CN117713289A - New energy automobile power supply system and control method thereof - Google Patents

Abstract

The embodiment of the application provides a new energy automobile power supply system and a control method of the new energy automobile power supply system, wherein the system comprises the following components: the system comprises a battery cell module, a first branch, a second branch, a whole vehicle low-voltage load and a control unit; the first branch circuit is connected with the cell module in parallel, the first branch circuit comprises a first switch and a DCDC converter which are sequentially connected in series, and the first switch comprises a plurality of power switches which are connected in series; the second branch is connected with the first branch in parallel, the second branch comprises a relay group, a whole-vehicle high-voltage load and a second switch, the relay group, the whole-vehicle high-voltage load and the second switch are sequentially connected in series, and the second switch comprises a plurality of power switches which are connected in series; the whole vehicle low-voltage load is connected with the DCDC converter in parallel; the control unit is used for adjusting the opening and closing states of all the switches in the power supply system. The technical scheme provided by the embodiment of the application can improve the safety of the power supply system of the new energy automobile.

Description

New energy automobile power supply system and control method thereof

Technical Field

The application relates to the technical field of new energy automobiles, in particular to a new energy automobile power supply system and a control method of the new energy automobile power supply system.

Background

Along with the rapid development of new energy automobiles and electronic information technologies, the new energy automobiles and intelligent electric equipment are also greatly integrated. Firstly, as the configuration of the new energy automobile is diversified and the low-voltage power consumption is increased sharply due to the fact that the new energy automobile is diversified and the new energy automobile is increased in quantity, the traditional storage battery is easy to generate low voltage or feed of the storage battery, and further a series of problems such as incapacity of power on, relay adhesion and relay mechanical damage are caused, and the safety problem of a power supply system is easy to cause. Secondly, when the short circuit occurs to the whole vehicle high-voltage load, the relay in the power supply system is extremely easy to adhere, and under the condition that the fuse cannot be quickly fused, the whole vehicle high-voltage load can cause irreversible damage, and the safety problem of the power supply system is also easy to be caused due to the fact that the existing relay and the fuse have protection dead zones.

Disclosure of Invention

The embodiment of the application provides a new energy automobile power supply system and a control method of the new energy automobile power supply system, and the safety of the new energy automobile power supply system can be improved based on the technical scheme.

Other features and advantages of the present application will be apparent from the following detailed description, or may be learned in part by the practice of the application.

According to a first aspect of embodiments of the present application, there is provided a new energy automobile power supply system, the power supply system including: the system comprises a battery cell module, a first branch, a second branch, a whole vehicle low-voltage load and a control unit; the first branch circuit is connected with the cell module in parallel, the first branch circuit comprises a first switch and a DCDC converter which are sequentially connected in series, and the first switch comprises a plurality of power switches which are connected in series; the second branch is connected with the first branch in parallel, the second branch comprises a relay group, a whole-vehicle high-voltage load and a second switch, the relay group, the whole-vehicle high-voltage load and the second switch are sequentially connected in series, and the second switch comprises a plurality of power switches which are connected in series; the whole vehicle low-voltage load is connected with the DCDC converter in parallel; the control unit is used for adjusting the opening and closing states of all the switches in the power supply system.

In some embodiments of the present application, based on the foregoing solution, the first switch includes a first preset number of power switches, the first preset number is determined by a rated current value of the power switches, a maximum power value of the DCDC converter, and a minimum voltage value of the battery cell module.

In some embodiments of the present application, based on the foregoing solution, the second switch includes a second preset number of power switches, where the second preset number is determined by a rated current value of the power switches and a fast charge current value of the battery cell module.

In some embodiments of the present application, based on the foregoing, the relay group includes a main positive relay and a precharge relay connected in parallel, and a precharge resistor connected in series with the precharge relay.

In some embodiments of the present application, based on the foregoing, the second branch further includes a fuse connected in series.

In some embodiments of the present application, based on the foregoing solution, the system further includes a standby power supply connected in parallel with the whole vehicle low voltage load, where the standby power supply is configured to supply power to the whole vehicle low voltage load in a failure state of the DCDC converter.

