阅读说明：本技术 一种动力电池回路中继电器的检测方法、装置及车辆 (Detection method and device for relay in power battery loop and vehicle ) 是由 刘嘉 于 2020-05-25 设计创作，主要内容包括：本发明提供了一种动力电池回路中继电器的检测方法、装置及车辆,其中,所述方法包括：接收上电请求；若第三电压的值为零且第二电压的值与第一电压的值相等,则控制预充继电器闭合；在预充继电器闭合后,若第三电压的值在第一预设时长内由零增长至第一电压的值,则确定主负继电器粘连,并控制动力电池回路停止上电；在接收到上电请求后,若先控制所述预充继电器闭合；并通过检测第三节点与第二节点之间的第三电压的值是否在第一预设时长内由零增长至所述第一电压的值,来确定主负继电器是否粘连,以实现有效地对主负继电器进行检测。在主负继电器粘连时,控制所述动力电池回路停止上电,可以避免安全隐患,进而提高所述车辆的安全性。(The invention provides a detection method and a detection device for a relay in a power battery loop and a vehicle, wherein the method comprises the following steps: receiving a power-on request; if the value of the third voltage is zero and the value of the second voltage is equal to the value of the first voltage, controlling the pre-charging relay to be closed; after the pre-charging relay is closed, if the value of the third voltage is increased to the value of the first voltage from zero within a first preset time period, determining that the main and negative relays are adhered, and controlling the power battery circuit to stop electrifying; after receiving a power-on request, if the pre-charging relay is controlled to be closed firstly; and whether the main and negative relays are adhered is determined by detecting whether the value of the third voltage between the third node and the second node is increased to the value of the first voltage from zero within a first preset time period, so that the main and negative relays are effectively detected. When the main and negative relays are adhered, the power battery loop is controlled to stop being electrified, so that potential safety hazards can be avoided, and the safety of the vehicle is improved.)

1. A detection method of a relay in a power battery loop is applied to a Battery Management System (BMS), the power battery loop comprises a first loop and a first branch, and the first loop comprises: the power battery, the main positive relay, the load and the main negative relay are sequentially connected in series; the first branch circuit comprises a pre-charging resistor and a pre-charging relay which are connected in series, the first branch circuit is connected with the main positive relay in parallel, and the pre-charging resistor is arranged close to the positive pole of the power battery, and the method is characterized by comprising the following steps:

receiving a power-on request;

if the value of the third voltage is zero and the value of the second voltage is equal to the value of the first voltage, controlling the pre-charging relay to be closed;

after the pre-charging relay is closed, if the value of the third voltage is increased to the value of the first voltage from zero within a first preset time period, determining that the main and negative relays are adhered, and controlling the power battery loop to stop electrifying;

the voltage between the positive electrode and the negative electrode of the power battery is a first voltage, the voltage between the first node and the second node is a second voltage, and the voltage between the third node and the second node is a third voltage; the first node is a node between a pre-charging resistor and the pre-charging relay, the second node is a node between the negative electrode of the power battery and the main negative relay, and the third node is a node between the main positive relay and the load.

2. The method of claim 1, wherein prior to controlling the pre-charge relay to close, the method further comprises:

if the value of the second voltage is zero, determining that the pre-charging resistor is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered and/or the pre-charging relay is adhered, and controlling the power battery loop to stop electrifying.

3. The method of claim 1, wherein after the pre-charge relay is closed, the method further comprises:

if the value of the third voltage is kept to be zero, determining that the pre-charging relay is open-circuited, and controlling the power battery loop to stop electrifying;

if the value of the third voltage is increased to the value of the first voltage from zero within a second preset time period, controlling the main and negative relays to be closed; and the second preset time length is less than the first preset time length.

4. The method of claim 3, wherein after controlling the main negative relay to close, the method further comprises:

if the value of the third voltage is equal to the value of the first voltage, determining that the main negative relay is open, and controlling the power battery loop to stop electrifying;

and if the value of the first voltage is greater than the value of the third voltage, and the value of the third voltage is greater than the product of the value of the first voltage and a preset coefficient, controlling the main positive relay to be closed and controlling the pre-charging relay to be opened.

