An electronic load for lithium battery testing

Abstract

The present invention provides an electronic load for lithium battery testing in the field of lithium battery testing technology, comprising a single-chip microcomputer TU1, an integral regulation circuit, a load linear regulation circuit, an integral regulation rate control circuit, a current acquisition circuit, a digital-to-analog conversion circuit, an analog-to-digital conversion chip U8, and a current response time acquisition circuit; the integral regulation rate control circuit is connected to the single-chip microcomputer TU1 and the integral regulation circuit; the load linear regulation circuit is connected to the integral regulation circuit; the input end of the current acquisition circuit is connected to the load linear regulation circuit, and the output end is connected to the integral regulation circuit, the current response time acquisition circuit, and the analog-to-digital conversion chip U8; the input end of the digital-to-analog conversion circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the integral regulation circuit and the current response time acquisition circuit; the current response time acquisition circuit and the analog-to-digital conversion chip U8 are connected to the single-chip microcomputer TU1. The advantage of the present invention is that it greatly improves the accuracy of lithium battery short-circuit protection performance testing.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery testing, and in particular to an electronic load for lithium battery testing. Background Art

[0002] After lithium batteries are manufactured, they need to undergo short-circuit protection testing to ensure their safety. This involves testing the short-circuit protection performance of the battery's protection board and the response rate (protection response rate) of shutting down the MOSFET within the protection circuit when in the protection state. This short-circuit protection test involves discharging the battery using an electronic load until the discharge current reaches the short-circuit current of the protection board. The test then measures the turn-off response time (protection response rate) of the MOSFET within the protection board after the short-circuit current is reached.

[0003] Due to the wide variety of lithium battery models, there are also many corresponding protection board models. This means that the short-circuit protection specifications for different lithium battery models vary, and the discharge current of the electronic load often needs to be adjusted. Traditional electronic loads use integral regulation feedback control circuits to adjust the discharge current, and connect current sampling resistors in series to test the current output and shutdown time to determine the short-circuit protection performance of the lithium battery. However, traditional electronic loads have the following disadvantages:

[0004] Since the capacitance of the integrating capacitor and the resistance of the integrating resistor in the circuit are immutable, the response time varies greatly under different current loading modes, which can easily cause convex waves in the current waveform, thereby affecting the test accuracy of the overcurrent protection value of the protection board and easily causing current shock damage to the protection board, making it even more difficult to accurately test the protection response rate of the protection board.

[0005] Therefore, how to provide an electronic load for lithium battery testing to improve the accuracy of lithium battery short-circuit protection performance testing has become an urgent problem to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an electronic load for lithium battery testing, so as to improve the accuracy of lithium battery short-circuit protection performance testing.

[0007] The present invention is implemented as follows: an electronic load for lithium battery testing, comprising a single-chip microcomputer TU1, an integral regulation circuit, a load linear regulation circuit, an integral regulation rate control circuit, a current acquisition circuit, a digital-to-analog conversion circuit, an analog-to-digital conversion chip U8, and a current response time acquisition circuit;

[0008] The input end of the integral regulation rate control circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the integral regulation circuit; the input end of the load linear regulation circuit is connected to the output end of the integral regulation circuit; the input end of the current acquisition circuit is connected to the load linear regulation circuit, and the output end is connected to the integral regulation circuit, the current response time acquisition circuit and the analog-to-digital conversion chip U8; the input end of the digital-to-analog conversion circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the integral regulation circuit and the current response time acquisition circuit; the current response time acquisition circuit and the analog-to-digital conversion chip U8 are both connected to the single-chip microcomputer TU1.

[0009] Furthermore, the integral adjustment circuit includes an operational amplifier U10A, an operational amplifier U10B, a resistor R36, a resistor R51, a resistor R67, a resistor R68, a resistor R69, a resistor RW1 and a capacitor CW1;

[0010] Pin 5 of the op amp U10B is connected to resistor R36, and pins 6 and 7 are connected to resistors R69 and RW1; pin 1 of the op amp U10A is connected to resistors R51, R68, and CW1, pin 2 is connected to resistors RW1 and CW1, and pin 3 is connected to resistor R67;

[0011] The resistor R36 is connected to the current acquisition circuit; the resistor R67 is connected to the digital-to-analog conversion circuit; the resistor R68 is connected to the load linear adjustment circuit; the resistor R69 and the resistor R51 are both grounded;

[0012] The resistor RW1 and the capacitor CW1 are respectively connected in parallel with the integral regulation rate control circuit.

