Vehicle battery detection method and battery detection device

Abstract

The embodiment of the present invention relates to the technical field of battery detection, and discloses a vehicle battery detection method and battery detection equipment, which obtains the initial voltage of the battery to be tested and the discharge voltage of the battery to be tested under preset discharge conditions, calculates the voltage drop value of the battery to be tested as the difference between the initial voltage and the discharge voltage, and then obtains the battery characteristics of the battery to be tested, and determines whether the battery to be tested needs to be replaced based on the voltage drop value, the battery characteristics, and the preset mapping relationship. That is, the embodiment of the present invention controls the battery to be tested to discharge under preset discharge conditions to obtain the voltage drop value, and determines whether the battery to be tested needs to be replaced based on the voltage drop value, the battery characteristics of the battery to be tested, and the preset mapping relationship, thereby making the detection fast and accurate and improving the detection efficiency.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of battery detection, and in particular to a vehicle battery detection method and battery detection equipment. Background Art

[0002] Vehicle batteries are essential components for vehicle operation. For example, the most common lead-acid batteries used in electric vehicles are not only used to start the vehicle, but also to support all electronic loads on the vehicle, such as the ECU. During use, it is extremely important to be able to determine in advance whether the vehicle battery needs to be replaced, so that users can clearly understand the battery's load capacity and replace it with a new battery in time to avoid starting and operating risks, such as battery damage during long-distance driving, or inability to carry the vehicle's ECU and other loads.

[0003] At present, for open-type batteries, the quality of the battery can be checked by observation, discharge method, specific gravity measurement, etc. to determine whether it needs to be replaced. However, for sealed batteries, the internal condition of the battery cannot be seen by observation, and the specific gravity of the electrolyte cannot be measured. Generally, the quality of the battery is checked by discharge method (inputting a large current into the battery to observe the battery characteristics) or conductivity method (inputting a small signal into the battery to calculate the conductivity value or other values ​​representing the battery characteristics) to determine whether it needs to be replaced.

[0004] In the process of implementing the embodiments of the present invention, the inventors of the present invention found that: currently, when the discharge method is used to detect batteries, the measurement time is long, a large amount of heat energy is generated during the measurement process, and continuous repeated measurements cannot be made, resulting in large test errors; when the conductivity method is used to detect batteries, there are problems of inaccuracy and measurement trouble. Summary of the invention

[0005] The main technical problem solved by the embodiments of the present invention is to provide a vehicle battery detection method and a battery detection device, which can quickly and accurately determine whether the battery to be tested needs to be replaced.

[0006] In order to solve the above technical problems, in a first aspect, an embodiment of the present invention provides a vehicle battery detection method, comprising:

[0007] Acquiring an initial voltage of a battery to be tested and battery characteristics of the battery to be tested;

[0008] Obtaining a discharge voltage of the battery to be tested when discharged under a preset discharge condition;

[0009] Calculating the voltage drop value of the battery to be tested as the difference between the initial voltage and the discharge voltage;

[0010] Determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and a preset mapping relationship;

[0011] Among them, the preset mapping relationship includes the correspondence between battery characteristics and voltage drop range, the lower limit value of the voltage drop range is determined by the voltage drop value obtained by the new battery according to the preset discharge condition, and the upper limit value of the voltage drop range is determined by the voltage drop value obtained by the critical battery according to the preset discharge condition, and the critical battery is a battery with a battery capacity of 80% of the rated capacity.

[0012] In some embodiments, the battery characteristics include a battery type, and at least one of a rated battery capacity and a rated battery voltage.

[0013] In some embodiments, the preset discharge condition includes discharging the battery to be tested for a preset time according to a preset discharge current.

[0014] In some embodiments, the step of obtaining a discharge voltage of the battery to be tested when the battery is discharged under a preset discharge condition includes:

[0015] During a period of time including a cut-off time point in the preset time length, a plurality of voltages of the battery to be tested discharged are collected at a preset sampling rate;

[0016] The discharge voltage is determined as an average value of the plurality of voltages.

[0017] In some embodiments, determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics, and the preset mapping relationship includes:

[0018] Determine a voltage drop interval corresponding to the battery characteristic in the preset mapping relationship;

[0019] Determine whether the voltage drop value falls within the voltage drop interval. If yes, determine that the battery to be tested does not need to be replaced. If no, determine that the battery to be tested needs to be replaced.

[0020] In some embodiments, the preset mapping relationship includes a correspondence between an initial voltage, a battery characteristic, and a voltage drop interval;

[0021] The step of determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and the preset mapping relationship includes:

[0022] Determine a voltage drop interval corresponding to the initial voltage and the battery characteristic in the preset mapping relationship;

[0023] Determine whether the voltage drop value falls within the voltage drop interval. If yes, determine that the battery to be tested does not need to be replaced. If no, determine that the battery to be tested needs to be replaced.

