Low-cost battery system negative side relay adhesion detection circuit

Abstract

The utility model relates to a low-cost battery system negative side relay adhesion detection circuit, which comprises a resistance voltage dividing unit, an anti-reverse circuit unit and a signal acquisition module, the resistance voltage dividing unit comprises a first resistor, a second resistor and a third resistor, the first resistor and the second resistor are connected in series, the two ends of the first resistor and the two ends of the second resistor are connected with the positive electrode and the negative electrode of the power battery respectively, a voltage detection point is arranged on a loop between the first resistor and the second resistor, and one end of the third resistor is connected to the voltage detection point. The other end of the resistor III, the anti-reverse circuit unit, the negative side relay and the negative electrode of the power battery are connected in sequence; and the signal acquisition module is connected with the voltage detection point to output a detection signal. According to the utility model, the state of the negative side relay is judged according to the voltage acquired by the signal acquisition module, so that the adhesion condition of the negative side relay is detected. The utility model has the advantages of simple structure, low cost and strong anti-interference performance.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicles, in particular to a low-cost battery system negative side relay adhesion detection circuit. Background Art

[0002] Lithium-ion power batteries are the most commonly used energy storage devices in electric vehicles. Due to the high voltage platform of power batteries, if not handled properly, it may cause electric shock accidents. Therefore, it is necessary to accurately and reliably detect the bus voltage of the power battery and the adhesion of the main and negative relays.

[0003] In the battery system, the output of the battery system is controlled by the relay in the BDU (battery energy distribution unit). It is particularly important to monitor the working status of the relay in real time to ensure the safe and reliable operation of the relay. The relay is used to control the opening and closing of the high-voltage circuit. In order to ensure the safety of the high-voltage circuit, it is necessary to detect whether the relay is sticking before closing the relay. The technology used for detection here is relay diagnosis technology.

[0004] The traditional negative side relay (the relay on the negative side of the battery, also called the main negative relay) detection circuit requires the use of two signal acquisition modules based on the two sides of the relay as reference points, collecting different voltage comparisons to determine whether the relay is stuck. The detection circuit structure is complex and costly, and different resistance bridge arms are used to connect to the high-voltage circuit. If not handled properly, there is a risk of voltage crossover, which poses a risk to the safety of the battery system. Utility Model Content

[0005] Based on this, it is necessary to target the current negative side relay (the relay on the negative side of the battery, also called the main negative relay) detection circuit. Two analog chips are needed to use the two sides of the relay as reference points to collect different voltage comparisons to determine whether the relay is stuck. The detection circuit has a complex structure and high cost. Different resistance bridge arms are used to connect to the high-voltage circuit. If not handled properly, there is a risk of voltage crossover, which poses a technical risk to the safety of the battery system. A low-cost battery system negative side relay adhesion detection circuit is provided.

[0006] The utility model proposes a low-cost battery system negative side relay adhesion detection circuit, including a resistor voltage divider unit, an anti-reverse circuit unit and a signal acquisition module; the resistor voltage divider unit includes a resistor 1, a resistor 2 and a resistor 3, the two ends of the resistor 1 and the resistor 2 are respectively connected in series and connected to the positive and negative electrodes of a power battery, a voltage detection point is set on the loop between the resistor 1 and the resistor 2, one end of the resistor 3 is connected to the voltage detection point, and the other end of the resistor 3, the anti-reverse circuit unit, the negative side relay and the negative electrode of the power battery are connected in sequence; the signal acquisition module is connected to the voltage detection point to output a detection signal.

[0007] As a further improvement of the above scheme of the utility model, the anti-reverse circuit unit includes diode 1 and diode 2; the anode of diode 1 is connected to resistor 3, the cathode of diode 1 is connected to the anode of diode 2, and the cathode of diode 2 is connected to the negative side relay.

[0008] As a further improvement of the above solution of the utility model, the model of the diode 1 and the diode 2 are both S-SOD4007-SH.

[0009] As a further improvement of the above-mentioned scheme of the utility model, the low-cost battery system negative side relay adhesion detection circuit also includes a filtering unit, and the filtering unit includes capacitor 1 and capacitor 2, one end of capacitor 1 is connected to the voltage detection point and the other end thereof is connected to the negative electrode of the power battery, and one end of capacitor 2 is connected to the signal acquisition module and the other end thereof is connected to the negative electrode of the power battery.

[0010] As a further improvement of the above-mentioned scheme of the utility model, the low-cost battery system negative side relay adhesion detection circuit also includes an isolation power supply unit, and the isolation power supply unit includes an isolation chip IC1, and pins 1 and 2 of the isolation chip IC1 are respectively connected to the negative pole and positive pole of the low-voltage battery, and pins 4 and 5 of the isolation chip IC1 are respectively connected to the negative pole and positive pole of the power battery.

[0011] As a further improvement of the above solution of the utility model, the isolation chip IC1 is CF0505XT-1WR2.