According to a second aspect of embodiments of the present application, there is provided a control method of a power supply system of a new energy automobile, the method being performed by the control unit of any one of the first aspect, the method including: in response to receiving a power supply request, detecting whether the state of the power supply system is abnormal; determining at least one target switch from the power supply system that matches the power supply request if there is no abnormality in the state of the power supply system; and completing the power supply request by adjusting the opening and closing states of the target switches.

In some embodiments of the present application, based on the foregoing solution, if the power supply request is a high voltage power supply request, the determining, from the power supply system, at least one target switch that matches the power supply request includes: a first switch, a second switch, a main positive relay and a pre-charging relay in a relay group in the power supply system are used as the target switches; the step of completing the power supply request by adjusting the opening and closing states of the target switches includes: closing the first switch to start the DCDC converter; after the DCDC converter is started, closing the second switch and closing the pre-charging relay to pre-charge the whole vehicle high-voltage load; after the pre-charging of the whole vehicle high-voltage load is completed, closing the main positive relay; and switching off the pre-charging relay to supply power to the high-voltage load of the whole vehicle at high voltage.

In some embodiments of the present application, based on the foregoing solution, if the power supply request is a low voltage power supply request, the determining, from the power supply system, at least one target switch that matches the power supply request includes: taking a first switch in the power supply system as the target switch; the step of completing the power supply request by adjusting the opening and closing states of the target switches includes: and closing the first switch to supply low-voltage power to the whole vehicle low-voltage load.

In some embodiments of the present application, based on the foregoing scheme, the method further includes: acquiring loop current of the power supply system; if the loop current is larger than or equal to a first preset value and smaller than or equal to a second preset value, the second switch and the main positive relay are controlled to be disconnected so as to protect the power supply system; if the loop current is larger than the second preset value and smaller than or equal to a third preset value, the second switch is controlled to be disconnected so as to protect the power supply system; and if the loop current is larger than the third preset value, protecting the power supply system through a fuse arranged in the second branch circuit.

According to the technical scheme, the new energy automobile power supply system comprises: the system comprises a battery cell module, a first branch, a second branch, a whole vehicle low-voltage load and a control unit; the first branch circuit is connected with the cell module in parallel, the first branch circuit comprises a first switch and a DCDC converter which are sequentially connected in series, and the first switch comprises a plurality of power switches which are connected in series; the second branch is connected with the first branch in parallel, the second branch comprises a relay group, a whole-vehicle high-voltage load and a second switch, the relay group, the whole-vehicle high-voltage load and the second switch are sequentially connected in series, and the second switch comprises a plurality of power switches which are connected in series; the whole vehicle low-voltage load is connected with the DCDC converter in parallel; the control unit is used for adjusting the opening and closing states of all the switches in the power supply system. Because the DCDC converter is integrated in the power supply system, the DCDC converter is used for supplying power to the low-voltage load of the whole vehicle, the problems that the relay cannot be attracted, the relay is adhered and the like when the traditional storage battery is low in the prior art can be solved, and the safety of the power supply system can be further improved; in addition, the first switch and the second switch designed in the power supply system are not traditional relays, but power switches are adopted to replace the traditional relays, and the problems that the relays are adhered and cannot be attracted and the like are solved due to the fact that the power switches are not used, so that large-current breaking can be achieved, and the safety of the power supply system can be improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application. It is apparent that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art. In the drawings:

fig. 1 shows a schematic structural diagram of a new energy automobile power supply system according to an embodiment of the present application;

fig. 2 shows a flow chart of a control method of a new energy automobile power supply system according to an embodiment of the application.

The reference numerals are explained as follows:

10-cell module, 20-E-BOX,

21-DCDC converter, 30-control unit,

40-high voltage load of the whole vehicle, 41-motor controller,

50-low-voltage load of the whole vehicle, 60-standby power supply,

70-current sensor, 22-fuse,

23-a pre-charge resistor, which is connected to the power source,

80-first branch, 90-second branch,

k1-main positive relay, K2-pre-charge relay,

k3-first switch, K4-second switch.