[0024] In order to solve the above technical problems, in a first aspect, an embodiment of the present invention provides a battery detection device, wherein the battery detection device comprises:

[0025] A first connection terminal, a second connection terminal, a third connection terminal and a fourth connection terminal, wherein the first connection terminal, the second connection terminal, the third connection terminal and the fourth connection terminal are respectively used to connect to a battery to be tested;

[0026] a discharge circuit, electrically connected to the battery to be tested via the first connection terminal and the fourth connection terminal, and used for triggering the battery to be tested to discharge under a preset discharge condition;

[0027] a voltage sampling circuit, electrically connected to the battery to be tested via the second connection terminal and the third connection terminal, and used for detecting the voltage at both ends of the battery to be tested;

[0028] A controller is electrically connected to the discharge circuit and the voltage sampling circuit respectively, and the controller is used for:

[0029] Acquiring the initial voltage of the battery to be tested through the voltage acquisition circuit;

[0030] Controlling the discharge circuit so that the discharge circuit triggers the storage battery to be tested to discharge under a preset discharge condition;

[0031] Acquiring, by means of the voltage acquisition circuit, a discharge voltage of the battery to be tested when discharged under the preset discharge condition;

[0032] Calculating the voltage drop value of the battery to be tested as the difference between the initial voltage and the discharge voltage;

[0033] Determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and a preset mapping relationship;

[0034] Among them, the preset mapping relationship includes the correspondence between battery characteristics and voltage drop range, the lower limit value of the voltage drop range is determined by the voltage drop value obtained by the new battery according to the preset discharge condition, and the upper limit value of the voltage drop range is determined by the voltage drop value obtained by the critical battery according to the preset discharge condition, and the critical battery is a battery with a battery capacity of 80% of the rated capacity.

[0035] In some embodiments, the discharge circuit includes a switch circuit, a load and a current sampling circuit:

[0036] The first end of the switch circuit is connected to the first connection end, the second end of the switch circuit is connected to the controller, and the third end of the switch circuit is connected to the fourth connection end through the load;

[0037] The first end of the current sampling circuit is connected to the controller, the second end of the current sampling circuit is connected to the load, and the current sampling circuit is used to detect the discharge current of the battery to be tested;

[0038] The controller is specifically used for:

[0039] The switch circuit is adjusted according to the discharge current detected by the current sampling circuit to discharge the battery under test under the preset discharge condition, wherein the preset discharge condition includes discharging the battery under test for a preset time according to the preset discharge current.

[0040] In some embodiments, the controller is specifically configured to:

[0041] During a period of time including a cut-off time point in the preset time length, a plurality of voltages of the battery to be tested discharged are collected at a preset sampling rate;

[0042] The discharge voltage is determined as an average value of the plurality of voltages.

[0043] In some embodiments, the switch circuit includes a MOS tube and a first operational amplifier;

[0044] The non-inverting input terminal of the first operational amplifier is connected to the controller, the inverting input terminal of the first operational amplifier is connected to the source of the MOS tube, the output terminal of the first operational amplifier is connected to the gate of the MOS tube, the source of the MOS tube is connected to the first end of the load, and the drain of the MOS tube is connected to the first connection terminal.

[0045] In some embodiments, the discharge circuit further includes a diode, a first end of the diode is connected to the first connection end, and a second end of the diode is connected to the drain of the MOS tube.

[0046] In some embodiments, the current sampling circuit includes a second operational amplifier, a non-inverting input terminal of the second operational amplifier is connected to the first terminal of the load, an inverting input terminal of the second operational amplifier is connected to the second terminal of the load, and an output terminal of the second operational amplifier is connected to the controller.

[0047] In some embodiments, the voltage sampling circuit includes:

[0048] A third operational amplifier, wherein the non-inverting input terminal of the third operational amplifier is connected to the second connection terminal, the inverting input terminal of the third operational amplifier is connected to the third connection terminal, and the output terminal of the third operational amplifier is connected to the controller.

[0049] In some embodiments, the controller is specifically configured to:

[0050] Determine a voltage drop interval corresponding to the battery characteristic in the preset mapping relationship;

[0051] Determine whether the voltage drop value falls within the voltage drop interval. If yes, determine that the battery to be tested does not need to be replaced. If no, determine that the battery to be tested needs to be replaced.

