Battery management unit, battery module and battery cluster

Abstract

The utility model discloses a battery management unit, a battery module and a battery cluster. The battery management unit comprises an analog front-end chip; the first protection circuit is positioned between a power supply input end and a power supply port of the analog front-end chip and is used for performing overvoltage protection on the analog front-end chip; and the second protection circuit is connected with the first protection circuit and is used for absorbing the overvoltage generated by the power supply input end, discharging and absorbing the discharge current. Wherein the second protection circuit comprises a voltage absorption unit which is used for absorbing overvoltage generated by the power supply input end and discharging; and the current absorption unit is connected in series with the voltage absorption unit and is used for absorbing the discharge current of the voltage absorption unit. By adopting the scheme, overvoltage protection can be carried out on the AFE chip, and meanwhile, the damage of an overvoltage protection device is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and in particular to a battery management unit, a battery module and a battery cluster. Background Art

[0002] Energy storage is becoming one of the key technologies used by my country to advance its carbon neutrality goals. It can not only solve the over-allocation and power limitation of photovoltaic power generation systems and achieve smooth grid connection, while maximizing the revenue of photovoltaic power generation, but also plays a positive role in maintaining grid stability and reducing peak loads and filling valleys.

[0003] A general energy storage system adopts the structure of battery module (PACK) → battery cluster (RACK) → container. Different PACKs are connected in series through copper bars or busbars to form a RACK, and different RACKs are further connected to form a container.

[0004] The Battery Management Unit (BMU) is a key component of the Battery Management System (BMS). It mainly monitors the status of the battery cell (voltage, temperature, etc.) through the Analog Front-End (AFE) chip and peripheral circuits, and provides a communication interface for the battery cell. Usually, one BMU is configured for one PACK.

[0005] In a PACK, the power supply of the AFE chip is provided by the battery cells inside the PACK. When the PACK is connected to a copper bus or busbar to form a RACK, the battery cells inside the PACK will generate instantaneous overvoltage, causing the AFE chip to break down and be damaged.

[0006] In order to prevent the AFE chip from being damaged by breakdown, a common method currently is to set an overvoltage protection device at the power supply port of the AFE chip to achieve overvoltage protection. However, this method has the problem that the overvoltage protection device is easily damaged. Utility Model Content

[0007] The problem to be solved by the utility model is: to reduce the damage of the overvoltage protection device while performing overvoltage protection on the AFE chip.

[0008] In order to solve the above problems, an embodiment of the utility model provides a battery management unit, and the battery management unit includes:

[0009] Analog front-end chip;

[0010] A first protection circuit, located between a power input terminal and a power supply port of the analog front-end chip, for performing overvoltage protection on the analog front-end chip;

[0011] and a second protection circuit connected to the first protection circuit, configured to absorb the overvoltage generated at the power input terminal and discharge it, and to absorb the discharge current;

[0012] Wherein, the second protection circuit comprises:

[0013] A voltage absorption unit, used for absorbing the overvoltage generated at the power input end and discharging it;

[0014] and a current absorption unit, which is connected in series with the voltage absorption unit and is used to absorb the discharge current of the voltage absorption unit.

[0015] Optionally, the second protection circuit is connected in parallel with the first protection circuit.

[0016] Optionally, the voltage absorption unit includes: a capacitor.

[0017] Optionally, the voltage absorption unit includes: two or more capacitors, and the two or more capacitors are connected in series.

[0018] Optionally, the discharge unit includes: a resistor.

[0019] Optionally, the current absorbing unit includes: more than two resistors, and the more than two resistors are connected in parallel.

[0020] Optionally, the first protection circuit includes: a TVS tube; an anode of the TVS tube is connected to the power input terminal, and a cathode is grounded.

[0021] Optionally, the battery management unit further includes: an electric fuse, one end of which is connected to the power input terminal, and the other end of which is connected to the first protection circuit.

[0022] Optionally, the battery management unit further includes: an inductor connected in series with the electric fuse.

[0023] The present utility model also provides a battery module, the battery module comprising:

[0024] at least one battery cell;

[0025] And a battery management unit connected to the battery cell, wherein the battery management unit is any one of the above-mentioned ones.

[0026] Optionally, the battery module includes more than two battery cells; the more than two battery cells are connected in series or in parallel.

[0027] The embodiment of the utility model further provides a battery cluster, which includes: two or more of the above-mentioned battery modules.

