MOS tube fault detection circuit and electric vehicle lithium battery

Abstract

The utility model provides an MOS transistor fault detection circuit and an electric vehicle lithium battery, the circuit comprises a sampling module, a discharge control circuit and a discharge signal detection circuit, the discharge control circuit comprises a fourth resistor and a first field effect transistor, and the discharge signal detection circuit comprises a first resistor, a second resistor and a fourth field effect transistor. The MOS tube fault detection circuit can detect the states of the control end and the first end of the first field-effect tube when the lithium battery of the electric vehicle discharges. If the fourth field-effect transistor is conducted by the enable signal during discharging of the battery and the signal received by the control unit is low level, the first field-effect transistor is judged to be normal, and if the fourth field-effect transistor is turned off during discharging and the signal received by the control unit is high level, the first field-effect transistor is judged to be abnormal; the discharge signal detection circuit confirms the state of the first field-effect tube through the on-off state of the fourth field-effect tube and the signal level detected by the control unit, so as to avoid the potential safety hazard caused in the use process of the battery.

Description

Technical Field

[0001] The present disclosure relates to the technical field of lithium batteries, and particularly to a MOS tube fault detection circuit and an electric vehicle lithium battery. Background Art

[0002] With the increasing trend towards green energy in daily life, electric vehicles are rising continuously in daily travel due to their advantages of convenience, environmental protection, and energy conservation. As the power source of electric vehicles, the stability, reliability, and safety of batteries are particularly important.

[0003] At present, in the case of discharging of electric vehicle lithium batteries, most of them adopt discharging with a communication protocol. If the discharge MOS tube of the battery management system BMS is damaged or fails due to current breakdown, and the lithium battery continues to discharge the load externally without being able to cut off the discharge in time, and the current circuit design does not detect the states of the source and gate of the discharge MOS tube during the discharge of the BMS, the service life of the electric vehicle lithium battery is reduced, and even potential safety hazards may occur. Summary of the Utility Model

[0004] The purpose of the present disclosure is to overcome the deficiencies in the prior art and provide a MOS tube fault detection circuit and an electric vehicle lithium battery with high safety performance that can detect the state of the discharge MOS tube at any time.

[0005] The purpose of the present disclosure is achieved through the following technical solutions:

[0006] A MOS tube fault detection circuit includes:

[0007] A sampling module;

[0008] A discharge control circuit, including a fourth resistor and a first field effect transistor. The first end of the fourth resistor is connected to the discharge signal enabling end of the sampling module, the second end of the fourth resistor is connected to the control end of the first field effect transistor, the first end of the first field effect transistor is grounded, and the second end of the first field effect transistor is used to connect to the drain of the charging MOS tube.

[0009] A discharge signal detection circuit, including a first resistor, a second resistor, and a fourth field effect transistor. The first end of the second resistor is connected to the first end of the fourth resistor, the second end of the second resistor is connected to the control end of the fourth field effect transistor, the first end of the fourth field effect transistor is connected to the first end of the first resistor, the first end of the first resistor is used to connect to the signal receiving end of the control unit, the second end of the first resistor is connected to the reference power supply, and the second end of the fourth field effect transistor is grounded.

[0010] In one embodiment, the discharge control circuit further includes a sixth resistor, and the first end of the fourth resistor is connected to the discharge signal enabling end of the sampling module through the sixth resistor.

[0011] In one embodiment, at least one of the fourth resistor and the sixth resistor is a variable resistor.

[0012] In one embodiment, the discharge signal detection circuit further includes a third resistor. The first end of the third resistor is connected to the second end of the second resistor, and the second end of the third resistor is connected to the second end of the fourth field effect transistor.

[0013] In one embodiment, at least one of the second resistor and the third resistor is a variable resistor.

[0014] In one embodiment, the MOS transistor fault detection circuit further includes a charging control circuit. The charging control circuit includes a second field effect transistor and a fifth resistor. The first end of the fifth resistor is connected to the charging signal enabling end of the sampling module, the second end of the fifth resistor is connected to the control end of the second field effect transistor, the first end of the second field effect transistor is connected to the second end of the first field effect transistor, and the second end of the second field effect transistor is connected to the negative power supply.

[0015] In one embodiment, the charging control circuit further includes a seventh resistor. The first end of the fifth resistor is connected to the charging signal enabling end of the sampling module through the seventh resistor.

[0016] In one embodiment, at least one of the fifth resistor and the seventh resistor is a variable resistor.

[0017] In one embodiment, the fourth field effect transistor is an N-type field effect transistor.