[0052] In some embodiments, the preset mapping relationship includes a corresponding relationship between an initial voltage, a battery characteristic, and a voltage drop interval, and the controller is specifically used to:

[0053] Determine a voltage drop interval corresponding to the initial voltage and the battery characteristic in the preset mapping relationship;

[0054] Determine whether the voltage drop value falls within the voltage drop interval. If yes, determine that the battery to be tested does not need to be replaced. If no, determine that the battery to be tested needs to be replaced.

[0055] Beneficial effects of the embodiments of the present invention: Different from the prior art, the vehicle battery detection method and battery detection equipment provided by the embodiments of the present invention control the battery to be tested to discharge under preset discharge conditions to obtain a voltage drop value. According to the voltage drop value, the battery characteristics of the battery to be tested and the preset mapping relationship, it can be determined whether the battery to be tested needs to be replaced, thereby making the detection fast and accurate and improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0057] Figure 1 A schematic diagram of the circuit structure of a battery detection device provided by an embodiment of the present invention;

[0058] Figure 2 for Figure 1 The circuit structure diagram of the discharge circuit and the voltage sampling circuit shown;

[0059] Figure 3 A circuit connection diagram of a battery detection device provided by an embodiment of the present invention;

[0060] Figure 4 A schematic flow chart of a vehicle battery detection method provided by an embodiment of the present invention;

[0061] Figure 5 for Figure 4 A schematic diagram of a sub-process of step 420 is shown in FIG.

[0062] Figure 6 for Figure 4 A sub-flow diagram of step 440 is shown in FIG.

[0063] Figure 7 A detection area diagram provided by an embodiment of the present invention;

[0064] Figure 8 for Figure 4 Another sub-flow chart of step 440 is shown in FIG. DETAILED DESCRIPTION

[0065] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0066] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0067] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, all within the scope of protection of the present application. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order than the module division in the device or the flow chart. In addition, the words "first", "second", "third", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0068] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification and in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0069] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0070] See also Figure 1 , is a schematic diagram of the circuit structure of a battery detection device provided by an embodiment of the present invention. Figure 1As shown, the battery testing device 100 is electrically connected to a battery to be tested 200 , and the battery testing device 100 includes a discharge circuit 10 , a voltage sampling circuit 20 and a controller 30 .

[0071] like Figure 2 As shown, the battery testing device 100 includes a first connection terminal 101, a second connection terminal 102, a third connection terminal 103 and a fourth connection terminal 104, and the first connection terminal 101, the second connection terminal 102, the third connection terminal 103 and the fourth connection terminal 104 are respectively used to connect the battery to be tested. In this embodiment, the first connection terminal 101 and the second connection terminal 102 are both electrically connected to the positive electrode of the battery to be tested 200, and the third connection terminal 103 and the fourth connection terminal 104 are both electrically connected to the negative electrode of the battery to be tested 200. In some embodiments, the first connection terminal 101, the second connection terminal 102, the third connection terminal 103 and the fourth connection terminal 104 can also be Kelvin connectors, that is, the battery testing device 100 is electrically connected to the battery to be tested 200 through the Kelvin connector, which can eliminate wiring, and eliminate the resistance generated by contact connection when current flows through the positive or negative electrode of the battery to be tested 100.

[0072] The discharge circuit 10 is electrically connected to the battery 200 to be tested via the first connection terminal 101 and the fourth connection terminal 104, so as to trigger the battery 200 to discharge. When the discharge circuit 10 is in the on state, the discharge circuit 10 and the battery 200 to be tested form a discharge loop, triggering the battery 100 to discharge.

[0073] In some of these embodiments, please also refer to Figure 2 The discharge circuit 10 includes a switch circuit 11, a load 12 and a current sampling circuit 13.

[0074] The first end of the switch circuit 11 is connected to the first connection end 104, the second end of the switch circuit 11 is connected to the controller 30, and the third end of the switch circuit 11 is connected to the fourth connection end 104 through the load 12, and is used to close or open the discharge circuit between the switch circuit 11, the load 12 and the battery 200 to be tested, and adjust the conduction degree of the discharge circuit according to the voltage signal sent by the controller 30.

[0075] The first end of the current sampling circuit 13 is connected to the controller 30, and the second end of the current sampling circuit 13 is connected to the load 12. The current sampling circuit 13 is used to detect the current in the discharge loop formed by the switch circuit 11, the load 12 and the battery 200 to be tested, that is, the discharge current of the battery 200 to be tested.

[0076] The controller 30 adjusts the switch circuit 11 according to the discharge current detected by the current sampling circuit 20 so that the battery 200 to be tested is discharged under the preset discharge condition, wherein the preset discharge condition includes discharging the battery 200 to be tested for a preset time according to the preset discharge current.