[0013] Furthermore, the integral regulation rate control circuit includes a digital potentiometer U9, a multiplexing switch U11, a resistor TR3, a resistor TR4, a capacitor CW2, a capacitor CW3, a capacitor CW4, a capacitor CW5, a capacitor CW6, a capacitor CW7, a capacitor CW8 and a capacitor CW9;

[0014] Pins 1, 2, and 3 of the digital potentiometer U9 are connected to the single-chip microcomputer TU1, pin 7 is connected to pin 8, pin 11 is connected to resistor TR4, pin 12 is connected to resistor TR3, and pins 6 and 9 are both connected to the integral adjustment circuit;

[0015] Pins 1, 15, and 16 of the multiplexing switch U11 are connected to the single-chip microcomputer TU1, and pin 8 is connected to the integral regulation circuit; one end of the capacitors CW2, CW3, CW4, CW5, CW6, CW7, CW8, and CW9 are respectively connected to pins 4, 5, 6, 7, 12, 11, 10, and 9 of the multiplexing switch U11, and the other ends are connected to the integral regulation circuit.

[0016] Furthermore, the load linear regulation circuit includes an NMOS transistor Q4, a resistor R71 and a resistor R73;

[0017] One end of the resistor R71 is connected to the integral regulation circuit, and the other end is connected to the resistor R73 and the gate of the NMOS transistor Q4; the source of the NMOS transistor Q4 is connected to the resistor R73 and the current acquisition circuit.

[0018] Furthermore, the current acquisition circuit includes a current sampling resistor RS1, an operational amplifier U12A, a resistor R70, a resistor R72, a resistor R74, a resistor R76 and a resistor R77;

[0019] Pin 1 of the current sampling resistor RS1 is connected to the load linear regulation circuit, pin 2 is connected to the resistor R72, pin 3 is connected to the resistor R76, and pin 4 is grounded;

[0020] Pin 1 of the operational amplifier U12A is connected to resistor R74, resistor R77, integral adjustment circuit, current response time acquisition circuit and analog-to-digital conversion chip U8, pin 2 is connected to resistor R76 and resistor R77, and pin 3 is connected to resistor R70 and resistor R72; the resistor R70 and resistor R74 are both grounded.

[0021] Furthermore, the digital-to-analog conversion circuit includes a digital-to-analog conversion chip N1, a capacitor TC6, a capacitor TC7, a capacitor TC8 and a resistor TR13;

[0022] After the capacitor TC6 and the capacitor TC7 are connected in parallel, one end is connected to pin 1 of the digital-to-analog conversion chip N1, and the other end is grounded; pin 3 of the digital-to-analog conversion chip N1 is connected to the current response time acquisition circuit, pin 7 is connected to the integral adjustment circuit, pins 12, 13, and 14 are connected to the microcontroller TU1, and pin 15 is connected to the resistor TR13, one end of the capacitor TC8, and the microcontroller TU1; the other end of the capacitor TC8 is grounded.

[0023] Furthermore, the current response time acquisition circuit includes a high-speed comparator U13, a resistor R75, a resistor R78, a resistor R79 and a resistor R80;

[0024] One end of the resistor R75 is connected to pin 3 of the high-speed comparator U13, and the other end is connected to the current acquisition circuit; one end of the resistor R78 is connected to pin 1 of the high-speed comparator U13 and the resistor R80, and the other end is connected to the digital-to-analog conversion circuit; one end of the resistor R79 is connected to pin 4 of the high-speed comparator U13 and the microcontroller TU1, and the other end is grounded.

[0025] Furthermore, pins 12, 13, 14, 94, 95, and 96 of the single-chip microcomputer TU1 are connected to the integral regulation rate control circuit, pins 1, 3, 4, and 5 are connected to the digital-to-analog conversion circuit, pin 77 is connected to the current response time acquisition circuit, and pins 33 and 34 are connected to the analog-to-digital conversion chip U8.

