Storage battery open circuit protection device

Abstract

The invention discloses a storage battery open circuit protection device which comprises a rectifier, a storage battery pack, a direct current load and a plurality of DC / DC modules. The direct-current load is respectively connected with the rectifier and the storage battery pack in parallel; the single batteries in the storage battery pack are divided and combined into a plurality of storage battery strings, and the positive electrode and the negative electrode of each storage battery string are connected with the input end of a DC / DC module in parallel. The output ends of all the DC / DC modules are connected in parallel with a DC bus of the DC load; and when the output of the rectifier is abnormal and the battery monomers in the storage battery strings are open-circuited, the other storage battery strings without open-circuited battery monomers supply power to the direct-current load through the connected DC / DC module. The problem that the whole battery pack loses the standby power supply capacity due to open circuit of the single storage batteries can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery open circuit protection, in particular to a battery open circuit protection device. BACKGROUND

[0002] Battery monomers are used in series to form a battery pack to supply power externally. In the actual use process of the battery, one or several battery monomers may be open-circuited, thereby causing the battery pack to lose the ability to supply power externally, causing the DC system to lose power, accidents, and other phenomena. Therefore, the open circuit of the battery pack is very serious. If the problem cannot be found early, when the AC power is off, if the battery cannot provide power due to the open circuit at this time, it will cause important equipment such as database, automation system, and DCS to lose power, system paralysis, production interruption, safety accidents, and large economic losses or social impact.

[0003] The causes of the open circuit of the battery monomer are generally divided into two kinds. One is caused by the internal open circuit of the battery monomer, such as water loss, swelling, thermal runaway, and substrate corrosion. The other is caused by the external environment, such as disconnection of the connecting wire and corrosion of the pole. The open circuit of the battery monomer is inevitable. We need to solve is how to minimize the loss caused by the open circuit of the battery monomer when the open circuit of the battery monomer occurs, that is, what means to make the battery pack still be able to supply power externally when the open circuit of the battery monomer occurs, avoid the load power loss caused by the open circuit of the battery monomer, and improve the safety and reliability of the DC power supply system. SUMMARY

[0004] The present application provides a battery open circuit protection device to solve the technical problem that the whole battery loses the standby power supply capability due to the open circuit of the battery monomer.

[0005] In order to solve the above technical problem, the present application provides a battery open circuit protection device, comprising: a rectifier, a battery pack, a DC load, and a plurality of DC / DC modules.

[0006] The DC load is connected in parallel with the rectifier and the battery pack, respectively.

[0007] The battery monomers in the battery pack are divided and combined into a plurality of battery strings, and the positive and negative poles of each battery string are connected in parallel with the input end of a DC / DC module.

[0008] The output ends of all DC / DC modules are connected in parallel with the DC bus of the DC load.

[0009] When the rectifier output is abnormal and there is an open circuit battery cell in the battery string, the remaining battery strings without open circuit battery cell supply power to the DC load through the connected DC / DC module.

[0010] As a preferred solution, when the rectifier output is normal, all DC / DC modules do not work, the rectifier supplies power to the DC load and charges the battery pack.

[0011] As a preferred solution, when the rectifier output is abnormal and there is no open circuit battery cell in the battery pack, all DC / DC modules do not work, and the battery supplies power to the DC load.

[0012] As a preferred solution, when the rectifier output is abnormal and there is an open circuit battery cell in the battery string, the remaining battery strings without open circuit battery cell supply power to the DC load through the connected DC / DC module, comprising:

[0013] When the rectifier output is abnormal and it is detected that there is an open circuit battery cell in the battery pack, the battery string to which the open circuit battery cell belongs is determined, and the battery string to which the open circuit battery cell belongs is determined as a failed battery string.

[0014] The DC / DC module connected to the failed battery string does not work, and the DC / DC module connected to the remaining battery string without open circuit battery cell works and supplies power to the DC load through the connected DC / DC module.

[0015] As a preferred solution, the DC / DC module supplies power to the DC load through the connected DC / DC module, comprising:

[0016] The voltage of the remaining battery string without open circuit battery cell is boosted to the working voltage of the DC load through the connected DC / DC module, and then the DC load is supplied with power according to the boosted voltage.

[0017] As a preferred solution, when the voltage of the DC bus decreases, it is determined that the rectifier output is abnormal and there is an open circuit battery cell in the battery string.

[0018] As a preferred solution, the voltage output by the DC / DC module is lower than the voltage of the DC bus.