Detailed Description

Exemplary embodiments that embody features and advantages of the present application are described in detail in the following description. It will be understood that the present application is capable of various modifications in various embodiments, all without departing from the scope of the present application, and that the description and illustrations herein are intended to be by way of illustration only and not to be limiting.

In the description of the present application, it should be noted that the azimuth or positional relationship indicated by the terms "vertical", "upper", "lower", "horizontal", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of description of the present application and simplification of the description, and do not indicate or imply that the system or element referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application.

In the description of the present application, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

According to a first aspect of embodiments of the present application, a new energy automobile power supply system is provided.

Referring to fig. 1, a schematic structural diagram of a new energy automobile power supply system according to one embodiment of the present application is shown.

In some embodiments, a power supply system is provided that includes a cell module 10.

The cell module 10 is used as a power source of the whole vehicle, can convert chemical energy into electric energy, and can further provide energy for loads.

In some embodiments, the cell module 10 includes a plurality of parallel cell modules, each of which includes a plurality of series-connected cell modules. For example, the cell module 10 may include three parallel cell groups, each including 34 series-connected cell units.

In some embodiments of the present application, the power supply system provided includes a first branch 80, where the first branch 80 is connected in parallel with the battery module 10, and the first branch 80 includes a first switch K3 and the DCDC converter 21 sequentially connected in series, and the first switch K3 includes a plurality of power switches connected in series.

In this embodiment, alternatively, the DCDC converter 21 may be a buck converter, which can convert an input high voltage into a low voltage.

In this embodiment, the power switch in the first switch K3 may be a power MOS transistor, an IGBT, a BJT, or the like, and specifically, the type of the selected power switch is not limited in this application.

In this embodiment, optionally, the first switch K3 includes a first preset number of power switches, where the first preset number is determined by a rated current value of the power switches, a maximum power value of the DCDC converter 21, and a minimum voltage value of the battery cell module 10.

For example, assuming that the cell module 10 includes 102 ternary lithium unit cells, the maximum voltage value of the 102 ternary lithium unit cells after being connected in series is 450V, the minimum voltage value is 284V, the highest power value of the dcdc converter 21 is 3KW, the power switch is a power MOS tube, and the rated current value of the power MOS tube is 20A, therefore, according to the electric power formula p=ui, it can be determined that the maximum current value through the first switch K3 is imax=p/u=3000/285= 10.526a.

Because the rated power that a power MOS pipe can endure is 20A, taking into account the impact of peak current, so under this kind of condition, can design first switch K3 to be by 2 power MOS switches to establish ties and make up, i.e. first preset quantity is 2.

In this embodiment, optionally, the DCDC converter 21 and the first switch K3 may be integrated in the E-BOX20, and the E-BOX20 may further include a main chip, and the main chip may be used to control the on/off state of the first switch K3, and may also control the distribution of the control of the DCDC converter 21.

In this embodiment, optionally, liquid cooling may be further configured in the E-BOX20, so that the DCDC converter 21 may be cooled, thereby improving the working performance and service life of the DCDC converter 21.

In some embodiments of the present application, the power supply system further includes a second branch 90, where the second branch 90 is connected in parallel with the first branch 80, the second branch 90 includes a relay group, a whole vehicle high voltage load 40, and a second switch K4, which are sequentially connected in series, and the second switch K4 includes a plurality of power switches connected in series.

In this embodiment, optionally, the entire vehicle high voltage load 40 may be connected to the high voltage connector so as to be connected in series in the second branch 90, where the high voltage connector is used to output the high voltage output by the cell module 10 to the entire vehicle high voltage load 40.

In this embodiment, alternatively, the whole vehicle high voltage load 40 may include a motor controller 41 of the whole vehicle, where the motor controller 41 can implement power distribution to a motor (EM), and the motor can implement conversion of electric energy into mechanical energy, so as to drive the vehicle.

In this embodiment, the power switch in the second switch K4 may be a power MOS transistor, an IGBT, a BJT, or the like, and specifically, the type of the selected power switch is not limited in this application.

