An output switch circuit, power supply system and vehicle-mounted 12V lithium battery

Abstract

The present invention relates to an output switch circuit, a power supply system and a vehicle of a vehicle-mounted 12V lithium battery. The output switch circuit comprises an output switch channel and a control circuit, wherein the output switch channel comprises a first output switch channel and a second output switch channel connected in parallel therewith, the first output switch channel and the second output switch channel are connected in parallel, wherein the first output switch channel comprises a normally open relay, the normally open relay is driven by a G high-side MOSFET tube and controls its on or off, the second output switch channel comprises a first PMOS tube and a second PMOS tube connected back to back to the first PMOS tube, when the whole vehicle is in an awake state, the first output switch channel is turned on, when the whole vehicle is in a dormant state, the first output switch channel is turned off and the second output switch channel is turned on; the control circuit comprises an MCU module, a first current acquisition module and a second current acquisition module.

Description

Technical Field

[0001] The present invention relates to the field of vehicle-mounted equipment, and in particular to an output switch circuit of a vehicle-mounted 12V lithium battery, a power supply system and a vehicle. Background Art

[0002] At present, as vehicle fuel consumption indicators become increasingly stringent, the vehicle needs to be further lightweight while meeting safety requirements. As the heaviest component in low-voltage electronic systems, 12V batteries have a lot of room for lightweighting. The existing solution uses 12V lithium batteries to reduce weight to the greatest extent, but lithium batteries suitable for the main power supply of the vehicle's 12V network are currently rarely used in the market.

[0003] Among them, since the chemical reaction of 12V lithium batteries is more violent than that of traditional 12V lead-acid batteries, the functional safety level requirements for overcharge / over-discharge are relatively high, and they need to be protected by output switches. At present, the output switch application of lithium batteries on the whole vehicle is mainly based on the application of 48V and 350V high-voltage lithium batteries. The output switches of lithium batteries in such applications are all normally open and need to be switched between on and off according to the enabling model provided by the whole vehicle. In order to meet the power demand of some modules during the dormant period of the whole vehicle, the output switch of the 12V network main battery needs to meet the normally closed requirement. It will only be disconnected when the 12V lithium battery is overcharged or over-discharged. Compared with the normally open switch, the functional safety requirements are more stringent, and the related application scenarios are more complex. The existing vehicle lithium battery output switch strategy cannot fully meet all usage scenarios of 12V lithium batteries. Summary of the invention

[0004] In view of this, the present invention provides an output switch circuit of a vehicle-mounted 12V lithium battery, a power supply system and a vehicle. The output switch circuit is based on a battery management system and is used to adapt to all vehicle application scenarios of a vehicle 12V lithium battery module.

[0005] To achieve one or more of the above objectives, the present invention provides the following technical solutions.

[0006] According to a first aspect of the present invention, an output switch circuit of a vehicle-mounted 12V lithium battery is provided, the output switch circuit comprising an output switch channel and a control circuit, wherein: the output switch channel comprises a first output switch channel and a second output switch channel, the first output switch channel and the second output switch channel are connected in parallel, wherein the first output switch channel comprises a normally open relay, the normally open relay is driven by a G high-side MOSFET tube and controls its conduction or disconnection, the second output switch channel comprises a first PMOS tube and a second PMOS tube connected back to back to the first PMOS tube, when the whole vehicle is in an awake state, the first output switch channel is turned on, and when the whole vehicle is in a dormant state, the first output switch channel is disconnected and the second output switch channel is turned on; the control circuit comprises an MCU module, a first current acquisition module and a second current acquisition module.

[0007] According to the output switch circuit of an embodiment of the present invention, the MCU module is configured to send a control signal for switching the output switch channel.

[0008] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the first current acquisition module is configured to detect the module battery current signal and send the module battery current signal to the MCU module.

[0009] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is further configured to switch the output switch channel according to the module battery current signal to realize charging wake-up of an external charging device and discharging wake-up of an external power-consuming device.

[0010] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the second current acquisition module is configured to detect the second channel current signal of the second output switch channel and send the second channel current signal to the MCU module.

[0011] According to the output switching circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is configured to periodically perform a turn-on and then turn-off operation on the normally open relay when the entire vehicle is in the sleep state, and determine whether the normally open relay is stuck by calculating the difference between the module battery current signal and the second channel current signal.

[0012] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is configured to detect the second channel current signal through the second current acquisition module when the on-board 12V lithium battery is connected to the charging and discharging equipment when the whole vehicle is in the sleep state, wherein if the second channel current signal is greater than the normal sleep current threshold, the first output switch channel is turned on and the second output switch channel is disconnected, and the whole vehicle enters the wake-up state.