[0028] Compared with the prior art, the technical solution of the embodiment of the utility model has the following advantages:

[0029] By applying the solution of the utility model, a second protection circuit is set up, which includes: a voltage absorption unit and a current absorption unit. The voltage absorption unit can absorb the overvoltage generated by the power input end and discharge it, and the current absorption unit absorbs the discharge current. Therefore, while the related devices in the first protection circuit are performing overvoltage protection, protection can be provided for the related devices in the first protection circuit to avoid damage to the related devices in the first protection circuit by overvoltage, thereby further enhancing the protection of the analog front-end chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of a protection circuit for an AFE chip power supply port;

[0031] Figure 2 It is a structural schematic diagram of a battery management unit in an embodiment of the utility model;

[0032] Figure 3 It is a schematic diagram of the circuit structure of a battery management unit in an embodiment of the utility model;

[0033] Figure 4 It is a schematic diagram of the circuit structure of another battery management unit in an embodiment of the utility model;

[0034] Figure 5 It is a circuit structure diagram of another battery management unit in an embodiment of the utility model;

[0035] Figure 6 This is a schematic diagram of the circuit structure of another battery management unit in an embodiment of the utility model;

[0036] Figure 7 It is a structural schematic diagram of a battery cluster in an embodiment of the utility model. DETAILED DESCRIPTION

[0037] Currently, in order to prevent the AFE chip from being damaged by breakdown, a Transient Voltage Suppressor (TVS) diode is usually set at the power supply port of the AFE chip to achieve overvoltage protection.

[0038] Specifically, refer to Figure 1 The power supply port power+ of the AFE chip is provided with a TVS tube 11, and the TVS tube 11 provides overvoltage protection for the AFE chip.

[0039] When this method is used for overvoltage protection, the battery cell will generate overvoltage and damage the TVS tube 11 at the moment of copper busbar or busbar connection, causing a micro short circuit between the battery cell and the ground. If it is not discovered in time, the battery cell will continue to discharge to a low-power state until the PACK is scrapped.

[0040] To address this problem, the utility model provides a battery management unit, in which a second protection circuit is provided. The second protection circuit can absorb the overvoltage generated at the power input end and absorb the discharge current. Thus, while the related devices in the first protection circuit are performing overvoltage protection, protection can be provided for the related devices in the first protection circuit to avoid damage to the related devices in the first protection circuit by overvoltage, thereby further enhancing the protection of the analog front-end chip and improving safety during use.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0042] Reference Figure 2 The present utility model embodiment provides a battery management unit, the battery management unit comprising: an analog front-end chip 21, a first protection circuit 22 and a second protection circuit 23, wherein:

[0043] The first protection circuit 22 is located between the power input terminal pack+ and the power supply port power+ of the analog front-end chip 21, and is used to perform overvoltage protection on the analog front-end chip 21;

[0044] The second protection circuit 23 is connected to the first protection circuit 21, and is used to absorb the overvoltage generated by the power input terminal pack+ and discharge it, and absorb the discharge current.

[0045] By providing the second protection circuit 23 to protect the first protection circuit 21 , it is possible to prevent the first protection circuit 21 from being damaged by overvoltage, thereby enhancing the protection effect on the analog front-end chip 21 .

[0046] In a specific implementation, the power input terminal pack+ of the battery management unit can be a battery cell. The analog front-end chip 21 is used to perform voltage sampling, voltage balancing and other operations on the battery cell, thereby realizing state monitoring of the battery cell (voltage, temperature, etc.) and providing a communication interface for the battery cell.

[0047] In other embodiments, the power input terminal of the battery management unit may also be other energy storage devices, which are not limited here. Accordingly, the analog front-end chip 21 can be used to perform other operations on analog signals, such as amplification, filtering, voltage conversion, etc., which are not limited here.

[0048] In a specific implementation, there may be multiple connection modes between the first protection circuit 22 and the second protection circuit 23. For example, the first protection circuit 22 may be connected in series with the second protection circuit 23, so that the second protection circuit 23 absorbs the overvoltage generated by the power input terminal pack+ and the discharge current.

[0049] In one embodiment of the present invention, referring to Figure 2 , the second protection circuit 23 is connected in parallel with the first protection circuit 22. At this time, the voltage of the second protection circuit 23 is the same as that of the first protection circuit 22, so that the overvoltage can be discharged more timely and the discharge current can be absorbed, so as to better protect the related components in the first protection circuit 23 and enhance the protection effect of the analog front-end chip 21.