[0026] Furthermore, pins 30 and 31 of the analog-to-digital conversion chip U8 are connected to the single-chip microcomputer TU1, and pin 24 is connected to the current acquisition circuit.

[0027] The advantages of the present invention are:

[0028] By setting up an integral regulation rate control circuit, the resistance and capacitance values can be dynamically adjusted, and then the integral rate of the integral regulation circuit can be adjusted to match the response rate of currents of different sizes. That is, when facing different types of lithium batteries, they can respond quickly to currents of different sizes to avoid convex waves in the current waveform and current shock damage to the protection board of the lithium battery; by setting up a current acquisition circuit, the collected current value is input into the integral regulation circuit for feedback adjustment, so that the current value output by the electronic load remains equal to the set value, and the current response time and the collected current value are transmitted to the microcontroller TU1 through the current response time acquisition circuit and the analog-to-digital conversion chip U8, so that the microcontroller TU1 can dynamically adjust the output of the electronic load based on the received data, which ultimately greatly improves the accuracy of the lithium battery short-circuit protection performance test. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Figure 1 The present invention is a circuit principle block diagram of an electronic load for lithium battery testing.

[0031] Figure 2 It is a circuit diagram of the integral regulation circuit of the present invention.

[0032] Figure 3 It is a circuit diagram of the integral regulation rate control circuit of the present invention.

[0033] Figure 4 It is a circuit diagram of the load linear regulation circuit of the present invention.

[0034] Figure 5It is a circuit diagram of the current acquisition circuit of the present invention.

[0035] Figure 6 It is a circuit diagram of the digital-to-analog conversion circuit of the present invention.

[0036] Figure 7 It is a circuit diagram of the current response time acquisition circuit of the present invention.

[0037] Figure 8 It is a circuit diagram of the single chip microcomputer TU1 of the present invention.

[0038] Figure 9 It is a circuit diagram of the analog-to-digital conversion chip U8 of the present invention. DETAILED DESCRIPTION

[0039] The technical solution in the embodiment of the present application has the following overall idea: an integral regulation rate control circuit is set to dynamically adjust the resistance value and the capacitance value, and then the integral rate of the integral regulation circuit is adjusted to quickly respond to currents of different sizes to avoid generating convex waves; a current acquisition circuit is set to input the collected current value into the integral regulation circuit for feedback adjustment, and a current response time acquisition circuit and an analog-to-digital conversion chip U8 are set to transmit the current response time and the collected current value to the single-chip microcomputer TU1, so that the single-chip microcomputer TU1 can dynamically adjust the output of the electronic load based on the received data to improve the accuracy of the lithium battery short-circuit protection performance test.

[0040] Please refer to Figures 1 to 9 As shown, a preferred embodiment of an electronic load for lithium battery testing of the present invention includes a single-chip microcomputer TU1, an integral regulation circuit, a load linear regulation circuit, an integral regulation rate control circuit, a current acquisition circuit, a digital-to-analog conversion circuit, an analog-to-digital conversion chip U8, and a current response time acquisition circuit;

[0041] The single-chip microcomputer TU1 is used to control the operation of the electronic load. In specific implementation, it is sufficient to select a single-chip microcomputer that can realize this function from the existing technology, and it is not limited to any model. For example, the single-chip microcomputer model is TM4C1294NCPDT, and the control program is well known to those skilled in the art. This is something that can be obtained by those skilled in the art without any creative work. The integral regulation circuit is used to control the operation of the NMOS tube Q4 of the load linear regulation circuit according to the analog voltage output by the digital-to-analog conversion circuit, thereby controlling the magnitude of the output current of the electronic load and the current response rate. The load linear regulation circuit is used to convert the input voltage into a corresponding resistance value, thereby adjusting the magnitude of the output current of the resistive load and the current response rate. The integral regulation circuit is used to control the operation of the NMOS tube Q4 of the load linear regulation circuit according to the analog voltage output by the digital-to-analog conversion circuit, thereby controlling the magnitude of the output current of the electronic load and the current response rate. The integral regulation rate control circuit is used to control the response rate of the electronic load by controlling the integration rate; the current acquisition circuit is used to acquire the current of the load linear regulation circuit and transmit it to the integral regulation circuit after amplification to achieve stable output of the current of the electronic load, and transmit the acquired current to the current response time acquisition circuit and the analog-to-digital conversion chip U8 for further signal processing; the digital-to-analog conversion circuit is used to convert digital signals into analog signals; the analog-to-digital conversion chip U8 is used to convert analog signals into digital signals; the current response time acquisition circuit is used to convert the current analog signal acquired by the current acquisition circuit into a level reversal signal, thereby allowing the microcontroller TU1 to capture the response time of the current change during the test with high precision.