[0019] Compared with the prior art, the embodiment of the present application has the following beneficial effects:

[0020] The application provides a battery open circuit protection device, comprising a rectifier, a battery pack, a DC load and a plurality of DC / DC modules; the DC load is connected in parallel with the rectifier and the battery pack respectively; the battery monomers in the battery pack are divided into a plurality of battery strings, the positive and negative poles of each battery string are connected in parallel with the input end of a DC / DC module; the output ends of all DC / DC modules are connected in parallel with the DC bus of the DC load; when the rectifier output is abnormal and there is a battery monomer open circuit in the battery string, the remaining battery strings without battery monomer open circuit supply power to the DC load through the connected DC / DC modules.

[0021] The application divides the battery pack into a plurality of battery strings without changing the original connection mode of the battery pack, connects each battery string in parallel with the input end of a DC / DC module, and connects all DC / DC modules in parallel with the DC bus of the DC load, so that each battery string can supply power to the DC load as an independent power supply, and each battery string can independently output a voltage meeting the power supply requirements of the DC load. When the rectifier output is abnormal and there is a battery monomer open circuit in the battery string, the remaining battery strings without battery monomer open circuit can supply power to the DC load through the connected DC / DC modules, solving the problem that the whole battery loses the standby power supply capability due to the battery monomer open circuit. The battery pack can prevent losing the backup emergency power supply capability when one or more battery monomers are open circuited, and can normally provide energy output when AC power is lost, i.e., the rectifier output is abnormal, even if there is a battery monomer open circuit, ensuring the normal operation of the DC system and improving the safety and reliability of the DC power supply system. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of a battery open circuit protection device provided by an embodiment of the application. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0025] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0028] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0029] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0030] Example 1

[0031] Please refer to Figure 1This is a schematic diagram of the structure of a battery open circuit protection device provided in an embodiment of the present invention, including: a rectifier, a battery pack, a DC load and several DC / DC modules;

[0032] The DC load is connected in parallel with the rectifier and the battery pack, respectively;

[0033] The battery cells in the battery pack are divided into several battery strings, and the positive and negative terminals of each battery string are connected in parallel to the input terminal of a DC / DC module.

[0034] The output terminals of all DC / DC modules are connected in parallel to the DC bus of the DC load;

[0035] When the rectifier output is abnormal and a single battery cell in the battery string is open-circuited, the remaining battery strings without open-circuited cells supply power to the DC load through the connected DC / DC module.

[0036] Preferably, when the rectifier output is normal, all DC / DC modules are not working, the rectifier supplies power to the DC load and charges the battery pack.

[0037] Preferably, when the rectifier output is abnormal and no individual battery cell in the battery pack is open-circuited, all DC / DC modules are not working, and the battery supplies power to the DC load.

[0038] Preferably, when the rectifier output is abnormal and an open circuit occurs in a battery cell within a battery string, the remaining battery strings without open circuits supply power to the DC load through their connected DC / DC modules. This includes: when the rectifier output is abnormal and an open circuit is detected in a battery cell, determining the battery string to which the open-circuited cell belongs, and designating the battery string to which the open-circuited cell belongs as a failed battery string; the DC / DC module connected to the failed battery string does not operate, while the DC / DC modules connected to the remaining battery strings without open circuits operate and supply power to the DC load through their connected DC / DC modules.

[0039] Preferably, the step of supplying power to the DC load through the connected DC / DC module includes: boosting the voltage of the remaining battery strings that have not experienced open circuits to the operating voltage of the DC load through the connected DC / DC module, and then supplying power to the DC load based on the boosted voltage.

[0040] Preferably, when the voltage of the DC bus drops, it is determined that the rectifier output is abnormal and that there is an open circuit in a single battery cell in the battery string.

[0041] Preferably, the voltage output by the DC / DC module is lower than the voltage of the DC bus.

[0042] Specifically, to overcome the shortcomings of existing batteries where the entire battery pack loses its backup power supply capability due to an open circuit in a single battery cell, and to further improve the reliability and stability of the DC system, this invention divides the DC system's battery pack into multiple battery strings. Each battery string is connected in parallel with a DC / DC module to provide energy output as an independent power source. This prevents the battery pack from losing its backup emergency power supply capability when one or more individual batteries are open-circuited. In the event of an AC power failure, even if there is an open circuit in a single battery cell, the battery pack can still provide normal energy output, and there will be no load power failure caused by an open circuit in the battery pack, thus ensuring the normal operation of the DC system.

[0043] The battery open-circuit protection includes a rectifier, a battery bank, a DC load, and several DC / DC modules. When constructing the battery open-circuit protection device, the original battery bank connection method is not changed. The battery bank is divided into several battery strings, and the positive and negative terminals of each battery string are connected in parallel to the input terminals of a DC / DC module. The output terminals of all DC / DC modules are connected to the DC bus, thus forming the power supply circuit for each battery string.

[0044] The output voltage of the DC / DC module is slightly lower than the bus voltage. The DC / DC module does not output power to the bus. When the bus is abnormal and the voltage is lower than the output of the DC / DC module, the DC / DC module supplies power to the bus to ensure the bus is powered.

