Integrated active discharge topology circuit for power battery

Abstract

The utility model belongs to the technical field of power battery output control, and discloses an integrated active discharge topology circuit for a power battery, which comprises the power battery, a power control device, a power plug connector, a bus support capacitor and a motor controller, the first switch device, the second switch device, the third switch device and the fourth switch device are respectively connected with the battery management system; the pre-charging circuit and the active discharging circuit are combined through the power control device, the circuit structure is simplified, the cost is reduced, the structural space is optimized, and the overall circuit experience can be guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of power battery output control, and particularly relates to an integrated active discharge topology circuit for a power battery. Background Technique

[0002] When the power battery system of a new energy vehicle drives a motor controller, a bus support capacitor is often set to smooth the bus voltage and absorb the peak instantaneous voltage to ensure the safety of the circuit. Among them, the power battery system also needs to set a pre-charge circuit for the bus support capacitor to avoid a huge transient large current impact in the high-voltage system at the moment when the high-voltage relay closing loop is connected, because the bus support capacitor is instantaneously equivalent to an open circuit and the resistance in the power battery system is too small.

[0003] In addition, in the event of a collision accident or other emergency conditions that cause the high-voltage loop to disconnect, the above-mentioned bus support capacitor, as an energy storage element, still has a high voltage after power-off, and the active discharge often takes a long time, which will also affect the safety of the entire high-voltage system.

[0004] The pre-charge circuit and the active discharge circuit of the existing power battery system are often designed separately. That is, the pre-charge circuit uses a pre-charge resistor to form a first-order charging circuit to charge the bus support capacitor, and the active discharge circuit is a discharge resistor or electronic component set at the motor controller end to consume the energy of the bus support capacitor. However, since this design method requires charging and discharging the bus support capacitor, not only is the overall circuit design too complex, occupying space, but also the design cost is relatively high, which affects the overall circuit experience. Summary of the Invention

[0005] In order to solve the problems of the existing design method mentioned above, that is, it is necessary to charge and discharge the bus support capacitor, not only the overall circuit design is too complex, occupying space, but also the design cost is relatively high, which affects the overall circuit experience, the utility model proposes an integrated active discharge topology circuit for a power battery, and its technical solution is as follows:

[0006] The utility model provides an integrated active discharge topology circuit for a power battery. The circuit includes a power battery, a power control device, a power connector, a bus support capacitor, a motor controller, and a first switch device, a second switch device, a third switch device, and a fourth switch device respectively connected to a battery management system, wherein:

[0007] The positive pole of the power battery is respectively connected to one end of the first switch device and one end of the second switch device, and the negative pole of the power battery is connected to one end of the third switch device;

[0008] One end of the power control device is connected to the other end of the second switching device, and the other end of the power control device is connected to the positive input terminal of the power connector;

[0009] The positive input terminal of the power connector is also connected to the other end of the first switching device. The positive output terminal of the power connector is respectively connected to one end of the bus support capacitor and one end of the motor controller. The negative input terminal of the power connector is respectively connected to the other end of the third switching device and one end of the fourth switching device. The negative output terminal of the power connector is respectively connected to the other end of the bus support capacitor and the other end of the motor controller;

[0010] The other end of the fourth switching device is connected to the other end of the second switching device.

[0011] In an alternative solution, the circuit further includes a fuse. One end of the fuse is connected to the positive electrode of the power battery, and the other end of the fuse is respectively connected to one end of the first switching device and one end of the second switching device.

[0012] In another alternative solution, the circuit further includes a current sensor. One end of the current sensor is connected to the negative electrode of the power battery, and the other end of the current sensor is connected to one end of the third switching device.

[0013] In another alternative solution, the first switching device includes a first relay and a first normally open contact corresponding to the first relay. The first relay is connected to the battery management system. One end of the first normally open contact is connected to the positive electrode of the power battery, and the other end of the first normally open contact is connected to the positive input terminal of the power connector.

[0014] In another alternative solution, the second switching device includes a second relay and a second normally open contact corresponding to the second relay. The second relay is connected to the battery management system. One end of the second normally open contact is connected to the positive electrode of the power battery, and the other end of the second normally open contact is respectively connected to one end of the power control device and the other end of the fourth switching device.

[0015] In another alternative solution, the third switching device includes a third relay and a third normally open contact corresponding to the third relay. The third relay is connected to the battery management system. One end of the third normally open contact is connected to the negative electrode of the power battery, and the other end of the third normally open contact is connected to the negative input terminal of the power connector.