[0042] The input end of the integral regulation rate control circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the integral regulation circuit; the input end of the load linear regulation circuit is connected to the output end of the integral regulation circuit, and the output end is connected to the lithium battery to be tested; the lithium battery to be tested is provided with a battery cell and a protection board; the input end of the current acquisition circuit is connected to the load linear regulation circuit, and the output end is connected to the integral regulation circuit, the current response time acquisition circuit and the analog-to-digital conversion chip U8; the input end of the digital-to-analog conversion circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the integral regulation circuit and the current response time acquisition circuit; the current response time acquisition circuit and the analog-to-digital conversion chip U8 are both connected to the single-chip microcomputer TU1.

[0043] The integral regulation circuit includes an operational amplifier U10A, an operational amplifier U10B, a resistor R36, a resistor R51, a resistor R67, a resistor R68, a resistor R69, a resistor RW1, and a capacitor CW1;

[0044] Pin 5 of the op amp U10B is connected to resistor R36, and pins 6 and 7 are connected to resistors R69 and RW1; pin 1 of the op amp U10A is connected to resistors R51, R68, and CW1, pin 2 is connected to resistors RW1 and CW1, and pin 3 is connected to resistor R67;

[0045] The resistor R36 is connected to pin 1 of the operational amplifier U12A of the current acquisition circuit; the resistor R67 is connected to pin 7 of the digital-to-analog conversion chip N1 of the digital-to-analog conversion circuit; the resistor R68 is connected to the resistor R71 of the load linear adjustment circuit; the resistor R69 and the resistor R51 are both grounded;

[0046] The resistor RW1 and the capacitor CW1 are respectively connected in parallel with the integral regulation rate control circuit.

[0047] The integral regulation circuit is connected to the digital potentiometer U9 through RW-IN and RW-OUT, and is connected to the multiplexing switch U11 through CW-IN and CW-OUT; the integral regulation circuit uses the virtual short and virtual open principles of the operational amplifier U10A and the operational amplifier U10B to make the voltages of pins 2 and 3 of the operational amplifier equal when the integral circuit reaches a stable state, and then controls the load linear regulation circuit through VOUT-1, so that the set value of the electronic load output current is consistent with the loop current of the lithium battery to be tested.

[0048] The integral regulation rate control circuit includes a digital potentiometer U9, a multiplexing switch U11, a resistor TR3, a resistor TR4, a capacitor CW2, a capacitor CW3, a capacitor CW4, a capacitor CW5, a capacitor CW6, a capacitor CW7, a capacitor CW8 and a capacitor CW9;

[0049] Pins 1, 2, and 3 of the digital potentiometer U9 are connected to pins 12, 13, and 14 of the single-chip microcomputer TU1, respectively; pin 7 is connected to pin 8; pin 11 is connected to resistor TR4; pin 12 is connected to resistor TR3; and pins 6 and 9 are both connected to the integral adjustment circuit; that is, the digital potentiometer U9 is connected in parallel to the resistor RW1 of the integral adjustment circuit through pins 6 and 9;

[0050] The model of the digital potentiometer U9 is preferably MCP42100, and the maximum value of the adjustable resistance is 100K; the resistance value set by the digital potentiometer U9 is used as the actual value of the resistor RW1 shown in the integral adjustment circuit;

[0051] Pins 1, 15, and 16 of the multiplexing switch U11 are connected to pins 94, 96, and 95 of the microcontroller TU1, respectively, and pin 8 is connected to the integral regulation circuit. One end of each of capacitors CW2, CW3, CW4, CW5, CW6, CW7, CW8, and CW9 is connected to pins 4, 5, 6, 7, 12, 11, 10, and 9 of the multiplexing switch U11, respectively, and the other end is connected to the integral regulation circuit. That is, the multiplexing switch U11 is connected in parallel to both ends of capacitor CW1 via pin 8 and CW-OUT.

