Battery simulation circuit and test system

Abstract

The invention relates to a battery simulation circuit and a test system. The battery simulation circuit comprises N voltage simulation units connected in series, one voltage simulation unit is used for simulating one single battery, the voltage simulation units are used for being connected with a battery management system, the voltage simulation units are used for outputting simulation voltage signals corresponding to set voltage parameters to the battery management system, and N is a positive integer larger than or equal to 2; and the temperature simulation unit is used for being connected with a battery management system, and the temperature simulation unit is used for outputting an analog voltage signal corresponding to a set temperature parameter to the battery management system, and the battery simulation circuit solves the problem of a battery management system test method based on a real battery pack in the prior art. And the output voltage and temperature of the battery pack are difficult to flexibly and quickly adjust according to test requirements.

Description

Technical Field

[0001] This application relates to the field of battery management system testing technology, and in particular to a battery simulation circuit and testing system. Background Technology

[0002] A Battery Management System (BMS) monitors the output voltage and temperature of the battery pack and controls its charging and discharging to prevent overcharging and over-discharging. To ensure the reliability of the BMS, reliability testing is necessary. Currently, BMS reliability testing includes voltage testing and temperature testing. Voltage testing verifies the accuracy of the BMS in acquiring the battery pack's output voltage, while temperature testing verifies the accuracy of the BMS in acquiring the battery pack's temperature.

[0003] Currently, voltage testing of battery management systems requires actual charging and discharging of a real battery pack to adjust its output voltage to the required test voltage. This process is time-consuming. Similarly, temperature testing of battery management systems necessitates adjusting the ambient temperature of the real battery pack using temperature control equipment to bring it to the required test temperature, which is also time-consuming. Therefore, existing battery management system testing methods based on real battery packs struggle to flexibly and quickly adjust the battery pack's output voltage and temperature according to test requirements. Summary of the Invention

[0004] This application provides a battery simulation circuit and testing system to solve the problem in existing battery management system testing methods based on real battery packs that it is difficult to flexibly and quickly adjust the output voltage and temperature of the battery pack according to testing requirements.

[0005] In a first aspect, this application provides a battery simulation circuit, comprising: N voltage simulation units connected in series, each voltage simulation unit simulating a single battery cell, the voltage simulation unit being connected to a battery management system, and the voltage simulation unit being used to output a simulated voltage signal corresponding to a set voltage parameter to the battery management system, where N is a positive integer greater than or equal to 2; and a temperature simulation unit, the temperature simulation unit being connected to the battery management system, and the temperature simulation unit being used to output a simulated voltage signal corresponding to a set temperature parameter to the battery management system.

[0006] Optionally, the voltage simulation unit includes: a power chip, the input terminal of which is connected to a power source, and the output terminal of which is connected to the battery management system; a first resistor, the first end of which is connected to the ground terminal of the power chip, and the second end of which is connected to the feedback loop terminal of the power chip, wherein the output voltage of the feedback loop terminal is a preset voltage; a second resistor, the first end of which is connected to the second end of the first resistor; and a third resistor, which is a digital resistor, the first end of which is connected to the second end of the second resistor, and the second end of which is connected to the output terminal of the power chip; wherein, when the control terminal of the third resistor receives a target control signal, the output terminal of the power chip outputs an analog voltage signal corresponding to the set voltage parameter to the battery management system, the target control signal indicating that the resistance value of the third resistor is adjusted to a target resistance value, and the magnitude of the analog voltage signal output by the output terminal of the power chip is related to the resistance value of the third resistor.

[0007] Optionally, the power supply is an AC power supply, and the voltage simulation unit includes an AC-DC conversion unit, the input terminal of which is connected to the AC power supply, and the output terminal of which is connected to the input terminal of the power chip.

[0008] Optionally, the voltage simulation unit further includes: a plurality of fourth resistors, each fourth resistor having a first end connected to the first end of the third resistor; a plurality of first optocouplers, each first optocoupler corresponding to one of the fourth resistors, the collector of each first optocoupler being connected to the second end of the third resistor, the emitter of each first optocoupler being connected to the second end of the corresponding fourth resistor, and the anode of each first optocoupler being connected to the output terminal of the AC-DC conversion unit. The first optocoupler is configured to conduct when its cathode receives a first target voltage signal, and when conducting, connects the emitter and collector of the first optocoupler so that the corresponding fourth resistor R4 is connected in parallel with the third resistor R3. When the control terminal of the third resistor receives the target control signal and the cathodes of the M first optocouplers receive the first target voltage signal, the output terminal of the power chip outputs the analog voltage signal corresponding to the set voltage parameter to the battery management system, where M is a positive integer and M is not greater than N.

