Battery pack short circuit test device

Abstract

The battery pack short-circuit test device provided by the present invention comprises: a plurality of battery pack short-circuit test modules, the plurality of battery pack short-circuit test modules are connected in parallel, the first end of each battery pack short-circuit test module receives a short-circuit control signal, the second end of each battery pack short-circuit test module is connected to the positive electrode of the battery pack under test, and the third end of each battery pack short-circuit test module is connected to the negative electrode of the battery pack under test. By connecting a plurality of battery pack short-circuit test modules in parallel and using a synchronization signal for unified control, a larger short-circuit current can be obtained, thereby providing short-circuit tests for battery packs of different voltage levels and solving the problem of difficulty in short-circuit testing large-capacity batteries.

Description

Technical Field

[0001] The present invention relates to the field of battery pack short-circuit testing, and in particular to a battery pack short-circuit testing device. Background Art

[0002] In recent years, with the popularization of lithium batteries in household products, the lithium battery industry has developed at a faster speed. However, since lithium batteries can explode and catch fire when overcharged or short-circuited, a battery management system (BMS) must be added to effectively protect lithium batteries.

[0003] When the existing lithium battery management system performs a short circuit test on a large-capacity battery, it is often accompanied by a large impact current, which may damage the battery and the test equipment itself. It can be seen that there is currently a lack of effective test circuits when performing short circuit tests on large-capacity batteries. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the prior art in the lack of an effective test circuit when performing a short-circuit test on a large-capacity battery, thereby providing a battery pack short-circuit test device.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An embodiment of the present invention provides a battery pack short-circuit test device, comprising: multiple battery pack short-circuit test modules, the multiple battery pack short-circuit test modules are connected in parallel, the first end of each battery pack short-circuit test module receives a short-circuit control signal, the second end of each battery pack short-circuit test module is connected to the positive electrode of the battery pack under test, and the third end of each battery pack short-circuit test module is connected to the negative electrode of the battery pack under test.

[0007] Preferably, the battery pack short-circuit test module comprises: a first controller, a pulse generating circuit, a first drive circuit and a short-circuit control circuit, wherein the first end of the first controller receives a short-circuit control signal, the second end of the first controller is connected to the enable end of the pulse generating circuit, the third end of the first controller is connected to the signal input end of the pulse generating circuit, the first controller is used to enable the pulse generating circuit, and send the short-circuit control signal to the pulse generating circuit to control the pulse generating circuit to generate a short-circuit pulse; the input end of the first drive circuit is connected to the output end of the pulse generating circuit, the output end of the first drive circuit is connected to the short-circuit control circuit, the positive end of the short-circuit control circuit is connected to the positive electrode of the battery pack under test, the negative end of the short-circuit control circuit is connected to the negative electrode of the battery pack under test, and the first drive circuit is used to drive the short-circuit control circuit to short-circuit according to the short-circuit pulse.

[0008] Preferably, the short-circuit control circuit includes: a first controllable switch, wherein the control end of the first controllable switch is connected to the output end of the first drive circuit, the first end of the first controllable switch is connected to the positive electrode of the battery pack under test, and the second end of the first controllable switch is connected to the negative electrode of the battery pack under test, and the first controllable switch is used to be turned on or off according to the short-circuit pulse.

[0009] Preferably, the short-circuit control circuit further includes: a slow-start circuit, which includes a second controllable switch, a third controllable switch, a first diode and a first resistor, wherein the first end of the second controllable switch is respectively connected to the positive electrode of the battery pack under test and the first end of the third controllable switch, the second end of the second controllable switch is respectively connected to the first end of the first controllable switch and one end of the first resistor, the control end of the second controllable switch is connected to the fourth end of the first controller; the second end of the third controllable switch is connected to the anode of the first diode, and the control end of the third controllable switch is connected to the fifth end of the first controller; the cathode of the first diode is connected to the other end of the first resistor.

[0010] Preferably, the short-circuit control circuit further includes: a first capacitor, a second resistor, a third resistor and a first voltage-stabilizing diode, wherein the first capacitor is connected in parallel with the second resistor, one end of the first capacitor after being connected in parallel with the second resistor is respectively connected to the second end of the second controllable switch and the first end of the first controllable switch, and the other end of the first capacitor after being connected in parallel with the second resistor is respectively connected to the other end of the third resistor, the other end of the first voltage-stabilizing diode and the second end of the first controllable switch; one end of the first voltage-stabilizing diode is respectively connected to the first end of the second controllable switch and the positive electrode of the battery pack under test, and one end of the third resistor is connected to the negative electrode of the battery pack under test.