[0077] In some embodiments, see Figure 3 The switch circuit 11 includes a MOS transistor Q and a first operational amplifier U1, the non-inverting input terminal of the first operational amplifier U1 is connected to the controller 30 (DAC port of the single-chip computer U4), the inverting input terminal of the first operational amplifier U1 is connected to the source of the MOS transistor Q, the output terminal of the first operational amplifier U1 is connected to the gate of the MOS transistor Q, the source of the MOS transistor Q is connected to the first terminal of the load 12, and the drain of the MOS transistor Q is connected to the first connection terminal 101. The second terminal of the load 12 is connected to the fourth connection terminal 104, and the fourth connection terminal 104 is electrically connected to the negative electrode of the battery 200 to be tested.

[0078] When the MOS tube Q is disconnected, the voltage at the first end of the load 12 and the source voltage of the MOS tube Q are both the negative electrode voltage of the battery 200 to be tested, that is, the negative electrode voltage is input to the inverting input terminal of the first operational amplifier U1. When the controller 30 sends a voltage signal to the non-inverting input terminal of the first operational amplifier U1, the first operational amplifier U1 processes the voltage signal and the negative electrode voltage, and outputs a first drive signal to the gate of the MOS tube Q, thereby forming a voltage difference V between the gate and the source of the MOS tube Q. GS The magnitude of the first driving signal is related to the magnitude of the voltage signal. By adjusting the voltage signal, the first driving signal is further adjusted so that the voltage difference V GS When the voltage is greater than the conduction voltage of the MOS tube Q, the MOS tube Q is turned on, and the discharge circuit generates current, that is, the battery 200 to be tested starts to discharge.

[0079] When the MOS tube Q is turned on, the discharge current flows through the load 12, and the voltage at the first end of the load 12 increases, that is, the voltage at the first end of the load 12 is equivalent to the voltage drop value of the load 12, and the voltage drop value of the load 12 is sent to the inverting input end of the first operational amplifier U1 as a voltage drop signal. Due to the negative feedback effect of the first operational amplifier U1, the first operational amplifier U1 processes the voltage signal and the voltage drop signal and outputs a stable second drive signal to the gate of the MOS tube Q. Under the action of the stable second drive signal, the conduction degree of the MOS tube Q is certain, and the channel internal resistance of the MOS tube Q is stable, thereby ensuring the stability of the discharge current in the discharge loop. In addition, the size of the second drive signal is related to the size of the voltage signal sent by the controller 30, so that a stable discharge current of a corresponding size can be obtained by adjusting the voltage signal sent by the controller 30.

[0080] In some embodiments, the load 12 includes a resistor, a first end of the resistor is electrically connected to the source of the MOS tube Q, and a second end of the resistor is electrically connected to the fourth connection terminal 104. The resistance of the resistor can be set according to actual conditions, for example, the resistance of the resistor is 10 mΩ, so that the discharge current of the battery 200 to be tested can be a large current.

[0081] In some embodiments, the current sampling circuit 13 includes a second operational amplifier U2, the non-inverting input terminal of the second operational amplifier U2 is connected to the first terminal of the load 12, the inverting input terminal of the second operational amplifier U2 is connected to the second terminal of the load 12, and the output terminal of the second operational amplifier U2 is connected to the controller. Thus, the voltage of the first terminal of the load 12 is input to the non-inverting terminal of the second operational amplifier U2, and the voltage of the second terminal of the load 12 is input to the inverting terminal of the second operational amplifier U2. After being processed by the second operational amplifier U2, the voltage across the two terminals of the load 12 is obtained and sent to the controller 30. The controller 30 can determine the current flowing through the load 12, that is, the discharge current in the discharge circuit, according to the resistance value of the load 12 and the voltage across the two terminals of the load 12.

[0082] In some embodiments, the discharge circuit 10 further includes a diode D1, a first end of the diode D1 is connected to the first connection end 101, a second end of the diode D1 is connected to the drain of the MOS tube Q, and the diode D1 is used to prevent the discharge current from flowing back to the battery to be tested 200. When the first connection end 101 is connected to the positive electrode of the battery to be tested 200, the anode of the diode D1 is connected to the first connection end 101, and the cathode of the diode D1 is connected to the drain of the MOS tube Q. By utilizing the unidirectional conductivity of the diode D1, in the discharge circuit, the discharge current always flows from the positive electrode of the battery to be tested 200 through the MOS tube Q and the load 12, and finally flows back to the negative electrode of the battery to be tested 200, thereby preventing the current from flowing back and burning the battery to be tested 200.