[0009] Optionally, the battery simulation circuit includes: a plurality of first MOS transistors, each first MOS transistor corresponding to a first optocoupler in each voltage simulation unit, the first end of each first MOS transistor being connected to the cathode of the corresponding first optocoupler in each voltage simulation unit, and the second end of each first MOS transistor being connected to ground; wherein, when the control terminal of the first MOS transistor receives a second target voltage signal, the first MOS transistor is turned on, and when the first MOS transistor is turned on, the cathode of the first optocoupler corresponding to the first MOS transistor receives the first target voltage signal.

[0010] Optionally, the voltage simulation unit further includes: a fifth resistor, the first end of which is connected to the output terminal of the power supply chip, and the second end of which is connected to the battery management system; an operational amplifier, the inverting input terminal of which is connected to the first end of the fifth resistor, the non-inverting input terminal of which is connected to the second end of the fifth resistor, the positive power supply terminal of which is connected to the output terminal of the AC-DC conversion unit, and the negative power supply terminal of which is connected to the ground terminal of the power supply chip; and a second MOSFET, the first end of which is connected to the second end of the fifth resistor, the second end of which is connected to the ground terminal of the power supply chip, and the control terminal of which is connected to the output terminal of the operational amplifier.

[0011] Optionally, the voltage simulation unit further includes a TVS diode, the first end of which is connected to the output terminal of the power chip, and the second end of which is connected to the ground terminal of the power chip.

[0012] Optionally, the temperature simulation unit includes: multiple sixth resistors, the first ends of which are all connected to the battery management system, and any two sixth resistors have different resistance values. Each of the multiple sixth resistors corresponds to a specific temperature parameter, and the magnitude of the temperature parameter is related to the resistance value of the sixth resistor. Multiple second optocouplers correspond to each of the sixth resistors, the emitters of each second optocoupler are connected to ground, the collectors of each second optocoupler are connected to the second ends of the corresponding sixth resistors, the anodes of each second optocoupler are connected to the output of the AC-DC conversion unit, and the cathodes of each second optocoupler are turned on when the first target voltage signal is received. When the cathode of the second optocoupler corresponding to the target resistor receives the first target voltage signal, the first end of the target resistor outputs an analog voltage signal corresponding to the set temperature parameter to the battery management system. The target resistor is the sixth resistor corresponding to the set temperature parameter.

[0013] Optionally, the battery simulation circuit further includes: a control chip, wherein the first MOS transistor corresponds one-to-one with the first output terminal of the control chip, the control terminal of the first MOS transistor is connected to the corresponding first output terminal, the second optocoupler corresponds one-to-one with the second output terminal of the control chip, and the cathode of the second optocoupler is connected to the corresponding second output terminal; wherein the first output terminal is used to output the second target voltage signal; and the second output terminal is used to output the first target voltage signal.

[0014] Secondly, this application provides a testing system comprising: any one of the battery simulation circuits described above; a battery management system connected to the output terminal of the power chip in each voltage simulation unit of the battery simulation circuit, the battery management system connected to the second terminal of the fifth resistor in the Nth voltage simulation unit and connected to the ground terminal of the power chip in the first voltage simulation unit, the battery management system connected to the first terminal of the sixth resistor in the temperature simulation unit of the battery simulation circuit; and a host computer connected to the control terminal of the third resistor in each voltage simulation unit, the host computer connected to all the first output terminals of the control chip in the battery simulation circuit, and the host computer connected to all the second output terminals of the control chip.

[0015] In the embodiments of this application, during the voltage testing of the battery management system, it is not necessary to spend a long time charging and discharging the actual battery pack to adjust its output voltage to the required test voltage. Simply changing the set voltage parameters allows the voltage simulation unit to instantly output the analog voltage signal corresponding to the set voltage parameters to the battery management system. Similarly, during the temperature testing of the battery management system, it is not necessary to spend a long time adjusting the temperature of the actual battery pack to reach the required test temperature. Simply changing the set temperature parameters allows the temperature simulation unit to instantly output the analog voltage signal corresponding to the set temperature parameters to the battery management system. This solves the problem in existing battery management system testing methods based on actual battery packs that it is difficult to flexibly and quickly adjust the output voltage and temperature of the battery pack according to test requirements. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a schematic diagram of a battery simulation circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of another battery simulation circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an optocoupler in the prior art; The symbols in the attached image are explained as follows: 1. Battery Management System; 2. Battery Simulation Circuit; 20. Voltage Simulation Unit; 21. Temperature Simulation Unit; 22. Control Chip; 210. Power Supply Chip; 220. AC-DC Conversion Unit. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0022] To address the technical problem in existing battery management system testing methods based on real battery packs that make it difficult to flexibly and quickly adjust the output voltage and temperature of the battery pack according to testing requirements, this application provides a battery simulation circuit and testing system that can solve the problem of existing battery management system testing methods based on real battery packs that make it difficult to flexibly and quickly adjust the output voltage and temperature of the battery pack according to testing requirements.

