Can network, can network control method, and energy storage device

Abstract

A CAN network, a CAN network control method, and an energy storage device. The CAN network comprises a plurality of BMSs. A first output end and a first input end of each BMS are respectively connected to a first input end and a first output end of a previous BMS, and a second output end and a second input end of each BMS are respectively connected to a second input end and a second output end of a next BMS. The plurality of BMSs each comprise a CAN chip. A first branch formed after a terminal resistor and a switch apparatus are connected in series is connected between a CAN high line of the CAN chip and a CAN low line of the CAN chip. By means of the present CAN network, a CAN network can be formed by only closing switch apparatuses in BMSs at endpoints, and the replacement of each BMS in the CAN network is simplified.

Description

A CAN network, a CAN network control method, and an energy storage device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed with the Chinese Patent Office on July 18, 2023, with application number 202310887806.6 and application name “A CAN network, a CAN network control method, and an energy storage device,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of battery management systems, and in particular to a CAN network, a CAN network control method, and an energy storage device. Background Art

[0004] Currently, in the Battery Management System (BMS) industry, BMS is divided into two major categories: master-slave integrated or master-slave distributed. In the entire battery system, information exchange between the master and slave or master-slave integrated hardware is generally achieved through Controller Area Network (CAN) communication. Among them, CAN communication requires two 120-ohm standard terminal resistors, which need to be equipped for the BMS after the battery system is connected. This is relatively troublesome for consumer-oriented application scenarios such as home energy storage, and there are also risks of subsequent mismatching and failure. In addition, for the stability of the CAN network, a BMS equipped with terminal resistors cannot be replaced with other BMSs.

[0005] Summary of the Invention

[0006] The present invention provides a CAN network, a CAN network control method and an energy storage device to solve the technical problem that BMSs are difficult to replace each other due to the configuration of terminal resistors in the existing CAN network.

[0007] In order to solve the above technical problems, the embodiments of the present invention provide a CAN network, a CAN network control method and an energy storage device, wherein the CAN network includes: a plurality of BMSs, terminal resistors and a switch device;

[0008] The plurality of BMSs include: a plurality of middle BMSs and two end BMSs;

[0009] The first output terminal of each intermediate BMS is connected to the second input terminal of the previous BMS;

[0010] The first input terminal of each intermediate BMS is connected to the second output terminal of the previous BMS;

[0011] The second output terminal of each intermediate BMS is connected to the first input terminal of the next BMS;

[0012] The second input terminal of each intermediate BMS is connected to the first output terminal of the next BMS;

[0013] The first input terminal of a BMS at one end is connected to the second output terminal of the previous BMS, and the first output terminal of the BMS at one end is connected to the second input terminal of the previous BMS; or the second input terminal of a BMS at one end is connected to the first output terminal of the next BMS, and the second output terminal of the BMS at one end is connected to the first input terminal of the next BMS;

[0014] The plurality of BMSs are provided with CAN chips; wherein the first branch after the terminal resistor and the switch device are connected in series is connected between the CAN high line of the CAN chip and the CAN low line of the CAN chip;

[0015] The switch device is used to close after the BMS receives the wake-up signal when only the first input end or the second input end of the BMS receives a level signal, or only the first output end or the second output end sends a level signal.

[0016] On the one hand, the present invention configures each BMS with a terminal resistor. When several BMSs are connected to each other, the terminal resistors in the BMSs at the ends of the CAN network are connected to the CAN high line and CAN low line of the CAN chip under the control of a switching device, thereby forming a CAN network. In this way, replacement between BMSs can be achieved without having to replace or install the terminal resistors.

[0017] Furthermore, the CAN network further includes: a main control chip;

[0018] The first end of the switching device is connected to the first end of the terminal resistor; the second end of the switching device is one end of the first branch; the second end of the terminal resistor is the other end of the first branch; the control end of the switching device is connected to the main control chip.

[0019] Furthermore, the switch device adopts a triode, a MOS tube or a relay device.