[0011] Preferably, the battery pack short circuit test module also includes: a first voltage detection circuit and a second voltage detection circuit, wherein the first end of the first voltage detection circuit is connected to the positive electrode of the battery pack under test, the second end of the first voltage detection circuit is connected to the negative electrode of the battery pack under test, the third end of the first voltage detection circuit is connected to the ninth end of the first controller, the first voltage detection circuit is used to detect the voltage of the battery pack under test, and send the detected voltage to the first controller, and the first controller determines whether to perform a short circuit test based on the voltage; the first end of the second voltage detection circuit is connected to one end of the second resistor, the second end of the second voltage detection circuit is connected to the other end of the second resistor, and the second voltage detection circuit is used to detect the voltage across the first capacitor.

[0012] Preferably, the battery pack short-circuit test module also includes: a second drive circuit and a third drive circuit, wherein the input end of the second drive circuit is connected to the fourth end of the first controller, the output end of the second drive circuit is connected to the control end of the second controllable switch, and the second drive circuit is used to drive the second controllable switch to operate according to the control signal of the first controller; the input end of the third drive circuit is connected to the fifth end of the first controller, the output end of the third drive circuit is connected to the control end of the third controllable switch, and the third drive circuit is used to drive the third controllable switch to operate according to the control signal of the first controller.

[0013] Preferably, the battery pack short-circuit test module also includes: a signal amplifying circuit, a first delay comparison circuit and a second delay comparison circuit, wherein the input end of the signal amplifying circuit is connected to the two ends of the third resistor, and the output end of the signal amplifying circuit is respectively connected to the first input end of the first delay comparison circuit and the first input end of the second delay comparison circuit; the second input end of the first delay comparison circuit is externally connected to a reference voltage, the first output end of the first delay comparison circuit is respectively connected to the input end of the second drive circuit and the fourth end of the first controller, and the second output end of the first delay comparison circuit is connected to the sixth end of the first controller; the second input end of the second delay comparison circuit is externally connected to a reference voltage, the first output end of the second delay comparison circuit is connected to the input end of the first drive circuit, and the second output end of the second delay comparison circuit is connected to the seventh end of the first controller.

[0014] Preferably, the eighth end of the first controller is respectively connected to the first input end of the first delay comparison circuit and the first input end of the second delay comparison circuit, and the first controller is used to send a reset operation signal to the first input end of the first delay comparison circuit and the first input end of the second delay comparison circuit after detecting an action signal output by the second output end of the first delay comparison circuit, so as to reset the first delay comparison circuit and the second delay comparison circuit.

[0015] Preferably, the short-circuit control circuit further includes: a fuse and a fourth resistor, wherein the fuse and the fourth resistor are connected in series, one end of the series connection of the fuse and the fourth resistor is connected to the positive electrode of the battery pack under test, and the other end of the series connection of the fuse and the fourth resistor is connected to the first end of the second controllable switch.

[0016] The technical solution of the present invention has the following advantages:

[0017] The battery pack short-circuit test device provided by the present invention comprises: a plurality of battery pack short-circuit test modules, the plurality of battery pack short-circuit test modules are connected in parallel, the first end of each battery pack short-circuit test module receives a short-circuit control signal, the second end of each battery pack short-circuit test module is connected to the positive electrode of the battery pack under test, and the third end of each battery pack short-circuit test module is connected to the negative electrode of the battery pack under test. By connecting a plurality of battery pack short-circuit test modules in parallel and using a synchronization signal for unified control, a larger short-circuit current can be obtained, thereby providing short-circuit tests for battery packs of different voltage levels and solving the problem of difficulty in short-circuit testing large-capacity batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a principle block diagram of a specific example of a battery pack short-circuit test device in an embodiment of the present invention;

[0020] Figure 2 is a principle block diagram of a specific example of a battery pack short-circuit test module in an embodiment of the present invention;

[0021] Figure 3 is a circuit diagram of a specific example of a battery pack short-circuit test module in an embodiment of the present invention;

[0022] Figure 4 is a circuit diagram of a specific example of a pulse generating circuit in an embodiment of the present invention;

[0023] Figure 5 is a circuit diagram of a specific example of a first voltage detection circuit in an embodiment of the present invention;

[0024] Figure 6 is a circuit diagram of a specific example of a driving circuit in an embodiment of the present invention;

[0025] Figure 7 is a circuit diagram of a specific example of a signal amplification circuit in an embodiment of the present invention;

[0026] Figure 8 FIG. 4 is a circuit diagram of a specific example of a delay comparison circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] An embodiment of the present invention provides a battery pack short circuit test device, such as Figure 1 As shown, it includes: multiple battery pack short-circuit test modules, the multiple battery pack short-circuit test modules are connected in parallel, the first end A of each battery pack short-circuit test module receives a short-circuit control signal, the second end B of each battery pack short-circuit test module is connected to the positive electrode P+ of the battery pack under test, and the third end C of each battery pack short-circuit test module is connected to the negative electrode P- of the battery pack under test.