[0052] The model of the multiplexing switch U11 is preferably MAX308, having 8 switch nodes. The capacitors CW2, CW3, CW4, CW5, CW6, CW7, CW8 and CW9 are connected to the 8 switch nodes respectively, and the actual value of the capacitor CW1 shown in the integral regulation circuit is selected through the switch.

[0053] That is, the digital potentiometer U9 and the multiplexer switch U11 are used to adjust the resistance and capacitance values, and then the integration rate of the integration adjustment circuit is adjusted to match the response rate of currents of different sizes, so as to achieve the purpose of fast response and no surging when loading currents of different sizes.

[0054] The principle of integral rate adjustment is as follows:

[0055] Assume that the current flowing through the capacitor CW1 is Ic1, the voltage is Uc1, the capacitance of the capacitor CW1 is C1, the resistance of the resistor RW1 is R1, and the voltage is Ur1, then Ic1 = C1*dUc1 / dt; according to the virtual disconnection principle of the operational amplifier, the current flowing through the capacitor CW1 and the resistor RW1 is equal, that is, Ur1 / R1 = C1*dUc1 / dt, and then it can be deduced that By controlling the size of R1 and C1, the time for the integral regulation circuit to reach the final steady state can be adjusted, that is, the time for the voltage of pins 2 and 3 of the op amp to be equal can be adjusted, thereby controlling the rise time of VOUT-1 and the response time of the electronic load discharge current.

[0056] The load linear regulation circuit includes an NMOS transistor Q4, a resistor R71 and a resistor R73;

[0057] One end of the resistor R71 is connected to the resistor R68 of the integral regulation circuit, and the other end is connected to the resistor R73 and the gate of the NMOS transistor Q4; the source of the NMOS transistor Q4 is connected to the resistor R73 and pin 1 of the current sampling resistor RS1 of the current acquisition circuit; the drain of the NMOS transistor Q4 is connected to the lithium battery to be tested; the load linear regulation circuit converts the different voltage values provided by VOUT-1 into resistance values, thereby stabilizing the output current at a set value;

[0058] The current acquisition circuit includes a current sampling resistor RS1, an operational amplifier U12A, a resistor R70, a resistor R72, a resistor R74, a resistor R76 and a resistor R77;

[0059] Pin 1 of the current sampling resistor RS1 is connected to the source of the NMOS tube Q4 of the load linear regulation circuit, pin 2 is connected to the resistor R72, pin 3 is connected to the resistor R76, and pin 4 is grounded;

[0060] Pin 1 of the operational amplifier U12A is connected to resistor R74, resistor R77, resistor R36 of the integral adjustment circuit, resistor R75 of the current response time acquisition circuit, and analog-to-digital conversion chip U8, pin 2 is connected to resistor R76 and resistor R77, and pin 3 is connected to resistor R70 and resistor R72; the resistor R70 and resistor R74 are both grounded.

[0061] The current sampling resistor RS1 converts the current in the load linear regulation circuit into a voltage and transmits it to the operational amplifier U12A. The operational amplifier U12A amplifies the received voltage through the resistors R70, R72, R76, and R77 and outputs the amplified voltage. The output voltage is calculated as follows:

[0062] V-IFB=((Vs1*R70 / (R72+R70)-Vs2) / R76)*(R76+R77)+Vs2.

[0063] The digital-to-analog conversion circuit includes a digital-to-analog conversion chip N1, a capacitor TC6, a capacitor TC7, a capacitor TC8, and a resistor TR13. The digital-to-analog conversion chip N1 is preferably an AD5689, which has dual channels and a 16-bit buffered voltage output. The digital-to-analog conversion circuit transmits a voltage value to the integral adjustment circuit via Iset-DA1 as the current set value of the electronic load, and transmits the voltage value to the current response time acquisition circuit via Iset-DA2 for comparison with the voltage value acquired by the current acquisition circuit.