[0020] On the other hand, an embodiment of the present invention further provides a CAN network control method, comprising:

[0021] After the plurality of BMSs receive the wake-up command, each of the plurality of BMSs sends a level signal to the BMS connected thereto through the output terminal;

[0022] The switch device of the BMS whose first input terminal or second input terminal receives the level signal is closed, or the switch device of the BMS whose first output terminal or second output terminal sends the level signal is closed.

[0023] The present invention utilizes the switch device in the BMS and the connection relationship between the BMSs, and determines whether the BMS is at the end through the sending or receiving of the level signal at the output or input end of each BMS, and automatically forms a CAN network by closing the terminal resistor in the end BMS; thereby, the replacement of one BMS with another is realized without the need to replace or install the terminal resistor.

[0024] Furthermore, after closing the switch device of the BMS that receives the level signal only at the first input terminal or the second input terminal, or closing the switch device of the BMS that sends the level signal only at the first output terminal or the second output terminal, the method further includes:

[0025] The BMS that receives the automatic numbering command in the CAN network is recorded as the master BMS;

[0026] The master BMS sends a coding request message to the slave BMS via the CAN network, so that the slave BMS performs numbering according to the received coding request message.

[0027] In the present invention, after several BMSs form a CAN network, the master BMS can send a message for automatic numbering to the slave BMSs, so that all BMSs in the CAN network complete automatic numbering, thereby simplifying the hardware numbering step and further facilitating the replacement of BMSs.

[0028] Furthermore, the BMS that receives the automatic numbering instruction in the CAN network is recorded as the master BMS, specifically:

[0029] The BMS receives the automatic numbering instruction preset by the user;

[0030] The BMS sets itself as the master BMS; wherein the master BMS uses the first preset value as its own number.

[0031] Furthermore, the master BMS sends a coding request message to the slave BMS via the CAN network, specifically:

[0032] The master BMS increases the preset byte of the encoding request message by the second preset value each time, sequentially outputs the encoding request message to each slave BMS via the CAN network, and receives the encoding completion message returned by each slave BMS via the CAN network;

[0033] Open the first output end of the master control BMS or the second output end of the master control BMS; wherein, the encoding end message is a message generated by the slave control BMS after receiving the encoding request message and setting the preset byte of the encoding request message to its own number; each of the encoding end messages contains the number of the BMS that sends the encoding end message.

[0034] The master BMS of the present invention increases the preset byte of the coding request message sent each time by a certain value, so that other BMSs that receive the coding request message set their own numbers according to the preset bytes with different values, so that each BMS in the CAN network has a unique number; and the number in the coding end message returned by the slave BMS should be equal to the preset byte of the coding request message sent by the master BMS. When the coding end message returned by each BMS is received and the preset byte of each coding end message is consistent with the number of the BMS that sent it, it indicates that the BMSs along the same direction have been numbered.

[0035] Furthermore, the slave BMS performs numbering according to the received coding request message, including:

[0036] When the slave BMS receives the encoding request message from the CAN network, the slave BMS sets the preset byte of the encoding request message to its own number, and returns the encoding completion message containing its own number to the master BMS through the CAN network;

[0037] The first output terminal of the slave-controlled BMS or the second output terminal of the slave-controlled BMS is opened.

[0038] The present invention utilizes the two output terminals and two input terminals of the BMS to receive the coding request message sent from the master BMS from either side, completes automatic numbering according to the coding request message, and transmits the next received coding request message to the next BMS or the previous BMS in the same direction, thereby realizing automatic numbering initiated from the master BMS to both sides, simplifying the numbering process of each hardware unit in the CAN network and facilitating the replacement of BMS in the CAN network.

[0039] Furthermore, after receiving the wake-up instruction, each BMS in the CAN network transmits a wake-up signal to the previous BMS and the next BMS, including:

[0040] Each of the BMSs receives a coding preparation message from the CAN network; wherein the coding preparation message is used to enable each of the BMSs to enter a waiting numbering state.