[0018] An electric vehicle lithium battery includes the MOS transistor fault detection circuit according to any one of the above embodiments.

[0019] Compared with the prior art, the present disclosure has at least the following advantages:

[0020] The MOS transistor fault detection circuit can detect the states of the control end and the first end of the first field effect transistor during the discharge of the electric vehicle lithium battery. If the enable signal turns on the fourth field effect transistor during battery discharge and the signal received by the control unit is low level, it is determined that the first field effect transistor is normal. If the fourth field effect transistor is turned off during discharge and the signal received by the control unit is high level, it is determined that the first field effect transistor is abnormal. The discharge signal detection circuit confirms the state of the first field effect transistor through the on-off state of the fourth field effect transistor and the signal level detected by the control unit, so as to avoid potential safety hazards during battery use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present disclosure and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic structural diagram of a MOS transistor fault detection circuit in an embodiment.

[0023] Reference numerals: 10, MOS transistor fault detection circuit; 100, sampling module; 200, discharge control circuit; 300, discharge signal detection circuit; 400, control unit; 500, charging control circuit; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; M1, first field-effect transistor; M2, second field-effect transistor; M4, fourth field-effect transistor. Specific embodiments

[0024] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant accompanying drawings. The preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure content of the present disclosure understood more thoroughly and comprehensively.

[0025] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only embodiment.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0027] To better understand the technical solutions and beneficial effects of the present disclosure, the present disclosure will be further described in detail below with reference to specific embodiments:

[0028] Please refer to Figure 1, which is the MOS transistor fault detection circuit 10 of an embodiment of the present utility model, includes a sampling module 100, a discharge control circuit 200, and a discharge signal detection circuit 300.

[0029] The discharge control circuit 200 includes a fourth resistor R4 and a first field effect transistor M1. The first end of the fourth resistor R4 is connected to the discharge signal enabling end of the sampling module 100, the second end of the fourth resistor R4 is connected to the control end of the first field effect transistor M1, the first end of the first field effect transistor M1 is grounded, and the second end of the first field effect transistor M1 is used to connect to the drain of the charging MOS transistor.

[0030] Further, the first field effect transistor M1 is a discharge MOS transistor.

[0031] The discharge signal detection circuit 300 includes a first resistor R1, a second resistor R2, and a fourth field effect transistor M4. The first end of the second resistor R2 is connected to the first end of the fourth resistor R4, the second end of the second resistor R2 is connected to the control end of the fourth field effect transistor M4, the first end of the fourth field effect transistor M4 is connected to the first end of the first resistor R1, the first end of the first resistor R1 is used to connect to the signal receiving end of the control unit 400, the second end of the first resistor R1 is connected to the reference power supply, and the second end of the fourth field effect transistor M4 is grounded.

[0032] In this embodiment, the MOS transistor fault detection circuit 10 can detect the states of the control end and the first end of the first field effect transistor M1, i.e., the discharge MOS transistor, during the discharge of the electric vehicle lithium battery. If the enabling signal turns on the fourth field effect transistor M4 during battery discharge and the signal received by the control unit 400 is low level, it is determined that the first field effect transistor M1 is normal. If the fourth field effect transistor M4 is turned off during discharge and the signal received by the control unit 400 is high level, it is determined that the first field effect transistor M1 is abnormal. The discharge signal detection circuit 300 confirms the state of the first field effect transistor M1 through the on-off state of the fourth field effect transistor M4 and the signal level detected by the control unit 400 to avoid potential safety hazards during battery use.

[0033] It can be understood that when the lithium battery of the electric vehicle discharges, under normal conditions, the sampling module 100 drives the discharge signal AFE_DSG to turn on the first field effect transistor M1, that is, the discharge MOS transistor. After this signal passes through the second resistor R2, the control terminal of the fourth field effect transistor M4 is in a high level state to conduct. Subsequently, the level of the reference power supply is grounded, and the control unit 400 detects that the DSG_MCU signal is at a low level. At this time, it can be determined that the first field effect transistor M1 is working normally; when the control terminal and the first terminal (i.e., the gate and the source) of the first field effect transistor M1 are broken down, the signal driven by the sampling module 100 directly passes through the first field effect transistor M1 to the ground. At this time, the control terminal of the fourth field effect transistor M4 is at a low level and cannot conduct, and the control unit 400 detects that the DSG_MCU signal is at a high level. At this time, it can be determined that the first field effect transistor M1 is damaged. That is to say, when the control unit 400 detects that the DSG_MCU signal is at a low level, the first field effect transistor M1 is normal, and when the control unit 400 detects that the DSG_MCU signal is at a high level, the first field effect transistor M1 is abnormal. Therefore, in the case of the lithium battery of the electric vehicle discharging, it is possible to confirm whether the first field effect transistor M1 is working normally according to the channel state of the fourth field effect transistor M4 and the state of the DSG_MCU signal detected by the control unit 400.