[0083] The voltage sampling circuit 20 is electrically connected to the battery 200 to be tested via the second connection terminal 102 and the third connection terminal 103, and is used to detect the voltage across the battery 200 to be tested. When the discharge circuit 10 is in a disconnected state, the voltage across the battery 200 to be tested collected by the voltage sampling circuit 20 is the initial voltage, and when the discharge circuit 10 is in a connected state, the battery 200 to be tested is discharged, and the voltage across the battery 200 to be tested collected by the voltage sampling circuit 20 is the voltage after discharge.

[0084] In some embodiments, the voltage sampling circuit 20 includes a third operational amplifier U3, the in-phase input terminal of the third operational amplifier U3 is connected to the second connection terminal 102, the inverting input terminal of the third operational amplifier U3 is connected to the third connection terminal 103, and the output terminal of the third operational amplifier U3 is connected to the controller 30. In this embodiment, the second connection terminal 102 is connected to the positive electrode of the battery to be tested 200, and the third connection terminal 103 is connected to the negative electrode of the battery to be tested 200, then the voltage collected by the third operational amplifier U3 is the voltage across the battery to be tested 200.

[0085] The controller 30 is electrically connected to the discharge circuit 10 and the voltage sampling circuit 20, respectively. The controller 30 is used to: obtain the initial voltage of the battery 200 to be tested through the voltage acquisition circuit 20, control the discharge circuit so that the discharge circuit 10 triggers the battery 200 to be tested to discharge under the preset discharge condition, obtain the discharge voltage of the battery 200 to be tested under the preset discharge condition through the voltage acquisition circuit 20, calculate the voltage drop value of the battery 200 to be tested as the difference between the initial voltage and the discharge voltage, and finally, determine whether the battery 200 to be tested needs to be replaced according to the voltage drop value, the battery characteristics and the preset mapping relationship. The preset mapping relationship includes the corresponding relationship between the battery characteristics and the voltage drop interval, the lower limit of the voltage drop interval is determined by the voltage drop value obtained by the new battery according to the preset discharge condition, and the upper limit of the voltage drop interval is determined by the voltage drop value obtained by the critical battery according to the preset discharge condition, and the critical battery is a battery with a battery capacity of 80% of the rated capacity.

[0086] like Figure 3 As shown, the controller 30 includes a single-chip microcomputer U4, which can be a 51 series, Arduino series, STM32 series, etc. The single-chip microcomputer U4 includes a DAC port, an ADC1 port, and an ADC2 port. The DAC port of the single-chip microcomputer U4 is electrically connected to the in-phase input terminal of the first operational amplifier U1, the ADC1 port of the single-chip microcomputer U4 is electrically connected to the output terminal of the second operational amplifier U2, and the ADC2 port of the single-chip microcomputer U4 is electrically connected to the output terminal of the third operational amplifier U3.

[0087] In other embodiments, the controller 30 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), an ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or any combination of these components; it can also be any traditional processor, controller, microcontroller or state machine; it can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0088] In summary, the working process of the battery testing device 100 is as follows:

[0089] (1) When the discharge circuit 10 is disconnected, the battery 200 to be tested is not discharged, and the third operational amplifier U3 performs signal processing on the voltage across the battery 200 to be tested to obtain the initial voltage of the battery 200 to be tested.

[0090] (2) The DAC port of the single-chip computer U4 outputs a voltage signal to the non-inverting input terminal of the first operational amplifier U1, and the source voltage of the MOS tube Q is input to the inverting input terminal of the first operational amplifier U1. At this time, the source voltage of the MOS tube Q is the negative electrode voltage of the battery 200 to be tested. The first operational amplifier U1 processes the voltage signal input to the non-inverting input terminal and the negative electrode voltage input to the inverting input terminal to obtain a first drive signal. The magnitude of the first drive signal is related to the magnitude of the voltage signal. The first drive signal acts on the gate of the MOS tube Q, so that a voltage difference V is formed between the gate and the source of the MOS tube Q. GS By adjusting the voltage signal, the first driving signal is further adjusted so that the voltage difference V GS When the voltage is greater than or equal to the on-state voltage of the MOS tube Q, the MOS tube Q is turned on, and the discharge circuit generates current, that is, the battery 200 to be tested starts to discharge.

[0091] When the MOS tube Q is turned on, the discharge current flows through the load 12, and the voltage at the first end of the load 12 increases, that is, the voltage at the first end of the load 12 is equivalent to the voltage drop value of the load 12, and the voltage drop value of the load 12 is sent to the inverting input end of the first operational amplifier U1 as a voltage drop signal. Due to the negative feedback effect of the first operational amplifier U1, the first operational amplifier U1 will output a stable second drive signal to the gate of the MOS tube Q after processing the voltage signal and the voltage drop signal. Under the action of the stable second drive signal, the battery 200 to be tested is discharged with a stable discharge current, wherein the magnitude of the discharge current is related to the magnitude of the second drive signal, and further, the magnitude of the discharge current is related to the voltage signal input by the controller 30. Therefore, by adjusting the voltage signal, the battery 200 to be tested can be discharged at a preset discharge current for a preset time.