[0041] On the other hand, an embodiment of the present invention further provides an energy storage device, comprising: a battery module and the CAN network described in an embodiment of the present invention;

[0042] Wherein, each battery in the battery module is controlled by the corresponding BMS in the CAN network. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic structural diagram of an embodiment of a CAN network provided by the present invention;

[0044] FIG2 is a schematic structural diagram of an embodiment of a CAN chip provided by the present invention;

[0045] FIG3 is a flow chart of an embodiment of a CAN network control method provided by the present invention;

[0046] FIG4 is a flow chart of another embodiment of a CAN network control method provided by the present invention;

[0047] FIG5 is a flow chart of CAN network control provided by the present invention. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] Please refer to FIG1 and FIG2, which are respectively a schematic diagram of the structure of a CAN network according to an embodiment of the present invention and a schematic diagram of the structure of a CAN chip according to an embodiment of the present invention, including:

[0050] Several BMSs, terminal resistors and switching devices;

[0051] The plurality of BMSs include: a plurality of middle BMSs and two end BMSs;

[0052] The first output terminal of each intermediate BMS is connected to the second input terminal of the previous BMS;

[0053] The first input terminal of each intermediate BMS is connected to the second output terminal of the previous BMS;

[0054] The second output terminal of each intermediate BMS is connected to the first input terminal of the next BMS;

[0055] The second input terminal of each intermediate BMS is connected to the first output terminal of the next BMS;

[0056] The first input terminal of a BMS at one end is connected to the second output terminal of the previous BMS, and the first output terminal of a BMS at one end is connected to the second input terminal of the previous BMS; or the second input terminal of a BMS at one end is connected to the first output terminal of the next BMS, and the second output terminal of a BMS at one end is connected to the first input terminal of the next BMS;

[0057] A CAN chip is provided in each of the BMSs; wherein a first branch after the terminal resistor and the switch device are connected in series is connected between a CAN high line and a CAN low line of the CAN chip;

[0058] The switch device is used to close after the BMS receives the wake-up signal when only the first input end or the second input end of the BMS receives a level signal, or only the first output end or the second output end sends a level signal.

[0059] In this embodiment, the switch device is used to control whether the terminal resistor connected in series with it is connected to the CAN network. After the BMS receives the wake-up signal, the BMS transmits a level signal to each other through the digital IO hard line. When only the first input end of the BMS receives the level signal or only the second input end receives the level signal, it is closed.

[0060] In this embodiment, when the CAN network needs to be numbered, the BMS that receives the automatic numbering instruction in the CAN network is recorded as the master BMS. The master BMS is generally specified by the user, and the specified BMS receives the automatic numbering instruction. The automatic numbering instruction is used to control the BMS to perform the automatic numbering procedure. It can be issued by the control module at the same time as the wake-up signal is issued, or it can be issued by the control module after the wake-up signal is issued, or it can be issued by a pre-set button when the user long presses the button. Select any BMS in the middle part as the master BMS, and the coding request message can be sent to the slave BMS in both directions; and select the BMS at both ends as the master BMS, and the coding request message can be sent to the slave BMS on the other side through the CAN network.

[0061] In this embodiment, a terminal resistor is connected in series between the high and low lines of the CAN chip in each BMS. This terminal resistor is connected between the high and low lines of the corresponding CAN chip only under the control of a switch device. Furthermore, based on the connection relationship of the multiple BMSs in this application, a BMS at an end can only receive a level signal at the first or second input terminal, and its switch device closes to connect to the terminal resistor, thereby forming a CAN network. Therefore, using the BMSs and corresponding connection relationships of the present invention, replacing any BMS does not affect the formation and automatic numbering of the CAN network.

[0062] In this embodiment, the BMS at the end is usually used as the master BMS.

[0063] Furthermore, the connection is a hard-wired connection.

[0064] In this embodiment, each BMS implements digital signal I / O transmission via hardwire. After waking up, the BMS outputs a level signal to the hardwire via its first and / or second output terminals. Therefore, a BMS that receives this level signal only at its first or second input terminal is considered an endpoint BMS, while a BMS that receives both levels is considered an intermediate BMS. When the BMS's CAN chip recognizes only one level signal through software, it controls the switch in that BMS to close.

[0065] Furthermore, the CAN network also includes: a main control chip; wherein the first end of the switching device is connected to the first end of the terminal resistor; the second end of the switching device is one end of the first branch; the second end of the terminal resistor is the other end of the first branch; and the control end of the switching device is connected to the main control chip.