[0013] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is further configured to detect the module battery current signal through the first current acquisition module when the on-board 12V lithium battery is disconnected from the external connection of the charging and discharging device, wherein if the module battery current signal is less than the normal wake-up current threshold for a long time, the MCU module turns on the second output switch channel and disconnects the first output switch channel by sending the control signal, and the entire vehicle enters the sleep state.

[0014] According to the output switch circuit of another embodiment or any of the above embodiments of the present invention, the MCU module is configured to disconnect the first output switch channel and the second output switch channel by sending the control signal when it is detected that the on-board 12V lithium battery is in an overcharge or over-discharge state.

[0015] According to the output switch circuit of another embodiment or any of the above embodiments of the present invention, the MCU module is further configured to disconnect the first output switch channel and the second output switch channel by sending the control signal when receiving the hardware protection trigger signal issued by the whole vehicle.

[0016] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is configured to determine the external status of the vehicle-mounted 12V lithium battery and the battery output, so as to achieve self-test reset after disconnecting the first output switch channel and the second output switch channel.

[0017] According to the output switching circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is configured to make the output switching circuit enter the awakening state through the charging and discharging device when it detects that the on-board 12V lithium battery is in a deep power feeding state, and judge whether the on-board 12V lithium battery can be maintained by judging the external state of the on-board 12V lithium battery and the battery output.

[0018] According to the output switch circuit of another embodiment or any one of the above embodiments of the present invention, the MCU module is further configured to disconnect the first output switch channel by sending the control signal after determining that the on-board 12V lithium battery can be maintained.

[0019] According to a second aspect of the present invention, there is provided a vehicle-mounted 12V lithium battery power system, comprising a plurality of lithium battery cells connected in series and parallel, wherein the power system is provided with an output switching circuit according to any one of the preceding claims.

[0020] According to a third aspect of the present invention, there is provided an automobile, in which is provided an on-vehicle 12V lithium battery power supply system according to claim 14.

[0021] The first advantage of the output switch circuit, power supply system and automobile of the vehicle-mounted 12V lithium battery according to the present invention is that: by adopting a mode of combining a microcontroller unit (MCU) with a relay and a PMOS tube, there is no need to purchase large-scale discharge protection equipment, which effectively reduces the comprehensive cost of the battery management system (BMS). At the same time, the structure of the output switch circuit of the vehicle-mounted 12V lithium battery of this solution is relatively simple, which is conducive to mass production.

[0022] The second advantage of the output switch circuit, power supply system and automobile of the vehicle-mounted 12V lithium battery according to the present invention is that the present solution adopts a lighter 12V lithium battery to replace the traditional 12V lead-acid battery, which greatly reduces the weight of the BMS, making the BMS device more portable and also prolonging the battery life.

[0023] The third advantage of the output switching circuit, power supply system and automobile of the vehicle-mounted 12V lithium battery according to the present invention is that the output switching circuit proposed in this case can meet all usage scenarios of the 12V lithium battery, including but not limited to the normal wake-up and sleep switching conditions of the whole vehicle, the charging / discharging conditions of the 12V lithium battery external device, the adhesion detection function of the power relay of the first output switch channel of the 12V lithium battery, the overcharge / over-discharge protection function of the 12V lithium battery output switch channel, the self-test reset function after the output switch channel protection is disconnected, the external device maintenance function of the output switch channel under deep battery feeding, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or other aspects and advantages of the present invention will become clearer and easier to understand through the following description in conjunction with the accompanying drawings, in which the same or similar elements are represented by the same reference numerals. The accompanying drawings include:

[0025] Figure 1 is a schematic block diagram of an output switch circuit 100 of a vehicle-mounted 12V lithium battery according to an embodiment of the present invention;

[0026] Figure 2 FIG. 2 is a schematic block diagram of a vehicle-mounted 12V lithium battery power system 200 according to another embodiment of the present invention. DETAILED DESCRIPTION

[0027] In this specification, the present invention is more fully described with reference to the accompanying drawings in which exemplary embodiments of the present invention are illustrated. However, the present invention may be implemented in different forms and should not be construed as being limited to the embodiments given herein. The embodiments given are intended to make the disclosure herein comprehensive and complete, so as to more fully convey the scope of the present invention to those skilled in the art.

[0028] Terms such as "comprising" and "including" indicate that in addition to the units and steps directly and clearly stated in the specification and claims, the technical solution of the present invention does not exclude the situation of having other units and steps that are not directly or clearly stated. Terms such as "first" and "second" do not indicate the order of units in terms of time, space, size, etc., but are only used to distinguish each unit.