[0012] As a further improvement of the above-mentioned scheme of the utility model, the low-cost battery system negative side relay adhesion detection circuit also includes a low-voltage electric filter unit, and the low-voltage electric filter power supply includes capacitor three, capacitor four and capacitor five, and one end of capacitor three, capacitor four and capacitor five are all connected to the positive pole of the low-voltage battery, and the other end of capacitor four and capacitor five are all connected to the negative pole of the low-voltage battery.

[0013] As a further improvement of the above-mentioned scheme of the utility model, the low-cost battery system negative side relay adhesion detection circuit also includes a high-voltage electric filter unit, and the high-voltage electric filter unit includes capacitor six and capacitor seven, one end of the capacitor six and the capacitor seven are both connected to the positive electrode of the power battery, and the other end of the capacitor six and the capacitor seven are both connected to the negative electrode of the power battery.

[0014] As a further improvement of the above solution of the utility model, the specifications of the capacitor three and the capacitor four are both 10uF / 16V, and the specification of the capacitor five is 100nF / 100V.

[0015] As a further improvement of the above solution of the utility model, the specifications of the capacitor six and the capacitor seven are both 10uF / 16V.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] The low-cost battery system negative side relay adhesion detection circuit provided by the utility model is on the outside of the negative side relay. When the negative side relay is not adhered, the negative side relay is disconnected, and the signal acquisition module collects the voltage division of resistors 1 and 2; when the negative side relay is adhered, the signal acquisition module collects the voltage division of resistors 1, 2 and 3 in parallel; the utility model judges the state of the negative side relay according to the voltage collected by the signal acquisition module, thereby realizing the detection of the adhesion of the negative side relay. The utility model has a simple structure, low cost, and strong anti-interference performance, and provides important guarantees for ensuring the safe and reliable operation of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a low-cost battery system negative side relay adhesion detection circuit proposed in an embodiment of the utility model. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] Reference Figure 1 This embodiment proposes a low-cost battery system negative side relay adhesion detection circuit, including a resistor voltage divider unit, an anti-reverse circuit unit and a signal acquisition module, and may also include an isolation power supply unit, a low-voltage filter unit, a high-voltage filter unit and a filter unit.

[0021] The resistor voltage divider unit includes a resistor R2, a resistor R3 and a resistor R4. One end of the resistor R2 is connected to the positive electrode VHX of the power battery, and the other end is connected to one end of the resistor R3. The other end of the resistor R3 is connected to the negative electrode BAT- of the power battery. A voltage detection point is set on the loop between the resistor R2 and the resistor R3. One end of the resistor R4 is connected to the voltage detection point.

[0022] The signal acquisition module is connected to the voltage detection point, and is used to collect the voltage at the voltage detection point and output a detection signal. In this embodiment, the signal acquisition module uses an analog signal acquisition chip, and the acquisition port ADC1 of the analog signal acquisition chip is connected to the voltage detection point.

[0023] The anti-reverse circuit unit includes a diode 1 D1 and a diode 2 D2. The anode of the diode 1 D1 is connected to the other end of the resistor 3 R4, the cathode of the diode 1 D1 is connected to the anode of the diode 2 D2, the cathode of the diode 2 D2 is connected to one end of the negative side relay, and the other end of the negative side relay is connected to the negative electrode BAT- of the power battery. The anti-reverse circuit unit can protect the detection circuit and prevent some large pulse voltages outside the negative side relay from damaging the detection circuit. In this embodiment, the models of the diode 1 D1 and the diode 2 D2 are both S-SOD4007-SH.

[0024] The filter unit includes capacitor 1 C6 and capacitor 2 C7. One end of capacitor 1 C6 is connected to the voltage detection point and the other end is connected to the negative electrode BAT- of the power battery. One end of capacitor 2 C7 is connected to the signal acquisition module and the other end is connected to the negative electrode BAT- of the power battery. The setting of the filter circuit unit enables the analog acquisition chip to collect stable voltage and improve the anti-interference performance of the product.

[0025] The isolated power supply unit includes an isolation chip IC1, wherein pins 1 and 2 of the isolation chip IC1 are respectively connected to the negative electrode GND and the positive electrode VHX of the low-voltage battery, and pins 4 and 5 of the isolation chip IC1 are respectively connected to the negative electrode and the positive electrode VHX of the power battery. In this embodiment, the isolation chip IC1 is CF0505XT-1WR2.

[0026] The low-voltage electric filter power supply includes capacitor three C1, capacitor four C2 and capacitor five C3. One end of capacitor three C1, capacitor four C2 and capacitor five C3 are all connected to the positive pole VLX of the low-voltage battery, and the other end of capacitor three C1, capacitor four C2 and capacitor five C3 are all connected to the negative pole GND of the low-voltage battery. The low-voltage filter unit can filter out the clutter of the low-voltage battery and make the input more stable. In this embodiment, the specifications of capacitor three C1 and capacitor four C2 are 10uF / 16V, and the specification of capacitor five C3 is 100nF / 100V.

