Overvoltage and overcurrent protection device for series energy storage system

Abstract

The application discloses a kind of overvoltage and overcurrent protection devices of series type energy storage system. Including control cabinet, upper terminal board and lower terminal board, between upper and lower terminal board installs electric core, is connected by control cabinet connecting wire. There is movable electrical connection column in the guide column of upper terminal board. When the voltage of electric core does not reach preset value, electrical connection column makes electric core in charging state;When reaching preset value, electrical connection column moves and cuts off the charging of electric core, and at the same time, control cabinet reduces charging voltage for other electric core charging. The device can effectively solve the overvoltage and overcurrent problem caused by battery inconsistency in series type energy storage system, improve the safety, stability of energy storage system, prolong the service life of battery, suitable for photovoltaic energy storage, electric vehicle charging pile and other various energy storage systems.

Description

Technical Field

[0001] This utility model relates to an overvoltage and overcurrent protection device for series circuits in energy storage systems, and is particularly suitable for energy storage battery packs composed of multiple cells connected in series. It enables real-time monitoring and active disconnection protection of overvoltage and overcurrent of individual cells during the charging process. Background Technology

[0002] In series-type energy storage systems, while series charging offers advantages such as increased charging voltage and simplified charging circuits, meeting high-voltage charging requirements and reducing cost and space requirements, individual battery variations in capacity, internal resistance, and self-discharge rate lead to asynchronous voltage changes in individual cells during charging and discharging. This causes higher-performing batteries to tend to charge faster; if charging continues beyond this point, the earlier charged battery may experience overvoltage, affecting battery life and performance, and even posing safety hazards.

[0003] As batteries age, their performance varies. Severely aged batteries experience reduced capacity and increased internal resistance, leading to higher voltages during series charging and further increasing the risk of overvoltage. Currently, there is a lack of effective protection devices to address these issues. Therefore, developing an overvoltage and overcurrent protection device capable of real-time monitoring and precise control is urgently needed. Utility Model Content

[0004] This utility model aims to provide an overvoltage and overcurrent protection device for a series energy storage system, effectively solving the overvoltage and overcurrent problems caused by battery inconsistency, and improving the safety, stability, and battery life of the energy storage system. The specific solution is as follows:

[0005] An overvoltage and overcurrent protection device for a series energy storage system includes a main frame, the main frame including an upper terminal block, a lower terminal block and a control cabinet;

[0006] The control cabinet is equipped with a real-time current and voltage detection device for each individual battery cell. When the control cabinet detects that the voltage of a battery cell has reached a preset value, it disconnects the electrical connection of that cell, thereby disconnecting it from the overall charging system. At the same time, a signal is sent to lower the subsequent charging voltage to complete the continuous charging of the remaining undisconnected battery cells.

[0007] The overvoltage and overcurrent protection method is as follows: when the control cabinet detects that the voltage of a certain cell has reached the preset value, it disconnects the electrical connection of the cell and sends a signal to lower the subsequent charging voltage to ensure that the remaining unconnected cells can continue to charge, thus avoiding overvoltage and overcurrent in the overall circuit.

[0008] The upper and lower terminal blocks form the battery cell installation area. The upper terminal block is connected to the positive terminal of the battery cell, and the lower terminal block is connected to the negative terminal of the battery cell. The wires in the upper and lower terminal blocks are connected in the set manner through the control cabinet.

[0009] The lower surface of the upper terminal block is provided with several guide posts that match the battery cell. Each guide post has a vertically movable contact post inside. When the contact post moves to the lowest point, it contacts the positive electrode of the battery cell; when the contact post moves to the highest point, it disconnects from the positive electrode of the battery cell.

[0010] The movement control structure of the charging post is an electromagnetic coil. When the real-time voltage value of the battery cell does not reach the preset value, the electromagnetic coil is de-energized, and the charging post is at its lowest point, thus charging the battery cell. When the real-time voltage value of the battery cell reaches the preset value, the electromagnetic coil is energized, and the charging post moves upward under the action of force, thus de-energizing the battery cell.

[0011] Another method for controlling the movement of the terminal block is through a micro motor. When the real-time voltage of the battery cell has not reached the preset value, the micro motor does not work, and the terminal block is at its lowest point, thus charging the battery cell. When the real-time voltage of the battery cell reaches the preset value, the micro motor works, and the terminal block moves upward under the control of the micro motor, thus cutting off the power to the battery cell.

[0012] Similar to the two control methods mentioned above, thermal springs and undervoltage release devices can also be used to move the contact post up and down. For example, a thermal spring can change its elasticity according to temperature changes. When the battery cell heats up during charging and the temperature reaches a certain value, the thermal spring deforms and pushes the contact post upward. An undervoltage release device can activate when an abnormal voltage is detected, controlling the movement of the contact post.

[0013] To secure the battery cell, the positive terminal of the cell has a concave structure, with its upper end face abutting against the lower surface of the guide post. The outer wall material of the guide post is an insulator. When it is necessary to fix the battery cell between the upper and lower terminal boards, a secure snap-fit ​​can be achieved through the lower surface of the guide post.