In this embodiment, optionally, the second switch K4 may be integrated in the E-BOX20, so as to enable the main chip in the E-BOX20 to control the on/off of the second switch K4.

In this embodiment, optionally, the second switch K4 includes a second preset number of power switches, where the second preset number is determined by a rated current value of the power switches and a fast charge current value of the battery module 10.

For example, assuming that the fast charge current value of the fast charge of the cell module 10 is 400A, a second preset number of power MOS transistors are connected in series to form a second switch K4, and the rated current value of the power MOS switches is 20A, since the main positive relay K1 in the relay module is closed and the second switch K4 in the second branch 90 is closed during the fast charge of the cell module 10, the second switch K4 needs to withstand 400A of current, and 20 power MOS switches need to be designed, that is, the second switch K4 includes 20 power MOS transistors connected in series, and the second preset number is 20.

In the present embodiment, alternatively, the relay group includes a main positive relay K1 and a precharge relay K2 connected in parallel, and a precharge resistor 23 connected in series with the precharge relay K2.

It can be understood that the precharge relay K2 is closed, the high-voltage load 40 of the whole vehicle can be precharged through the cooperation of the precharge resistor 23, and then the high-voltage power supply of the battery cell module 10 to the high-voltage load 40 of the whole vehicle can be realized after the precharge relay K2 is opened through the closing of the main positive relay K1.

In this embodiment, optionally, the second branch 90 further includes a fuse 22 connected in series.

The fuse 22 can realize rapid power cut-off when the problems of short circuit, overcurrent and the like occur in the new energy automobile, thereby protecting a power supply system, protecting passengers and load safety and reducing the loss of the whole automobile.

In some embodiments of the present application, the power supply system further includes a whole-vehicle low-voltage load 50, where the whole-vehicle low-voltage load 50 is connected in parallel with the DCDC converter 21.

In this embodiment, the low-voltage load 50 is a low-voltage power load of the whole vehicle, including but not limited to a controller, an audio-visual system, a small-sized motor, etc.

In this embodiment, alternatively, the whole-vehicle low-voltage load 50 may be connected to a low-voltage connector for realizing output of the low voltage output from the DCDC converter 21 to the whole-vehicle low-voltage load 50 in parallel with the DCDC converter 21.

In the present application, the following three advantageous effects can be achieved by integrating the DCDC converter 21 inside the battery: in the first aspect, low-voltage power supply to the whole vehicle low-voltage load 50 can be realized without interruption even in the high-voltage power supply process; in the second aspect, after the DCDC converter 21 is placed in the battery, the DCDC converter 21 can be cooled by the liquid cooling system in the battery, so that the performance and the service life of the DCDC converter 21 can be improved; in the third aspect, the DCDC converter 21 is used for supplying power to the low-voltage load 50 of the whole vehicle, so that the problems that the relay cannot be attracted and the relay is stuck due to low voltage of the storage battery can be solved, and the safety of a power supply system can be improved.

In some embodiments of the present application, a standby power supply 60 may also be designed in the power supply system, where the standby power supply 60 is connected in parallel with the low voltage load 50 of the whole vehicle, and the standby power supply 60 is used to supply power to the low voltage load 50 of the whole vehicle in the failure state of the DCDC converter 21.

In this embodiment, it should be noted that, if the first switch K3 fails, the DCDC converter 21 fails, so that the DCDC converter 21 is in a failure state, so that low-voltage power cannot be supplied to the whole vehicle low-voltage load 50 through the DCDC converter 21, and the set standby power supply 60 can be started to supply power to the whole vehicle low-voltage load 50, so that the working stability of the whole vehicle low-voltage load 50 can be ensured, and further the riding experience of a user is improved.

In this embodiment, alternatively, a 12V power supply may be used as the backup power supply 60.

In the present embodiment, it is understood that if the electric energy stored in the backup power supply 60 is consumed, it can be charged through the DCDC converter 21.

Therefore, in the present application, since the DCDC converter 21 is integrated inside the battery, the standby power supply 60 of the whole vehicle can select the battery product with low cost, low weight and low capacity for backup, and further the cost performance of the whole vehicle can be improved.