[0016] In another alternative solution, the fourth switching device includes a fourth relay and a fourth normally open contact corresponding to the fourth relay. The fourth relay is connected to the battery management system. One end of the fourth normally open contact is connected to the negative input terminal of the power connector, and the other end of the fourth normally open contact is connected to the other end of the second normally open contact.

[0017] In yet another alternative, the power connector is a power connector.

[0018] In yet another alternative, the power control device is a power resistor.

[0019] In yet another alternative, the power control device is a digital potentiometer.

[0020] Advantages of the present utility model:

[0021] An integrated active discharge topology circuit is provided in the power battery system. The circuit includes a power battery, a power control device, a power connector, a bus support capacitor, a motor controller, and a first switch device, a second switch device, a third switch device, and a fourth switch device respectively connected to the battery management system. When the power battery system enters the high-voltage stage, the battery management system sends driving signals to the second switch device and the third switch device respectively, so that the bus support capacitor and the power control device form a first-order charging circuit, and the voltage of the bus support capacitor gradually rises under the output of the power battery until it approaches the voltage of the power battery. When the power battery system enters the low-voltage stage, the battery management system stops sending driving signals to the second switch device and the third switch device, and sends a driving signal to the fourth switch device, so that the bus support capacitor and the power control device form a first-order discharge circuit, and the energy of the bus support capacitor is quickly released through the heating of the power control device. Furthermore, the pre-charging circuit and the active discharge circuit are combined through the power control device, which not only simplifies the circuit structure, reduces costs, and optimizes the structural space, but also ensures the overall circuit experience. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic diagram of the effect of an integrated active discharge topology circuit for a power battery provided by an embodiment of the present utility model;

[0024] Figure 2 It is a schematic diagram of the structure of an integrated active discharge topology circuit for a power battery provided by an embodiment of the present utility model;

[0025] Figure 3 It is another schematic diagram of the structure of an integrated active discharge topology circuit for a power battery provided by an embodiment of the present utility model;

[0026] Figure 4It is a schematic structural diagram of another integrated active discharge topology circuit for power batteries provided by an embodiment of the present utility model. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model.

[0028] In the following description, the terms "first" and "second" are only for the purpose of description and cannot be construed as indicating or implying relative importance. The following description provides multiple embodiments of the present utility model. Different embodiments can be replaced or combined. Therefore, the present utility model can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present utility model should also be considered to include embodiments containing all other possible combinations of A, B, C, and D, although such embodiments may not be explicitly described in the following content.

[0029] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes can be made to the functions and arrangements of the described elements without departing from the scope of the content of the present utility model. Each example can appropriately omit, substitute, or add various processes or components. For example, the described method can be executed in a different order from the described order, and various steps can be added, omitted, or combined. In addition, the features described in some examples can be combined into other examples.

[0030] Please refer to Figure 1 , Figure 1 which shows a schematic diagram of the effect of an integrated active discharge topology circuit for power batteries provided by an embodiment of the present application.

[0031] As Figure 1 shown, the integrated active discharge topology circuit for power batteries can at least include a power battery, a power control device, a power connector, a bus support capacitor, a motor controller, and a first switch device, a second switch device, a third switch device, and a fourth switch device respectively connected to a battery management system (Battery Management System, BMS). The battery management system can be an automotive control system well known in the art and will not be elaborated here too much.

[0032] Among them, the power battery in the power battery system can be used to output power to the motor controller. The positive electrode of the power battery is respectively connected to one end of the first switch device and one end of the second switch device, and the negative electrode of the power battery is connected to one end of the third switch device.

[0033] The power control device can act as a resistor within the power battery system for pre-charging the bus support capacitor and also for actively discharging the bus support capacitor. That is, through the power control device, the pre-charging circuit and the active discharging circuit of the bus support capacitor are combined. One end of the power control device is connected to the other end of the second switching device, and the other end of the power control device is connected to the positive input terminal of the power connector.

[0034] The power connector can be understood as an important component within the power battery system that connects the power battery and the motor controller for transmitting power and signals, such as but not limited to the well-known high-voltage power connector in the art. The positive input terminal of the power connector is also connected to the other end of the first switching device. The positive output terminal of the power connector is respectively connected to one end of the bus support capacitor and one end of the motor controller. The negative input terminal of the power connector is respectively connected to the other end of the third switching device and one end of the fourth switching device. The negative output terminal of the power connector is respectively connected to the other end of the bus support capacitor and the other end of the motor controller.