[0032] In a specific embodiment, the battery pack short-circuit test device includes a plurality of battery pack short-circuit test modules connected in parallel. After the battery pack to be tested is determined, the number of battery pack short-circuit test modules connected in parallel is selected according to the test current required. By connecting a plurality of battery pack short-circuit test modules in parallel and using a synchronous signal for unified control, a larger short-circuit current can be obtained, thereby providing short-circuit tests for battery packs of different voltage levels, solving the problem of difficulty in short-circuit testing of large-capacity batteries.

[0033] In one embodiment, if Figure 2 As shown, the above-mentioned battery pack short-circuit test module includes: a first controller 1, a pulse generating circuit 2, a first drive circuit 3 and a short-circuit control circuit 4, wherein the first end D of the first controller 1 receives a short-circuit control signal, the second end E of the first controller 1 is connected to the enable end of the pulse generating circuit 2, and the third end F of the first controller 1 is connected to the signal input end of the pulse generating circuit 2. The first controller 1 is used to enable the pulse generating circuit 2 and send the short-circuit control signal to the pulse generating circuit 2 to control the pulse generating circuit 2 to generate a short-circuit pulse; the input end of the first drive circuit 3 is connected to the output end of the pulse generating circuit 2, the output end of the first drive circuit 3 is connected to the short-circuit control circuit 4, the positive end of the short-circuit control circuit 4 is connected to the positive electrode of the battery pack under test, and the negative end of the short-circuit control circuit 4 is connected to the negative electrode of the battery pack under test, and the first drive circuit 3 is used to drive the short-circuit control circuit 4 to short-circuit according to the short-circuit pulse.

[0034] In a specific embodiment, if Figure 3 As shown, when a short-circuit test is performed, the first controller 1 starts to detect in real time whether a short-circuit control signal is received. When port I of the first controller 1 receives the short-circuit control signal, it first sends an enable signal to the enable end of the pulse generating circuit 2 through port II to enable the pulse generating circuit, and then sends the short-circuit control signal to the signal input end of the pulse generating circuit 2 through port III to control the pulse generating circuit 2 to generate a short-circuit pulse. When the first controller 1 detects that the short-circuit pulse has become a low level, it stops outputting the enable signal to prevent the pulse generating circuit 2 from being triggered by mistake. Among them, the short-circuit pulse duration is determined by the hardware of the pulse generating circuit 2 itself to improve the control reliability. In an embodiment of the present invention, the pulse width duration here is 2ms, which is only taken as an example and is not limited to this. The short-circuit time resolution can be controlled within 1ms by the pulse generating circuit 2 to meet the safety requirements of short-circuit testing of lithium battery products. In an embodiment of the present invention, the pulse generating circuit 2 adopts the following Figure 4 The monostable timing pulse generating circuit shown includes a logic device of model 74LS123, a resistor and a capacitor. By using the above logic device in combination with peripheral resistors and capacitors, a single pulse waveform with precise duration can be generated. In the embodiment of the present invention, the first controller 1 is an MCU, and its model is not limited here. Most MCUs on the current market meet the requirements.

[0035] Furthermore, if Figure 3As shown, the short-circuit control circuit 4 includes: a first controllable switch S1, the control end of the first controllable switch S1 is connected to the output end of the first drive circuit 3, the first end of the first controllable switch S1 is connected to the positive electrode of the battery pack under test, and the second end of the first controllable switch S1 is connected to the negative electrode of the battery pack under test. The first controllable switch S1 is used to turn on or off according to the short-circuit pulse.

[0036] In the embodiment of the present invention, after the short-circuit pulse is generated, the first drive circuit 3 drives the first controllable switch S1 in the short-circuit control circuit 4 to turn on according to the short-circuit pulse, so that the short-circuit control circuit 4 is short-circuited within the short-circuit time determined by the short-circuit pulse, and the short-circuit test is completed. In the embodiment of the present invention, the first controllable switch S1 is a MOS tube connected in reverse series, and the MOS tube can be an N-channel MOS tube or a P-channel MOS tube.

[0037] During the short-circuit test, a short-circuit pulse is generated by a pulse generating circuit, so that the short-circuit pulse can accurately set the short-circuit delay, and then a short-circuit waveform with high delay accuracy is generated by controlling the short-circuit duration, and the short-circuit control circuit is driven to perform a short-circuit test, thereby improving the accuracy of the short-circuit test.