[0092] When the battery 200 to be tested is discharged at the preset discharge current, the battery 200 to be tested generates a discharge voltage. The third operational amplifier U3 processes the discharge voltage to obtain the discharge voltage, and sends the discharge voltage to the ADC2 port of the single-chip microcomputer U4.

[0093] When the discharge time reaches the preset time, the voltage signal is stopped from being output or the voltage signal is adjusted so that the voltage difference V between the gate and the source of the MOS tube Q is GS is smaller than the on-state voltage of the MOS tube Q, the MOS tube Q is turned off, the discharge circuit of the tested battery 200 is cut off, and the tested battery 200 stops discharging.

[0094] (3) The single chip microcomputer U4 calculates the voltage drop value of the battery 200 to be tested as the difference between the initial voltage and the discharge voltage.

[0095] (4) The single chip computer U4 determines whether the battery 200 to be tested needs to be replaced according to the voltage drop value, the battery characteristics and the preset mapping relationship.

[0096] The above product can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, please refer to the method provided by the embodiment of the present invention.

[0097] See also Figure 4 , is a flow chart of a vehicle battery detection method provided by an embodiment of the present invention, the method can be applied to any suitable battery detection circuit, for example, the battery detection device described in any of the above embodiments, such as Figure 4 As shown, the detection method comprises:

[0098] Step 410: Obtain the initial voltage of the battery to be tested and the battery characteristics of the battery to be tested.

[0099] The initial voltage is the voltage across the two ends of the battery under test when it is not discharged, and can be obtained by detecting the voltage across the positive and negative electrodes of the battery under test when it is in an open circuit. The battery characteristics refer to the unique properties of the battery, such as the factory parameters and rated parameters of the battery.

[0100] In some embodiments, the battery characteristics include battery type, and at least one of rated battery capacity and rated battery voltage. For example, when the battery characteristics include battery type, the battery characteristics may be an AGM battery, an EFB battery, or a Flooded battery. In this embodiment, obtaining the battery characteristics of the battery to be tested is to obtain the battery type of the battery to be tested. When the characteristics to be tested include battery type and rated battery capacity, obtaining the battery characteristics of the battery to be tested is to obtain the battery type and rated battery capacity of the battery to be tested, respectively. It is understandable that these battery characteristics may be obtained from the nameplate of the battery to be tested, or from the factory data of the battery to be tested.

[0101] Step 420: Obtain the discharge voltage of the battery to be tested when discharged under a preset discharge condition.

[0102] The discharge voltage is the voltage across the positive and negative electrodes of the battery to be tested, which is collected during the process of the battery to be tested being discharged under preset discharge conditions.

[0103] In some embodiments, the preset discharge condition includes discharging the battery to be tested for a preset time according to a preset discharge current.

[0104] Wherein, the preset discharge current can be set according to the rated parameters of the battery to be tested, for example, by presetting the corresponding relationship between the rated parameters and the preset discharge current, and combining the rated parameters to determine the preset discharge current. In some embodiments, the preset discharge current can be determined according to the rated current of the battery to be tested, for example, the preset discharge current is less than the rated current and accounts for a preset percentage of the rated current. If the rated current is large, the preset percentage can be reduced to reduce the heat generated by the discharge of the battery to be tested. It can be understood that the preset discharge current can also be set manually according to historical experience values, for example, the preset discharge current is a large current such as 10A, 20A or 30A. In addition, in order to stabilize the preset discharge current to a preset value, a preset value of the preset discharge current is set in the battery detection device, and a voltage signal is output according to the preset discharge current and the current-voltage signal relationship table pre-stored in the battery detection device, so as to control the discharge current of the battery to be tested to be equal to the preset discharge current, that is, the current of the discharge circuit of the battery detection device and the battery to be tested is equal to the preset discharge current.

[0105] The preset duration refers to the duration of the battery to be tested being discharged at a preset discharge current. The discharge current is a large current, and the preset duration is relatively short. In some embodiments, the preset duration is in the millisecond level, for example, the preset duration is 50ms, 100ms, 200ms or 300ms, etc. The preset duration is related to the discharge current. For example, when the discharge current is relatively large, a shorter preset duration can be selected for discharge. By discharging with a shorter preset duration to detect whether the battery to be tested needs to be replaced, on the one hand, it saves detection time, can quickly determine whether the battery to be tested needs to be replaced, and improves detection efficiency. On the other hand, the preset duration is in the millisecond level, and the short discharge time can avoid the battery to be tested from generating a large amount of heat, so that no additional heat dissipation device is required during the detection process.