[0064] After the capacitor TC6 and the capacitor TC7 are connected in parallel, one end is connected to pin 1 of the digital-to-analog conversion chip N1, and the other end is grounded; pin 3 of the digital-to-analog conversion chip N1 is connected to the resistor R78 of the current response time acquisition circuit, pin 7 is connected to the resistor R67 of the integral adjustment circuit, pins 12, 13, and 14 are connected to pins 4, 3, and 5 of the microcontroller TU1, respectively, and pin 15 is connected to the resistor TR13, one end of the capacitor TC8, and pin 1 of the microcontroller TU1; the other end of the capacitor TC8 is grounded.

[0065] The current response time acquisition circuit includes a high-speed comparator U13, a resistor R75, a resistor R78, a resistor R79 and a resistor R80;

[0066] One end of the resistor R75 is connected to pin 3 of the high-speed comparator U13, and the other end is connected to pin 1 of the operational amplifier U12A of the current acquisition circuit; one end of the resistor R78 is connected to pin 1 of the high-speed comparator U13 and the resistor R80, and the other end is connected to pin 3 of the digital-to-analog conversion chip N1 of the digital-to-analog conversion circuit; one end of the resistor R79 is connected to pin 4 of the high-speed comparator U13 and pin 77 of the microcontroller TU1, and the other end is grounded.

[0067] The current response time acquisition circuit is a positive feedback circuit to accelerate the response time of the high-speed comparator U13. Ist-DA2 is the comparison point for the output of the digital-to-analog conversion circuit controlled by the microcontroller TU1. When no current is applied, Time-GET, corresponding to the IO port of the microcontroller TU1, is configured to a high level. When the current in the loop reaches the comparison point Iset-DA2, the Time-GET output of the high-speed comparator U13 is rapidly pulled low, at which point the microcontroller TU1 begins test timing. When the protection circuit of the tested lithium battery is activated, the MOSFET in the protection circuit is disconnected, the current in the loop disappears, and the Time-GET output of the high-speed comparator U13 is rapidly pulled high, at which point the microcontroller TU1 ends timing, thereby obtaining the response time of the protection board of the tested lithium battery shutting down the MOSFET in the loop. The voltage of Iset-DA2 is provided by the analog-to-digital conversion circuit, so the start and end values of the current timing of the microcontroller TU1 can be freely set as needed.

[0068] Pins 12, 13, 14, 94, 95, and 96 of the single-chip microcomputer TU1 are connected to the integral regulation rate control circuit, pins 1, 3, 4, and 5 are connected to the digital-to-analog conversion circuit, pin 77 is connected to the current response time acquisition circuit, and pins 33 and 34 are connected to the analog-to-digital conversion chip U8.

[0069] Pins 30 and 31 of the analog-to-digital conversion chip U8 are connected to the microcontroller TU1, and pin 24 is connected to the current acquisition circuit; the model of the analog-to-digital conversion chip U8 is preferably ADUCM360, and the data collected by the current acquisition circuit is transmitted to the microcontroller TU1 through serial communication.

[0070] Working principle of the present invention:

[0071] The single chip microcomputer TU1 sets the first voltage value output by the digital-to-analog conversion circuit and transmits it to the integral regulation circuit and the current response time acquisition circuit respectively. The integral regulation circuit adjusts the current value output by the load linear regulation circuit based on the received first voltage value.

[0072] The current acquisition circuit collects the current value of the load linear regulation circuit and converts it into a second voltage value, which is then transmitted to the integral regulation circuit, the current response time acquisition circuit, and the analog-to-digital conversion chip U8. The integral regulation circuit performs feedback adjustment on the output based on the second voltage value, ensuring that the current value output by the load linear regulation circuit is the same as the set value. The single-chip microcontroller TU1 adjusts the integral regulation circuit's integral rate through the integral regulation rate control circuit, automatically matching the response rate to different currents.