5. The method of claim 4, wherein after controlling the main positive relay to close and the pre-charge relay to open, the method further comprises:

if the value of the third voltage is updated to zero, determining that the main positive relay is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, controlling the power battery loop to be electrified.

6. The method of claim 5, further comprising:

receiving a power-off request, and controlling the main positive relay and the main negative relay to be switched off;

if the value of the third voltage is updated to 0 from the value of the first voltage, and the value of the fourth voltage is updated to zero, controlling the power battery loop to be powered off; the voltage between the fourth node and the fifth node is a fourth voltage; the fourth node is a node between the positive pole of the power battery and the main positive relay, and the fifth node is a node between the main negative relay and the load.

7. The method of claim 6, wherein after controlling the main positive relay and controlling the main negative relay to open, the method further comprises:

if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered, and outputting alarm information;

and if the value of the fourth voltage is updated to the value of the first voltage, determining that the main and negative relays are adhered, and outputting alarm information.

8. A detection device of a relay in a power battery loop is applied to a Battery Management System (BMS), the power battery loop comprises a first loop and a first branch, and the first loop comprises: the power battery, the main positive relay, the load and the main negative relay are sequentially connected in series; first branch road is including the preliminary filling resistance and the preliminary filling relay of establishing ties, first branch road with main positive relay is parallelly connected, just preliminary filling resistance is close to power battery's anodal setting, its characterized in that, the device includes:

the receiving module is used for receiving a power-on request;

the control module is used for controlling the pre-charging relay to be closed if the value of the third voltage is zero and the value of the second voltage is equal to the value of the first voltage, determining that the main and negative relays are adhered if the value of the third voltage is increased from zero to the value of the first voltage within a first preset time period after the pre-charging relay is closed, and controlling the power battery loop to stop electrifying;

the voltage between the positive electrode and the negative electrode of the power battery is a first voltage, the voltage between the first node and the second node is a second voltage, and the voltage between the third node and the second node is a third voltage; the first node is a node between a pre-charging resistor and the pre-charging relay, the second node is a node between the negative electrode of the power battery and the main negative relay, and the third node is a node between the main positive relay and the load.

9. The apparatus of claim 8, wherein the control module, prior to controlling the pre-charge relay to close, is further configured to:

if the value of the second voltage is zero, determining that the pre-charging resistor is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered and/or the pre-charging relay is adhered, and controlling the power battery loop to stop electrifying.

10. The apparatus of claim 8, wherein the control module, after the pre-charge relay is closed, is further configured to:

if the value of the third voltage is kept to be zero, determining that the pre-charging relay is open-circuited, and controlling the power battery loop to stop electrifying;

if the value of the third voltage is increased to the value of the first voltage from zero within a second preset time period, controlling the main and negative relays to be closed; and the second preset time length is less than the first preset time length.

11. The apparatus of claim 10, wherein the control module, after controlling the main negative relay to close, is further configured to:

if the value of the third voltage is equal to the value of the first voltage, determining that the main negative relay is open, and controlling the power battery loop to stop electrifying;

and if the value of the first voltage is greater than the value of the third voltage, and the value of the third voltage is greater than the product of the value of the first voltage and a preset coefficient, controlling the main positive relay to be closed and controlling the pre-charging relay to be opened.

12. The apparatus of claim 11, wherein the control module, after controlling the main positive relay to close and the pre-charge relay to open, is further configured to:

if the value of the third voltage is updated to zero, determining that the main positive relay is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, controlling the power battery loop to be electrified.

13. The apparatus of claim 12, wherein the control module is further configured to:

receiving a power-off request, and controlling the main positive relay and the main negative relay to be switched off;

if the value of the third voltage is updated to 0 from the value of the first voltage, and the value of the fourth voltage is updated to zero, controlling the power battery loop to be powered off; the voltage between the fourth node and the fifth node is a fourth voltage; the fourth node is a node between the positive pole of the power battery and the main positive relay, and the fifth node is a node between the main negative relay and the load.

14. The apparatus of claim 13, wherein the control module, after controlling the main positive relay and controlling the main negative relay to open, is further configured to:

if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered, and outputting alarm information;

and if the value of the fourth voltage is updated to the value of the first voltage, determining that the main and negative relays are adhered, and outputting alarm information.

