Mixing household energy storage system

Abstract

The invention discloses a mix-match household energy storage system, which uses a sodium battery pack to expand the capacity of an original lithium battery energy storage system, does not change the communication architecture of the original system, and is easy to operate. The mixed household energy storage system comprises a lithium battery system, a sodium battery system, a battery stack master control module and an inverter. The lithium battery system comprises m lithium battery packs connected in parallel; the lithium battery pack comprises a lithium battery module and a lithium battery management module; parallel operation communication among the lithium battery packs is realized through the first CAN bus, and the battery information of the lithium battery packs is periodically and actively reported through the lithium battery management module; the sodium battery system comprises n sodium battery packs which are connected in parallel; the sodium battery pack comprises a sodium battery module, a sodium battery management module and a DC / DC conversion module; each sodium battery pack is merged into the first CAN bus; the battery stack master control module communicates with the lithium battery pack through a first CAN bus and is used for receiving battery information; and the inverter communicates with the battery stack master control module through a second CAN bus and is used for receiving battery information.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a hybrid household energy storage system. Background Art

[0002] As the technology level in the field of energy storage continues to advance, batteries composed of cells made of emerging materials have the advantages of low cost, high safety, and environmental protection. Incorporating them into existing energy storage systems can expand the capacity of the energy storage systems and achieve the goal of reducing costs and increasing efficiency.

[0003] However, the discharge characteristics of different battery materials are not the same, resulting in batteries composed of different battery materials not being able to show consistent discharge characteristics when discharged in parallel, and poor system stability. For example, when a battery module of lithium batteries and a battery module of sodium batteries are discharged in parallel, at the end of the discharge, due to the larger discharge current of the lithium battery, the lithium battery may end the discharge before the sodium battery. The inconsistency of the discharge end time of the two batteries will result in insufficient discharge power at the end of the system discharge, which will cause the system to power off prematurely and poor stability.

[0004] The existing technology is difficult to deal with the instability problem of the energy storage system after mixing lithium-sodium batteries. There are still certain defects in using sodium battery packs to expand the original lithium battery energy storage system, especially the problem of how to manage and use the two after mixing. Summary of the invention

[0005] The purpose of the present invention is to provide a hybrid household energy storage system to solve the problems existing in the prior art and to expand the capacity of the original lithium battery energy storage system by using a sodium battery pack without changing the communication architecture of the original system. The system is easy to operate and has strong adaptability.

[0006] In order to achieve the above object, the solution of the present invention is: A hybrid household energy storage system, comprising a lithium battery system, a sodium battery system, a battery stack master control module and an inverter; the lithium battery system comprises m parallel-connected lithium battery packs, where m is an integer greater than or equal to 2; the lithium battery pack comprises a lithium battery module and a lithium battery management module, the lithium battery management module having data acquisition and calculation functions, battery charging and discharging and balancing functions and external communication functions; the lithium battery packs communicate in parallel via a first CAN bus, and the corresponding lithium battery management module periodically and actively reports battery information of the lithium battery pack to the battery stack master control module; the sodium battery system comprises n parallel-connected sodium battery packs, where n is an integer greater than or equal to 2; the sodium battery The pack includes a sodium battery module, a sodium battery management module and a DC / DC conversion module, wherein the sodium battery management module has data acquisition and calculation functions and battery fault diagnosis functions; each sodium battery pack is incorporated into the first CAN bus; the DC / DC conversion module realizes the bidirectional change function of the sodium battery pack; the battery stack master control module communicates with the lithium battery pack through the first CAN bus, and is used to receive, summarize and store battery information reported by the lithium battery pack; the inverter communicates with the battery stack master control module through the second CAN bus, and is used to receive battery information reported by the battery stack master control module; the inverter is electrically connected to the lithium battery pack and the sodium battery pack.

[0007] The value range of the number m of lithium battery packs in the lithium battery system is 2≤m≤32; the value range of the number n of sodium battery packs in the sodium battery system is 2≤n≤32.

[0008] The addresses of the lithium battery packs in the lithium battery system are respectively determined by their DIP switches.

[0009] The data collection function of the lithium battery management module includes data collection of battery cell voltage, battery cell temperature, battery pack total pressure and battery current, and its data calculation function includes SOC calculation and SOH estimation.

[0010] The baud rate of the CAN bus between the lithium battery packs of the lithium battery system is 500k.

[0011] The battery information periodically reported by the lithium battery management module includes a charging cut-off voltage, a discharging cut-off voltage, a maximum allowable charging current, and a maximum allowable discharging current.

[0012] The data calculation function of the sodium battery management module includes SOC calculation.