[0014] Meanwhile, in order to simplify the internal wire distribution, the lower surface of the power receiving post is provided with a first contact, the side of the power receiving post is provided with a second contact, and the inner wall of the guide post is provided with a third contact.

[0015] When the terminal is at the bottom position, the first contact contacts the positive terminal of the battery cell, and the second and third contacts are disconnected. At this time, the battery cell is in the overall charging circuit.

[0016] When the terminal is in the uppermost position, the first contact does not contact the positive terminal of the battery cell, and the second and third contacts are in contact. At this time, the battery cell is disconnected from the overall charging circuit.

[0017] Furthermore, a reset spring is provided on the upper surface of the terminal block. The reset spring ensures that the terminal block and the positive terminal of the battery cell are connected under normal conditions.

[0018] Preferably, a micro motor can be used to control the movement of the charging post. The movement of the charging post is controlled by the micro motor, which is connected to the control cabinet. When the real-time voltage of the battery cell does not reach the preset value, the micro motor does not work, and the charging post remains in the lowest charging state. When the voltage reaches the preset value, the micro motor starts and drives the charging post to move upward through the transmission mechanism, thereby de-energizing the battery cell.

[0019] To save costs, the power supply post can also be controlled by an undervoltage release device, which activates when an abnormal voltage is detected to control the movement of the power supply post.

[0020] To further improve the time for equalization charging, a battery equalization module is installed in the control cabinet.

[0021] This protection device can be applied to solar energy storage systems, electric vehicle charging pile energy storage systems, and uninterruptible power supply systems. Beneficial effects

[0022] By monitoring the cell voltage in real time, cells whose voltage has reached the preset value can be disconnected in a timely manner, effectively preventing battery damage caused by overcharging, extending battery life, and improving the overall performance of the energy storage system.

[0023] This also avoids safety hazards caused by battery overvoltage and overcurrent, such as fire and explosion, ensuring the safety of the energy storage system, surrounding equipment, and personnel. After disconnecting the overvoltaged cell, the charging voltage is automatically reduced to continue charging other cells, improving charging efficiency and ensuring charging stability and reliability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of an overvoltage and overcurrent protection device for a series energy storage system.

[0025] Figure 2 This is a schematic diagram showing the battery cells when the overvoltage and overcurrent protection device is not installed.

[0026] Figure 3 This is a structural diagram of the top wiring panel;

[0027] Figure 4 yes Figure 3 A magnified view of the circular selected area in the image;

[0028] Figure 5 This is a schematic diagram showing the position of the terminals when the specified battery cell is not disconnected;

[0029] Figure 6 This is a schematic diagram showing the position of the terminal block when a specific battery cell is disconnected;

[0030] Figure 7This is a schematic diagram of the electrical connections of the specified battery cell under different conditions;

[0031] In the diagram: 1. Control cabinet 2. Upper terminal block 21. Guide post 211. Third contact 22. Power connection post 221. First contact 222. Second contact 3. Lower terminal block 4. Battery cell. Detailed Implementation

[0032] To enhance understanding of this utility model, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. These embodiments are only used to explain the present utility model and do not constitute a limitation on the scope of protection of the present utility model. Example

[0033] like Figure 1-7 As shown, in a typical photovoltaic energy storage system, this overvoltage and overcurrent protection device is configured to protect a lithium battery pack composed of multiple lithium batteries connected in series. The system mainly includes solar panels, a charge controller, this overvoltage and overcurrent protection device, and the lithium battery pack. The components of the protection device are numbered as follows: 1 is the control cabinet; 2 is the upper terminal block, 21 is the guide post on the lower surface of the upper terminal block, and 211 is the third contact on the inner wall of the guide post; 22 is the vertically movable contact post inside the guide post, 221 is the first contact on the lower surface of the contact post, and 222 is the second contact on the side of the contact post; 3 is the lower terminal block; and 4 is the battery cell.

[0034] Under sufficient sunlight, the solar panel (not listed separately in the component numbering) converts solar energy into electrical energy, which is then input into the lithium battery pack via the charging controller (not listed separately in the component numbering). During the initial charging phase, the voltage of each cell 4 is at a low level. At this time, with the electromagnetic coil (not shown in the attached diagram, controlled by the control cabinet 1) de-energized, the terminal 22 is at its lowest point due to the action of the reset spring (not shown in the attached diagram), and the first contact 221 contacts the positive terminal of the cell 4, allowing all cells 4 to charge normally in series. During this process, the detection device inside the control cabinet 1 continuously monitors the voltage and current of each cell 4.