[0023] Figure 1 A battery simulation circuit 2 provided in this application embodiment includes: N voltage simulation units 20 connected in series, one of the voltage simulation units 20 is used to simulate a single battery cell, the voltage simulation unit 20 is used to connect to the battery management system 1, and the voltage simulation unit 20 is used to output the simulated voltage signal corresponding to the set voltage parameters to the battery management system 1, where N is a positive integer greater than or equal to 2. Temperature simulation unit 21 is used to connect to the battery management system 1 and outputs an analog voltage signal corresponding to the set temperature parameter to the battery management system 1.

[0024] Through the above embodiments, during the voltage testing of the battery management system, it is not necessary to spend a long time charging and discharging the actual battery pack to adjust its output voltage to the required test voltage. Simply changing the set voltage parameters allows the voltage simulation unit to instantly output the analog voltage signal corresponding to the set voltage parameters to the battery management system. Similarly, during the temperature testing of the battery management system, it is not necessary to spend a long time adjusting the temperature of the actual battery pack to reach the required test temperature. Simply changing the set temperature parameters allows the temperature simulation unit to instantly output the analog voltage signal corresponding to the set temperature parameters to the battery management system. This solves the problem in existing battery management system testing methods based on actual battery packs that it is difficult to flexibly and quickly adjust the output voltage and temperature of the battery pack according to test requirements.

[0025] In one alternative embodiment, such as Figure 2 As shown, the voltage simulation unit 20 includes: The power chip 210 has an input terminal for connecting to a power source and an output terminal for connecting to the battery management system 1. It should be noted that, as Figure 2 As shown, the output terminal of power chip 210 is used for SW representation. Figure 2 The connection between the output of the power chip 210 and the battery management system 1 is not shown.

[0026] In one alternative embodiment, such as Figure 2 As shown, the power supply is an AC power supply, and the voltage simulation unit 20 includes: The AC-DC conversion unit 220 has an input terminal for connecting to an AC power source and an output terminal for connecting to the input terminal of the power chip 210.

[0027] For example, the AC power supply mentioned above is 220V AC mains power. Figure 2 In the AC-DC conversion unit 220, there is a chip U and a capacitor Cb. The C+ terminal of the chip U is connected to the live wire (220V / L) of the 220V AC mains power, the C- terminal of the chip U is connected to the neutral wire (220V / N) of the 220V AC mains power and is also connected to the ground GND. The V- terminal of the chip U is connected to the ground GND. The V+ terminal of the chip U is connected to the output terminal of the AC-DC conversion unit 220, which is denoted by Vout. The output terminal of the AC-DC conversion unit 220 is connected to the input terminal of the power supply chip 210, which is denoted by Vin. By setting the AC-DC conversion unit 220 in the voltage simulation unit 20, the voltage simulation unit 20 can be directly connected to the 220V AC mains power, avoiding secondary power supply.

[0028] The first resistor R1 has its first end connected to the ground terminal of the power chip 210, and its second end connected to the feedback loop terminal of the power chip 210. The output voltage of the feedback loop terminal is a preset voltage. The second resistor R2, the first end of which is connected to the second end of the first resistor R1; The third resistor R3 is a digital resistor. The first end of the third resistor R3 is connected to the second end of the second resistor R2. The second end of the third resistor R3 is connected to the output end of the power chip 210. Specifically, at least when the control terminal of the third resistor R3 receives the target control signal, the output terminal of the power chip 210 outputs the analog voltage signal corresponding to the set voltage parameter to the battery management system 1. The target control signal indicates that the resistance value of the third resistor R3 is adjusted to the target resistance value. The magnitude of the analog voltage signal output by the output terminal of the power chip 210 is related to the resistance value of the third resistor R3.

[0029] For example, the voltage parameter is a digital representation of the analog voltage signal. The following will uniformly use output voltage to represent the voltage parameter as an analog voltage signal, such as... Figure 2 As shown, the output voltage of the power chip 210 of a voltage simulation unit 20 (denoted by SW) is used to simulate the output voltage of a single battery cell. The output voltage of the power chip 210 of each voltage simulation unit 20 is adjustable to simulate the output voltage of the battery cell when it is in a depleted state, a normal state, and a fully charged state. Taking the Nth voltage simulation unit 20 as an example, the adjustment strategy of the output voltage of the power chip 210 of the voltage simulation unit 20 is explained. The first end of the first resistor R1 is connected to the ground terminal GNDN of the power chip 210, and the second end of the first resistor R1 is connected to the power chip 210. The feedback loop terminal (denoted by FB) of power chip 210 is connected. The output voltage of the feedback loop terminal is always a preset voltage, exemplarily 0.75V. The first terminal of the second resistor R2 is connected to the second terminal of the first resistor R1, the second terminal of the second resistor R2 is connected to the first terminal of the third resistor R3, and the second terminal of the third resistor R3 is connected to the output terminal (denoted by SW) of power chip 210. The first resistor R1, the second resistor R2, and the third resistor R3 are connected in series. Therefore, the first resistor R1, the second resistor R2, and the third resistor R3 form a voltage divider. The output voltage of the output terminal (denoted by SW) of power chip 210 is: , The output voltage of the power chip 210. The output voltage (denoted by FB) at the feedback loop terminal of the power chip 210 is a preset voltage. The resistance value of the first resistor is fixed; for example, the resistance value of the first resistor R1 is fixed at 10KΩ. The resistance value of the second resistor is also fixed; for example, the resistance value of the second resistor R2 is fixed at 7.5KΩ. The resistance value of the third resistor R3 is adjustable. Therefore, adjusting the resistance value of the third resistor R3 adjusts the output voltage at the output terminal of the power chip 210. Table 1 provides an example of the output voltage V at the output terminal of the power chip 210. SW There is a mapping relationship between the voltage across R2 and R3, the resistance of R3, and the resistance of R2 + R3, where V SW 1.5V, 2V, and 2.5V represent the output voltage of a battery cell when it is in a depleted state. SW 3V is the output voltage of a single battery cell when it is fully charged. SW 3.5V, 4V, and 4.5V are the output voltages of a battery cell when it is under over-electricity.