In this application, it should be noted that the cell module 10 and the second branch 90 are connected in series to form a loop, and in some embodiments, a current sensor 70 may be disposed in the loop, where the current sensor 70 can collect loop current in the power supply system.

In some embodiments of the present application, the power supply system further comprises a control unit 30, wherein the control unit 30 is configured to adjust the open/close states of the respective switches in the power supply system.

In this embodiment, alternatively, the control unit 30 may be a BMS (BATTERY MANAGEMENT SYSTEM), i.e., a BATTERY management system.

In this embodiment, the control unit 30 may optionally be communicatively coupled to the current sensor 70, the main chip, the main positive relay K1, the pre-charge relay K2, the fuse 22, the backup power supply 60, and the like.

Therefore, the control unit 30 can obtain the loop current in the power supply system, so as to determine whether to disconnect certain switches or control the fuse 22 to work, so as to protect the power supply system, and the control unit 30 can also adjust the opening and closing states of all the switches in the power supply system, so as to realize power-up of the vehicle and power supply of the load; the control unit 30 can also control the backup power supply 60 to supply power to the whole-vehicle low-voltage load 50, and the like, when the DCDC converter 21 is in the disabled state.

In this application, the specific embodiment of the control unit 30 for adjusting the opening and closing states of the switches in the power supply system may be executed according to the control method of the new energy automobile power supply system provided in the second aspect, which is not described herein.

According to a second aspect of the embodiments of the present application, a control method of a new energy automobile power supply system is provided. The method is performed by the control unit 30 according to any of the embodiments of the first aspect.

Referring to fig. 2, a flow chart of a control method of a new energy automobile power supply system according to an embodiment of the present application is shown, which specifically includes the following steps 210 to 230:

in step 210, in response to receiving the power supply request, it is detected whether an abnormality exists in the state of the power supply system.

In step 210, the received power supply request may be a high voltage power supply request, where the high voltage power supply request is used to instruct the power supply system to supply power to the high voltage load 40 of the whole vehicle; the received power supply request may also be a low voltage power supply request that instructs the power supply system to perform a low voltage load on the entire vehicle low voltage load 50.

In step 210, if the types of the received power supply requests are different, there may be a difference in specific embodiments for detecting whether there is an abnormality in the state of the power supply system.

If the power supply request is a high voltage power supply request, in step 210, the specific embodiment of detecting whether there is an abnormality in the state of the power supply system may be performed as follows steps 211A to 215A:

step 211A, controlling each controller in the whole vehicle to perform self-test, if the self-test result of each controller in the whole vehicle shows that the whole vehicle is in a normal state, continuing to step 212A, and if the self-test result of each controller in the whole vehicle shows that the whole vehicle has related faults, acquiring the existing fault level; if the fault level is lower than the preset level, continuing to execute step 212A, and if the fault level is higher than or equal to the preset level, sending a fault message to prohibit the completion of the power supply request.

Step 212A, performing self-checking on the first switch K3, and determining whether the first switch K3 has a fault; if the first switch K3 has no fault, continuing to step 213A; if the first switch K3 has a fault, a fault message is sent and the power supply request is forbidden to be completed.

Step 213A, performing self-checking on the second switch K4, and determining whether the second switch K4 has a fault; if the second switch K4 has no fault, continuing to step 214A; if the second switch K4 has a fault, a fault message is sent and the power supply request is forbidden to be completed.

Step 214A, performing self-checking (for example, performing pre-charging three times continuously) on the pre-charging relay K2, and determining whether there is a fault in the pre-charging relay K2; if the pre-charge relay K2 has no fault, proceeding to step 215A, if the pre-charge relay K2 has a fault, sending a fault message and prohibiting completion of the power supply request.

Step 215A, performing self-checking on the main positive relay K1 (for example, charging is performed for a certain time and then the main positive relay K1 is disconnected), and determining whether the main positive relay K1 has a fault; if the main positive relay K1 has no fault, determining that the state of the power supply system has no abnormality, sending a success message, and continuing to step 220; if the main positive relay K1 has a fault, a fault message is sent, and the power supply request is forbidden to be completed.