[0034] In this embodiment, the first field effect transistor M1 is an N-type field effect transistor, its first terminal is the source, the second terminal is the drain, and the control terminal is the gate; the fourth field effect transistor M4 is an N-type field effect transistor, its first terminal is the drain, the second terminal is the source, and the control terminal is the gate.

[0035] In one of the embodiments, the discharge control circuit 200 further includes a sixth resistor R6. The first terminal of the fourth resistor R4 is connected to the discharge signal enable terminal of the sampling module 100 through the sixth resistor R6. It can be understood that the sixth resistor R6 and the fourth resistor R4 are in series with the control terminal of the first field effect transistor M1 to further protect the first field effect transistor M1 and reduce the situation that the first field effect transistor M1 is broken down due to too low a resistance value resulting in too large a current; the sixth resistor R6 and the second resistor R2 are in series with the control terminal of the fourth field effect transistor M4 to further protect the fourth field effect transistor M4 and reduce the situation that the fourth field effect transistor M4 is broken down due to too low a resistance value resulting in too large a current.

[0036] Further, at least one of the fourth resistor R4 and the sixth resistor R6 is a variable resistor. In this embodiment, when one or both of the fourth resistor R4 and the sixth resistor R6 are variable resistors, the resistance ratio of the fourth resistor R4 to the sixth resistor R6 can be adjusted by adjusting the resistance value of one or both of the fourth resistor R4 and the sixth resistor R6, thereby adjusting the conduction condition of the first field effect transistor M1 to adapt to more models of the first field effect transistor M1, that is, the N-type MOS transistor; when the sixth resistor R6 is a variable resistor, the conduction condition of the fourth field effect transistor M4 can also be adjusted by adjusting the sixth resistor R6 to adjust the resistance ratio of the second resistor R2 to the sixth resistor R6, so as to adapt to more models of the fourth field effect transistor M4, that is, the N-type MOS transistor.

[0037] In one embodiment, the discharge signal detection circuit 300 further includes a third resistor R3. The first end of the third resistor R3 is connected to the second end of the second resistor R2, and the second end of the third resistor R3 is connected to the second end of the fourth field effect transistor M4. It can be understood that the second resistor R2 and the third resistor R3 are connected in series. When the signal enabled by the sampling module 100 is at a high level, the second resistor R2 and the third resistor R3 divide the voltage, generating a voltage drop across the third resistor R3, and this voltage drop can turn on the fourth field effect transistor M4.

[0038] Further, at least one of the second resistor R2 and the third resistor R3 is a variable resistor. In this embodiment, when one or both of the second resistor R2 and the third resistor R3 are variable resistors, the resistance ratio of the second resistor R2 to the third resistor R3 can be adjusted by adjusting the resistance value of one or both of the second resistor R2 and the third resistor R3, thereby adjusting the conduction condition of the fourth field effect transistor M4.

[0039] In one embodiment, the MOS transistor fault detection circuit 10 further includes a charging control circuit 500. The charging control circuit 500 includes a second field effect transistor M2 and a fifth resistor R5. The first end of the fifth resistor R5 is connected to the charging signal enabling end of the sampling module 100, the second end of the fifth resistor R5 is connected to the control end of the second field effect transistor M2, the first end of the second field effect transistor M2 is connected to the second end of the first field effect transistor M1, and the second end of the second field effect transistor M2 is connected to the negative power supply. It can be understood that when the electric vehicle lithium battery is in a charging state, the sampling module 100 no longer enables the discharge signal AFE_DSG, causing the first field effect transistor M1 to turn off, while enabling the charging signal AFE_CHG to make the second field effect transistor M2 conduct normally.

[0040] Further, the second field effect transistor M2 is a charging MOS transistor and is an N-type field effect transistor. Its first end is the drain, the second end is the source, and the control end is the gate.

[0041] In one embodiment, the charging control circuit 500 further includes a seventh resistor R7. The first end of the fifth resistor R5 is connected to the charging signal enabling end of the sampling module 100 through the seventh resistor R7. It can be understood that the fifth resistor R5 and the seventh resistor R7 are connected in series to the control end of the second field effect transistor M2 to further protect the second field effect transistor M2 and reduce the situation that the second field effect transistor M2 is broken down due to excessive current caused by too low resistance value of the resistor.