[0035] Here, the first switching device, the second switching device, the third switching device, and the fourth switching device are all connected to the battery management system to achieve the on / off of the corresponding circuits according to the drive signals output by the battery management system. For example, but not limited to, when the battery management system outputs a drive signal to the first switching device, the first switching device can be switched from the off state to the on state, that is, the circuit between the positive electrode of the power battery and the positive input terminal of the power connector is turned on; another example is that when the battery management system outputs a drive signal to the second switching device, the second switching device can be switched from the off state to the on state, that is, the circuit between the positive electrode of the power battery and the power control device is turned on, and the circuit between the positive electrode of the power battery and the fourth switching device is turned on; another example is that when the battery management system stops outputting a drive signal to the third switching device, the third switching device can be switched from the on state to the off state, that is, the circuit between the negative electrode of the power battery and the negative input terminal of the power connector is turned off; another example is that when the battery management system stops outputting a drive signal to the fourth switching device, the fourth switching device can be switched from the on state to the off state, that is, the circuit between the second switching device and the negative input terminal of the power connector is turned off.

[0036] It can be understood that the drive signals output by the battery management system can be but not limited to high-level signals, and the manner in which the battery management system outputs drive signals to any of the above switching devices is a well-known battery management technical means in the art.

[0037] In the embodiment of the present utility model, when the battery management system monitors that the power battery system enters the high-voltage stage, the battery management system can send drive signals to the second switching device and the third switching device respectively, so that the bus support capacitor and the power control device form a first-order charging circuit, and the voltage of the bus support capacitor gradually rises under the output of the power battery until it approaches the power battery voltage. Here, after the bus support capacitor approaches the power battery voltage (that is, the pre-charging is completed), the battery management system can also send a drive signal to the first switching device to conduct the circuit between the positive pole of the power battery and the positive input terminal of the power connector, that is, to make the circuit where the power control device is located in a short-circuit state. At this time, the power battery can directly output the power supply to the motor controller, thereby avoiding additional power loss.

[0038] When the vehicle high-voltage system causes the high-voltage circuit to be disconnected due to other emergency conditions such as accidental collision or disconnection of the high-voltage plug, and the battery management system monitors that the power battery system enters the low-voltage stage, the battery management system can stop sending drive signals to the second switching device and the third switching device (when the first switching device is in the conducting state, it is also necessary to synchronously stop sending drive signals to the first switching device), and send a drive signal to the fourth switching device, so that the bus support capacitor and the power control device form a first-order discharging circuit, and the energy of the bus support capacitor is quickly released through the heat generation of the power control device. Furthermore, the pre-charging circuit and the active discharging circuit are combined through the power control device, which not only simplifies the circuit structure, reduces costs and optimizes the structural space, but also ensures the overall circuit experience.

[0039] As an option in the embodiment of the present utility model, the first switching device specifically includes a first relay and a first normally open contact corresponding to the first relay. The first relay can be connected to the signal output terminal of the battery management system. One end of the first normally open contact can be connected to the positive pole of the power battery, and the other end of the first normally open contact can be connected to the positive input terminal of the power connector. It can be understood that when the first relay does not receive the drive signal (or low-level signal) sent by the battery management system, the first normally open contact is in the open state; when the first relay receives the drive signal (or high-level signal) sent by the battery management system, the first normally open contact is in the conducting state.

[0040] As another option of the embodiment of the present utility model, the second switch device specifically includes a second relay and a second normally open contact corresponding to the second relay. The second relay can be connected to the signal output end of the battery management system. One end of the second normally open contact can be connected to the positive electrode of the power battery, and the other end of the second normally open contact is respectively connected to one end of the power control device and the other end of the fourth switch device. It can be understood that when the second relay does not receive the driving signal (or low-level signal) sent by the battery management system, the second normally open contact is in the off state; when the second relay receives the driving signal (or high-level signal) sent by the battery management system, the second normally open contact is in the on state.

[0041] As another option of the embodiment of the present utility model, the third switch device specifically includes a third relay and a third normally open contact corresponding to the third relay. The third relay can be connected to the signal output end of the battery management system. One end of the third normally open contact can be connected to the negative electrode of the power battery, and the other end of the third normally open contact is connected to the negative electrode input end of the power plug-in. It can be understood that when the third relay does not receive the driving signal (or low-level signal) sent by the battery management system, the third normally open contact is in the off state; when the third relay receives the driving signal (or high-level signal) sent by the battery management system, the third normally open contact is in the on state.