If the power supply request is a low voltage power supply request, in step 210, the specific implementation of detecting whether there is an abnormality in the state of the power supply system may be performed according to the following steps 211B to 212B:

step 211A, controlling each controller in the whole vehicle to perform self-checking, if the self-checking result of each controller in the whole vehicle indicates that the whole vehicle is in a normal state, continuing to step 212B, and if the self-checking result of each controller in the whole vehicle indicates that the whole vehicle has related faults, acquiring the existing fault level; if the fault level is lower than the preset level, continuing to execute the step 212B, and if the fault level is higher than or equal to the preset level, sending a fault message and prohibiting the completion of the power supply request;

step 212B, performing self-checking on the first switch K3, and determining whether the first switch K3 has a fault; if the first switch K3 has no fault, determining that the state of the power supply system has no abnormality, sending a success message, and continuing to step 220; if the first switch K3 has a fault, the standby power supply 60 is started to supply power for the whole vehicle low-voltage load 50.

In summary, in the present application, before the power supply request is completed, the state detection is performed on the power supply system, so that the working safety of the power supply system can be improved, and further the riding safety, the load safety and the like of the user can be improved.

With continued reference to FIG. 2, if there is no anomaly in the state of the power supply system, at least one target switch is determined from the power supply system that matches the power supply request, step 220.

With continued reference to fig. 2, the power request is completed by adjusting the open and closed states of each of the target switches, step 230.

In this application, if the type of power supply request received is different, the specific implementation of performing step 220 and step 230 may be different.

If the received power supply request is a high voltage power supply request, embodiments of step 220 may be performed as follows step 221A, and embodiments of step 230 may be performed as follows steps 231A through 234A:

step 221A, using the first switch K3, the second switch K4, and the main positive relay K1 and the pre-charge relay K2 in the relay group in the power supply system as the target switches.

It will be appreciated that when high voltage power supply is required to the high voltage load 40 of the whole vehicle, the second switch K4 in the power supply system is required to be closed, and the main positive relay K1 is therefore closed, so that the target switch includes the second switch K4 and the main positive relay K1. In addition, before high-voltage power is supplied to the entire vehicle high-voltage load 40, the entire vehicle high-voltage load 40 needs to be precharged, so the target switch further includes a precharge relay K2; in addition, in order to realize that the power supply system can also realize low-voltage power supply to the whole vehicle low-voltage load 50 during high-voltage power supply, the target switch may further include the first switch K3, so that in a state where the first switch K3 is closed, the power supply system can also realize that the power supply system can also supply power to the whole vehicle low-voltage load 50 during high-voltage power supply.

In the present embodiment, the precondition that the first switch K3 is set as the target switch is that the first switch K3 is in an open state, and if the first switch K3 is detected to be in a closed state, the first switch K3 is not required to be set as the target switch.

At step 231A, the first switch K3 is closed to start the DCDC converter 21.

Step 232A, after the DCDC converter 21 is started, closes the second switch K4 and closes the precharge relay K2 to precharge the entire vehicle high voltage load 40.

Step 233A, after the priming of the whole vehicle high voltage load 40 is completed, the main positive relay K1 is closed.

Step 234A, the precharge relay K2 is turned off to supply the high voltage to the high voltage load 40 of the whole vehicle.

It will be appreciated that the received high voltage power supply request can be completed through steps 231A through 234A described above.

If the received power supply request is a high voltage power supply request, embodiments of step 220 may be performed as follows step 221B, and embodiments of step 230 may be performed as follows step 231B.

Step 221B, taking the first switch K3 in the power supply system as the target switch.

In step 231B, the first switch K3 is closed to supply low voltage to the low voltage load 50 of the whole vehicle.

It can be appreciated that when the received power supply request is a low voltage power supply request, the second switch K4 and the main positive relay K1 are not required to be closed, and the precharge process is not required to be executed, so that the low voltage power supply to the low voltage load 50 of the whole vehicle can be realized under the condition that only the first switch K3 is closed.