[0029] The present invention is described below with reference to the flowchart illustration, block diagram and / or flow chart of the method and system according to an embodiment of the present invention. It will be understood that each frame of these flowchart illustrations and / or block diagrams, and the combination of flowchart illustrations and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to form a machine, so that these instructions executed by the processor of a computer or other programmable data processing device create parts for implementing the functions / operations specified in these flowcharts and / or frames and / or one or more flowcharts.

[0030] These computer program instructions can be loaded onto a computer or other programmable data processor so that a series of operating steps are performed on the computer or other programmable processor to form a computer-implemented process so that these instructions performed on the computer or other programmable data processor provide steps for implementing the functions or operations specified in one or more frames of this flow chart and / or block diagram. It should also be noted that in some alternative implementations, the functions / operations shown in the frames may not occur in the order shown in the flow chart. For example, the two frames shown in sequence can actually be performed substantially simultaneously or these frames can sometimes be performed in reverse order, depending on the functions / operations involved.

[0031] In reference Figure 1 , Figure 1The present invention is a schematic block diagram of an output switch circuit 100 of a vehicle-mounted 12V lithium battery according to an embodiment of the invention. The output switch circuit 100 includes an output switch channel connected to a subsequent load and a control circuit for controlling its conduction and closure, state detection, and functional protection. The output switch channel includes a first output switch channel 110 and a second output switch channel 120, and the first output switch channel 110 and the second output switch channel are connected in parallel 120, wherein the first output switch channel 110 includes a normally open relay 111, and the normally open relay 111 is driven by a G high-side MOSFET tube and controls its conduction or disconnection. The second output switch channel 120 includes a first PMOS tube and a second PMOS tube connected back to back to the first PMOS tube. When the whole vehicle is in an awake state, the first output switch channel 110 is turned on, and when the whole vehicle is in a dormant state, the first output switch channel 110 is disconnected and the second output switch channel 120 is turned on. The control circuit includes an MCU module 130, a first current acquisition module 140, and a second current acquisition module 150.

[0032] The trigger conditions for switching the 12V lithium battery output switch from the normally closed channel 120 to the first output switch channel 110 include: the control signal sent by the MCU module 130 controls the channel switching to realize bus wake-up, power feeding maintenance and other working conditions; the module current sampling signal controls the channel switching to realize external charging device charging wake-up and external power-consuming device discharging wake-up.

[0033] The first output switch channel 110 has a relay contact sticking diagnosis function. The MCU module 130 regularly switches the relay on and off during the non-working hours of the first output switch channel 110, and tests whether there is current passing through the first output switch channel 110 when it is disconnected again, so as to determine whether the relay contacts can be completely disconnected and whether there is a risk of sticking.

[0034] The output switch circuit 100 of the vehicle-mounted 12V lithium battery has an external charging / discharging device wake-up function. When the battery terminal is connected to an external charging / discharging device, the MCU module 130 detects the module battery current signal through the first current detection module 150 without receiving the vehicle wake-up enable command, and autonomously switches the second output switch channel 120 to the first output switch channel 110, and switches the first output switch channel 110 to the second output switch channel 120 after charging is completed.

[0035] The output switch circuit 100 is also configured to have an overcharge / over-discharge protection disconnection function under all working conditions. That is, when the protection is triggered, the first output switch channel 110 and the second output switch channel 120 are disconnected at the same time. The protection triggering conditions include: the MCU module 130 determines that the 12V lithium battery module is overcharged / over-discharged and triggered; the hardware protection is triggered.

[0036] The output switch circuit 100 is also configured to have a self-checking and resetting function after the channel protection is disconnected, that is, the MCU module 130 implements the self-checking and resetting after the channel protection by judging the external state of the 12V lithium battery module and the battery output.

[0037] The output switch circuit 100 is also configured to have an external device maintenance function in the case of deep battery feeding. When the 12V lithium battery is fed and the first output switch channel 110 and the second output switch channel 120 are disconnected, the MCU module 130 can wake up the output switch circuit 100 by the output voltage of the external charging device, and determine whether the 12V lithium battery can be maintained by judging the 12V lithium battery feeding situation and the external charging device output situation, and turn on the first output switch channel 110 for maintenance after maintenance is allowed.

[0038] In reference Figure 2 , Figure 2 FIG. 2 is a schematic block diagram of a vehicle-mounted 12V lithium battery power system 200 according to another embodiment of the present invention.

[0039] As will be described in detail below, the system 200 can achieve different functions under the following vehicle operating conditions.