15. A vehicle characterized by comprising a detection device of a power cell circuit relay according to any one of claims 8 to 14.

Technical Field

The invention relates to the field of new energy automobiles, in particular to a method and a device for detecting a relay in a power battery loop and a vehicle.

Background

The control circuit of the power battery of the electric automobile mainly comprises a main positive relay, a main negative relay and a pre-charging relay, the three relays bear the duty of whether the electric energy of the power battery can be normally output or not, and the control circuit of the power battery of the electric automobile is also one of important guarantees of vehicle safety. If the three relays cannot be effectively detected, especially the main and negative relays cannot be effectively detected, the safety of the vehicle can be reduced, and potential safety hazards are caused.

Disclosure of Invention

The invention provides a detection method of a relay in a power battery loop, which solves the problems that a main relay and a negative relay cannot be effectively detected in the prior art, the safety of a vehicle is possibly reduced, and potential safety hazards are caused.

In order to achieve the above object, the present invention provides a method for detecting a relay in a power battery loop, which is applied to a battery management system BMS, wherein the power battery loop includes a first loop and a first branch, and the first loop includes: the power battery, the main positive relay, the load and the main negative relay are sequentially connected in series; first branch road is including the preliminary filling resistance and the preliminary filling relay of establishing ties, first branch road with main positive relay is parallelly connected, just preliminary filling resistance is close to power battery's anodal setting includes:

receiving a power-on request;

if the value of the third voltage is zero and the value of the second voltage is equal to the value of the first voltage, controlling the pre-charging relay to be closed;

after the pre-charging relay is closed, if the value of the third voltage is increased to the value of the first voltage from zero within a first preset time period, determining that the main and negative relays are adhered, and controlling the power battery loop to stop electrifying;

the voltage between the positive electrode and the negative electrode of the power battery is a first voltage, the voltage between the first node and the second node is a second voltage, and the voltage between the third node and the second node is a third voltage; the first node is a node between a pre-charging resistor and the pre-charging relay, the second node is a node between the negative electrode of the power battery and the main negative relay, and the third node is a node between the main positive relay and the load.

Optionally, before controlling the pre-charge relay to close, the method further comprises:

if the value of the second voltage is zero, determining that the pre-charging resistor is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered and/or the pre-charging relay is adhered, and controlling the power battery loop to stop electrifying.

Optionally, after the pre-charge relay is closed, the method further comprises:

if the value of the third voltage is kept to be zero, determining that the pre-charging relay is open-circuited, and controlling the power battery loop to stop electrifying;

if the value of the third voltage is increased to the value of the first voltage from zero within a second preset time period, controlling the main and negative relays to be closed; and the second preset time length is less than the first preset time length.

Optionally, after controlling the main negative relay to close, the method further comprises:

if the value of the third voltage is equal to the value of the first voltage, determining that the main negative relay is open, and controlling the power battery loop to stop electrifying;

and if the value of the first voltage is greater than the value of the third voltage, and the value of the third voltage is greater than the product of the value of the first voltage and a preset coefficient, controlling the main positive relay to be closed and controlling the pre-charging relay to be opened.

Optionally, after controlling the main positive relay to be closed and the pre-charge relay to be opened, the method further comprises:

if the value of the third voltage is updated to zero, determining that the main positive relay is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, controlling the power battery loop to be electrified.

Optionally, the method further comprises:

receiving a power-off request, and controlling the main positive relay and the main negative relay to be switched off;

if the value of the third voltage is updated to 0 from the value of the first voltage, and the value of the fourth voltage is updated to zero, controlling the power battery loop to be powered off; the voltage between the fourth node and the fifth node is a fourth voltage; the fourth node is a node between the positive pole of the power battery and the main positive relay, and the fifth node is a node between the main negative relay and the load.

Optionally, after controlling the main positive relay and controlling the main negative relay to be turned off, the method further comprises:

if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered, and outputting alarm information;

and if the value of the fourth voltage is updated to the value of the first voltage, determining that the main and negative relays are adhered, and outputting alarm information.