[0050] In a specific implementation, the second protection circuit 23 may have a variety of circuit structures, which are not limited here.

[0051] In one embodiment of the present invention, referring to Figure 2 , the second protection circuit 23 may include: a voltage absorption unit 231 and a current absorption unit 232. Wherein:

[0052] The voltage absorption unit 231 is used to absorb the overvoltage generated by the power input terminal pack+ and discharge it;

[0053] The current absorption unit 232 is connected in series with the voltage absorption unit 231 and is used to absorb the discharge current of the voltage absorption unit 231 .

[0054] In a specific implementation, the voltage absorption unit 231 and the current absorption unit 232 can be implemented by using a variety of devices.

[0055] In an embodiment of the present invention, in order to reduce the cost, capacitors may be used to implement the voltage absorption unit 231. The number of capacitors used may be set according to the capacitance of the capacitors themselves, different system requirements and the actual overvoltage level.

[0056] In an embodiment of the present invention, the voltage absorption unit 231 may include only one capacitor. Figure 3, the voltage absorption unit may only include the first capacitor C1. In this case, the first capacitor C1 can absorb the overvoltage generated by the power input terminal pack+, and the absorbed voltage is stored on the plate. The overvoltage generated by the power input terminal pack+ is equivalent to charging the first capacitor C1. After being fully charged, a discharge loop is formed between the first capacitor C1 and the current absorption unit. Through the discharge loop, the current absorption unit can absorb the discharge current of the first capacitor C1, thereby protecting the relevant devices in the first protection circuit.

[0057] In another embodiment of the utility model, the voltage absorption unit 231 may include more than two capacitors, and the two or more capacitors may be connected in series, thereby improving the overvoltage absorption effect and the capacitor withstand voltage capability. At this time, the overvoltage generated by the power input terminal pack+ can charge the two or more capacitors at the same time, and the current absorption unit 232 can absorb the discharge current of the two or more capacitors, thereby protecting the related devices in the first protection circuit 22.

[0058] For example, refer to Figure 4 The voltage absorption unit may include: a second capacitor C2 and a third capacitor C3 connected in series. The overvoltage generated by the power input terminal pack+ charges the second capacitor C2 and the third capacitor C3 at the same time. The second capacitor C2 and the third capacitor C3 form a discharge loop with the current absorption unit, so that the current absorption unit absorbs the discharge current of the second capacitor C2 and the third capacitor C3 through the discharge loop.

[0059] In one embodiment of the present invention, in order to reduce costs, resistors may be used to implement the current absorption unit 232. The number of resistors used may be set according to the resistance of the resistors themselves, different system requirements, and the actual discharge size of the voltage absorption unit 231.

[0060] In one embodiment, the current absorbing unit 232 may include only one resistor. Figure 3 and Figure 4 The current absorption unit may only include a first resistor R1, and the first resistor R1 is connected in series with the capacitor in the voltage absorption unit to absorb the current discharged by the capacitor.

[0061] In another embodiment, the current absorbing unit 232 may include more than two resistors, and the two or more resistors may be connected in parallel, thereby improving the discharge current absorbing effect and reducing the instantaneous power of the resistors.

[0062] For example, refer to Figure 5 and Figure 6The current absorbing unit may include a second resistor R2 and a third resistor R3 connected in parallel. The second resistor R2 and the third resistor R3 jointly absorb the current discharged by the capacitor.

[0063] In some embodiments, the voltage absorption unit may include more than two capacitors, and the current absorption unit may include more than two resistors, so as to improve the voltage absorption effect and the current absorption effect at the same time, and further enhance the protection effect.

[0064] In the specific implementation, refer to Figures 3 to 6 , the first protection circuit 22 may include: a TVS tube, the anode of the TVS tube is connected to the power input terminal, and the cathode is grounded. The number of TVS tubes in the first protection circuit 22 may be only one, or two or more. When the number of TVS tubes is more than two, the more than two TVS tubes may be connected in series.

[0065] In the specific implementation, refer to Figures 3 to 6 The battery management unit may further include an electric fuse F. One end of the electric fuse F is connected to the power input terminal pack+, and the other end is connected to the first protection circuit 22, and is used to be blown when the current provided by the power input terminal pack+ is too large, thereby providing overcurrent protection for the analog front-end chip 22.

[0066] In one embodiment of the present invention, referring to Figures 3 to 6 The battery management unit may further include: an inductor L. The inductor L may be used to prevent a voltage mutation provided by the power input terminal pack+, thereby providing voltage mutation protection for the analog front-end chip 22 .