[0013] After adopting the above technical solution, the present invention has the following technical effects: (1) It is composed of a separate sodium battery pack and a lithium battery pack connected in parallel. The system strategy can adaptively adapt to the charging and discharging characteristics, temperature and other characteristics of the sodium battery or lithium battery. Even if the system is powered off in advance for various reasons, it can still continue to operate; (2) When the present invention uses sodium batteries to expand the capacity of the original energy storage system, it is only necessary to incorporate the sodium battery pack into the first CAN bus used for internal communication in the original system, without changing the communication architecture of the original system. It is easy to operate and has strong adaptability. (3) Since the sodium battery pack is charged and discharged based on a bidirectional DC / DC conversion module, the present invention has the following advantages after using sodium batteries to expand the capacity of the original energy storage system: ① No pre-charging is required; ② The capacity of the sodium battery does not need to be consistent with that of the lithium battery; ③ The sodium battery system itself will not have a circulation problem; ④ The sodium battery system can perform the SOC balancing function between battery packs according to its own SOC; ⑤ The sodium battery system can perform battery current balancing control; ⑥ Sodium batteries can be mixed with lithium batteries to achieve new and old use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A system connection diagram of a specific embodiment of the present invention; Figure 2 A schematic diagram of the working logic of a battery stack master control module according to a specific embodiment of the present invention; Description of Figure Numbers: 1-lithium battery system; 11-lithium battery pack; 2-Sodium battery system; 21-Sodium battery pack; 3-Battery stack master control module; 4-Inverter; 5- First CAN bus; 6- Second CAN bus. DETAILED DESCRIPTION

[0015] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0016] refer to Figure 1 As shown, the present invention discloses a hybrid household energy storage system, including a lithium battery system 1, a sodium battery system 2, a battery stack master control module 3 and an inverter 4; The lithium battery system 1 includes m lithium battery packs 11 connected in parallel, where m is an integer greater than or equal to 2; the lithium battery pack 11 includes a lithium battery module and a lithium battery management module, and the lithium battery management module has data acquisition and calculation functions, battery charging, discharging and balancing functions, and external communication functions; the lithium battery packs 11 communicate with each other in parallel through a first CAN (Controller Area Network) bus 5, and periodically and actively report battery information of the lithium battery packs 11 to the battery stack master control module 3 through the corresponding lithium battery management module; The sodium battery system 2 includes n sodium battery packs 21 connected in parallel, where n is an integer greater than or equal to 2; the sodium battery pack 21 includes a sodium battery module, a sodium battery management module and a DC / DC conversion module, and the sodium battery management module has a data acquisition and calculation function and a battery fault diagnosis function; each sodium battery pack 21 is incorporated into the first CAN bus 5 to keep the original communication architecture unchanged; the DC / DC conversion module realizes the bidirectional change function of the sodium battery pack 21, that is, realizes the 48V to 48V function of the bidirectional battery pack; The battery stack master control module 3 communicates with the lithium battery pack 11 via the first CAN bus 5, and is used to receive, summarize and store battery information reported by the lithium battery pack 11; The inverter 4 communicates with the battery stack master control module 3 via the second CAN bus 6 for receiving battery information reported by the battery stack master control module 3 ; the inverter 4 is electrically connected to the lithium battery pack 11 and the sodium battery pack 21 .

[0017] Through the above scheme, the present invention is composed of a separate sodium battery pack 21 connected in parallel with a lithium battery pack 11, and the system strategy can adaptively adapt to the charging and discharging characteristics, temperature and other characteristics of the sodium battery or lithium battery, so that the system can continue to operate even if it is powered off in advance for various reasons; when the present invention uses sodium batteries to expand the original energy storage system, it only needs to incorporate the sodium battery pack 21 on the first CAN bus 5 used for internal communication in the original system, and will not change the communication architecture of the original system, which is easy to operate and has strong adaptability; because the sodium battery pack 21 is charged and discharged based on a bidirectional DC / DC conversion module, the present invention has the following advantages after expanding the original energy storage system by using sodium batteries: ① No pre-charging is required; ② The capacity of the sodium battery does not need to be consistent with that of the lithium battery; ③ There is no circulation problem in the sodium battery system 2 itself; ④ The sodium battery system 2 can perform the SOC balancing function between battery packs according to its own SOC; ⑤ The sodium battery system 2 can perform battery current balancing control; ⑥ Sodium batteries can be mixed with lithium batteries for new and old use.

[0018] Specific embodiments of the present invention are shown below.

[0019] The value range of the number m of the lithium battery packs 11 in the lithium battery system 1 is 2≤m≤32; the value range of the number n of the sodium battery packs 21 in the sodium battery system 2 is 2≤n≤32.

[0020] The addresses of the lithium battery packs 11 in the lithium battery system 1 are determined by their respective DIP switches. Each battery pack has a DIP switch and an address allocation input line and an address allocation output line. The first battery pack DIPs the battery number and the DIP allocation start switch to automatically allocate the system battery pack address.