[0038] In one embodiment, if Figure 3 As shown, the short-circuit control circuit 4 also includes: a slow-start circuit 41, which includes a second controllable switch S2, a third controllable switch S3, a first diode D1 and a first resistor R1, wherein the first end of the second controllable switch S2 is respectively connected to the positive electrode of the battery pack under test and the first end of the third controllable switch S3, the second end of the second controllable switch S2 is respectively connected to the first end of the first controllable switch S1 and one end of the first resistor R1, the control end of the second controllable switch S2 is connected to the fourth end IV of the first controller 1; the second end of the third controllable switch S3 is connected to the anode of the first diode D1, and the control end of the third controllable switch S3 is connected to the fifth end V of the first controller 1; the cathode of the first diode D1 is connected to the other end of the first resistor R1.

[0039] In a specific embodiment, due to the presence of a capacitor device in the short-circuit control circuit 4, when the battery pack under test is connected to the short-circuit control circuit 4, sparking will occur, damaging the interface. Therefore, in order to avoid the sparking phenomenon, a slow-start circuit 41 is added to the short-circuit control circuit 4. When the short-circuit control circuit 4 is turned on, the third controllable switch S3 is first driven to turn on, and then the second controllable switch S2 is driven to turn on, and the third controllable switch S3 is driven to turn off at the same time. In this way, the short-circuit control circuit 4 is turned on to avoid sparking and protect the interface. In an embodiment of the present invention, the second controllable switch S2 is a MOS tube connected in reverse series, which can be an N-channel MOS tube or a P-channel MOS tube. The third controllable switch S3 is an N-channel MOS tube or a P-channel MOS tube. By using semiconductor power devices, the stability of the loop impedance is improved.

[0040] In one embodiment, if Figure 3 As shown, the short-circuit control circuit 4 also includes: a first capacitor C1, a second resistor R2, a third resistor R3 and a first voltage regulator TVS, wherein the first capacitor C1 is connected in parallel with the second resistor R2, one end of the first capacitor C1 after being connected in parallel with the second resistor R2 is respectively connected to the second end of the second controllable switch S2 and the first end of the first controllable switch S1, and the other end of the first capacitor C1 after being connected in parallel with the second resistor R2 is respectively connected to the other end of the third resistor R3, the other end of the first voltage regulator TVS and the second end of the first controllable switch S1; one end of the first voltage regulator TVS is respectively connected to the first end of the second controllable switch S2 and the positive electrode of the battery pack under test, and one end of the third resistor R3 is connected to the negative electrode of the battery pack under test.

[0041] In a specific embodiment, when the first controllable switch S1 cuts off a large current, due to the distributed inductance in the loop, a large voltage spike will be generated between points L+ and L-, and the spike will be absorbed by the first capacitor C1, and then slowly released through the second resistor R2, thereby improving the reliability of cutting off the large current. When the second controllable switch S2 cuts off a large current, due to the distributed inductance in the loop, a large voltage spike will be generated between points A and L-, and the spike will be absorbed by the first voltage regulator TVS, thereby improving the reliability of cutting off the large current. The third resistor R3 is used as a current detection resistor to detect the short-circuit current after the short-circuit current is generated. In the embodiment of the present invention, the resistance value of the third resistor R3 is 1mΩ, which is only taken as an example and is not limited to this.

[0042] In one embodiment, if Figure 3 As shown, the battery pack short-circuit test module also includes: a first voltage detection circuit 5 and a second voltage detection circuit 6, wherein the first end of the first voltage detection circuit 5 is connected to the positive electrode of the battery pack under test, the second end of the first voltage detection circuit 5 is connected to the negative electrode of the battery pack under test, and the third end of the first voltage detection circuit 5 is connected to the ninth end Ⅸ of the first controller 1, and the first voltage detection circuit 5 is used to detect the voltage of the battery pack under test and send the detected voltage to the first controller 1, and the first controller 1 determines whether to perform a short-circuit test based on the voltage; the first end of the second voltage detection circuit 6 is connected to one end of the second resistor R2, and the second end of the second voltage detection circuit 6 is connected to the other end of the second resistor R2, and the second voltage detection circuit 6 is used to detect the voltage across the first capacitor C1.

[0043] In a specific embodiment, if Figure 3As shown, the battery pack short-circuit test module also includes: a second drive circuit 7 and a third drive circuit 8, wherein the input end of the second drive circuit 7 is connected to the fourth end IV of the first controller 1, the output end of the second drive circuit 7 is connected to the control end of the second controllable switch S2, and the second drive circuit 7 is used to drive the second controllable switch S2 to operate according to the control signal of the first controller 1; the input end of the third drive circuit 8 is connected to the fifth end V of the first controller 1, the output end of the third drive circuit 8 is connected to the control end of the third controllable switch S3, and the third drive circuit 8 is used to drive the third controllable switch S3 to operate according to the control signal of the first controller 1.