[0067] It should be noted that, in a specific implementation, the battery management unit may only be provided with an electric fuse, or only be provided with an inductor, or may be provided with an electric fuse and an inductor at the same time between the power input terminal pack+ and the first protection circuit.

[0068] From the above content, it can be seen that by setting up a second protection circuit to absorb overvoltage, provide a discharge circuit, and absorb the discharge current at the same time, it is possible to protect the related devices in the first protection circuit and enhance the protection of the analog front-end chip. In addition, according to different system requirements and actual overvoltage waveforms, a variety of resistor and capacitor combinations are set to implement the second protection circuit, which can greatly reduce costs.

[0069] The present utility model also provides a battery module, which may include:

[0070] at least one battery cell;

[0071] and a battery management unit connected to the battery cell;

[0072] The battery management unit may refer to the description in the above embodiment and will not be described again here.

[0073] In a specific implementation, the battery module includes more than two battery cells; the more than two battery cells are connected in series or in parallel.

[0074] The embodiment of the present utility model further provides a battery cluster, which may include two or more battery modules in the above embodiments.

[0075] Figure 7 FIG. 1 is a schematic diagram of the structure of a battery cluster in an embodiment. Figure 7 The battery cluster may include X battery modules, namely, the first battery module Pack1, the second battery module Pack2, ..., the Xth battery module PackX, where X≥2. Each battery module may include n battery cells, namely, the first battery cell Cell1, the second battery cell Cell2, ..., the nth battery cell Celln, where n≥1. The n battery cells are connected in parallel.

[0076] Each battery module may further include a battery management unit, wherein the first battery module Pack1 includes a first battery management unit BMU1, the second battery module Pack2 includes a second battery management unit BMU2, ..., and the Xth battery module PackX includes an Xth battery management unit BMUX.

[0077] After X battery modules are connected in series, they are connected to a switch box SG through a busbar or copper bar to form a battery cluster. Each battery management unit is equipped with an AFE chip, based on which communication between battery modules and between battery modules and switch box SG can be realized.

[0078] The battery management unit in the embodiment of the utility model can not only protect the power supply port of the AFE chip, but also prevent overvoltage from breaking through the TVS tube to form a ground loop, avoid self-discharge of the battery cell until the PACK is scrapped, thereby improving the economy and safety of the energy storage system.

[0079] Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the scope defined by the claims.

Claims

1. A battery management unit, characterized in that: include: Analog front-end chip; A first protection circuit, located between a power input terminal and a power supply port of the analog front-end chip, for performing overvoltage protection on the analog front-end chip; and a second protection circuit connected to the first protection circuit, configured to absorb the overvoltage generated at the power input terminal and discharge it, and to absorb the discharge current; The second protection circuit includes: a voltage absorption unit for absorbing the overvoltage generated at the power input end; and a current absorption unit connected in series with the voltage absorption unit for absorbing the discharge current of the voltage absorption unit.

2. The battery management unit according to claim 1, characterized in that: The second protection circuit is connected in parallel with the first protection circuit.

3. The battery management unit according to claim 1 or 2, characterized in that: The voltage absorption unit includes: a capacitor.

4. The battery management unit according to claim 1 or 2, characterized in that: The voltage absorption unit includes: two or more capacitors, and the two or more capacitors are connected in series.

5. The battery management unit according to claim 1 or 2, characterized in that: The current absorbing unit includes: a resistor.

6. The battery management unit according to claim 1 or 2, characterized in that: The current absorbing unit includes: more than two resistors, and the more than two resistors are connected in parallel.

7. The battery management unit according to claim 1 or 2, characterized in that: The first protection circuit includes: a TVS tube; an anode of the TVS tube is connected to the power input terminal, and a cathode is grounded.

8. The battery management unit according to claim 1 or 2, characterized in that: Also includes: An electric fuse has one end connected to the power input end and the other end connected to the first protection circuit.

9. The battery management unit according to claim 8, characterized in that: Also includes: An inductor is connected in series with the electrical fuse.

10. A battery module, characterized in that: include: at least one battery cell; And a battery management unit connected to the battery cell, wherein the battery management unit is as described in any one of claims 1 to 9.

11. The battery module according to claim 10, characterized in that: The battery module includes more than two battery cells; the more than two battery cells are connected in series or in parallel.

12. A battery cluster, characterized in that: include: Two or more battery modules according to claim 10 or 11.

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