[0066] In this embodiment, the switching device includes an optocoupler switch and various transistors, such as MOS tubes, triodes, and IGBT modules. When the main control chip recognizes that only one input terminal of a BMS receives a level signal, it sends a control signal to the switching device in the BMS to turn on the switching device.

[0067] In this embodiment, the 120Ω terminal resistor can be formed by connecting two 60Ω resistors in series. The connection of the terminal resistor can quickly eliminate the high and low frequency energy signals, parasitic capacitance and reflected energy, thereby improving the anti-interference ability of the CAN network and making the CAN network quickly enter the recessive state.

[0068] Please refer to FIG3 , which is a flow chart of an embodiment of the CAN network control method provided by the present invention, mainly including steps 101-102, as follows:

[0069] Step 101: After a plurality of BMSs receive a wake-up instruction, each of the plurality of BMSs sends a level signal to a correspondingly connected BMS via an output terminal.

[0070] Step 102 : closing a switch device of the BMS whose first input terminal or second input terminal receives a level signal only, or closing a switch device of the BMS whose first output terminal or second output terminal sends a level signal only.

[0071] Please refer to FIG4 , which is a flow chart of another embodiment of the CAN network control method provided by the present invention, mainly including steps 201-202, as follows:

[0072] Step 201: The BMS receiving the automatic numbering instruction in the CAN network is recorded as the master BMS.

[0073] Step 202: the master BMS sends a coding request message to the slave BMS via the CAN network, so that the slave BMS performs numbering according to the received coding request message.

[0074] Please refer to Figure 5, which is a CAN network control flow chart provided by the present invention, which mainly includes steps S1-S3, S1 is specifically step 101, S2 is specifically step 102, S3: determine whether the automatic numbering instruction received by the master BMS is valid; if not, return to S2; if so, execute the master numbering and slave numbering steps respectively.

[0075] Furthermore, at the same time as or after step S1, the CAN network control method further includes:

[0076] The BMS that receives the automatic numbering command in the CAN network is recorded as the master BMS;

[0077] In this embodiment, when encoding is required, the CAN network issues an automatic numbering command, and the master BMS is configured to receive the automatic numbering command from the CAN network; the master BMS uses the first preset value as its own number. In this embodiment, the first preset value is described and shown as 1 as an example.

[0078] Furthermore, the BMS that receives the automatic numbering instruction in the CAN network is recorded as the master BMS, specifically:

[0079] The BMS receives an automatic numbering instruction preset by the user;

[0080] The BMS sets itself as the master BMS; wherein the master BMS uses the first preset value as its own number.

[0081] After all BMSs are awakened, the present invention connects the terminal resistors in the end BMSs to the CAN high and CAN low lines of the CAN chip under the control of a switch device, thereby forming a CAN network. This allows BMSs to be replaced without having to replace or install terminal resistors. In addition, when several BMSs form a CAN network and a master BMS is set, the master BMS can send a coding request message to the slave BMSs to automatically number all BMSs in the CAN network, thereby simplifying the hardware numbering process and further facilitating BMS replacement.

[0082] Furthermore, the master control numbering step includes steps S401-S412, specifically:

[0083] S401: Maintain the current terminal resistance state, close the IO port output of the master BMS, and send a coding preparation message to the CAN bus;

[0084] S402, determining whether the preparation time is greater than a first preset time;

[0085] S403: If not, continue to send the encoding preparation message;

[0086] S404: If yes, send a coding request message to each slave BMS;

[0087] S405: Determine whether the requested time is greater than a second preset time;

[0088] S406: If not, continue to send the encoding request message;

[0089] S407: If yes, turn on the IO port output of the master BMS, that is, turn on the first output terminal or the second output terminal;

[0090] S408, determining whether a coding completion message is received;

[0091] S409: If yes, the second preset number value is automatically incremented, and a coding request message is sent to the next slave BMS;

[0092] S410: If not, determine whether the end time is greater than a third preset time;

[0093] S411, if not, turn on the first output terminal or the second output terminal of the master BMS;

[0094] S412: If yes, store the current data and record the number of the master BMS as the preset number.