[0044] In an embodiment of the present invention, before performing a short-circuit test, the voltage of the battery pack under test is first detected to determine whether the battery pack under test is ready. Specifically, the voltage of the battery pack under test is detected by the first voltage detection circuit 5 to determine whether the voltage is normal or connected in reverse. When it is detected that the voltage of the battery pack under test is less than a certain value (for example: 2V) or is a negative voltage, it can be considered that the battery pack is not ready and the short-circuit test cannot be performed. When it is detected that the voltage of the battery pack under test is normal, the battery pack is considered to be ready.

[0045] Furthermore, the first controller 1 outputs a control signal to drive the third controllable switch S3 to turn on through the third drive circuit 8. The battery pack under test charges the first capacitor C1 through the third controllable switch S3, the first diode D1 and the first resistor R1, and the voltage of L+ will slowly rise. The first controller 1 detects the voltage across the first capacitor C1 through the second voltage detection circuit 6, and compares the voltage across the first capacitor C1 with the voltage of the battery pack under test to determine whether the charging of the first capacitor C1 is completed. Specifically, the voltage difference between L+ and P+ can be set to be less than a certain value (for example: 2V) to consider that charging is completed.

[0046] Further, after the first capacitor C1 is charged, the first controller 1 outputs a control signal to drive the second controllable switch S2 to be turned on through the second drive circuit 7 , and drives the third controllable switch S3 to be turned off through the third drive circuit 8 .

[0047] Furthermore, the above operations prepare for the short-circuit test and are ready to receive the short-circuit control signal at any time. When the first controller 1 determines that the battery pack under test has been prepared and detects the short-circuit control signal, it determines that a short-circuit test will be performed. Specifically, the first controller 1 sends an enable signal to the enable end of the pulse generating circuit 2 through port II to enable the pulse generating circuit, and then sends the short-circuit control signal to the signal input end of the pulse generating circuit 2 through port III to control the pulse generating circuit 2 to generate a short-circuit pulse. After the short-circuit pulse is generated, the first drive circuit 3 drives the first controllable switch S1 in the short-circuit control circuit 4 to turn on according to the short-circuit pulse, so that the short-circuit control circuit 4 is short-circuited within the short-circuit time determined by the short-circuit pulse, and the short-circuit test is completed.

[0048] Furthermore, after the detection is completed, the first controller 1 outputs a control signal to drive the first controllable switch S1 to turn off through the first drive circuit 3, so as to avoid long-term high current affecting the service life of the loop device. The second controllable switch S2 is used as a redundant shut-off switch. When the first controllable switch S1 cannot be turned off, the second controllable switch S2 is driven to turn off through the second drive circuit 7, which can also cut off the short-circuit current. By redundantly setting the second controllable switch S2, the safety of short-circuit protection is further improved.

[0049] In the embodiment of the present invention, the first voltage detection circuit 5 can be used as follows: Figure 5 The voltage detection circuit shown in FIG. Among them, the first voltage detection circuit 5 sends the voltage of the battery pack under test to the first controller 1 through the ninth terminal IX. The first drive circuit 3, the second drive circuit 7 and the third drive circuit 8 can all be used as shown in FIG. Figure 6 In the MOS driving circuit shown, when U3 is activated, the SG1 signal outputs a high level, turning on the MOS.

[0050] In one embodiment, if Figure 3 As shown, the battery pack short-circuit test module also includes: a signal amplifying circuit 9, a first delay comparison circuit 10 and a second delay comparison circuit 11, wherein the input end of the signal amplifying circuit 9 is connected to the two ends of the third resistor R3, and the output end of the signal amplifying circuit 9 is respectively connected to the first input end of the first delay comparison circuit 10 and the first input end of the second delay comparison circuit 11; the second input end of the first delay comparison circuit 10 is externally connected to a reference voltage, the first output end of the first delay comparison circuit 10 is respectively connected to the input end of the second drive circuit 7 and the fourth end IV of the first controller 1, and the second output end of the first delay comparison circuit 10 is connected to the sixth end VI of the first controller 1; the second input end of the second delay comparison circuit 11 is externally connected to a reference voltage, the first output end of the second delay comparison circuit 11 is connected to the input end of the first drive circuit 3, and the second output end of the second delay comparison circuit 11 is connected to the seventh end VII of the first controller 1.