[0045] The working principle of the battery open circuit protection device is as follows:

[0046] (1) When the rectifier output is normal, all DC / DC modules are not working. The rectifier directly supplies power to the DC load and charges the battery pack. The connection of the DC / DC module will not affect the normal charging of the battery pack.

[0047] A rectifier is a standard component of a DC system that converts alternating current (AC) to direct current (DC). The DC output varies depending on the battery's state of charge, offering various voltage and current output modes such as constant current, constant voltage, equalizing charge, and float charge. Rectifier malfunctions primarily involve AC power loss or fuse blowouts, resulting in no DC output. In current technology, when the rectifier output is abnormal, the battery switches to supply power to the DC load, ensuring uninterrupted power. However, if both the rectifier and battery have no output, the DC load will lack power, potentially leading to an accident.

[0048] (2) When the rectifier output is abnormal, but the battery pack can operate normally, all DC / DC modules will not work. The battery pack will output normally to power the DC load, and the DC system will power the load according to the original power supply method.

[0049] (3) Third step: When the rectifier output is abnormal and a battery cell in a certain battery string is open-circuited, the battery string fails and cannot supply power to the outside. However, other battery strings can quickly provide energy output to DC loads through the DC / DC module and will not be affected by the open-circuited battery cell.

[0050] Furthermore, the DC / DC module has an isolation boost function, capable of boosting the voltage of the battery string to the operating voltage required to supply the DC load. When the rectifier output is normal, the DC / DC module does not work, and the DC load is directly powered by the rectifier; when the rectifier output is abnormal, and no open circuit is detected in a single battery cell of the battery pack, the DC / DC module still does not work, and the DC load is seamlessly powered by the battery pack; when the rectifier output is abnormal, and an open circuit is detected in a single battery cell of the battery pack, the battery string with the open circuit fails, and the DC load is powered by other battery strings after being boosted by the DC / DC module.

[0051] An open circuit in a single battery cell will cause no output when powered by the battery pack, resulting in a rapid drop in the battery pack voltage and no current output. This drop in battery voltage can be detected and used to make a judgment.

[0052] Furthermore, the battery pack is divided into at least two battery strings. The number of battery strings can be set according to actual usage. The more battery strings there are, the better the open circuit protection effect of the battery pack.

[0053] Furthermore, each of the battery strings can independently support the DC load power supply during an AC power outage, improving the uninterrupted power supply capability of the backup power supply.

[0054] Furthermore, the battery open-circuit protection device uses isolation to achieve electrical isolation of the power supply circuits of each battery string, ensuring that each battery string forms its own independent power supply circuit and does not interfere with each other.

[0055] Furthermore, the battery open-circuit protection device of the present invention is applicable to applications including but not limited to lead-acid battery packs, and other batteries such as lithium-ion batteries and nickel-metal hydride batteries are also within the scope of protection claimed by the present invention.

[0056] In a specific embodiment, such as Figure 1As shown, DC / DC modules are connected to points A and B, and points B and C, respectively, of the battery pack. The output of the DC / DC module is connected to the DC bus of the DC load, so that the battery pack is divided into two battery strings, battery string 1 and battery string 2, forming two independent battery string power supply circuits.

[0057] Figure 1 In the diagram, the AC bus is the busbar for the DC load. The DC / DC converter connected to battery string 1 has positive terminal A and negative terminal B as inputs, and the DC / DC converter connected to battery string 2 has positive terminal B and negative terminal C as inputs. The outputs of the two DC / DC modules are directly connected in parallel to the AC busbar.

[0058] Its working principle is as follows:

[0059] (1) When the rectifier output is normal, all DC / DC modules are not working. The rectifier directly supplies power to the DC load and charges the battery pack. The connection of the DC / DC module will not affect the normal charging of the battery pack.

[0060] (2) When the rectifier output is abnormal, but the battery pack can operate normally, all DC / DC modules will not work. The normal output of the battery pack will supply power to the DC load, and the DC system will supply power to the load according to the original power supply method.

[0061] (3) When the rectifier output is abnormal and a single battery cell in a battery string is open-circuited, the DC / DC module starts working. This battery string fails and cannot supply power externally. Other battery strings can quickly provide energy output to DC loads through the DC / DC module, unaffected by the open-circuited battery cell. For example, if the open-circuited battery belongs to battery string 1, then battery string 1 cannot supply power externally. However, battery string 2 can be rapidly boosted by the DC / DC module to independently supply power to the load, completely unaffected by the open-circuited battery cell.

[0062] In another specific embodiment, assuming the total voltage of the lead-acid battery pack is 48V and the voltage of each individual cell is 2V, the battery pack is divided into four battery strings, corresponding to four DC / DC modules. Each battery string consists of six individual cells connected in series, and the four battery strings are still connected in series. The positive and negative terminals of the four battery strings are respectively connected to the input terminals of their respective DC / DC modules, and the output terminals of all DC / DC modules are connected to the DC bus, forming an independent boost power supply circuit for the four battery strings.