In some embodiments of the present application, during the high voltage power supply of the power supply system, the following steps 310 to 340 may be further performed:

step 310, obtaining a loop current of the power supply system.

In the present embodiment, alternatively, the loop current of the power supply system may be obtained by acquiring current data acquired by the current sensor 70 provided in the loop of the power supply system.

Step 320, if the loop current is greater than or equal to a first preset value and less than or equal to a second preset value, the second switch K4 and the main positive relay K1 are controlled to be turned off so as to protect the power supply system.

In this embodiment, optionally, the first preset value may be set to a current value of 1100A, 1200A, 1300A, or the like, which is not limited herein.

In this embodiment, optionally, the second preset value may be set to a current value of 2000A, 2100A, or the like, which is not limited herein.

In this embodiment, it should be noted that, in the current interval where the loop current is comprised of the first preset value and the second preset value, it is possible to indicate that the high voltage load 40 of the whole vehicle has a short circuit, but the short circuit current value is low and does not cause adhesion of the main positive relay K1, so that the power supply system can be protected by cutting off the second switch K4 and the main positive relay K1.

Step 330, if the loop current is greater than the second preset value and less than or equal to a third preset value, the second switch K4 is controlled to be turned off to protect the power supply system.

In this embodiment, optionally, the third preset value may be set to a current value of 3000a,3100a, or the like, which is not limited herein.

In this embodiment, it should be noted that, in the current interval where the loop current is comprised of the second preset value and the third preset value, it is possible to indicate that the entire vehicle high voltage load 40 has a short circuit, and the short circuit current value is high, if the main positive relay K1 is cut off, the main positive relay K1 will be stuck, so that only the second switch K4 is cut off.

It can be understood that, since the second switch K4 is obtained by connecting a plurality of power switches in series, even if the second switch K4 is turned off under the condition of high short-circuit current, the relay adhesion and other problems of the second switch K4 are not caused, and the power supply system can be protected with high efficiency.

Step 340, if the loop current is greater than the third preset value, protecting the power supply system through the fuse 22 disposed in the second branch 90.

Because in the prior art, the switch arranged in the power supply system is only a relay, if the whole vehicle high voltage load 40 is short-circuited, the fuse 22 is not fused timely, the relay adhesion is easy to be caused, and the whole vehicle high voltage is irreversibly damaged. In summary, since in the technical scheme of the application, different protection strategies can be executed based on different short-circuit working conditions, the main positive relay K1 existing in the power supply system cannot be adhered, and therefore a good protection effect can be achieved on the power supply system, and the safety of the power supply system is improved.

In some embodiments of the present application, a new energy automobile power supply system is provided, including: the cell module 10, the first leg 80, the second leg 90, the overall vehicle low voltage load 50, and the control unit 30; the first branch circuit 80 is connected in parallel with the battery cell module 10, the first branch circuit 80 includes a first switch K3 and a DCDC converter 21 sequentially connected in series, and the first switch K3 includes a plurality of power switches connected in series; the second branch 90 is connected in parallel with the first branch 80, the second branch 90 includes a relay group, a whole vehicle high-voltage load 40, and a second switch K4, which are sequentially connected in series, and the second switch K4 includes a plurality of power switches connected in series; the whole vehicle low-voltage load 50 is connected with the DCDC converter 21 in parallel; the control unit 30 is used for adjusting the open and closed states of the individual switches in the power supply system. Based on the technical scheme provided by the application, the following technical effects can be at least realized:

in the first aspect, since the DCDC converter 21 is integrated in the power supply system, the DCDC converter 21 is used for supplying power to the low-voltage load 50 of the whole vehicle, so that the problems that the relay cannot be attracted and the relay is adhered when the traditional storage battery is low in the prior art can be solved, and the safety of the power supply system can be improved;

in the second aspect, the first switch K3 and the second switch K4 designed in the power supply system are not traditional relays, but power switches are adopted to replace the traditional relays, and the problems that the relays are adhered and cannot be attracted and the like are solved, so that high-current breaking can be achieved, and the safety of the power supply system can be improved.