[0042] As another option of the embodiment of the present utility model, the fourth switch device specifically includes a fourth relay and a fourth normally open contact corresponding to the fourth relay. The fourth relay can be connected to the signal output end of the battery management system. One end of the fourth normally open contact can be connected to the negative electrode input end of the power plug-in, and the other end of the fourth normally open contact is connected to the other end of the second normally open contact. It can be understood that when the fourth relay does not receive the driving signal (or low-level signal) sent by the battery management system, the fourth normally open contact is in the off state; when the fourth relay receives the driving signal (or high-level signal) sent by the battery management system, the fourth normally open contact is in the on state.

[0043] As another option of the embodiment of the present utility model, the integrated active discharge topology circuit for the power battery may further include a fuse to avoid potential safety hazards to the entire circuit caused by current impact. One end of the fuse can be connected to the positive electrode of the power battery, and the other end of the fuse is respectively connected to one end of the first switch device and one end of the second switch device.

[0044] As another option of the embodiment of the present utility model, the integrated active discharge topology circuit for a power battery may further include a current sensor to feedback the real-time collected current signal to the battery management system, thereby ensuring the safety of the entire circuit. One end of the current sensor may be connected to the negative electrode of the power battery, and the other end of the current sensor is connected to one end of the third switching device.

[0045] Reference may also be made here Figure 2 to the structural schematic diagram of an integrated active discharge topology circuit for a power battery provided by the embodiment of the present utility model shown, as Figure 2 shown, the power connector may be exemplified as a line segment between end A and end B. End A may be used as the positive electrode of the power connector (including the positive electrode input terminal and the positive electrode output terminal), and end B may be used as the negative electrode of the power connector (including the negative electrode input terminal and the negative electrode output terminal).

[0046] Reference may also be made here Figure 3 to the structural schematic diagram of another integrated active discharge topology circuit for a power battery provided by the embodiment of the present utility model shown, as Figure 3 shown, when the battery management system monitors that the power battery system enters the high-voltage stage, the battery management system may respectively send drive signals to the second switching device and the third switching device (that is, turn on the circuits where the second switching device and the third switching device are located. The second switching device includes a relay connected to the battery management system and the normally open contact corresponding to the relay, and the third switching device includes a relay connected to the battery management system and the normally open contact corresponding to the relay), so that the bus support capacitor and the power control device form a first-order charging circuit, and the bus support capacitor gradually rises under the output of the power battery until it approaches the power battery voltage. Here, after the bus support capacitor approaches the power battery voltage (that is, the pre-charging is completed), the battery management system may also send a drive signal to the first switching device to turn on the circuit between the positive electrode of the power battery and the positive electrode input terminal of the power connector, that is, make the circuit where the power control device is located in a short-circuit state. At this time, the power battery can directly output the power supply to the motor controller, thereby avoiding additional power loss.

[0047] Reference may also be made here Figure 4 to the structural schematic diagram of another integrated active discharge topology circuit for a power battery provided by the embodiment of the present utility model shown, as Figure 4As shown, when the vehicle's high-voltage system experiences an emergency condition such as an accidental collision or disconnection of a high-voltage plug, resulting in the disconnection of the high-voltage circuit, and the battery management system monitors that the power battery system enters the low-voltage stage, the battery management system can stop sending drive signals to the second switch device and the third switch device (when the first switch device is in the conducting state, it is also necessary to synchronously stop sending drive signals to the first switch device), and send a drive signal to the fourth switch device (that is, turn on the circuit where the fourth switch device is located, and the fourth switch device includes a relay connected to the battery management system and the normally open contact corresponding to the relay), so that the bus support capacitor and the power control device form a first-order discharge circuit, and the energy of the bus support capacitor is quickly released through the heating of the power control device, and then the power control device merges and processes the pre-charge circuit and the active discharge circuit, which not only simplifies the circuit structure, reduces costs and optimizes the structural space, but also ensures the overall circuit experience.

[0048] As another option of the embodiment of the present invention, the power connector can be a power connector, for example but not limited to the HVP series high-voltage connectors of TE Connectivity, its rated voltage can be set to 600V, and the rated current can be set at 200A, and it is not limited to this.