[0051] In a specific embodiment, when the first controller 1 outputs a control signal and the path driving the first controllable switch S1 or the second controllable switch S2 to turn off is abnormal, the second controllable switch S2 can be driven to turn off through the first delay comparison circuit 10 or the first controllable switch S1 can be driven to turn off through the second delay comparison circuit 11 to complete the short-circuit current cutting off, so as to ensure that the first controllable switch S1 or the second controllable switch S2 can be effectively disconnected, and the entire short-circuit test will not be out of control, thereby further improving the reliability of control and ensuring the safety of the test.

[0052] Specifically, when the short-circuit current is generated, the signal amplification circuit 9 amplifies the voltage signal detected by the third resistor R3 and sends it to the first delay comparison circuit 10 and the second delay comparison circuit 11 for comparison. When the detected voltage is greater than the reference voltage, it is determined that the first controllable switch S1 or the second controllable switch S2 has not been turned off, but the short-circuit control circuit 4 loop has reached the maximum voltage it can withstand. At this time, the first controllable switch S1 needs to be driven to turn off by the first drive circuit 3 or the second controllable switch S2 needs to be driven to turn off by the second drive circuit 7. Since the delay time of the first delay comparison circuit 10 is longer than that of the second delay comparison circuit 11. Therefore, the first controllable switch S1 is disconnected first, and the second controllable switch S2 is disconnected later. By setting the first delay comparison circuit redundantly, after the loop device circuit is abnormal, the first controllable switch S1 and the second controllable switch S2 can be effectively disconnected, so that the entire short-circuit test will not be out of control, further improving the reliability of control and ensuring the safety of the test.

[0053] In the embodiment of the present invention, the signal amplifying circuit 9 can be used as follows: Figure 7 The signal amplification circuit shown in the figure uses a universal integrated operational amplifier (U1) to form a differential amplifier circuit with peripheral resistors (R3, R4). When current flows through Rs, the voltage signal generated on Rs is conditioned by the differential amplifier circuit and output to MCU for collection. The first delay comparison circuit 10 and the second delay comparison circuit 11 can both be used as shown in the figure. Figure 8 The delay comparison circuit shown in the figure uses a universal integrated operational amplifier (U2) to form a positive feedback comparison circuit with peripheral resistors and diodes (R5, R6, R7, D1); R6 and C1 form a delay circuit. When Vin rises to a certain value, the comparison circuit is activated and M1 and M2 are turned on.

[0054] In one embodiment, if Figure 3As shown, the eighth terminal VIII of the first controller is respectively connected to the first input terminal of the first delay comparison circuit 10 and the first input terminal of the second delay comparison circuit 11, and the first controller is used to send a reset operation signal to the first input terminal of the first delay comparison circuit 10 and the first input terminal of the second delay comparison circuit 11 after detecting the action signal output by the second output terminal of the first delay comparison circuit 10, so as to reset the first delay comparison circuit 10 and the second delay comparison circuit 11.

[0055] In a specific embodiment, after the first delay comparison circuit 10 and the second delay comparison circuit 11 are actuated, the sixth terminal VI of the first controller 1 will detect the action signal output by the second output terminal of the first delay comparison circuit 10. After a delay of a period of time, the eighth terminal VIII of the first controller 1 outputs a reset operation signal to reset the first delay comparison circuit 10 and the second delay comparison circuit 11. When the first controller 1 completes the reset operation of the first delay comparison circuit 10 and the second delay comparison circuit 11, it will return to the stage of determining whether the battery pack under test is ready, check the local equipment, and prepare for the next short-circuit test. In one embodiment, if Figure 3 As shown, the short-circuit control circuit 4 also includes a fuse FUSE and a fourth resistor R4, wherein the fuse FUSE and the fourth resistor R4 are connected in series, one end of the fuse FUSE and the fourth resistor R4 connected in series is connected to the positive electrode of the battery pack under test, and the other end of the fuse FUSE and the fourth resistor R4 connected in series is connected to the first end of the second controllable switch S2. First, when the first controllable switch S1 and the second controllable switch S2 fail, the fourth resistor R4 starts the current limiting function to limit the current in the loop. When the fourth resistor R4 fails, the fuse FUSE will perform the final short-circuit protection to improve the safety of the entire system. The value of the fourth resistor R4: Usually the impedance of the battery system itself is about 20mΩ~50mΩ.

[0056] In one embodiment, the battery pack short circuit test method can be implemented by the following steps:

[0057] First, before performing a short-circuit test, the voltage of the battery pack under test is first detected to determine whether the battery pack under test is ready. Specifically, the voltage of the battery pack under test is detected by the first voltage detection circuit 5 to determine whether the voltage is normal or connected in reverse. When it is detected that the voltage of the battery pack under test is less than the first preset threshold (for example: 2V) or is a negative voltage, it can be considered that the battery pack is not ready and the short-circuit test cannot be performed. When the voltage of the battery pack under test is detected to be normal, the battery pack is considered to be ready.