In the third aspect, the DCDC converter 21 is integrated inside the battery, and the temperature of the DCDC converter can be reduced by the liquid cooling system in the battery, so that the product performance and the service life are improved.

In the fourth aspect, after the DCDC converter 21 is placed in the battery, the battery backup power supply 60 of the whole vehicle can be backed up by using a product with low cost, low weight and low capacity, so that the cost performance of the whole vehicle can be improved.

The foregoing is merely exemplary of the present application and is not intended to limit the present application, and various modifications and variations may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the scope of the claims of the present application.

Claims (10)

1. A new energy automobile power supply system, characterized in that the power supply system comprises: the system comprises a battery cell module, a first branch, a second branch, a whole vehicle low-voltage load and a control unit;

the first branch circuit is connected with the cell module in parallel, the first branch circuit comprises a first switch and a DCDC converter which are sequentially connected in series, and the first switch comprises a plurality of power switches which are connected in series;

the second branch is connected with the first branch in parallel, the second branch comprises a relay group, a whole-vehicle high-voltage load and a second switch, the relay group, the whole-vehicle high-voltage load and the second switch are sequentially connected in series, and the second switch comprises a plurality of power switches which are connected in series;

the whole vehicle low-voltage load is connected with the DCDC converter in parallel;

the control unit is used for adjusting the opening and closing states of all the switches in the power supply system.

2. The system of claim 1, wherein the first switch comprises a first preset number of power switches, the first preset number determined by a rated current value of the power switches, a maximum power value of the DCDC converter, and a minimum voltage value of the cell module.

3. The system of claim 1, wherein the second switch comprises a second preset number of power switches, the second preset number determined by a rated current value of the power switches and a fast charge current value of the battery cell module.

4. The system of claim 1, wherein the relay set comprises a main positive relay and a pre-charge relay connected in parallel, and a pre-charge resistor connected in series with the pre-charge relay.

5. The system of claim 1, further comprising a series-connected fuse in the second branch.

6. The system of any one of claims 1 to 5, further comprising a backup power source connected in parallel with the whole vehicle low voltage load for powering the whole vehicle low voltage load in a failure state of the DCDC converter.

7. A control method of a new energy vehicle power supply system, characterized in that the method is performed in the control unit of any one of claims 1 to 6, the method comprising:

in response to receiving a power supply request, detecting whether the state of the power supply system is abnormal;

determining at least one target switch from the power supply system that matches the power supply request if there is no abnormality in the state of the power supply system;

and completing the power supply request by adjusting the opening and closing states of the target switches.

8. The method of claim 7, wherein if the power supply request is a high voltage power supply request, the determining at least one target switch from the power supply system that matches the power supply request comprises:

a first switch, a second switch, a main positive relay and a pre-charging relay in a relay group in the power supply system are used as the target switches;

the step of completing the power supply request by adjusting the opening and closing states of the target switches includes:

closing the first switch to start the DCDC converter;

after the DCDC converter is started, closing the second switch and closing the pre-charging relay to pre-charge the whole vehicle high-voltage load;

after the pre-charging of the whole vehicle high-voltage load is completed, closing the main positive relay;

and switching off the pre-charging relay to supply power to the high-voltage load of the whole vehicle at high voltage.

9. The method of claim 7, wherein if the power request is a low voltage power request, the determining at least one target switch from the power system that matches the power request comprises:

taking a first switch in the power supply system as the target switch;

the step of completing the power supply request by adjusting the opening and closing states of the target switches includes:

and closing the first switch to supply low-voltage power to the whole vehicle low-voltage load.

10. The method of claim 8, wherein the method further comprises:

acquiring loop current of the power supply system;

if the loop current is larger than or equal to a first preset value and smaller than or equal to a second preset value, the second switch and the main positive relay are controlled to be disconnected so as to protect the power supply system;

if the loop current is larger than the second preset value and smaller than or equal to a third preset value, the second switch is controlled to be disconnected so as to protect the power supply system;

and if the loop current is larger than the third preset value, protecting the power supply system through a fuse arranged in the second branch circuit.