[0030] It should be noted that, as Figure 2 As shown, the output voltage at the feedback loop terminal of the power chip 210 is relative to the voltage at the ground terminal of the power chip 210, such as... Figure 2 As shown, GND1, GND2...GNDN represent the grounding terminals of the power supply chip 210 of the first voltage simulation unit 20, the power supply chip 210 of the second voltage simulation unit 20, and so on, the grounding terminals of the power supply chip 210 of the Nth voltage simulation unit 20, respectively. The grounding terminals of the power supply chips 210 of different voltage simulation units 20 are not connected together. The grounding terminal of the power supply chip 210 of the first voltage simulation unit 20 is connected to the ground terminal GND.

[0031] Table 1

[0032] For example, such as Figure 2 As shown, the battery management system 1 collects the output voltage of the power chip 210. By comparing the collected value with the actual value of the output voltage of the power chip 210, the accuracy of the battery management system in collecting the output voltage of the battery cell can be tested.

[0033] In one alternative embodiment, such as Figure 2 As shown, the voltage simulation unit 20 further includes: Multiple fourth resistors R4, the first end of each of the above-mentioned fourth resistors R4 is connected to the first end of the above-mentioned third resistor R3; Multiple first optocouplers P1 are provided, each corresponding to a fourth resistor R4. The collector of each first optocoupler P1 is connected to the second end of the third resistor R3, the emitter of each first optocoupler P1 is connected to the second end of the corresponding fourth resistor R4, and the anode of each first optocoupler P1 is connected to the output terminal of the AC-DC conversion unit 220. Each first optocoupler P1 is used to conduct when the cathode of the first optocoupler P1 receives a first target voltage signal, and when conducting, the emitter of the first optocoupler P1 is connected to the collector of the first optocoupler P1 so that the corresponding fourth resistor R4 is connected in parallel with the third resistor R3. When the control terminal of the third resistor R3 receives the target control signal and the cathodes of the M first optocouplers P1 receive the first target voltage signal, the output terminal of the power chip 210 outputs the analog voltage signal corresponding to the set voltage parameter to the battery management system 1, where M is a positive integer and M is not greater than N.

[0034] For example, such as Figure 3 As shown, the optocoupler comprises a phototransistor L and a light-emitting diode D. The arrow indicates the direction of illumination. The working principle of the optocoupler is as follows: the anode e of the light-emitting diode D is connected to a high voltage, and the cathode f of the light-emitting diode D is connected to a low voltage. When the voltage difference between the anode e and the cathode f is greater than the turn-on voltage of the light-emitting diode D, the light-emitting diode D conducts and emits light. The light enters the base c of the phototransistor L. When the voltage difference between the base c and the emitter b of the phototransistor L is greater than the turn-on voltage difference of the phototransistor L, the collector a of the phototransistor L generates current, that is, the phototransistor L conducts. The collector a of the phototransistor L is connected to the emitter b. For example, the first target voltage signal is an analog voltage signal and is less than the output voltage of the output terminal of the AC-DC conversion unit 220.

[0035] For example, such as Figure 2 As shown, the magnitude of the analog voltage signal output by the power chip 210 is related to the resistance value of the third resistor R3, and also to the number of fourth resistors R4 connected in parallel with the third resistor R3, and the resistance value of the fourth resistors R4 connected in parallel with the third resistor R3. The resistance values ​​of the multiple fourth resistors R4 in each voltage analog unit 20 can be the same or different, and this application does not impose any restrictions.