[0058] Furthermore, after determining that the battery pack under test is ready, the first controller 1 outputs a control signal to drive the third controllable switch S3 to turn on through the third drive circuit 8. The battery pack under test charges the first capacitor C1 through the third controllable switch S3, the first diode D1 and the first resistor R1, and the voltage of L+ will slowly rise. The first controller 1 detects the voltage across the first capacitor C1 through the second voltage detection circuit 6, and compares the voltage across the first capacitor C1 with the voltage of the battery pack under test to determine whether the charging of the first capacitor C1 is complete. Specifically, the voltage difference between L+ and P+ can be set to be less than a certain value (for example: 2V) to consider that charging is complete.

[0059] When the first capacitor C1 is charged, the first controller 1 outputs a control signal to drive the second controllable switch S2 to turn on through the second drive circuit 7, and to drive the third controllable switch S3 to turn off through the third drive circuit 8. The loop is connected by the slow-start circuit to avoid sparking and protect the interface.

[0060] The above operations prepare for the short-circuit test and are ready to receive the short-circuit control signal at any time. When the first controller 1 determines that the battery pack under test has been prepared and detects the short-circuit control signal, it determines that a short-circuit test will be performed. Specifically, the first controller 1 sends an enable signal to the enable end of the pulse generating circuit 2 through port II to enable the pulse generating circuit, and then sends the short-circuit control signal to the signal input end of the pulse generating circuit 2 through port III to control the pulse generating circuit 2 to generate a short-circuit pulse.

[0061] After the short-circuit pulse is generated, the first drive circuit 3 drives the first controllable switch S1 in the short-circuit control circuit 4 to turn on according to the short-circuit pulse, so that the short-circuit control circuit 4 is short-circuited within the short-circuit time determined by the short-circuit pulse, completing the short-circuit test.

[0062] After the detection is completed, the first controller 1 outputs a control signal to drive the first controllable switch S1 to turn off through the first drive circuit 3 to prevent long-term high current from affecting the service life of the loop components. The second controllable switch S2 is used as a redundant shut-off switch. When the first controllable switch S1 cannot be turned off, the second controllable switch S2 is driven to turn off through the second drive circuit 7, which can also cut off the short-circuit current. By redundantly setting the second controllable switch S2, the safety of short-circuit protection is further improved.

[0063] Furthermore, when the first controller 1 outputs a control signal and the path for driving the first controllable switch S1 or the second controllable switch S2 to be turned off is abnormal, the first delay comparison circuit 10 can be used to drive the first controllable switch S1 to be turned off or the second delay comparison circuit 11 can be used to drive the second controllable switch S2 to be turned off, so as to complete the short-circuit current cutting off, so as to ensure that the first controllable switch S1 or the second controllable switch S2 can be effectively disconnected, and the entire short-circuit test will not be out of control, thereby further improving the reliability of control and ensuring the safety of the test.

[0064] After the first controller completes the reset operation of the first delay comparison circuit 10 and the second delay comparison circuit 11, it will return to the step of performing voltage detection on the battery pack under test to determine whether the battery pack under test is ready, thereby checking the local equipment and preparing for the next short circuit test.

[0065] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A battery pack short circuit test device, characterized in that: include: A plurality of battery pack short-circuit test modules, wherein the plurality of battery pack short-circuit test modules are connected in parallel, wherein a first end of each of the battery pack short-circuit test modules receives a short-circuit control signal, a second end of each of the battery pack short-circuit test modules is connected to a positive electrode of a battery pack under test, and a third end of each of the battery pack short-circuit test modules is connected to a negative electrode of a battery pack under test; The battery pack short-circuit test module includes: a first controller, a pulse generating circuit, a first driving circuit and a short-circuit control circuit, wherein: The first end of the first controller receives a short-circuit control signal, the second end of the first controller is connected to the enable end of the pulse generating circuit, and the third end of the first controller is connected to the signal input end of the pulse generating circuit. The first controller is used to enable the pulse generating circuit and send the short-circuit control signal to the pulse generating circuit to control the pulse generating circuit to generate a short-circuit pulse; The input end of the first driving circuit is connected to the output end of the pulse generating circuit, the output end of the first driving circuit is connected to the short-circuit control circuit, the positive terminal of the short-circuit control circuit is connected to the positive electrode of the battery pack under test, and the negative terminal of the short-circuit control circuit is connected to the negative electrode of the battery pack under test, and the first driving circuit is used to drive the short-circuit control circuit to short-circuit according to the short-circuit pulse; The short-circuit control circuit comprises: a first controllable switch, wherein a control end of the first controllable switch is connected to an output end of the first drive circuit, a first end of the first controllable switch is connected to a positive electrode of a battery pack under test, a second end of the first controllable switch is connected to a negative electrode of the battery pack under test, and the first controllable switch is used to be turned on or off according to the short-circuit pulse; The short-circuit control circuit further includes: a slow-start circuit, the slow-start circuit including a second controllable switch, a third controllable switch, a first diode and a first resistor, wherein: The first end of the second controllable switch is respectively connected to the positive electrode of the tested battery pack and the first end of the third controllable switch, the second end of the second controllable switch is respectively connected to the first end of the first controllable switch and one end of the first resistor, and the control end of the second controllable switch is connected to the fourth end of the first controller; The second end of the third controllable switch is connected to the anode of the first diode, and the control end of the third controllable switch is connected to the fifth end of the first controller; A cathode of the first diode is connected to the other end of the first resistor.

