AP; The battery node BP number is the unique number in the cluster assigned by the AP to the BP, which is the time slot number of the instant access guaranteed time slot; The battery node BP identity ID is the unique identity physical address of the battery node BP; The successful binding mark is used to record the successful binding information.

5. The wireless network-based battery management system according to claim 1, characterized in that: The specific steps for the master device to network the wireless access point AP are as follows: 2.1) Frequency point set step: The master device or a wireless access point AP detects the current available frequency points to form an available frequency point set; 2.2) Allocation step: The master device counts the number of online wireless access points AP, and allocates a frequency point to each online wireless access point AP according to the available frequency point set and the number of online wireless access points AP; If the number of wireless access points APs is greater than the number of available frequencies, 2 or 3 wireless access points APs are required to form a reuse group. The reuse group uses the same frequency. After the reuse group is determined, idle frequencies are allocated to the reuse group first. 2.3) Cluster networking steps: The master device traverses the online wireless access points AP and networks the clusters where each wireless access point AP is located in turn; If a wireless access point AP fails to network, it is allowed to retry once immediately. If the network still fails after the retry, the wireless access point AP will be skipped and added to the networking failure list; 2.4) Network determination steps: After the master device traverses the online wireless access points AP, it traverses the list of failed networking, and retries the networking for each wireless access point AP that failed to network; If there are still wireless access points AP that cannot be networked, repeat step 2.1) to re-network; in step 2.2), give priority to allocating frequencies to the failed wireless access points AP; if there are still wireless access points AP that cannot be networked after the second networking, exit the networking and report an error message.

6. A wireless network-based battery management system according to claim 5, characterized in that: In step 2.2), when the available frequency set and the number of online wireless access points AP allocate frequencies to each online wireless access point AP, the allocated frequencies include one main frequency and three backup frequencies.

7. A wireless network-based battery management system according to claim 1, characterized in that: The networking process of the battery node BP is as follows: 3.1) Listening step: When the battery node BP is networked for the first time after binding, it will traverse all default frequencies in turn and listen to the networking beacon; the listening time of each frequency is not less than 2 times the networking beacon time length, until the battery node BP hears the networking beacon broadcast by the bound wireless access point AP; 3.2) Time slot synchronization step: According to the time slot information carried in the TOD frame of the networking beacon, the time slot synchronization between the battery node BP and the wireless access point AP is completed; 3.3) Networking feedback step: add the TOD end time carried in the networking beacon TOD frame and the time slot number of the time-division access guarantee time slot obtained during the battery node BP binding process to obtain a networking feedback frame return time; When the slot count value increases to the return time, the battery node BP sends a networking feedback frame to the wireless access point AP; 3.4) Judgment step: After the networking feedback frame is sent, the battery node BP starts to listen to the networking result feedback NE frame returned by the wireless access point AP; if the NE frame indicates that the networking is successful, the battery node BP networking is completed; if the NE frame indicates that the networking fails or the NE frame is not received due to timeout, it returns to 3.1) listening step.

8. A wireless network-based battery management system according to claim 7, characterized in that: If the wireless access point AP and the battery node BP have successfully completed a networking, the networking configuration information is stored in the non-volatile memory of the system; When the computer is restarted, the configuration information is directly read from the non-volatile memory and the networking is completed according to the configuration information.

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