[0040] First, the vehicle wakes up normally from sleep switching. When the vehicle is in sleep mode, the gate of the fourth PMOS tube (shown as "Q4" in the figure) is connected to the positive power supply of the 12V lithium battery module to achieve the normal conduction of Q4. The first output switch channel of the 12V lithium battery system is directly grounded through Q4, thereby achieving the normally closed function of the first output switch channel under this condition.

[0041] When the vehicle sends a wake-up signal to the system 200, the MCU module receives the wake-up signal and sends action signals to set the first MCU control signal high and the second MCU control signal low to the first output switch channel and the second output switch channel respectively, that is, turning on the first output switch channel, and disconnecting the second output switch channel when the first output switch channel is turned on, thereby completing the switching process of the 12V lithium battery output channel after the vehicle is awakened.

[0042] When the vehicle is about to enter the sleep mode, the vehicle sends a sleep signal to the system 200. After receiving the sleep signal, the MCU module sends action signals to the first output switch channel and the second output switch channel, respectively, to pull down the first MCU control signal and set the second MCU control signal high, that is, to turn on the second output switch channel. When the second output switch channel is turned on, the first output switch channel is disconnected, thereby completing the 12V lithium battery output channel switching process when the vehicle is in sleep mode. At this time, since the system 200 enters the sleep state, the second output switch channel is turned on to the ground through the fourth PMOS tube with the gate electrode always pulled high, and since the power consumption required for the PMOS tube itself to turn on is extremely small, the low-power consumption and always-on function of the 12V lithium battery output switch circuit under the sleep condition of the vehicle is realized.

[0043] Second, the charging / discharging condition of the 12V lithium battery external device. When the 12V lithium battery power system 200 is in a dormant state and an external charging / discharging device is connected, the second shunt (shown as "shunt 2" in the figure) of the normally closed second output switch channel loop identifies the current change of the module power supply at this time. If the identified current signal is greater than the normal dormant current threshold, it is determined that the 12V lithium battery module is externally connected to a charging / discharging device at this time. The system turns on the first output switch channel and disconnects the second output switch channel through the output signal of the second current acquisition module (i.e., the second channel current signal). At the same time, the system 200 is awakened by this signal and enters a controllable state. When the external charging and discharging device is removed, the first shunt (shown as "shunt 1" in the figure) outputs a module battery current signal. If the signal is less than the wake-up threshold for a long time, the MCU module sends an action signal to the first output switch channel and the first output switch channel, respectively, to pull down the first MCU control signal and set the second MCU control signal high, that is, to turn on the first output switch channel, and disconnect the first output switch channel after the first output switch channel is turned on, thereby realizing the sleep action of the system 200 after the external charging is completed.

[0044] Third, the power relay adhesion detection function of the first output switch channel of the 12V lithium battery. The 12V lithium battery power system 200 regularly performs contact adhesion inspections on the power relay of the first output switch channel during the dormant period of the vehicle. When the second output switch channel is normally closed, the system 200 turns on the first output switch channel, and then disconnects the first output switch channel. The system 200 uses the difference between the module battery current signal and the second channel current signal in the process as the current signal of the first output switch channel. If the current signal of the first output switch channel has a relatively obvious process of first increasing and then decreasing (returning to the initial value) during the whole process, it proves that the power relay contacts of the first output switch channel can be turned on and off normally, and there is no adhesion.

[0045] Fourth, the 12V lithium battery output switch channel overcharge / over-discharge protection function. When the 12V lithium battery power system 200 detects that the 12V lithium battery module is overcharged / over-discharged, the MCU module sends an action signal to the first output switch channel and the second output switch channel, respectively, setting the first MCU control signal high and the second MCU control signal low, that is, disconnecting the first output switch channel and the second output switch channel at the same time.

[0046] When the 12V lithium battery power system 200 enters the overcharge / over-discharge protection mode, the system 200 periodically detects the internal and external states of the battery module, evaluates the system reset conditions, and turns on the corresponding output switch channel when the reset conditions are met.

[0047] When the system 200 is in an overcharge state, the system 200 periodically detects the external voltage and the real-time state of charge (SOC) of the 12V lithium battery module to determine whether the external charging condition disappears. If the external environment does not charge the 12V lithium battery, the system 200 controls the first output switch channel to be turned on. If it is determined that the vehicle is in a dormant state at this time, the MCU module controls the second output switch channel to be turned on and the first output switch channel to be turned off, so that the system 200 enters a dormant state.

[0048] Among them, SOC, also known as the remaining capacity, represents the ratio of the remaining capacity of the battery after it has been used for a period of time or has been left unused for a long time to its fully charged capacity, usually expressed as a percentage. Its value range is 0 to 1. When SOC = 0, it means that the battery is fully discharged, and when SOC = 1, it means that the battery is fully charged.