Another preferred embodiment of the present invention provides a detection apparatus for a relay in a power battery loop, which is applied to a battery management system BMS, wherein the power battery loop includes a first loop and a first branch, and the first loop includes: the power battery, the main positive relay, the load and the main negative relay are sequentially connected in series; first branch road is including the pre-charge resistance and the pre-charge relay of establishing ties, first branch road with main positive relay is parallelly connected, just the pre-charge resistance is close to power battery's positive setting, the device includes:

the receiving module is used for receiving a power-on request;

the control module is used for controlling the pre-charging relay to be closed if the value of the third voltage is zero and the value of the second voltage is equal to the value of the first voltage, determining that the main and negative relays are adhered if the value of the third voltage is increased from zero to the value of the first voltage within a first preset time period after the pre-charging relay is closed, and controlling the power battery loop to stop electrifying;

the voltage between the positive electrode and the negative electrode of the power battery is a first voltage, the voltage between the first node and the second node is a second voltage, and the voltage between the third node and the second node is a third voltage; the first node is a node between a pre-charging resistor and the pre-charging relay, the second node is a node between the negative electrode of the power battery and the main negative relay, and the third node is a node between the main positive relay and the load.

Optionally, the control module is further configured to, before controlling the pre-charge relay to close:

if the value of the second voltage is zero, determining that the pre-charging resistor is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered and/or the pre-charging relay is adhered, and controlling the power battery loop to stop electrifying.

Optionally, the control module is further configured to, after the pre-charge relay is closed:

if the value of the third voltage is kept to be zero, determining that the pre-charging relay is open-circuited, and controlling the power battery loop to stop electrifying;

if the value of the third voltage is increased to the value of the first voltage from zero within a second preset time period, controlling the main and negative relays to be closed; and the second preset time length is less than the first preset time length.

Optionally, after controlling the main negative relay to close, the control module is further configured to:

if the value of the third voltage is equal to the value of the first voltage, determining that the main negative relay is open, and controlling the power battery loop to stop electrifying;

and if the value of the first voltage is greater than the value of the third voltage, and the value of the third voltage is greater than the product of the value of the first voltage and a preset coefficient, controlling the main positive relay to be closed and controlling the pre-charging relay to be opened.

Optionally, after controlling the main positive relay to be closed and the pre-charge relay to be opened, the control module is further configured to:

if the value of the third voltage is updated to zero, determining that the main positive relay is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, controlling the power battery loop to be electrified.

Optionally, the control module is further configured to:

receiving a power-off request, and controlling the main positive relay and the main negative relay to be switched off;

if the value of the third voltage is updated to 0 from the value of the first voltage, and the value of the fourth voltage is updated to zero, controlling the power battery loop to be powered off; the voltage between the fourth node and the fifth node is a fourth voltage; the fourth node is a node between the positive pole of the power battery and the main positive relay, and the fifth node is a node between the main negative relay and the load.

Optionally, after controlling the main positive relay and controlling the main negative relay to be turned off, the control module is further configured to:

if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered, and outputting alarm information;

and if the value of the fourth voltage is updated to the value of the first voltage, determining that the main and negative relays are adhered, and outputting alarm information.

Still another preferred embodiment of the present invention provides a vehicle including the detection device of the power battery circuit relay as described above.

The technical method of the invention has the following beneficial effects:

according to the detection method of the relay in the power battery loop, after the power-on request is received, if the pre-charging relay is controlled to be closed firstly; and determining whether the main and negative relays are adhered or not by detecting whether the value of the third voltage between the third node and the second node is increased from zero to the value of the first voltage within a first preset time period or not, so as to effectively detect the main and negative relays. When the main and negative relays are adhered, the power battery loop is controlled to stop being electrified, so that potential safety hazards can be avoided, and the safety of the vehicle is improved.