[0073] The current response time acquisition circuit calculates the current response time by comparing the first voltage value with the second voltage value and transmits it to the microcontroller TU1; the analog-to-digital conversion chip U8 converts the received second voltage value from an analog signal to a digital signal and transmits it to the microcontroller TU1; the microcontroller TU1 dynamically adjusts the output of the electronic load based on the received data.

[0074] In summary, the advantages of the present invention are:

[0075] By setting up an integral regulation rate control circuit, the resistance and capacitance values can be dynamically adjusted, and then the integral rate of the integral regulation circuit can be adjusted to match the response rate of currents of different sizes. That is, when facing different types of lithium batteries, they can respond quickly to currents of different sizes to avoid convex waves in the current waveform and current shock damage to the protection board of the lithium battery; by setting up a current acquisition circuit, the collected current value is input into the integral regulation circuit for feedback adjustment, so that the current value output by the electronic load remains equal to the set value, and the current response time and the collected current value are transmitted to the microcontroller TU1 through the current response time acquisition circuit and the analog-to-digital conversion chip U8, so that the microcontroller TU1 can dynamically adjust the output of the electronic load based on the received data, which ultimately greatly improves the accuracy of the lithium battery short-circuit protection performance test.

[0076] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An electronic load for lithium battery testing, characterized by: It includes a single chip microcomputer TU1, an integral regulation circuit, a load linear regulation circuit, an integral regulation rate control circuit, a current acquisition circuit, a digital-to-analog conversion circuit, an analog-to-digital conversion chip U8 and a current response time acquisition circuit; The input end of the integral regulation rate control circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the integral regulation circuit; the input end of the load linear regulation circuit is connected to the output end of the integral regulation circuit; the input end of the current acquisition circuit is connected to the output end of the load linear regulation circuit, and the output end is connected to the input end of the integral regulation circuit, the input end of the current response time acquisition circuit, and the input end of the analog-to-digital conversion chip U8; the input end of the digital-to-analog conversion circuit is connected to the single-chip microcomputer TU1, and the output end is connected to the input end of the integral regulation circuit and the input end of the current response time acquisition circuit; the output end of the current response time acquisition circuit and the output end of the analog-to-digital conversion chip U8 are both connected to the single-chip microcomputer TU1; The integral regulation circuit includes an operational amplifier U10A, an operational amplifier U10B, a resistor R36, a resistor R51, a resistor R67, a resistor R68, a resistor R69, a resistor RW1, and a capacitor CW1; Pin 5 of the op amp U10B is connected to resistor R36, and pins 6 and 7 are connected to resistors R69 and RW1; pin 1 of the op amp U10A is connected to resistors R51, R68, and CW1, pin 2 is connected to resistors RW1 and CW1, and pin 3 is connected to resistor R67; The resistor R36 is connected to the resistor R74 of the current acquisition circuit and pin 1 of the operational amplifier U12A; the resistor R67 is connected to pin 7 of the digital-to-analog conversion chip N1 of the digital-to-analog conversion circuit; the resistor R68 is connected to the resistor R71 of the load linear adjustment circuit; the resistor R69 and the resistor R51 are both grounded; The resistor RW1 and the capacitor CW1 are respectively connected in parallel with the integral rate adjustment control circuit, that is, one end of the resistor RW1 is connected to pin 6 of the digital potentiometer U9 of the integral rate adjustment control circuit, and the other end is connected to pin 8 of the multiplexing switch U11 of the integral rate adjustment control circuit; one end of the capacitor CW1 is connected to pin 8 of the multiplexing switch U11 of the integral rate adjustment control circuit, and the other end is connected to capacitors CW2, CW3, CW4, CW5, CW6, CW7, CW8, and CW9 of the integral rate adjustment control circuit; The