[0095] Specifically, the master BMS uses the first preset value as its own number.

[0096] In this embodiment, the first preset value can be 0 or 1; when the master BMS completes its own numbering, it sends a coding request message to the slave BMS through the CAN network. When sending automatic numbering instructions to other BMSs in turn, the second preset value can be added to the first preset value, so that different BMSs can obtain different first preset values ​​from the received automatic numbering instructions, thereby having different numbers. After the master BMS increases the preset byte of the coding request message by the second preset value each time, it outputs the coding request message to each slave BMS in turn through the CAN network, and receives the coding end message returned by each slave BMS through the CAN network; opens the first output terminal of the master BMS or the second output terminal of the master BMS; wherein, the coding end message is a message generated by the slave BMS after receiving the coding request message and setting the preset byte of the coding request message to its own number; each coding end message contains the number of the BMS that sends the coding end message.

[0097] The master BMS sends a coding request message to the slave BMS via the CAN network. The slave BMS numbering step mainly includes steps S501-S510, specifically:

[0098] S501: Determine whether the slave BMS receives a numbering preparation message and whether the first byte of the numbering preparation message is 1;

[0099] S502: If not, the master BMS continues to determine whether the received automatic numbering instruction is valid;

[0100] S503: If yes, maintain the current terminal resistance state and turn off the IO port output of the slave BMS;

[0101] S504, determining whether the detected IO signal input is valid;

[0102] If not, maintain the current terminal resistance state and turn off the IO port output of the slave BMS;

[0103] S506: If yes, use the first byte of the received encoding request message as the second preset value and store the BMS number;

[0104] S507, sending a coding completion message;

[0105] S508: Obtain a coding request message, and determine whether the first byte of the coding request message matches the value after the second preset value is incremented;

[0106] S509: If not, continue to send the encoding end message;

[0107] S510: If yes, enable the IO port output.

[0108] In this embodiment, when sending coding request messages to other BMSs in sequence, different incremental values ​​can be added on the basis of the first preset value, so that different BMSs can obtain different values ​​from the received coding request messages and thus have different numbers.

[0109] The master BMS of the present invention increases the preset byte of the encoding request message sent each time by a certain value, so that other BMSs that receive the encoding request message set their own numbers according to the preset bytes with different values, so that each BMS in the CAN network has a unique number; and the number in the encoding end message returned by the slave BMS should be equal to the preset byte of the encoding request message sent by the master BMS. When the number is less than the preset byte, it indicates that the BMSs along the same direction have completed numbering.

[0110] In this embodiment, each time the master BMS increases the preset byte of the coding request message by the second preset value, it outputs the coding request message to the next BMS through the second output end, and receives the coding end message returned by the next BMS until the number contained in the coding end message is not equal to the preset byte of the coding request message. Specifically, the master BMS sends the coding request message to the next BMS through the second output end; receives the coding end message returned from the next BMS; when the number of the coding end message is the same as the preset byte of the coding request message sent by the master BMS to the slave BMS, the second preset value is increased in the preset byte of the coding request message and the above steps are repeated; when the number of the coding end message sent by the slave BMS to the master BMS is not equal to the preset byte of the coding request message sent by the master BMS to the slave BMS, it means that the slave BMS numbering is completed.

[0111] Specifically, the slave BMS performs numbering according to the received coding request message, including:

[0112] When the slave BMS receives the encoding request message from the CAN network, it sets the preset byte of the encoding request message to its own number and returns the encoding completion message containing its own number to the master BMS through the CAN network;

[0113] The first output terminal of the slave-controlled BMS or the second output terminal of the slave-controlled BMS is turned on.

[0114] Furthermore, before the master BMS sends a coding request message to the slave BMS through the CAN network so that the slave BMS performs numbering according to the received coding request message, the method includes:

[0115] The master BMS sends a coding preparation message to all slave BMSs via the CAN network, so that all slave BMSs enter the coding state.