Drawings

Fig. 1 is a schematic diagram of a power battery circuit provided in the present invention;

fig. 2 is a schematic flow chart of a method for detecting a relay in a power battery circuit according to the present invention;

fig. 3 is a schematic flow chart of a method for detecting a relay in a power battery loop power-on process according to the present invention;

fig. 4 is a schematic flow chart of a method for detecting a relay in a power down process of a power battery circuit according to the present invention;

fig. 5 is a schematic block diagram of a detection device of a relay in a power battery circuit according to the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments. In the following description, specific details such as specific configurations and components are provided only to help the full understanding of the embodiments of the present invention. Thus, it will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In various embodiments of the present invention, it should be understood that the sequence numbers of the following processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

It should be understood that the term "and/or" herein is merely one type of association relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiments provided herein, it should be understood that "B corresponding to a" means that B is associated with a from which B can be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may be determined from a and/or other information.

Example 1:

referring to fig. 1, a preferred embodiment of the present invention provides a power battery circuit including a first circuit and a first branch, the first circuit including: the power battery, the main positive relay, the load and the main negative relay are sequentially connected in series; the first branch circuit comprises a pre-charging resistor and a pre-charging relay which are connected in series, the first branch circuit is connected with the main positive relay in parallel, and the pre-charging resistor is close to the positive pole of the power battery. The voltage between the positive electrode and the negative electrode of the power battery is a first voltage (marked as V1 in figure 1), the voltage between the first node and the second node is a second voltage (marked as V2 in figure 1), and the voltage between the third node and the second node is a third voltage (marked as V3 in figure 1); the first node is a node between a pre-charging resistor and the pre-charging relay, the second node is a node between the negative electrode of the power battery and the main negative relay, and the third node is a node between the main positive relay and the load. The first voltage is represented by the V1, the second voltage is represented by the V2, and the third voltage is represented by the V3.

Example 2:

on the basis of the above embodiment, as shown in fig. 2, the present invention provides a schematic diagram of a detection method for a relay in a power battery circuit shown in fig. 1, which is applied to a Battery Management System (BMS), and includes the following steps:

it should be noted that, after receiving a power-on request, controlling the pre-charge relay to be closed, controlling the main negative relay to be closed, controlling the main positive relay to be closed, and controlling the pre-charge relay to be opened, the BMS detects and acquires the value of V1, the value of V2, and the value of V3, and determines the values.

Step 201: a power-up request is received.

Step 202: obtaining the value of V1, the value of V2, and the value of V3.

Step 203: if the value of V3 is zero and the value of V2 is equal to the value of V1, then the pre-charge relay is controlled to close.

Step 204: and after the pre-charging relay is closed, detecting the value of V3 again, and if the value of V3 is increased from zero to the value of V1 within a first preset time period, determining that the main relay and the negative relay are stuck, and controlling the power battery loop to stop electrifying.

Optionally, the BMS may output alarm information for prompting a relay failure, which is convenient for a driver or a service man to overhaul.

After receiving a power-on request, if the pre-charging relay is controlled to be closed firstly; and determining whether the main and negative relays are adhered or not by detecting whether the value of the third voltage between the third node and the second node is increased from zero to the value of the first voltage within a first preset time period or not, so as to effectively detect the main and negative relays. When the main and negative relays are adhered, the power battery loop is controlled to stop being electrified, so that potential safety hazards can be avoided, and the safety of the vehicle is improved.

Example 3:

on the basis of the above embodiments, as shown in fig. 3, the present invention provides a schematic flow chart of a method for detecting a relay in a power battery loop power-on process.

Step 301: a power-up request is received.

Step 302: obtaining the value of V1, the value of V2, and the value of V3.

Step 303: if the value of V2 is zero, determining that the pre-charging resistor is open-circuited, and controlling the power battery loop to stop powering up;

step 304: if the value of the V3 is equal to the value of the V1, which can also be expressed as V1-V3 being 0, the main positive relay is determined to be stuck and/or the pre-charging relay is determined to be stuck, and the power battery circuit is controlled to stop being powered up. Optionally, the BMS may output alarm information for prompting a relay failure, which is convenient for a driver or a service man to overhaul.

By determining the open circuit of the pre-charging resistor and/or the adhesion of the main positive relay and/or the adhesion of the pre-charging relay, the BMS controls the power battery loop to stop being powered on, so that the potential safety hazard can be avoided, and the safety of the vehicle is improved.