2. The battery pack short circuit test device according to claim 1, characterized in that: The short-circuit control circuit further includes: a first capacitor, a second resistor, a third resistor and a first voltage regulator tube, wherein: The first capacitor is connected in parallel with the second resistor, one end of the first capacitor and the second resistor being connected in parallel is respectively connected to the second end of the second controllable switch and the first end of the first controllable switch, and the other end of the first capacitor and the second resistor being connected in parallel is respectively connected to the other end of the third resistor, the other end of the first voltage regulator tube and the second end of the first controllable switch; One end of the first voltage regulator is connected to the first end of the second controllable switch and the positive electrode of the battery pack under test respectively, and one end of the third resistor is connected to the negative electrode of the battery pack under test.

3. The battery pack short circuit test device according to claim 2, characterized in that: The battery pack short circuit test module further includes: a first voltage detection circuit and a second voltage detection circuit, wherein: The first end of the first voltage detection circuit is connected to the positive electrode of the battery pack under test, the second end of the first voltage detection circuit is connected to the negative electrode of the battery pack under test, and the third end of the first voltage detection circuit is connected to the ninth end of the first controller. The first voltage detection circuit is used to detect the voltage of the battery pack under test and send the detected voltage to the first controller, and the first controller determines whether to perform a short circuit test according to the voltage; A first end of the second voltage detection circuit is connected to one end of the second resistor, a second end of the second voltage detection circuit is connected to the other end of the second resistor, and the second voltage detection circuit is used to detect the voltage across the first capacitor.

4. The battery pack short circuit test device according to claim 2, characterized in that: The battery pack short circuit test module further includes: a second drive circuit and a third drive circuit, wherein: The input end of the second driving circuit is connected to the fourth end of the first controller, the output end of the second driving circuit is connected to the control end of the second controllable switch, and the second driving circuit is used to drive the second controllable switch to operate according to the control signal of the first controller; The input end of the third drive circuit is connected to the fifth end of the first controller, the output end of the third drive circuit is connected to the control end of the third controllable switch, and the third drive circuit is used to drive the third controllable switch to operate according to the control signal of the first controller.

5. The battery pack short circuit test device according to claim 4, characterized in that: The battery pack short circuit test module further includes: a signal amplification circuit, a first delay comparison circuit and a second delay comparison circuit, wherein: The input end of the signal amplifying circuit is connected to the two ends of the third resistor, and the output end of the signal amplifying circuit is connected to the first input end of the first delay comparison circuit and the first input end of the second delay comparison circuit respectively; The second input terminal of the first delay comparison circuit is externally connected to a reference voltage, the first output terminal of the first delay comparison circuit is respectively connected to the input terminal of the second driving circuit and the fourth terminal of the first controller, and the second output terminal of the first delay comparison circuit is connected to the sixth terminal of the first controller; The second input end of the second delay comparison circuit is externally connected to a reference voltage, the first output end of the second delay comparison circuit is connected to the input end of the first driving circuit, and the second output end of the second delay comparison circuit is connected to the seventh end of the first controller.

6. The battery pack short circuit test device according to claim 5, characterized in that: The eighth end of the first controller is connected to the first input end of the first delay comparison circuit and the first input end of the second delay comparison circuit, respectively. The first controller is used to send a reset operation signal to the first input end of the first delay comparison circuit and the first input end of the second delay comparison circuit after detecting an action signal output by the second output end of the first delay comparison circuit, so as to reset the first delay comparison circuit and the second delay comparison circuit.

7. The battery pack short circuit test device according to claim 1, characterized in that: The short-circuit control circuit also includes: a fuse and a fourth resistor, wherein the fuse and the fourth resistor are connected in series, one end of the series connection of the fuse and the fourth resistor is connected to the positive electrode of the battery pack under test, and the other end of the series connection of the fuse and the fourth resistor is connected to the first end of the second controllable switch.

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