[0063] An AC power outage or rectifier failure can cause a drop in DC bus voltage. The battery bank supplies power to the DC bus. If one or more batteries in the battery bank deteriorate, the battery bank voltage will continue to drop. When the output of the DC / DC module connected to the deteriorated battery bank is also affected, a normal DC / DC module can supply power to the load independently. If all the corresponding battery cells on all the DC / DC modules have open circuits, the DC system will collapse, but this situation is extremely rare.

[0064] When the rectifier output is normal, the rectifier supplies power to the load. When the rectifier output is abnormal and no open circuit is detected in the battery, the battery pack seamlessly supplies power to the load. When the mains power is interrupted or the rectifier fails, causing abnormal DC output, if an open circuit battery is detected in the battery pack and it cannot output normally, the battery string independently supplies power to the load after being boosted by the corresponding DC / DC module. If there is an open circuit battery cell in battery string 1, battery string 1 fails and does not provide energy output, while the other three battery strings still provide energy output normally and uninterruptedly, supplying power to the bus load. If there are open circuit batteries in both battery string 1 and battery string 2, then battery strings 3 and 4 can still seamlessly supply power to the load after being boosted by the DC / DC device.

[0065] Therefore, the present invention provides a battery open-circuit protection device, which can achieve the following beneficial effects:

[0066] (1) Without changing the original connection method of the battery pack, the battery pack is divided into multiple battery strings. Each battery string can independently output a voltage that meets the load power supply requirements in the form of isolated voltage boost, thus solving the problem that the entire battery pack loses its backup power supply capability due to open circuit of a single battery cell.

[0067] (2) By using the battery string isolation voltage boost method, the load is continuously supplied with energy without interruption. Without power loss, it can also provide operators with enough time to inspect and replace open-circuit batteries.

[0068] (3) Each battery string can independently support the load power supply during the moment of AC power failure, improve the uninterrupted power supply capability of the backup power supply, and reduce the economic losses caused by fluctuations or power outages due to system failures.

[0069] (4) The battery pack can be replaced online without interruption.

[0070] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0071] Those skilled in the art will clearly understand that, for convenience and simplicity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0072] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A battery open circuit protection device, characterized by, The application relates to a rectifier, a battery pack, a direct-current load and a plurality of DC / DC modules. The direct-current load is connected in parallel with the rectifier and the battery pack respectively. The battery cells in the battery pack are divided into a plurality of battery strings, and the positive and negative poles of each battery string are connected in parallel with the input end of a DC / DC module. The output ends of all the DC / DC modules are connected in parallel with the direct-current bus of the direct-current load. When the rectifier output is abnormal and there is an open circuit of a battery cell in a battery string, the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules. When the rectifier output is normal, all the DC / DC modules do not work, the rectifier supplies power to the direct-current load and charges the battery pack.

2. The battery open-circuit protection device of claim 1, wherein When the rectifier output is abnormal and there is no open circuit of a battery cell in the battery pack, all the DC / DC modules do not work, and the battery pack supplies power to the direct-current load.

3. The battery open-circuit protection device of claim 2, wherein When the rectifier output is abnormal and there is an open circuit of a battery cell in a battery string, the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules.

4. The battery open-circuit protection device of claim 3, wherein When the rectifier output is abnormal and it is detected that there is an open circuit of a battery cell in the battery pack, the battery string to which the battery cell with the open circuit belongs is determined, and the battery string to which the battery cell with the open circuit belongs is regarded as a failed battery string. The DC / DC module connected with the failed battery string does not work, the DC / DC modules connected with the remaining battery strings without the open circuit of the battery cell work, and the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules. The DC / DC module connected with the failed battery string does not work, the DC / DC modules connected with the remaining battery strings without the open circuit of the battery cell work, and the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules.

5. The battery open-circuit protection device of claim 4, wherein The DC / DC module connected with the failed battery string does not work, the DC / DC modules connected with the remaining battery strings without the open circuit of the battery cell work, and the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules. The DC / DC module connected with the failed battery string does not work, the DC / DC modules connected with the remaining battery strings without the open circuit of the battery cell work, and the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules.

6. The battery open-circuit protection device of claim 1, wherein The DC / DC module connected with the failed battery string does not work, the DC / DC modules connected with the remaining battery strings without the open circuit of the battery cell work, and the remaining battery strings without the open circuit of the battery cell supply power to the direct-current load through the connected DC / DC modules.

7. The battery open-circuit protection device of claim 1, wherein The voltage output by the DC / DC module is lower than the voltage of the direct-current bus.

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