Step 305: if the value of V3 is zero and the value of V2 is equal to the value of V1, and the value of V3 is zero, which may also be represented as V1-V3 (i.e., V1), the precharge relay is controlled to be closed.

Step 306: after the pre-charging relay is closed, if the value of V3 is increased from zero to the value of V1 within a first preset time period, which can also be understood as that the value of V3 is rapidly increased from zero (millisecond level) to the value of V1, the main and negative relays are determined to be stuck, and the power battery circuit is controlled to stop being electrified. Optionally, the BMS may output alarm information for prompting a relay failure, which is convenient for a driver or a service man to overhaul.

By determining the adhesion of the main and negative relays, the BMS controls the power battery loop to stop being powered on, so that the potential safety hazard can be avoided, and the safety of the vehicle is improved.

After controlling the pre-charge relay to close, the BMS again detects the value of V3.

Step 307: and if the value of the V3 is kept to be zero, determining that the pre-charging relay is open, and controlling the power battery circuit to stop electrifying.

By determining that the pre-charging relay is open, the BMS controls the power battery loop to stop being powered on, so that potential safety hazards can be avoided, and the safety of the vehicle is improved.

Step 308: if the value of the V3 increases from zero to the value of the V1 within a second preset time period, which can also be understood as the value of the V3 suddenly changes from zero to the value of the V1, controlling the main and negative relays to be closed; and the second preset time length is less than the first preset time length.

After controlling the main negative relay to close, the BMS again detects the value of V3.

Step 309: and if the value of the V3 and the value of the V1 are equal, determining that the main negative relay is open, and controlling the power battery loop to stop electrifying. Optionally, the BMS may output alarm information for prompting a relay failure, which is convenient for a driver or a service man to overhaul.

By determining that the pre-charging relay is open, the BMS controls the power battery loop to stop being powered on, so that potential safety hazards can be avoided, and the safety of the vehicle is improved.

Step 310: and if the value of V1 is greater than the value of V3 and the value of V3 is greater than the product of the value of V1 and a preset coefficient, controlling the main positive relay to be closed and controlling the pre-charging relay to be opened.

Optionally, the value of V3 is greater than the product of the value of V1 and a predetermined coefficient, such as V3 > 0.95V1, or V3 > 0.9V1, where the predetermined coefficient may be determined according to the specific situation, for example, V3 > 0.95V 1.

After controlling the main positive relay to be closed and the pre-charge relay to be opened, the BMS again detects the value of V3.

Step 311: and if the value of the V3 is updated to be zero, determining that the main positive relay is open-circuited, and controlling the power battery loop to stop electrifying. Optionally, the BMS may output alarm information for prompting a relay failure, which is convenient for a driver or a service man to overhaul.

When the main positive relay is determined to be open, the BMS controls the power battery loop to stop electrifying, so that potential safety hazards can be avoided, and the safety of the vehicle is improved.

Step 312: and if the value of the V3 is equal to the value of the V1, controlling the power battery loop to be powered on, wherein the power battery loop is powered on successfully.

Example 4:

on the basis of the above embodiments, as shown in fig. 4, the present invention provides a schematic flow chart of a method for detecting a relay in a power down process of a power battery loop.

Step 401: and receiving a power-off request, and controlling the main positive relay to be switched off and the main negative relay to be switched off.

Wherein the BMS detects the value of the V3 and detects the value of a fourth voltage (labeled V4 in FIG. 1) again after controlling the main positive relay and the main negative relay to be turned off; wherein the voltage between the fourth node and the fifth node is the V4; the fourth node is a node between the positive pole of the power battery and the main positive relay, and the fifth node is a node between the main negative relay and the load.

Step 402: if the value of V3 is updated from the value of V1 to 0, which may be represented as V1-V3 (i.e., V1) and the value of V4 is updated to zero, which may be represented as V1-V4 (i.e., V1) respectively, then the power battery circuit is controlled to be powered down, i.e., the power battery circuit is successfully powered down.

Step 403: and if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered, and outputting alarm information.

Step 404: and if the value of the fourth voltage is updated to the value of the first voltage, determining that the main and negative relays are adhered, and outputting alarm information.