[0116] In this embodiment, to ensure that the message can be received normally, after the master BMS sends the encoding preparation message and after a first preset time, the master BMS sends the encoding request message again to ensure that each slave BMS can receive the encoding preparation message within the first preset time; after sending the encoding request message and after a second preset time, the master BMS opens the first output terminal or the second output terminal to ensure that the corresponding slave BMS can complete the corresponding slave numbering step and send the encoding completion message; after the master BMS receives the encoding completion message and before a third preset time, the master BMS keeps the IO port open to ensure that the master BMS can send and receive the level signal in a timely manner. The first preset time, the second preset time, and the third preset time are all greater than or equal to 3 seconds, such as 3 seconds, 5 seconds, and 7 seconds, and the preset time interval is preferably 3 seconds.

[0117] In this embodiment, the second preset value may be an integer greater than or equal to 1. According to the logic obeyed by the automatic numbering in the present invention, the numbers of the BMSs in a certain direction along the master control are sequentially increased by an integer greater than or equal to 1, thereby distinguishing each BMS.

[0118] In this embodiment, after the automatic coding is completed, the serial number data of each BMS is stored and the number of BMSs is recorded.

[0119] The present invention utilizes the two output terminals and two input terminals of the BMS to receive the coding request message sent from the master BMS from either side, completes automatic numbering according to the coding request message, and transmits the next received coding request message to the next BMS or the previous BMS in the same direction, thereby realizing automatic numbering initiated from the master BMS to both sides, simplifying the numbering process of each hardware unit in the CAN network and facilitating the replacement of BMS in the CAN network.

[0120] In this embodiment, since only the BMS at the end can receive the wake-up signal only at the first input end or the second input end, replacing the end BMS with the BMS in the present invention will not affect the access of the terminal resistor and the formation of the CAN network while keeping the BMS connection relationship unchanged.

[0121] In this embodiment, before a BMS receives the Nth encoding request message, the BMS turns off its second output end or first output end. For example, when the master BMS sends a numbering instruction to the previous BMS, it turns off its first output end to prevent the previous BMS from receiving the encoding request message through the first input end; and when the master BMS sends a numbering instruction to the next BMS, it turns off its second output end to prevent the next BMS from receiving the encoding request message through the second input end.

[0122] In this embodiment, the encoding request message is a 0x612 message, which is a message used by the master BMS to number the other BMSs. The first byte of the message can be a preset byte as the BMS number. The master BMS gradually adds a second preset value to the first byte of the 0x612 message, thereby sending a different 0x612 message to each BMS.

[0123] Furthermore, after receiving the wake-up instruction, each BMS in the CAN network transmits a wake-up signal to the previous BMS and the next BMS, including: each BMS receives a coding preparation message from the CAN network; wherein the coding preparation message is used to enable each BMS to enter a waiting numbering state.

[0124] In this embodiment, the coding preparation message is a 0x611 message, which is a reminder message for notifying each BMS that it is about to enter automatic numbering.

[0125] In this embodiment, the wake-up instruction includes: a high-level signal transmitted by an IO hard line or a low-level signal transmitted by an IO hard line.

[0126] In this embodiment, the wake-up instruction further includes: a button signal from the BMS or a button signal from the battery.

[0127] In an embodiment, the BMS is awakened by a main control chip or manually. After awakening, the end BMS can be determined according to the number of received signals, so that the end BMS is connected to the terminal resistor to form a CAN network; the subsequent automatic numbering can be carried out by the main control BMS sending different encoding request messages to different BMSs in sequence, so that different BMSs can automatically encode according to their respective encoding request messages.

[0128] On the other hand, an embodiment of the present invention further provides an energy storage device, comprising: a battery module and a CAN network as described in an embodiment of the present invention;

[0129] Each battery in the battery module is controlled by the corresponding BMS in the CAN network.

[0130] The present invention configures each BMS with a terminal resistor. When several BMSs are connected to each other, the terminal resistors in the BMSs at the ends of the CAN network are connected to the CAN high line and CAN low line of the CAN chip under the control of a switch device, thereby forming a CAN network. In this way, replacement between BMSs can be achieved without having to replace or install the terminal resistors.