[0042] Furthermore, at least one of the fifth resistor R5 and the seventh resistor R7 is a variable resistor. In this embodiment, when one or both of the fifth resistor R5 and the seventh resistor R7 are variable resistors, the resistance value of one or both of the fifth resistor R5 and the seventh resistor R7 can be adjusted to adjust the resistance ratio of the fifth resistor R5 to the seventh resistor R7, and then the conduction condition of the second field effect transistor M2 can be adjusted to adapt to more models of the second field effect transistor M2, that is, the N-type MOS transistor.

[0043] The present disclosure also provides an electric vehicle lithium battery, including the MOS transistor fault detection circuit 10 in any of the above embodiments.

[0044] Compared with the prior art, the present disclosure has at least the following advantages:

[0045] The MOS transistor fault detection circuit 10 can detect the states of the control end and the first end of the first field effect transistor M1 during the discharge of the electric vehicle lithium battery. If the enabling signal turns on the fourth field effect transistor M4 during battery discharge and the signal received by the control unit 400 is low level, it is determined that the first field effect transistor M1 is normal. If the fourth field effect transistor M4 is turned off during discharge and the signal received by the control unit 400 is high level, it is determined that the first field effect transistor M1 is abnormal. The discharge signal detection circuit 300 confirms the state of the first field effect transistor M1 through the on-off state of the fourth field effect transistor M4 and the signal level detected by the control unit 400 to avoid potential safety hazards during battery use.

[0046] The above embodiments only represent several implementation manners of the present disclosure, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the disclosed patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several deformations and improvements can still be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.

Claims

1. A MOS transistor fault detection circuit, characterized in that, Comprising: Sampling module; Discharge control circuit, including a fourth resistor and a first field effect transistor, a first end of the fourth resistor is connected to an enabling end of a discharge signal of the sampling module, a second end of the fourth resistor is connected to a control end of the first field effect transistor, a first end of the first field effect transistor is grounded, and a second end of the first field effect transistor is used for connecting a drain of a charging MOS transistor; Discharge signal detection circuit, including a first resistor, a second resistor and a fourth field effect transistor, a first end of the second resistor is connected to the first end of the fourth resistor, a second end of the second resistor is connected to a control end of the fourth field effect transistor, a first end of the fourth field effect transistor is connected to a first end of the first resistor, the first end of the first resistor is used for connecting a signal receiving end of a control unit, a second end of the first resistor is connected to a reference power supply, and a second end of the fourth field effect transistor is grounded.

2. The MOS transistor fault detection circuit according to claim 1, characterized in that The discharge control circuit further includes a sixth resistor, and the first end of the fourth resistor is connected to the enabling end of the discharge signal of the sampling module through the sixth resistor.

3. The MOS transistor fault detection circuit according to claim 2, wherein At least one of the fourth resistor and the sixth resistor is a variable resistor.

4. The MOS transistor fault detection circuit according to claim 1, characterized in that, The discharge signal detection circuit further includes a third resistor, a first end of the third resistor is connected to the second end of the second resistor, and a second end of the third resistor is connected to the second end of the fourth field effect transistor.

5. The MOS transistor fault detection circuit according to claim 4, characterized in that, At least one of the second resistor and the third resistor is a variable resistor.

6. The MOS transistor fault detection circuit according to claim 1, wherein The MOS transistor fault detection circuit further includes a charging control circuit, the charging control circuit includes a second field effect transistor and a fifth resistor, a first end of the fifth resistor is connected to an enabling end of a charging signal of the sampling module, a second end of the fifth resistor is connected to a control end of the second field effect transistor, a first end of the second field effect transistor is connected to the second end of the first field effect transistor, and a second end of the second field effect transistor is connected to a negative power supply terminal.

7. The MOS transistor fault detection circuit according to claim 6, wherein The charging control circuit further includes a seventh resistor, and the first end of the fifth resistor is connected to the enabling end of the charging signal of the sampling module through the seventh resistor.

8. The MOS transistor fault detection circuit according to claim 7, wherein, At least one of the fifth resistor and the seventh resistor is a variable resistor.

9. The MOS transistor fault detection circuit according to claim 1, wherein, The fourth field effect transistor is an N-type field effect transistor.

10. A lithium battery for an electric vehicle, characterized in that, Comprising the MOS transistor fault detection circuit according to any one of claims 1-9.

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