[0035] As the charging process progresses, due to individual differences among the battery cells, one of the cells, 4, with its smaller capacity, reaches the preset voltage value first. Upon detecting this, control cabinet 1 immediately energizes the electromagnetic coil of the corresponding cell 4's contact post 22. The electromagnetic coil generates electromagnetic force, overcoming the spring force of the return spring, causing contact post 22 to move upwards. At this point, the first contact 221 disconnects from the positive terminal of the cell 4, while the second contact 222 and the third contact 211 make contact, disengaging the cell 4 from the charging circuit. Simultaneously, control cabinet 1 issues a command to adjust the output voltage of the charging controller, lowering it by a standard value, to continue charging the other cells 4 that have not yet reached the preset voltage.

[0036] Specific combination Figure 7As can be seen, when the first contact 221 contacts the positive terminal of the battery cell 4, the designated battery cell 4 is in a charging state, and the overall circuit is stable. When it is detected that the voltage of the designated battery cell 4 has reached the preset voltage level, in order to prevent overcharging from damaging the battery cell 4, the terminal 22 moves upward, the first contact 221 no longer contacts the positive terminal of the battery cell 4, and the second contact 222 and the third contact 211 make contact with each other. At this time, the designated battery cell 4 is in an open state, and the control cabinet 1 controls the overall charging voltage to drop by a standard value. This will not cause overvoltage or overcurrent in the overall circuit, and can continue to charge the other battery cells 4. Example

[0037] In the energy storage system of electric vehicle charging piles, this overvoltage and overcurrent protection device is used to protect the series-connected lithium battery packs. During the charging process, due to differences in capacity, internal resistance, etc., among the individual cells 4, if one cell 4 experiences a faster voltage rise and reaches the preset voltage value first, the control cabinet 1 detects this and sends a signal to the electromagnetic coil (or other driving component, not listed separately in the component serial number) controlling the movement of the terminal 22, causing the terminal 22 to move upward. After the terminal 22 moves upward, the first contact 221 disconnects from the positive terminal of the cell 4, and the second contact 222 and the third contact 211 make contact, thereby disconnecting the cell 4 from the charging circuit and removing it from the charging loop. At the same time, the control cabinet 1 adjusts the parameters of the charging circuit, reduces the charging voltage, and continues to charge other cells 4 that have not yet reached the preset voltage. This avoids potential safety issues caused by overvoltage of a single cell 4 and the impact on the charging efficiency of the entire energy storage system, ensuring the stable and safe operation of the electric vehicle charging pile energy storage system.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. An overvoltage and overcurrent protection device for a series-type energy storage system, characterized in that, The main frame includes an upper terminal block, a lower terminal block, and a control cabinet. The upper and lower terminal blocks form the battery cell installation area. The upper terminal block is connected to the positive terminal of the battery cell, and the lower terminal block is connected to the negative terminal of the battery cell. The wires in the upper and lower terminal blocks are connected in the set manner through the control cabinet. The lower surface of the upper terminal block is provided with several guide posts that match the battery cell. Each guide post has a vertically movable contact post inside. When the contact post moves to the lowest point, it contacts the positive electrode of the battery cell; when the contact post moves to the highest point, it disconnects from the positive electrode of the battery cell.

2. The overvoltage and overcurrent protection device for a series energy storage system according to claim 1, characterized in that... The positive electrode of the battery cell has a concave structure, and the upper end face of the positive electrode abuts against the lower surface of the guide post. The outer wall material of the guide post is an insulator.

3. The overvoltage and overcurrent protection device for a series energy storage system according to claim 2, characterized in that... The lower surface of the power receiving post is provided with a first contact, the side of the power receiving post is provided with a second contact, and the inner wall of the guide post is provided with a third contact. When the terminal is at the bottom position, the first contact contacts the positive terminal of the battery cell, and the second and third contacts are disconnected. At this time, the battery cell is in the overall charging circuit. When the terminal is in the uppermost position, the first contact does not contact the positive terminal of the battery cell, and the second and third contacts are in contact. At this time, the battery cell is disconnected from the overall charging circuit.

4. An overvoltage and overcurrent protection device for a series energy storage system according to claim 1 or 3, characterized in that... A reset spring is provided on the upper surface of the electrical terminal.

5. The overvoltage and overcurrent protection device for a series energy storage system according to claim 4, characterized in that... The movement of the charging post is controlled by a micro motor, which is connected to the control cabinet. When the real-time voltage of the battery cell does not reach the preset value, the micro motor does not work, and the charging post remains in the lowest charging state. When the voltage reaches the preset value, the micro motor starts and drives the charging post to move upward through the transmission mechanism, thereby cutting off the power to the battery cell.

6. The overvoltage and overcurrent protection device for a series energy storage system according to claim 4, characterized in that... The power connection post is controlled by an undervoltage release device, which activates when an abnormal voltage is detected, controlling the movement of the power connection post.

7. The overvoltage and overcurrent protection device for a series energy storage system according to claim 4, characterized in that... The control cabinet is equipped with a battery balancing module.

8. The overvoltage and overcurrent protection device for a series energy storage system according to claim 4, characterized in that... The protection device is applied to solar energy storage systems, electric vehicle charging pile energy storage systems, and uninterruptible power supply systems.

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