[0036] For example, such as Figure 2As shown, due to the limitation of the resistance adjustment step size of the third resistor R3, adjusting the output voltage of the power chip 210 solely by adjusting the resistance of the third resistor R3 will result in a limited adjustable range and accuracy of the output voltage of the power chip 210. To improve the adjustment accuracy of the output voltage of the power chip 210 in each voltage simulation unit 20 and to accurately simulate the characteristics of the battery cell's output voltage, multiple fourth resistors R4 and multiple first optocouplers P1 are added to each voltage simulation unit 20. The first optocouplers P1 are used to connect the corresponding fourth resistor R4 in parallel with the third resistor R4. Taking the Nth voltage simulation unit 20 as an example, the strategy for adjusting the output voltage of the power chip 210 in the voltage simulation unit 20 will be explained. , This represents the equivalent resistance value after the third resistor R3 and one or more fourth resistors R4 are connected in parallel. According to the principle of parallel resistors, this equivalent resistance is less than the third resistor R3. For example, the resistance adjustment step of the third resistor R3 is 2.5KΩ. When one fourth resistor R4 is connected in parallel, the resistance value of the fourth resistor R4 is 2.5KΩ, and the equivalent resistance value is 1.25KΩ. The resistance adjustment step is reduced from 2.5KΩ to about 1.25KΩ. The adjustment step of the output voltage VSW at the output terminal of the power chip 210 can be reduced synchronously, thereby improving the adjustment accuracy of the output voltage at the output terminal of the power chip 210 and expanding the adjustable range of the output voltage at the output terminal of the power chip 210 to accurately simulate the output voltage characteristics of a single battery cell.

[0037] In one alternative embodiment, such as Figure 2 As shown, the battery simulation circuit 2 includes: Multiple first MOS transistors Q1 are provided, and each first MOS transistor Q1 corresponds to a first optocoupler P1 in each of the voltage simulation units 20. The first end of each first MOS transistor Q1 is connected to the cathode of the corresponding first optocoupler P1 in each of the voltage simulation units 20, and the second end of each first MOS transistor Q1 is connected to ground GND. When the control terminal of the first MOS transistor Q1 receives the second target voltage signal, the first MOS transistor Q1 is turned on. When the first MOS transistor Q1 is turned on, the cathode of the first optocoupler P1 corresponding to the first MOS transistor Q1 receives the first target voltage signal.

[0038] For example, the first target voltage signal is 0.

[0039] For example, the control terminal of the first MOS transistor is the gate. The first MOS transistor can be a PMOS (P Channel Metal Oxide Semiconductor) or an NMOS (N Channel Metal Oxide Semiconductor). If the first MOS transistor is a PMOS transistor, the first terminal of the first MOS transistor is the drain and the first terminal of the first MOS transistor is the source. The second target voltage signal is a negative voltage. If the first MOS transistor can be an NMOS transistor, the second target voltage signal is a positive voltage. The first terminal of the first MOS transistor is the source and the first terminal of the first MOS transistor is the drain.

[0040] For example, in the case of a real battery pack, to ensure the safety of the real battery pack, the output voltage of each battery cell must be as consistent as possible. Therefore, as Figure 2 As shown, the output voltage of the power chip 210 of each voltage simulation unit 20 should also be as consistent as possible. The output voltage of the power chip 210 is related to the number of fourth resistors R4 connected in parallel with the third resistor R3, and is also related to the resistance value of the fourth resistor R4 connected in parallel with the third resistor R3. Therefore, the control strategy of the fourth resistor R4 of each voltage simulation unit 20 is the same. Thus, the fourth resistor R4 in each voltage simulation unit 20 is connected to the corresponding first MOS transistor. By controlling the control terminal of the first MOS transistor, the control of whether the fourth resistor R4 is connected in parallel with the third resistor R3 is uniformly controlled, and the resistance value of the fourth resistor R4 connected to the same first MOS transistor is the same.

[0041] The voltage test also tests whether the battery management system can properly control the charging and discharging of the battery pack. In an optional embodiment, to test whether the battery management system can properly control the charging and discharging of the battery pack, the voltage simulation unit further includes: The fifth resistor R5 has its first end connected to the output terminal of the power chip 210, and its second end connected to the battery management system 1. For example, the resistance of the fifth resistor is 0.01 ohms.

[0042] Operational amplifier H, the inverting input terminal (-) of the operational amplifier H is connected to the first terminal of the fifth resistor R5, the non-inverting input terminal (+) of the operational amplifier H is connected to the second terminal of the fifth resistor R5, the positive power supply terminal of the operational amplifier H is connected to the output terminal of the AC-DC conversion unit 220, and the negative power supply terminal of the operational amplifier H is connected to the ground terminal of the power chip 210. For example, the operational amplifier uses the ADI / MAX44248ASA+ operational chip, which has a power supply voltage range of up to 36V, high precision and low power consumption, and a quiescent current as low as 90uA, providing precision and low power consumption for high voltage applications.

[0043] The second MOSFET Q2 has its first terminal connected to the second terminal of the fifth resistor R5, its second terminal connected to the ground terminal of the power chip 210, and its control terminal connected to the output terminal of the operational amplifier H.

[0044] It should be noted that the second MOSFET is a PMOS transistor, which is turned on by a forward voltage. The first terminal of the second MOSFET is the source, the second terminal is the drain, and the control terminal is the gate.

