An on-line battery monitoring system

Abstract

The utility model belongs to the technical field of battery on -line monitoring, provide a kind of battery on -line monitoring system, including the monitoring host computer connected to direct current bus, further include complete battery set, complete battery set includes multiple groups of series connection battery module, complete battery set is connected to direct current bus by one-way isolation device, each group of battery module is configured with battery grouping charge-discharge switching device, the one-way isolation device is connected to the direct current bus, and each group of battery module is connected to monitoring host computer by battery grouping charge-discharge switching device. Compared with the conventional maintenance mode needs to be detected by withdrawing battery pack from system, not only operation is complex, but also there is maintenance blind area, the utility model can realize the accurate management and maintenance of battery.

Description

Technical Field

[0001] This utility model belongs to the field of battery monitoring technology, and in particular relates to an online battery monitoring system. Background Technology

[0002] A 35kV substation is a terminal distribution center in the regional power grid, primarily responsible for distributing local loads. Its upstream power source is typically a 110kV substation, while its downstream supply directly reaches 10kV or 0.4kV users. The 110kV substation is a core hub in the high-voltage backbone network, connecting to the 220kV and above grid, and serving as a relay station connecting upstream and downstream. It not only supplies power to downstream 35kV substations and 10kV ring main units but also needs to stabilize the regional power distribution, ensuring the electricity needs of urban industrial and commercial sectors and large residential areas. 35kV or 110kV substations are generally widely distributed and located in remote areas, resulting in high battery maintenance costs.

[0003] 35kV or 110kV substation batteries are single-cell batteries and are in a floating charge state for a long time. Overcharging, undervoltage, and excessive internal resistance of individual cells within the cell are common. The lack of automatic maintenance technology results in a service life that is generally shorter than the design life.

[0004] A large number of 35kV or 110kV substation batteries are essentially in a state of "unmanaged". Substation maintenance companies manage their own 35kV or 110kV substations because they are responsible for maintenance and management. However, the batteries in some county-level substations are basically unmanaged, and some haven't even had their capacity assessed. The operational status of these substation batteries is difficult to control, posing a significant safety hazard.

[0005] Existing substation battery management systems cannot provide a direct view of battery health status and pose safety risks. Battery maintenance is primarily manual, requiring significant manpower and time, making it difficult to perform systematic and comprehensive maintenance according to relevant technical procedures. Furthermore, the actual lifespan of batteries is short, resulting in high replacement costs. The actual lifespan of batteries is shorter than their design lifespan, and battery replacement and installation lead to substantial operation and maintenance costs.

[0006] In the field of backup power for power systems, the reliability and lifespan of lead-acid battery banks are directly related to power supply security. Traditional maintenance methods require removing the battery bank from the system for testing, which is not only complex but also creates blind spots in maintenance. Especially for high-voltage systems composed of 104 batteries connected in series, the performance differences between individual cells can lead to a decrease in the overall capacity of the bank, making it difficult to achieve precise maintenance using traditional methods. Utility Model Content

[0007] In view of the above problems, the purpose of this utility model is to provide an online battery monitoring system, which aims to solve the technical problem that existing substation battery systems cannot accurately perform online capacity verification and maintenance.

[0008] The present invention adopts the following technical solution:

[0009] The battery online monitoring system includes a monitoring host connected to the DC bus and a complete battery pack. The complete battery pack includes multiple sets of battery modules connected in series. Each set of battery modules consists of multiple battery cells. The complete battery pack is connected to the DC bus through a unidirectional isolation device. Each set of battery modules is equipped with a battery group charging and discharging switching device. The unidirectional isolation device is connected to the DC bus. Each set of battery modules is connected to the monitoring host through the battery group charging and discharging switching device.

[0010] Furthermore, the unidirectional isolation device includes a unidirectional diode, a normally closed electronically controlled switch, and a current sensor. The unidirectional diode and the normally closed electronically controlled switch are connected in parallel and then connected to the DC bus through the current sensor. The control terminal of the normally closed electronically controlled switch and the data terminal of the current sensor are both connected to the monitoring host.

[0011] Furthermore, the battery group charging and discharging switching device includes an MCU control unit, an optocoupler, a relay drive circuit, a relay, a high-power diode, and a power module. The optocoupler and the relay each have two paths. The power module is connected to the MCU control unit, the optocoupler, and the relay drive circuit. The MCU control unit is connected to the relay drive circuit through the two optocouplers. The relay drive circuit is connected to the input terminals of the two relays. The two relays have two controllable switches. One end of the two controllable switches is connected to the monitoring host as a charging and discharging bus. The other end of the two controllable switches is connected to the two ends of the corresponding battery modules, and a high-power diode is connected between them.

[0012] Furthermore, the MCU control unit is also connected to a YBUS communication unit, which is used to receive commands from the monitoring host and return action information of the switching device.