[0049] When the system 200 is in an over-discharge state, the system 200 determines whether the external discharge condition has disappeared and is in a charging standby condition by periodically detecting the external voltage and the real-time SOC of the 12V lithium battery module through the detection system. If the system is in a charging standby mode externally, the system 200 is powered by an external charging power supply, and the MCU module controls the first output switch channel to be turned on for charging maintenance of the lithium battery.

[0050] The embodiments and examples set forth herein are provided to best illustrate embodiments according to the present technology and its specific applications, and thereby enable those skilled in the art to make and use the present invention. However, those skilled in the art will appreciate that the above description and examples are provided for ease of illustration and example only. The description set forth is not intended to cover all aspects of the present invention or to limit the invention to the precise form disclosed.

Claims

1. An output switch circuit for a vehicle-mounted 12V lithium battery, characterized in that: The output switch circuit comprises an output switch channel and a control circuit, wherein: The output switch channel includes a first output switch channel and a second output switch channel, the first output switch channel and the second output switch channel are connected in parallel, wherein: The first output switch channel includes a normally open relay, which is driven by a G high-side MOSFET tube and controls its on or off. The second output switch channel includes a first PMOS tube and a second PMOS tube connected back-to-back with the first PMOS tube. When the vehicle is in the awake state, the first output switch channel is turned on. When the vehicle is in a dormant state, the first output switch channel is disconnected and the second output switch channel is turned on; The control circuit includes an MCU module, a first current acquisition module and a second current acquisition module. The first current acquisition module is configured to detect a module battery current signal and send the module battery current signal to the MCU module. The second current acquisition module is configured to detect a second channel current signal of the second output switch channel and send the second channel current signal to the MCU module. The MCU module is configured to periodically perform a turn-on and then turn-off operation on the normally open relay when the vehicle is in the dormant state, and determine whether the normally open relay is stuck by calculating the difference between the module battery current signal and the second channel current signal.

2. The output switch circuit according to claim 1, characterized in that: The MCU module is configured to send a control signal for switching the output switch channel.

3. The output switch circuit according to claim 1, characterized in that: The MCU module is further configured to switch the output switch channel according to the module battery current signal to achieve charging wake-up of an external charging device and discharging wake-up of an external power-consuming device.

4. The output switch circuit according to claim 1, characterized in that: The MCU module is configured to detect the second channel current signal through the second current acquisition module when the vehicle-mounted 12V lithium battery is connected to a charging and discharging device when the vehicle is in a dormant state, wherein: If the second channel current signal is greater than the normal sleep current threshold, the first output switch channel is turned on and the second output switch channel is turned off, and the entire vehicle enters the wake-up state.

5. The output switch circuit according to claim 4, characterized in that: The MCU module is further configured to detect the module battery current signal through the first current acquisition module when the vehicle-mounted 12V lithium battery is disconnected from the external connection of the charging and discharging device, wherein: If the module battery current signal is less than the normal wake-up current threshold for a long time, the MCU module turns on the second output switch channel and turns off the first output switch channel by sending the control signal, and the entire vehicle enters the sleep state.

6. The output switch circuit according to claim 5, characterized in that: The MCU module is configured to disconnect the first output switch channel and the second output switch channel by sending the control signal when it is detected that the on-board 12V lithium battery is in an overcharge or over-discharge state.

7. The output switch circuit according to claim 5, characterized in that: The MCU module is further configured to disconnect the first output switch channel and the second output switch channel by sending the control signal when receiving the hardware protection trigger signal issued by the whole vehicle.

8. The output switch circuit according to claim 6 or 7, characterized in that: The MCU module is configured to determine the external status of the vehicle-mounted 12V lithium battery and the battery output, so as to implement a self-test reset after disconnecting the first output switch channel and the second output switch channel.

9. The output switch circuit according to claim 8, characterized in that: The MCU module is configured to, when detecting that the on-board 12V lithium battery is in a deep power feeding state, enable the output switch circuit to enter the awakening state through the charging and discharging device, and determine whether the on-board 12V lithium battery can be maintained by judging the external state of the on-board 12V lithium battery and the battery output.

10. The output switch circuit according to claim 9, characterized in that: The MCU module is further configured to disconnect the first output switch channel by sending the control signal after determining that the vehicle-mounted 12V lithium battery can be maintained.

11. A vehicle-mounted 12V lithium battery power system, comprising a plurality of lithium battery cells connected in series and parallel, characterized in that: The power supply system is provided with an output switching circuit according to any one of the preceding claims.

12. A car, characterized in that: An on-vehicle 12V lithium battery power system according to claim 11 is provided.

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