[0045] For example, such as Figure 2As shown, BAT1-, BAT2-...BATN- represent the positive terminals of the first voltage simulation unit 20, the second voltage simulation unit 20, and so on, the Nth voltage simulation unit 20, respectively, simulating the positive terminals of the first, second, and Nth battery cells. BAT1+, BAT2+...BATN+ represent the positive terminals of the first, second, and Nth voltage simulation units 20, respectively, simulating the positive terminals of the first, second, and Nth battery cells. When simulating battery pack discharge, the current flows in the direction of F; when simulating battery pack discharge, the current flows in the opposite direction of F. When testing whether the battery management system 1 can normally control the battery pack to discharge, the battery management system 1 receives current in the direction of F1. The power chip 210, the battery management system 20, and the device being charged form a circuit to simulate the battery pack discharge process. At this time, the voltage at the first end of the fifth resistor R5 is higher than the voltage at the second end of the fifth resistor R5, that is, the voltage at the inverting input terminal (-) of the operational amplifier H is higher than the voltage at the non-inverting input terminal (+) of the operational amplifier H. At this time, the output terminal of the operational amplifier H outputs a small voltage, which is less than the turn-on voltage of the second MOSFET Q2. At this time, the second MOSFET Q2 is turned off. If the battery management system 1 does not report an error, it means that the battery management system can normally control the battery pack to discharge. If an error is reported, it means that the battery management system 1 has an abnormality and cannot normally control the battery pack to discharge. When the battery pack is being charged under normal control, the battery management system 1 applies a current in the opposite direction to F1 to the voltage simulation unit 20. At this time, the voltage at the first end of the fifth resistor R5 is less than the voltage at the second end of the fifth resistor R5, that is, the voltage at the inverting input terminal (-) of the operational amplifier H is less than the voltage at the non-inverting input terminal (+) of the operational amplifier H. At this time, the output terminal of the operational amplifier H outputs a higher voltage, which is greater than the turn-on voltage of the second MOSFET Q2. At this time, the second MOSFET Q2 is turned on. At this time, the second MOSFET Q2, the battery management system 1, and the device charging the battery pack form a circuit to simulate the battery pack charging process. If the battery management system 1 does not report any errors during the simulated discharge process, it means that the battery management system 1 can control the battery pack to discharge normally. If an error is reported, it means that the battery management system 1 has an abnormality and cannot control the battery pack to discharge normally.

[0046] For example, such as Figure 2 As shown, when testing whether the battery management system can control the battery pack to charge normally, through the design of the fifth resistor R5, operational amplifier H and second MOSFET Q2, only a small portion of the current flows to the output terminal of the power chip 210 (denoted by SW), ensuring the safety of the output terminal of the power chip 210.

[0047] In an optional embodiment, the voltage simulation unit further includes: The first end of the TVS transistor (Transient Voltage Suppressor) is connected to the output terminal of the power chip 210, and the second end of the TVS transistor is connected to the ground terminal of the power chip 210.

[0048] For example, such as Figure 2 As shown, when testing whether the battery management system can control the battery pack to charge normally, there may be a situation where the second MOSFET Q2 fails to turn on in time, resulting in a large current flowing to the output terminal of the power chip 210 (denoted as SW), which could burn out the power chip 210. In order to protect the safety of the output terminal of the power chip (denoted as SW), a TVS transistor T is also provided in the voltage simulation unit. When the second MOSFET Q2 fails to turn on in time, a large current in the opposite direction to F flows through the fifth resistor R5. If the current is large enough, the voltage across the TVS transistor T will reach the breakdown voltage, causing the TVS transistor T to break down and clamping the voltage at the output terminal of the power chip 210 to a lower voltage to ensure the safety of the power chip 210.

[0049] In one alternative embodiment, such as Figure 2 As shown, the temperature simulation unit 21 includes: Multiple sixth resistors R6, the first end of each of the above sixth resistors R6 is connected to the above battery management system 1, any two of the above sixth resistors R6 have different resistance values, the above multiple sixth resistors R6 correspond one-to-one with multiple temperature parameters, and the magnitude of the above temperature parameters is related to the magnitude of the resistance value of the above sixth resistors R6. Multiple second optocouplers P2 are provided, each corresponding to a sixth resistor R6. The emitter of each second optocoupler P2 is connected to the ground terminal GND, the collector of each second optocoupler P2 is connected to the second end of the corresponding sixth resistor R6, and the anode of each second optocoupler P2 is connected to the output terminal of the AC-DC conversion unit 220. The cathode of each second optocoupler P2 is used to conduct when the first target voltage signal is received, and when conducting, it connects the emitter and collector of each second optocoupler P2 to raise the voltage at the first end of the corresponding sixth resistor R6. When the cathode of the second optocoupler P2 corresponding to the target resistor receives the first target voltage signal, the first end of the target resistor outputs the analog voltage signal corresponding to the set temperature parameter to the battery management system 1. The target resistor is the sixth resistor R6 corresponding to the set temperature parameter.