[0021] The above-mentioned lithium battery module consists of 15 battery cells 1p15s; the data acquisition function of the lithium battery management module includes the collection of data such as battery cell voltage, battery cell temperature, battery pack total pressure and battery current, and its data calculation function includes SOC (State of Charge) calculation and SOH (State of Health) estimation.

[0022] The baud rate of the CAN bus between the lithium battery packs 11 of the lithium battery system 1 is 500k.

[0023] The battery information periodically reported by the lithium battery management module includes the charge cut-off voltage, the discharge cut-off voltage, the maximum allowable charge current and the maximum allowable discharge current.

[0024] The sodium battery pack 21 is composed of a 15s sodium battery module; the data calculation function of the sodium battery management module includes SOC (State of Charge) calculation.

[0025] refer to Figure 2 As shown, the working logic of the battery stack master control module (BAU) in the present invention is as follows: Case 0: Lithium battery system 1 allows charging and discharging; sodium battery system 2 prohibits charging and discharging. Then BAU takes the charging cut-off voltage of the lithium battery, the discharging cut-off voltage of the lithium battery, the maximum allowed charging current accumulated by the lithium battery system 1, and the maximum discharge current accumulated by the lithium battery system 1 and reports them to the inverter 4.

[0026] Case 1: Lithium battery system 1 allows charging and discharging; sodium battery system 2 allows charging and prohibits discharging. Then BAU takes the sodium battery charging cut-off voltage, the lithium battery discharging cut-off voltage, the maximum allowable charging current accumulated by lithium battery system 1 and sodium battery system 2, and the maximum allowable discharging current accumulated by lithium battery system 1 and reports them to inverter 4.

[0027] Case 2: Lithium battery system 1 allows charging and discharging; sodium battery system 2 prohibits charging and allows discharging. Then BAU takes the sodium battery charging cut-off voltage, sodium battery discharging cut-off voltage, the maximum allowable charging current accumulated by lithium battery system 1 and sodium battery system 2, and the maximum discharge current accumulated by lithium battery system 1 and reports them to inverter 4.

[0028] Case 3: Lithium battery system 1 allows charging and discharging; sodium battery system 2 allows charging and discharging. Then BAU takes the charging cut-off voltage of the lithium battery, the discharging cut-off voltage of the sodium battery, the maximum allowed charging current accumulated by lithium battery system 1 and sodium battery system 2, and the maximum allowed discharging current accumulated by lithium battery system 1 and sodium battery system 2 and reports them to inverter 4.

[0029] Case 4: Lithium battery system 1 allows charging but prohibits discharging; sodium battery system 2 allows charging and discharging. Then BAU takes the charging cut-off voltage of the lithium battery, the discharging cut-off voltage of the sodium battery, the maximum allowed charging current accumulated by lithium battery system 1 and sodium battery system 2, and the maximum allowed discharging current accumulated by sodium battery system 2 and reports them to inverter 4.

[0030] Case 5: Lithium battery system 1 allows charging but prohibits discharging; sodium battery system 2 prohibits charging but allows discharging. Then BAU takes the charging cut-off voltage of the lithium battery, the discharging cut-off voltage of the sodium battery, the maximum allowed charging current accumulated by lithium battery system 1, and the maximum allowed discharging current accumulated by sodium battery system 2 and reports them to inverter 4.

[0031] Case 6: Lithium battery system 1 allows charging but prohibits discharging; sodium battery system 2 allows charging but prohibits discharging. Then BAU takes the charging cut-off voltage of the lithium battery, the discharging cut-off voltage of the sodium battery, the maximum allowed charging current accumulated by lithium battery system 1 and sodium battery system 2, and the maximum allowed discharging current (0) and reports them to inverter 4.

[0032] Case 7: Lithium battery system 1 allows charging but prohibits discharging; sodium battery system 2 prohibits charging and discharging. Then BAU takes the charging cut-off voltage of the lithium battery, the discharging cut-off voltage of the sodium battery, the maximum allowed charging current accumulated by lithium battery system 1, and the maximum allowed discharging current (0) and reports them to inverter 4.

[0033] Case 8: Lithium battery system 1 is prohibited from charging but allowed to discharge; sodium battery system 2 is allowed to charge and discharge. Then BAU takes the sodium battery charging cut-off voltage, sodium battery discharging cut-off voltage, the maximum allowable charging current accumulated by sodium battery system 2, and the maximum allowable discharge current accumulated by lithium battery system 1 and sodium battery system 2 and reports them to inverter 4.

[0034] Case 9: Lithium battery system 1 is prohibited from charging but allowed to discharge; sodium battery system 2 is prohibited from charging but allowed to discharge. Then BAU takes the sodium battery's charge cut-off voltage, sodium battery's discharge cut-off voltage, maximum allowable charge current (0), and the maximum allowable discharge current accumulated by lithium battery system 1 and sodium battery system 2 and reports them to inverter 4.