[0131] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A CAN network, characterized in that: include: Several BMS, terminal resistors and switch devices; Wherein, the several BMSs include: several middle BMSs and two end BMSs; The first output terminal of each intermediate BMS is connected to the second input terminal of the previous BMS; The first input terminal of each intermediate BMS is connected to the second output terminal of the previous BMS; The second output terminal of each intermediate BMS is connected to the first input terminal of the next BMS; The second input terminal of each intermediate BMS is connected to the first output terminal of the next BMS; The first input terminal of a certain end BMS is connected to the second output terminal of the previous BMS, and the first output terminal of the certain end BMS is connected to the second input terminal of the previous BMS; or the second input terminal of a certain end BMS is connected to the first output terminal of the next BMS, and the second output terminal of the certain end BMS is connected to the first input terminal of the next BMS; A CAN chip is provided in the plurality of BMSs; wherein the first branch after the terminal resistor and the switch device are connected in series is connected between the CAN high line of the CAN chip and the CAN low line of the CAN chip; The switch device is used to close after the BMS receives the wake-up signal when only the first input end or the second input end of the BMS receives a level signal, or only the first output end or the second output end sends a level signal.

2. The CAN network according to claim 1, characterized in that Also includes: Main control chip; The first end of the switch device is connected to the first end of the terminal resistor; the second end of the switch device is one end of the first branch; the second end of the terminal resistor is the other end of the first branch; the control end of the switch device is connected to the main control chip.

3. The CAN network according to claim 2, characterized in that: The switch device adopts a triode, a MOS tube or a relay device.

4. A CAN network control method, characterized in that: include: After the plurality of BMSs receive the wake-up instruction, each of the plurality of BMSs sends a level signal to the BMSs connected to it through an output terminal; Closing the switch device of the BMS that receives the level signal at only the first input terminal or the second input terminal, or, The switch device of the BMS that sends the level signal only at the first output terminal or the second output terminal is closed.

5. The CAN network control method according to claim 4, characterized in that: After closing the switch device of the BMS that receives the level signal only at the first input terminal or the second input terminal, or closing the switch device of the BMS that sends the level signal only at the first output terminal or the second output terminal, the method comprises: The BMS that receives the automatic numbering command in the CAN network is recorded as the master BMS; The master BMS sends a coding request message to the slave BMS via the CAN network, so that the slave BMS performs numbering according to the received coding request message.

6. The CAN network control method according to claim 5, characterized in that: The BMS that receives the automatic numbering command in the CAN network is recorded as the main control BMS, specifically: The BMS receives the automatic numbering instruction preset by the user; The BMS sets itself as the master BMS; wherein the master BMS uses the first preset value as its own number.

7. The CAN network control method according to claim 5, characterized in that: The master BMS sends a coding request message to the slave BMS via the CAN network, specifically: After the master control BMS increases the preset byte of the encoding request message by the second preset value each time, it sequentially outputs the encoding request message to each slave control BMS through the CAN network, and receives the encoding end message returned by each slave control BMS through the CAN network; Open the first output end of the master control BMS or the second output end of the master control BMS; wherein the encoding end message is a message generated by the slave control BMS after receiving the encoding request message and setting the preset byte of the encoding request message to its own number; each of the encoding end messages contains the number of the BMS that sends the encoding end message.

8. The CAN network control method according to claim 7, characterized in that: The slave BMS performs numbering according to the received coding request message, including: When the slave BMS receives the encoding request message from the CAN network, the slave BMS sets the preset byte of the encoding request message to its own number, and returns an encoding completion message including its own number to the master BMS through the CAN network; The first output terminal of the slave-controlled BMS or the second output terminal of the slave-controlled BMS is opened.

9. The CAN network control method according to any one of claims 5 to 8, characterized in that: Before the master BMS sends a coding request message to the slave BMS through the CAN network so that the slave BMS performs numbering according to the received coding request message, the method includes: The master BMS sends a coding preparation message to all slave BMSs via the CAN network, so that all slave BMSs enter the coding state.

10. An energy storage device, characterized in that: include: A battery module and a CAN network as claimed in any one of claims 1 to 3; Wherein, each battery in the battery module is controlled by the corresponding BMS in the CAN network.

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