[0050] For example, a thermistor is installed on the battery pack. The resistance of the thermistor changes with the temperature of the battery pack. The battery management system determines the temperature of the battery pack by detecting the resistance of the thermistor. The resistance of the thermistor corresponds one-to-one with the temperature of the battery pack. Furthermore, the battery management system determines the resistance of the thermistor by detecting the voltage across its terminals. Figure 2 As shown, this application employs multiple sixth resistors R6 with different resistance values ​​to simulate the resistance values ​​of the thermistors when the battery pack is at different temperatures. Simultaneously, multiple corresponding second optocouplers P2 are configured. The cathode of the second optocoupler P2 is turned on when it receives the aforementioned first target voltage signal (the first target voltage signal is 0, equivalent to the cathode of the second optocoupler P2 being grounded). When turned on, it connects the emitter and collector of the second optocoupler P2. The collector of the second optocoupler P2 generates current to raise the voltage at the first terminal of the corresponding sixth resistor R6. Since the resistance values ​​of different sixth resistors R6 are different, the voltage at the first terminal of different sixth resistors R6 is different.

[0051] For example, by collecting the resistance value of the sixth resistor R6 and comparing the collected value with the actual resistance value of the sixth resistor R6, the accuracy of the battery management system in collecting the temperature of the battery pack can be tested.

[0052] In an optional embodiment, the battery simulation circuit 2 further includes: The control chip 22 has a first MOS transistor Q1 that corresponds to the first output terminal IO1 of the control chip 22, the control terminal of the first MOS transistor Q1 is connected to the corresponding first output terminal IO1, the second optocoupler P2 corresponds to the second output terminal IO2 of the control chip 22, and the cathode of the second optocoupler P2 is connected to the corresponding second output terminal IO2. The first output terminal IO1 is used to output the second target voltage signal. For example, in order to enable a host computer or other device to control the battery simulation circuit, a control chip is added to the battery simulation circuit, and the first output terminal and the second output terminal are both GPIO pins (General Purpose Input / Output).

[0053] Embodiments of this application also provide a testing system, which includes: Any of the above-mentioned battery simulation circuits; The battery management system is connected to the output terminal of the power chip in each voltage simulation unit of the battery simulation circuit, the battery management system is connected to the second terminal of the fifth resistor in the Nth voltage simulation unit, and is connected to the ground terminal of the power chip in the first voltage simulation unit, and the battery management system is connected to the first terminal of the sixth resistor in the temperature simulation unit of the battery simulation circuit. For example, such as Figure 2 As shown, the second end of the fifth resistor in the Nth voltage simulation unit 20 is connected to the positive terminal BATN+ of the Nth voltage simulation unit 20, and the ground terminal of the power supply chip in the first voltage simulation unit 20 is the positive terminal of the first voltage simulation unit.

[0054] The host computer is connected to the control terminal of the third resistor in each of the voltage simulation units, the host computer is connected to all the first output terminals of the control chip in the battery simulation circuit, and the host computer is connected to all the second output terminals of the control chip.

[0055] The beneficial technical effects of this application are as follows: 1) The output voltage and temperature of the battery pack can be adjusted flexibly and quickly according to testing requirements; 2) Low cost.

[0056] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0057] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A battery simulation circuit, characterized in that, The battery simulation circuit includes: N voltage simulation units are connected in series. Each voltage simulation unit is used to simulate a single battery cell. The voltage simulation unit is used to connect to the battery management system. The voltage simulation unit is used to output a simulated voltage signal corresponding to a set voltage parameter to the battery management system. N is a positive integer greater than or equal to 2. A temperature simulation unit is provided, which is connected to the battery management system and outputs an analog voltage signal corresponding to a set temperature parameter to the battery management system.

2. The battery simulation circuit according to claim 1, characterized in that, The voltage simulation unit includes: A power chip, wherein the input terminal of the power chip is used to connect to a power source, and the output terminal of the power chip is used to connect to the battery management system; A first resistor, the first end of which is connected to the ground terminal of the power chip, and the second end of which is connected to the feedback loop terminal of the power chip, wherein the output voltage of the feedback loop terminal is a preset voltage; The second resistor has its first end connected to the second end of the first resistor. The third resistor is a digital resistor. The first end of the third resistor is connected to the second end of the second resistor, and the second end of the third resistor is connected to the output terminal of the power chip. When the control terminal of the third resistor receives the target control signal, the output terminal of the power chip outputs the analog voltage signal corresponding to the set voltage parameter to the battery management system. The target control signal indicates that the resistance value of the third resistor is adjusted to the target resistance value. The magnitude of the analog voltage signal output by the output terminal of the power chip is related to the resistance value of the third resistor.

3. The battery simulation circuit according to claim 2, characterized in that, The power supply is an AC power supply, and the voltage simulation unit includes: An AC-DC conversion unit is provided, wherein the input terminal of the AC-DC conversion unit is connected to an AC power supply, and the output terminal of the AC-DC conversion unit is connected to the input terminal of the power supply chip.