[0035] Case 10: Lithium battery system 1 is prohibited from charging but allowed to discharge; sodium battery system 2 is allowed to charge but prohibited from discharging. Then BAU takes the sodium battery charging cut-off voltage, lithium battery discharging cut-off voltage, maximum allowable charging current accumulated by sodium battery system 2, and maximum allowable discharging current accumulated by lithium battery system 1 and reports them to inverter 4.

[0036] Case 11: Lithium battery system 1 is prohibited from charging but allowed to discharge; sodium battery system 2 is prohibited from charging but not discharging. Then BAU takes the sodium battery’s charge cut-off voltage, the lithium battery’s discharge cut-off voltage, the maximum allowable charge current (0), and the maximum allowable discharge current accumulated by lithium battery system 1 and reports them to inverter 4.

[0037] Case 12: Lithium battery system 1 is prohibited from charging and discharging; sodium battery system 2 is allowed to charge and discharge. Then BAU takes the sodium battery charging cut-off voltage, sodium battery discharging cut-off voltage, sodium battery system 2 accumulated maximum allowable charging current, sodium battery system 2 accumulated maximum allowable discharging current and reports them to inverter 4.

[0038] Case 13: Lithium battery system 1 is prohibited from charging and discharging; sodium battery system 2 is prohibited from charging and allowed to discharge. Then BAU takes the sodium battery's charge cut-off voltage, sodium battery's discharge cut-off voltage, maximum allowable charge current (0), and the maximum allowable discharge current accumulated by sodium battery system 2 and reports them to inverter 4.

[0039] Case 14: Lithium battery system 1 is prohibited from charging and discharging; sodium battery system 2 is prohibited from charging and discharging. Then BAU takes the sodium battery's charge cut-off voltage, sodium battery's discharge cut-off voltage, maximum allowable charge current (0), and maximum allowable discharge current (0) and reports them to inverter 4.

[0040] Case 15: Lithium battery system 1 is prohibited from charging and discharging; sodium battery system 2 is allowed to charge and prohibited from discharging. Then BAU takes the sodium battery charging cut-off voltage, sodium battery discharging cut-off voltage, the maximum allowable charging current accumulated by sodium battery system 2, and the maximum allowable discharging current (0) and reports them to inverter 4.

[0041] The above embodiments do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A hybrid household energy storage system, characterized by: Including lithium battery system, sodium battery system, battery stack master control module and inverter; The lithium battery system includes m lithium battery packs connected in parallel, where m is an integer greater than or equal to 2; the lithium battery pack includes a lithium battery module and a lithium battery management module, and the lithium battery management module has data acquisition and calculation functions, battery charging, discharging and balancing functions, and external communication functions; the lithium battery packs communicate in parallel through a first CAN bus, and the corresponding lithium battery management modules periodically and actively report battery information of the lithium battery packs to the battery stack master control module; The sodium battery system includes n sodium battery packs connected in parallel, where n is an integer greater than or equal to 2; the sodium battery pack includes a sodium battery module, a sodium battery management module and a DC / DC conversion module, the sodium battery management module has data acquisition and calculation functions and battery fault diagnosis functions; each sodium battery pack is incorporated into the first CAN bus; the DC / DC conversion module realizes a bidirectional change function of the sodium battery pack; The battery stack master control module communicates with the lithium battery pack via the first CAN bus, and is used to receive, summarize and store battery information reported by the lithium battery pack; The inverter communicates with the battery stack master control module via a second CAN bus for receiving battery information reported by the battery stack master control module; the inverter is electrically connected to the lithium battery pack and the sodium battery pack.

2. The hybrid household energy storage system according to claim 1, characterized in that: The value range of the number m of lithium battery packs in the lithium battery system is 2≤m≤32; the value range of the number n of sodium battery packs in the sodium battery system is 2≤n≤32.

3. The hybrid household energy storage system according to claim 1, characterized in that: The addresses of the lithium battery packs in the lithium battery system are respectively determined by their DIP switches.

4. The hybrid household energy storage system according to claim 1, characterized in that: The data collection function of the lithium battery management module includes data collection of battery cell voltage, battery cell temperature, battery pack total pressure and battery current, and its data calculation function includes SOC calculation and SOH estimation.

5. The hybrid household energy storage system according to claim 1, characterized in that: The baud rate of the CAN bus between the lithium battery packs of the lithium battery system is 500k.

6. The hybrid household energy storage system according to claim 1, characterized in that: The battery information periodically reported by the lithium battery management module includes a charging cut-off voltage, a discharging cut-off voltage, a maximum allowable charging current, and a maximum allowable discharging current.

7. The hybrid household energy storage system according to claim 1, characterized in that: The data calculation function of the sodium battery management module includes SOC calculation.

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