[0013] Furthermore, each battery cell in the battery module is connected to a cell monitoring module at both ends to monitor the voltage, resistance, and temperature of the battery cell. The cell monitoring module is connected to the YBUS communication unit of the switching device via a YBUS communication line.

[0014] Furthermore, the individual cell monitoring module is also equipped with a temperature sensor attached to the surface of the battery cell.

[0015] The beneficial effects of this utility model are: by setting a unidirectional isolation device and a battery group charging and discharging switching device, this utility model realizes the operation and maintenance management of each group of battery modules, can realize accurate switching of charging and discharging, can also realize online capacity verification, and can realize effective and precise management of batteries. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an online battery monitoring system provided by this utility model.

[0017] Figure 2 This is a schematic diagram of the battery group charging and discharging switching device provided by this utility model. Detailed Implementation

[0018] To make the purpose, technical solution, and advantages of this utility model patent clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0019] To illustrate the technical solution described in this utility model, specific embodiments are described below.

[0020] For ease of explanation, only the parts relevant to the embodiments of this utility model are shown.

[0021] Combination Figure 1-2 As shown, the battery online monitoring system includes a monitoring host 1 connected to the DC bus, and a complete battery pack. The complete battery pack includes multiple sets of battery modules 2 connected in series. Each set of battery modules 2 consists of multiple battery cells 21. The complete battery pack is connected to the DC bus through a unidirectional isolation device 3. Each set of battery modules 2 is equipped with a battery group charging and discharging switching device 4. The unidirectional isolation device 3 is connected to the DC bus, and each set of battery modules 2 is connected to the monitoring host 1 through the battery group charging and discharging switching device 4.

[0022] In practical applications, the DC bus is also connected to charging devices and DC loads. Figure 1This is a specific application example. A complete battery pack of 104 2V cells is divided into 13 groups (battery modules), with each group containing 8 cells (cells) totaling 16V. As a preferred configuration, each cell 21 in the battery module is connected to a cell monitoring module at both ends to monitor its voltage and resistance. The cell monitoring module connects to the positive and negative terminals of the cell, using U-shaped connectors. Furthermore, the cell monitoring module is equipped with a temperature sensor attached to the surface of the cell. During normal operation, each group's cell monitoring module monitors the voltage, internal resistance, and temperature of the battery in that group online, displaying the data in real-time on the monitoring host. The data from the monitoring host can be transmitted to a backend system. The monitoring host is also connected to a display device (with a 7-inch screen).

[0023] In this structure, the unidirectional isolation device 3 allows the entire battery pack to be directly connected to the DC bus under normal conditions. When battery maintenance (discharging, charging, equalization, activation) is required, it avoids the influence of the DC bus on charging and discharging during discharge or charging. As a specific structure, such as... Figure 1 As shown, the unidirectional isolation device includes a unidirectional diode, a normally closed electronically controlled switch, and a current sensor. The unidirectional diode and the normally closed electronically controlled switch are connected in parallel and then connected to the DC bus through the current sensor. The control terminal of the normally closed electronically controlled switch and the data terminal of the current sensor are both connected to the monitoring host.

[0024] When the unidirectional isolation device is operating normally, the normally closed electrical control switch is closed, directly connecting the entire battery pack to the DC bus. When battery maintenance is required (discharging, charging, equalizing, activation), the normally closed electrical control switch is disconnected and the reverse-blocking unidirectional diode is connected in series to prevent the DC bus from affecting the charging and discharging process. After maintenance is completed, the switch is closed again to restore normal DC circuit operation.

[0025] Therefore, under normal operating conditions (battery in float charging state), the normally closed electronic control switch closes to allow float charging of the battery. The monitoring host can collect battery operating parameters (voltage, current, internal resistance, temperature, etc.) in real time and perform fault diagnosis (when these parameters exceed limits). The functionality of the monitoring host can be achieved using existing technology and is not the focus of this embodiment, so it will not be elaborated here.

[0026] The monitoring host has a built-in bidirectional charging and discharging power supply. When online capacity verification is required, in the verification state, the normally closed electrical control switch is opened. After the switching device switches, the battery pack can only discharge to the DC bus through the monitoring host's discharge power supply, and cannot be charged by the DC bus (due to the unidirectional conductivity of diodes). At this time, the battery pack still has the ability to provide backup output power. However, when the charging device is operating normally, the battery pack has no output. In this case, it is equivalent to the battery pack simply being connected to the DC bus without current exchange. At this time, capacity verification tests can be performed on each battery individually.

[0027] The specific capacity verification process is not the focus of this embodiment and will not be elaborated here. Generally, the battery is first recharged (only by fully charging the battery before discharging can the true battery capacity be obtained). Then, the battery is subjected to constant current discharge at a current of 0.1C. The DC bus is supplied with constant current through the monitoring host (reducing energy waste). Constant current discharge continues until the discharge stop condition is met (any single battery cell reaches 1.8V or the module voltage reaches the lower limit), and the capacity discharged at this point is the battery capacity. Finally, the battery is recharged, again by drawing power from the DC bus through the monitoring host. The above process can be repeated.