[0106] In order to make the discharge voltage more accurate, in some embodiments, see Figure 5 , the step 420 specifically includes:

[0107] Step 421: within the period of the preset time length including the cut-off time point, a plurality of discharge voltages of the battery to be tested are collected at a preset sampling rate.

[0108] Step 422: Determine the discharge voltage as an average value of the multiple voltages.

[0109] The multiple voltages are obtained by sampling the discharge voltage within the period including the cut-off time point in the preset time length at a certain sampling rate. The period including the cut-off time point in the preset time length is the period from a certain time point in the preset time length to the cut-off time point, that is, the tail section of the preset time length. For example, when the preset time length is 100ms and the preset sampling rate is 1ms, within the period of 91ms-100ms of the preset time length, the number is sampled every 1ms at the sampling rate to obtain voltage values ​​V1, V2..V10, wherein V1 corresponds to the discharge voltage at 91ms of discharge, V2 corresponds to the discharge voltage at 92ms of discharge, and so on, V10 corresponds to the discharge voltage at 100ms of discharge. Then, the average value Va of the multiple voltages is calculated and used as the discharge voltage.

[0110] Specifically, the preset duration is accumulated by means of a timer. When the discharge time of the battery to be tested reaches the preset duration, the timer reaches the set stop threshold, triggering the battery to be tested to stop discharging. Within the preset duration, that is, during the discharge of the battery to be tested, the counter is used to count 0 at a preset sampling rate. When n=0, the initial voltage of the battery to be tested is collected. When the counter n is greater than the preset number, for example, when n>90, the number is collected once every preset sampling rate, for example, once every 1ms, until the counter reaches the stop threshold set in the timer, then the number collection stops. When the counter n is greater than the preset number, the collected voltage is the discharge voltage at the end of the preset duration. In some embodiments, before starting the timer and the counter, the method further includes: initializing the battery detection device.

[0111] In this embodiment, by collecting multiple voltages at the tail end of the preset time length and taking the average value of the multiple voltages as the discharge voltage, the error risk can be reduced, abnormal data can be eliminated, and the accuracy of the discharge voltage can be increased.

[0112] Step 430: Calculate the voltage drop value of the battery to be tested as the difference between the initial voltage and the discharge voltage.

[0113] After the battery to be tested is discharged for the preset time, the voltage across the battery to be tested will decrease. After obtaining the initial voltage and the discharge voltage, the difference between the initial voltage and the discharge voltage is calculated as the voltage drop value of the battery to be tested.

[0114] Step 440: Determine whether the battery to be tested needs to be replaced based on the voltage drop value, the battery characteristics and a preset mapping relationship.

[0115] The preset mapping relationship can be pre-constructed and stored in the battery detection device. The preset mapping relationship includes a correspondence between battery characteristics and voltage drop intervals, the lower limit of the voltage drop interval is determined by the voltage drop value obtained by a new battery according to the preset discharge condition, and the upper limit of the voltage drop interval is determined by the voltage drop value obtained by a critical battery according to the preset discharge condition, and the critical battery is a battery with a battery capacity of 80% of the rated capacity.

[0116] The battery characteristics correspond to the voltage drop intervals one by one, for example, the voltage drop intervals corresponding to the battery characteristics C1, C2, Cn are S1, S2, Sn. In some embodiments, the battery characteristics include the battery type, and at least one of the rated battery capacity and the rated battery voltage, that is, the battery type, and at least one of the rated battery capacity and the rated battery voltage constitute the battery characteristics. Among them, the rated battery capacity and the rated battery voltage can be classified by range, for example, the rated battery capacity includes 0-50Ah / 50-100Ah / 100Ah or above, or, includes 0-30Ah / 30-60Ah / 60-90Ah / 90-120Ah, etc. For example, when the battery characteristic C1 = (battery type, rated battery capacity), the battery is divided into characteristics according to the battery type and the rated battery capacity. In the preset mapping relationship, each battery characteristic corresponds to a voltage drop interval. Therefore, after the voltage drop value and the battery characteristics of the battery to be tested are determined, the corresponding voltage drop interval can be obtained after the battery characteristics corresponding to the battery characteristics of the battery to be tested are found in the preset mapping relationship.

[0117] The lower limit of the voltage drop interval is determined by the voltage drop value obtained by the new battery according to the preset discharge condition. The new battery refers to a battery that has just passed the factory inspection and can be used as a reference for voltage drop judgment. When constructing the preset mapping relationship, the new battery is classified according to the battery characteristics, and the voltage drop value of the new battery can be calculated according to steps 410, 420 and 430, and the voltage drop value of the new battery is used as the lower limit of the voltage drop interval and recorded in the preset mapping relationship.