integral regulation rate control circuit includes a digital potentiometer U9, a multiplexing switch U11, a resistor TR3, a resistor TR4, a capacitor CW2, a capacitor CW3, a capacitor CW4, a capacitor CW5, a capacitor CW6, a capacitor CW7, a capacitor CW8 and a capacitor CW9; The model of the digital potentiometer U9 is MCP42100; the model of the multiplexer switch U11 is MAX308; Pins 1, 2, and 3 of the digital potentiometer U9 are connected to the single-chip microcomputer TU1, pin 7 is connected to pin 8, pin 11 is connected to resistor TR4, pin 12 is connected to resistor TR3, and pins 6 and 9 are connected to both ends of the resistor RW1 of the integral adjustment circuit; Pins 1, 15, and 16 of the multiplexing switch U11 are connected to the single-chip microcomputer TU1, and pin 8 is connected to the integral regulation circuit; one end of the capacitors CW2, CW3, CW4, CW5, CW6, CW7, CW8, and CW9 are respectively connected to pins 4, 5, 6, 7, 12, 11, 10, and 9 of the multiplexing switch U11, and the other ends are connected to the integral regulation circuit; The load linear regulation circuit includes an NMOS transistor Q4, a resistor R71 and a resistor R73; One end of the resistor R71 is connected to the resistor R68 of the integral regulation circuit, and the other end is connected to one end of the resistor R73 and the gate of the NMOS transistor Q4; the source of the NMOS transistor Q4 is connected to the other end of the resistor R73 and pin 1 of the current sampling resistor RS1 of the current acquisition circuit, and the drain is connected to the positive power supply; The current acquisition circuit includes a current sampling resistor RS1, an operational amplifier U12A, a resistor R70, a resistor R72, a resistor R74, a resistor R76 and a resistor R77; Pin 1 of the current sampling resistor RS1 is connected to the load linear regulation circuit, pin 2 is connected to the resistor R72, pin 3 is connected to the resistor R76, and pin 4 is grounded; Pin 1 of the operational amplifier U12A is connected to resistor R74, resistor R77, resistor R36 of the integral adjustment circuit, resistor R35 of the current response time acquisition circuit, and analog-to-digital conversion chip U8; pin 2 is connected to resistor R76 and resistor R77; pin 3 is connected to resistor R70 and resistor R72; the resistor R70 and resistor R74 are both grounded; The digital-to-analog conversion circuit includes a digital-to-analog conversion chip N1, a capacitor TC6, a capacitor TC7, a capacitor TC8 and a resistor TR13; the model of the digital-to-analog conversion chip N1 is AD5689; After the capacitors TC6 and TC7 are connected in parallel, one end is connected to pin 1 of the digital-to-analog conversion chip N1, and the other end is grounded; pin 3 of the digital-to-analog conversion chip N1 is connected to the resistor R78 of the current response time acquisition circuit, pin 7 is connected to the resistor R67 of the integral adjustment circuit, pins 12, 13, and 14 are connected to the single-chip microcomputer TU1, and pin 15 is connected to one end of the resistor TR13, one end of the capacitor TC8, and the single-chip microcomputer TU1; the other end of the capacitor TC8 is grounded; the other end of the resistor TR13 is connected to positive 3.3V; The current response time acquisition circuit includes a high-speed comparator U13, a resistor R75, a resistor R78, a resistor R79 and a resistor R80; One end of the resistor R75 is connected to pin 3 of the high-speed comparator U13, and the other end is connected to pin 1 of the operational amplifier U12A of the current acquisition circuit; one end of the resistor R78 is connected to pin 1 of the high-speed comparator U13 and the resistor R80, and the other end is connected to pin 3 of the digital-to-analog conversion chip N1 of the digital-to-analog conversion circuit; one end of the resistor R79 is connected to pin 4 of the high-speed comparator U13 and the single-chip microcomputer TU1, and the other end is grounded; Pins 12, 13, 14, 94, 95, and 96 of the single-chip microcomputer TU1 are connected to the integral regulation rate control circuit, pins 1, 3, 4, and 5 are connected to the digital-to-analog conversion circuit, pin 77 is connected to the current response time acquisition circuit, and pins 33 and 34 are connected to the analog-to-digital conversion chip U8; the model of the single-chip microcomputer TU1 is TM4C1294NCPDT; Pins 30 and 31 of the analog-to-digital conversion chip U8 are connected to the single-chip microcomputer TU1, and pin 24 is connected to the current acquisition circuit; the model of the analog-to-digital conversion chip U8 is ADUCM360.

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