[0049] As another option of the embodiment of the present invention, the power control device can be a power resistor, and in order to ensure the normal operation of both the pre-charge circuit and the active discharge circuit, the resistance value of the power resistor can be determined according to but not limited to the pre-charge depth, the active discharge depth, the pre-charge time, and the active discharge time. Here, the system voltage is preset as U0, the vehicle-mounted capacitor is preset as C, the pre-charge time is measured as T1, the active discharge time is measured as T2, the pre-charge depth is measured as 98%U0, and the active discharge depth is measured as 80%U0. Refer to the following calculation formula to obtain the power resistor:

[0050] T = R * C * ln[U0 / (U0 - U1)]

[0051] In the above formula, T can correspond to the minimum value between T1 and T2, R can correspond to the power resistor, C can correspond to the vehicle-mounted capacitor, and U1 can correspond to the maximum value between 98%U0 and 80%U0 (that is, 98%U0).

[0052] As another option of the embodiment of the present utility model, the power control device may also, but is not limited to, be a digital potentiometer. In addition to being connected to one end of the second switching device at one end and to the positive input terminal of the power connector at the other end, the digital potentiometer may also be connected to the battery management system to adjust a corresponding resistance value according to the digital signal output by the battery management system, and be applied in a pre-charge circuit or an active discharge circuit to further ensure the normal operation of the circuit on the basis of facilitating maintenance and replacement. Of course, in the embodiment of the present utility model, the power control device may also, but is not limited to, be an electronic adjustable resistor module, which specifically includes structures such as a digital adjustable resistor, a microcontroller, and a protection circuit, and is not limited thereto.

Claims

1. An integrated active discharge topology circuit for a power battery, characterized in that The circuit includes a power battery, a power control device, a power plug connector, a bus support capacitor, a motor controller, and a first switch device, a second switch device, a third switch device, and a fourth switch device respectively connected to a battery management system, where: The positive electrode of the power battery is respectively connected to one end of the first switch device and one end of the second switch device, and the negative electrode of the power battery is connected to one end of the third switch device; One end of the power control device is connected to the other end of the second switch device, and the other end of the power control device is connected to the positive input terminal of the power plug connector; The positive input terminal of the power plug connector is further connected to the other end of the first switch device. The positive output terminal of the power plug connector is respectively connected to one end of the bus support capacitor and one end of the motor controller. The negative input terminal of the power plug connector is respectively connected to the other end of the third switch device and one end of the fourth switch device. The negative output terminal of the power plug connector is respectively connected to the other end of the bus support capacitor and the other end of the motor controller; The other end of the fourth switch device is connected to the other end of the second switch device.

2. The circuit according to claim 1, wherein The circuit further includes a fuse. One end of the fuse is connected to the positive electrode of the power battery, and the other end of the fuse is respectively connected to one end of the first switch device and one end of the second switch device.

3. The circuit according to claim 1, characterized in that, The circuit further includes a current sensor. One end of the current sensor is connected to the negative electrode of the power battery, and the other end of the current sensor is connected to one end of the third switch device.

4. The circuit according to claim 1, wherein The first switch device includes a first relay and a first normally open contact corresponding to the first relay. The first relay is connected to the battery management system. One end of the first normally open contact is connected to the positive electrode of the power battery, and the other end of the first normally open contact is connected to the positive input terminal of the power plug connector.

5. The circuit according to claim 1, wherein The second switch device includes a second relay and a second normally open contact corresponding to the second relay. The second relay is connected to the battery management system. One end of the second normally open contact is connected to the positive electrode of the power battery, and the other end of the second normally open contact is respectively connected to one end of the power control device and the other end of the fourth switch device.

6. The circuit according to claim 1, wherein The third switch device includes a third relay and a third normally open contact corresponding to the third relay. The third relay is connected to the battery management system. One end of the third normally open contact is connected to the negative electrode of the power battery, and the other end of the third normally open contact is connected to the negative input terminal of the power plug connector.

7. The circuit according to claim 5, wherein The fourth switch device includes a fourth relay and a fourth normally open contact corresponding to the fourth relay. The fourth relay is connected to the battery management system. One end of the fourth normally open contact is connected to the negative input terminal of the power plug connector, and the other end of the fourth normally open contact is connected to the other end of the second normally open contact.

8. The circuit according to claim 1, wherein The power plug connector is a power connector.

9. The circuit according to claim 1, wherein The power control device is a power resistor.

10. The circuit according to claim 1, characterized in that, The power control device is a digital potentiometer.

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