4. The battery simulation circuit according to claim 3, characterized in that, The voltage simulation unit also includes: Multiple fourth resistors, each of which has a first terminal connected to the first terminal of the third resistor; Multiple first optocouplers are provided, each corresponding to a fourth resistor. The collector of each first optocoupler is connected to the second end of the third resistor, the emitter of each first optocoupler is connected to the second end of the corresponding fourth resistor, and the anode of each first optocoupler is connected to the output terminal of the AC-DC conversion unit. The first optocoupler is used to conduct when the cathode of the first optocoupler receives a first target voltage signal, and when conducting, the emitter of the first optocoupler is connected to the collector of the first optocoupler so that the corresponding fourth resistor is connected in parallel with the third resistor. When the target control signal is received at the control terminal of the third resistor and the first target voltage signal is received at the cathodes of the M first optocouplers, the output terminal of the power chip outputs the analog voltage signal corresponding to the set voltage parameter to the battery management system, where M is a positive integer and M is not greater than N.

5. The battery simulation circuit according to claim 4, characterized in that, The battery simulation circuit includes: Multiple first MOS transistors are provided, each first MOS transistor corresponds to a first optocoupler in each voltage simulation unit, the first end of each first MOS transistor is connected to the cathode of the corresponding first optocoupler in each voltage simulation unit, and the second end of each first MOS transistor is connected to ground. Specifically, when the control terminal of the first MOS transistor receives the second target voltage signal, the first MOS transistor is turned on, and when the first MOS transistor is turned on, the cathode of the first optocoupler corresponding to the first MOS transistor receives the first target voltage signal.

6. The battery simulation circuit according to claim 3, characterized in that, The voltage simulation unit also includes: The fifth resistor has its first end connected to the output terminal of the power chip, and its second end connected to the battery management system. An operational amplifier, wherein the inverting input terminal of the operational amplifier is connected to the first terminal of the fifth resistor, the non-inverting input terminal of the operational amplifier is connected to the second terminal of the fifth resistor, the positive power supply terminal of the operational amplifier is connected to the output terminal of the AC-DC conversion unit, and the negative power supply terminal of the operational amplifier is connected to the ground terminal of the power chip. The second MOSFET has its first terminal connected to the second terminal of the fifth resistor, its second terminal connected to the ground terminal of the power supply chip, and its control terminal connected to the output terminal of the operational amplifier.

7. The battery simulation circuit according to claim 6, characterized in that, The voltage simulation unit also includes: A TVS diode is provided, with its first end connected to the output terminal of the power chip and its second end connected to the ground terminal of the power chip.

8. The battery simulation circuit according to claim 5, characterized in that, The temperature simulation unit includes: Multiple sixth resistors are provided, the first end of which is connected to the battery management system. Any two sixth resistors have different resistance values. Each of the multiple sixth resistors corresponds to a multiple temperature parameters, and the magnitude of the temperature parameters is related to the resistance value of the sixth resistor. Multiple second optocouplers are provided, each corresponding to a sixth resistor. The emitter of each second optocoupler is connected to the ground terminal, the collector of each second optocoupler is connected to the second terminal of the corresponding sixth resistor, the anode of each second optocoupler is connected to the output terminal of the AC-DC conversion unit, and the cathode of each second optocoupler is used to conduct when the first target voltage signal is received, and connects the emitter and collector of the second optocoupler when conducting, so as to raise the voltage at the first terminal of the corresponding sixth resistor. Specifically, when the cathode of the second optocoupler corresponding to the target resistor receives the first target voltage signal, the first end of the target resistor outputs the analog voltage signal corresponding to the set temperature parameter to the battery management system, and the target resistor is the sixth resistor corresponding to the set temperature parameter.

9. The battery simulation circuit according to claim 8, characterized in that, The battery simulation circuit also includes: The control chip has a first MOS transistor that corresponds to a first output terminal of the control chip, and the control terminal of the first MOS transistor is connected to the corresponding first output terminal. The second optocoupler corresponds to a second output terminal of the control chip, and the cathode of the second optocoupler is connected to the corresponding second output terminal. The first output terminal is used to output the second target voltage signal; The second output terminal is used to output the first target voltage signal.

10. A testing system, characterized in that, The testing system includes: The battery simulation circuit according to any one of claims 1 to 9; The battery management system is connected to the output terminal of the power chip in each voltage simulation unit of the battery simulation circuit, the battery management system is connected to the second terminal of the fifth resistor in the Nth voltage simulation unit, and is connected to the ground terminal of the power chip in the first voltage simulation unit, and the battery management system is connected to the first terminal of the sixth resistor in the temperature simulation unit of the battery simulation circuit. The host computer is connected to the control terminal of the third resistor in each of the voltage simulation units, the host computer is connected to all the first output terminals of the control chip in the battery simulation circuit, and the host computer is connected to all the second output terminals of the control chip.

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