Alternatively, the BMS may output alarm information to a vehicle control unit, for example, and the vehicle control unit controls a display device to prompt. The display device can be an instrument panel in a vehicle or a vehicle-mounted display terminal, and the prompting mode can be prompting in a form of 'characters + icons', or alarming prompting through voice. The driver can be according to alarm information, the manual control vehicle is gone off the electricity, and then is right the vehicle overhauls, avoids the emergence of incident. The invention adopts a voltage comparison method to detect the power-on and power-off states of the relay, and has the advantages of low false alarm rate, wide fault coverage, cost and the like.

Based on the same technical concept as the detection method of the power battery loop relay described above, as shown in fig. 5, another preferred embodiment of the present invention provides a detection apparatus of a power battery loop relay, which is applied to a battery management system BMS, wherein the power battery loop includes a first loop and a first branch, and the first loop includes: the power battery, the main positive relay, the load and the main negative relay are sequentially connected in series; first branch road is including the pre-charge resistance and the pre-charge relay of establishing ties, first branch road with main positive relay is parallelly connected, just the pre-charge resistance is close to power battery's positive setting, the device includes:

a receiving module 501, configured to receive a power-on request;

the control module 502 is configured to control the pre-charge relay to be closed if a value of a third voltage is zero and a value of a second voltage is equal to a value of the first voltage, and after the pre-charge relay is closed, determine that the main and negative relays are adhered if the value of the third voltage increases from zero to the value of the first voltage within a first preset time period, and control the power battery circuit to stop powering up;

the voltage between the positive electrode and the negative electrode of the power battery is a first voltage, the voltage between the first node and the second node is a second voltage, and the voltage between the third node and the second node is a third voltage; the first node is a node between a pre-charging resistor and the pre-charging relay, the second node is a node between the negative electrode of the power battery and the main negative relay, and the third node is a node between the main positive relay and the load.

Optionally, the control module 502 is further configured to, before controlling the pre-charge relay to close:

if the value of the second voltage is zero, determining that the pre-charging resistor is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered and/or the pre-charging relay is adhered, and controlling the power battery loop to stop electrifying.

Optionally, the control module 502 is further configured to, after the pre-charge relay is closed:

if the value of the third voltage is kept to be zero, determining that the pre-charging relay is open-circuited, and controlling the power battery loop to stop electrifying;

if the value of the third voltage is increased to the value of the first voltage from zero within a second preset time period, controlling the main and negative relays to be closed; and the second preset time length is less than the first preset time length.

Optionally, the control module 502 is further configured to, after controlling the main negative relay to close:

if the value of the third voltage is equal to the value of the first voltage, determining that the main negative relay is open, and controlling the power battery loop to stop electrifying;

and if the value of the first voltage is greater than the value of the third voltage, and the value of the third voltage is greater than the product of the value of the first voltage and a preset coefficient, controlling the main positive relay to be closed and controlling the pre-charging relay to be opened.

Optionally, the control module 502 is further configured to, after controlling the main positive relay to be closed and controlling the pre-charge relay to be opened:

if the value of the third voltage is updated to zero, determining that the main positive relay is open-circuited, and controlling the power battery loop to stop electrifying;

and if the value of the third voltage is equal to the value of the first voltage, controlling the power battery loop to be electrified.

Optionally, the control module 502 is further configured to:

receiving a power-off request, and controlling the main positive relay and the main negative relay to be switched off;

if the value of the third voltage is updated to 0 from the value of the first voltage, and the value of the fourth voltage is updated to zero, controlling the power battery loop to be powered off; the voltage between the fourth node and the fifth node is a fourth voltage; the fourth node is a node between the positive pole of the power battery and the main positive relay, and the fifth node is a node between the main negative relay and the load.

Optionally, after controlling the main positive relay and the main negative relay to be turned off, the control module 502 is further configured to:

if the value of the third voltage is equal to the value of the first voltage, determining that the main positive relay is adhered, and outputting alarm information;

and if the value of the fourth voltage is updated to the value of the first voltage, determining that the main and negative relays are adhered, and outputting alarm information.

Still another preferred embodiment of the present invention provides a vehicle including the detection device of the power battery circuit relay as described above.

Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.