[0027] The high-voltage electric filter unit includes a capacitor C4 and a capacitor C5. One end of the capacitor C4 and the capacitor C5 are connected to the positive electrode VHX of the power battery, and the other end of the capacitor C4 and the capacitor C5 are connected to the negative electrode BAT- of the power battery. The high-voltage electric filter unit can filter out the clutter of the power battery output circuit and make the output voltage more stable. In this embodiment, the specifications of the capacitor C4 and the capacitor C5 are both 10uF / 16V.

[0028] This embodiment is set up with the above structure. When the negative side relay is not adhered, the negative side relay is disconnected, resistor 1 R2 and resistor 2 R3 divide the voltage, and the analog signal acquisition chip collects voltage A; when the negative side relay is adhered, resistor 1 R2 is connected in parallel with resistor 2 R3 and resistor 3 R4 to divide the voltage, and the analog signal acquisition chip collects voltage B; by identifying two different voltages, the state of the negative side relay is judged, thereby realizing the detection of the adhesion of the negative side relay. This embodiment is low in cost, safe and reliable. By using the different resistance values ​​of the negative side relay in different states and the different voltages collected by the analog signal acquisition chip, the state of the negative side relay can be diagnosed in real time. It has a simple structure, low cost, and strong anti-interference performance, providing important guarantees for ensuring the safe and reliable operation of electric vehicles.

[0029] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0030] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A low-cost battery system negative side relay adhesion detection circuit, characterized in that: It includes a resistor voltage divider unit, an anti-reverse circuit unit and a signal acquisition module; the resistor voltage divider unit includes resistor 1, resistor 2 and resistor 3, the two ends of the resistor 1 and the resistor 2 are respectively connected to the positive and negative electrodes of the power battery after being connected in series, a voltage detection point is set on the loop between the resistor 1 and the resistor 2, one end of the resistor 3 is connected to the voltage detection point, and the other end of the resistor 3, the anti-reverse circuit unit, the negative side relay, and the negative electrode of the power battery are connected in sequence; the signal acquisition module is connected to the voltage detection point to output a detection signal.

2. The low-cost battery system negative side relay adhesion detection circuit according to claim 1, characterized in that: The anti-reverse circuit unit includes a diode 1 and a diode 2; the anode of the diode 1 is connected to the resistor 3, the cathode of the diode 1 is connected to the anode of the diode 2, and the cathode of the diode 2 is connected to the negative side relay.

3. The low-cost battery system negative side relay adhesion detection circuit according to claim 2, characterized in that: The model of the diode 1 and the diode 2 are both S-SOD4007-SH.

4. The low-cost battery system negative side relay adhesion detection circuit according to claim 1, characterized in that: The low-cost battery system negative side relay adhesion detection circuit also includes a filtering unit, which includes capacitor 1 and capacitor 2, one end of capacitor 1 is connected to the voltage detection point and the other end is connected to the negative electrode of the power battery, one end of capacitor 2 is connected to the signal acquisition module and the other end is connected to the negative electrode of the power battery.

5. The low-cost battery system negative side relay adhesion detection circuit according to claim 1, characterized in that: The low-cost battery system negative side relay adhesion detection circuit also includes an isolation power supply unit, which includes an isolation chip IC1, wherein pins 1 and 2 of the isolation chip IC1 are respectively connected to the negative electrode and the positive electrode of the low-voltage battery, and pins 4 and 5 of the isolation chip IC1 are respectively connected to the negative electrode and the positive electrode of the power battery.

6. The low-cost battery system negative side relay adhesion detection circuit according to claim 5, characterized in that: The isolation chip IC1 is CF0505XT-1WR2.

7. The low-cost battery system negative side relay adhesion detection circuit according to claim 5, characterized in that: The low-cost battery system negative side relay adhesion detection circuit also includes a low-voltage electrical filter unit, which includes capacitor three, capacitor four and capacitor five, one end of capacitor three, capacitor four and capacitor five are all connected to the positive pole of the low-voltage battery, and the other end of capacitor four and capacitor five are all connected to the negative pole of the low-voltage battery.

8. The low-cost battery system negative side relay adhesion detection circuit according to claim 4, characterized in that: The low-cost battery system negative side relay adhesion detection circuit also includes a high-voltage electric filter unit, which includes capacitor six and capacitor seven, one end of the capacitor six and the capacitor seven are both connected to the positive electrode of the power battery, and the other end of the capacitor six and the capacitor seven are both connected to the negative electrode of the power battery.

9. The low-cost battery system negative side relay adhesion detection circuit according to claim 7, characterized in that: The specifications of the capacitor three and the capacitor four are both 10uF / 16V, and the specification of the capacitor five is 100nF / 100V.

10. The low-cost battery system negative side relay adhesion detection circuit according to claim 8, characterized in that: The specifications of the capacitor six and the capacitor seven are both 10uF / 16V.

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