[0028] When a system malfunction causes a capacity interruption, the normally closed electrical control switch closes instantaneously, connecting the battery to the DC bus to supply power to the load. Simultaneously, the monitoring host enters emergency power replenishment mode, replenishing power to the undercharged battery (the battery pack interrupted during the capacity interruption) via the DC bus. This is a function to replenish power to batteries that are undercharged due to capacity discharge in the event of a fault-induced capacity interruption.

[0029] The above-mentioned functionality is based on the structural design of the unidirectional isolation device and the switching device, which are the focus of this embodiment. Regarding the switching device, such as... Figure 2 As shown, the battery group charging and discharging switching device includes an MCU control unit, an optocoupler, a relay drive circuit, a relay, a high-power diode, and a power module. The optocoupler and the relay each have two paths. The power module is connected to the MCU control unit, the optocoupler, and the relay drive circuit. The MCU control unit is connected to the relay drive circuit through the two optocouplers. The relay drive circuit is connected to the input terminals of the two relays. The two relays have two controllable switches. One end of the two controllable switches is connected to the monitoring host as a charging and discharging bus. The other end of the two controllable switches is connected to the two ends of the corresponding battery modules, and a high-power diode is connected between them.

[0030] When one of the switching devices switches, the corresponding battery module connects to the charging / discharging bus of the monitoring host and enters maintenance mode. Furthermore, the MCU control unit is also connected to a YBUS communication unit, which receives commands from the monitoring host and returns action information from the switching device. The individual unit monitoring module is connected to the YBUS communication unit of the switching device via a YBUS communication line.

[0031] like Figure 2 As shown, when the MCU control unit receives a command from the monitoring host to close or open a relay, the MCU control unit controls the relay through an optocoupler and a relay drive circuit. The optocoupler isolates the control circuit from the drive circuit, protecting the control unit. The relay drive circuit amplifies the drive signal, providing sufficient current to drive the relay. Closing both relays connects a battery module (i.e.,...). Figure 2 When the two controllable switches on the right side of the relay shown are closed, the battery module is connected to the bidirectional power supply for charging and discharging the monitoring host (the monitoring host has a battery group discharge power supply (DC / DC) and a battery group charging power supply (DC / DC)), allowing the battery group to be charged and discharged. The power module provides 3.3V and 24V voltages for the entire circuit.

[0032] In summary, compared to traditional maintenance methods that require removing the battery pack from the system for testing, which is not only complex but also creates blind spots in maintenance, this embodiment enables precise management and maintenance of batteries.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A battery online monitoring system, characterized in that: The online monitoring system includes a monitoring host connected to the DC bus and a complete battery pack. The complete battery pack includes multiple sets of battery modules connected in series. Each set of battery modules consists of multiple battery cells. The complete battery pack is connected to the DC bus through a unidirectional isolation device. Each set of battery modules is equipped with a battery group charging and discharging switching device. The unidirectional isolation device is connected to the DC bus. Each set of battery modules is connected to the monitoring host through the battery group charging and discharging switching device.

2. The battery online monitoring system as described in claim 1, characterized in that: The unidirectional isolation device includes a unidirectional diode, a normally closed electronically controlled switch, and a current sensor. The unidirectional diode and the normally closed electronically controlled switch are connected in parallel and then connected to the DC bus through the current sensor. The control terminal of the normally closed electronically controlled switch and the data terminal of the current sensor are both connected to the monitoring host.

3. The battery online monitoring system as described in claim 2, characterized in that: The battery group charging and discharging switching device includes an MCU control unit, an optocoupler, a relay drive circuit, a relay, a high-power diode, and a power module. The optocoupler and the relay each have two paths. The power module is connected to the MCU control unit, the optocoupler, and the relay drive circuit. The MCU control unit is connected to the relay drive circuit through the two optocouplers. The relay drive circuit is connected to the input terminals of the two relays. The two relays have two controllable switches. One end of the two controllable switches is connected to the monitoring host as a charging and discharging bus. The other end of the two controllable switches is connected to the two ends of the corresponding battery modules, and a high-power diode is connected between them.

4. The battery online monitoring system as described in claim 3, characterized in that: The MCU control unit is also connected to a YBUS communication unit, which is used to receive commands from the monitoring host and return action information of the switching device.

5. The battery online monitoring system as described in claim 4, characterized in that: Each battery cell in the battery module is connected to a cell monitoring module at both ends to monitor the voltage, resistance and temperature of the battery cell. The cell monitoring module is connected to the YBUS communication unit of the switching device via a YBUS communication line.

6. The battery online monitoring system as described in claim 5, characterized in that: The single-cell monitoring module is also equipped with a temperature sensor attached to the surface of the battery cell.

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