[0118] As the battery is used, it will gradually age, the battery capacity will decrease, and the voltage drop will increase. When the battery capacity is less than 80% of the rated battery capacity, the battery capacity may drop sharply, resulting in insufficient load-carrying capacity of the battery. The load-carrying capacity of the battery refers to the output power of the battery when it supplies power to the load and drives the load to work. That is, when the battery capacity is less than 80% of the rated battery capacity, the output power of the battery is not enough to drive the load to work.

[0119] Therefore, a battery with a battery capacity of 80% of the rated battery capacity is used as a critical battery, and according to the preset discharge condition, a voltage drop value is obtained as the upper limit value of the voltage drop interval, which is used to compare and judge the load capacity of the battery to be tested. When constructing the preset mapping relationship, the critical batteries are classified according to the battery characteristics, and the voltage drop value of the critical battery can be calculated according to step 410, step 420 and step 430, and the voltage drop value of the critical battery is used as the upper limit value of the voltage drop interval and recorded in the preset mapping relationship.

[0120] In this embodiment, for each battery feature, according to the voltage drop value of the battery to be tested, the voltage drop value of the new battery, and the voltage drop value of the critical battery, it is determined whether the load capacity of the battery to be tested is sufficient. When the load capacity of the battery to be tested is insufficient, the battery to be tested needs to be replaced. Otherwise, the battery to be tested can still be used. In addition, the voltage drop test takes a short time, is simple and efficient.

[0121] In some embodiments, see Figure 6 , the step 440 further comprises:

[0122] Step 441a: Determine the voltage drop interval corresponding to the battery characteristic in the preset mapping relationship.

[0123] By matching battery characteristics, the battery characteristics corresponding to the battery characteristics of the battery to be tested are found in the preset mapping relationship, and the corresponding voltage drop range can be determined according to the preset mapping relationship.

[0124] Step 442a: Determine whether the voltage drop value falls within the voltage drop interval. If yes, determine that the battery to be tested does not need to be replaced. If no, determine that the battery to be tested needs to be replaced.

[0125] If the voltage drop value of the battery to be tested falls within the voltage drop interval, the voltage drop value is greater than or equal to the lower limit value of the voltage drop interval, and less than or equal to the upper limit value of the voltage drop interval. That is, when the load capacity of the battery to be tested is greater than the load capacity of the critical battery and less than the load capacity of the new battery, the load capacity of the battery to be tested is sufficient and does not need to be replaced. If the voltage drop value of the battery to be tested is outside the voltage drop interval, the voltage drop value is greater than the upper limit value of the voltage drop interval, the load capacity of the battery to be tested is less than the load capacity of the critical battery, the load capacity of the battery to be tested is insufficient and needs to be replaced, or the voltage drop value is less than the lower limit of the voltage drop interval, then the battery to be tested is abnormal and needs to be replaced.

[0126] In this embodiment, the battery to be tested is controlled to discharge under preset discharge conditions to obtain a voltage drop value. Based on the voltage drop value, the battery characteristics of the battery to be tested and the preset mapping relationship, it can be determined whether the battery to be tested needs to be replaced, thereby making the detection fast and accurate and improving the detection efficiency.

[0127] In order to make the preset mapping relationship more accurate, considering the influence of the initial voltage of the battery on the voltage drop interval, in some embodiments, the preset mapping relationship includes the correspondence between the initial voltage, the battery characteristics and the voltage drop interval. As shown in Table 1, it shows a way of the preset mapping relationship. In the range of the initial voltage of 6V-14V, the voltage interval is constructed with an interval interval of 0.05V. For each of the voltage intervals and each of the battery characteristics, obtain a number of new batteries whose initial voltages are in the voltage interval and whose battery characteristics correspond. According to steps 410, 420 and 430, the voltage drop value of the new battery is calculated for the new batteries, and the maximum voltage drop value among the new batteries is used as the lower limit value of the voltage drop interval. Repeat the above operation to cover each voltage interval between 6V-14V, and obtain the lower limit value of the voltage drop interval corresponding to each voltage interval and each battery characteristic. For example, for 50 new batteries with a rated capacity of 0-50Ah, a battery type of AGM, and an initial voltage of 12.75V-12.80V, the voltage drop values ​​are obtained according to the above steps 410, 420, and 430 respectively. The lower limit value of the voltage drop range corresponding to the initial voltage (12.75V-12.80V) and the battery characteristics (battery rated capacity of 0-50Ah, battery type of AGM) is the maximum value of the 50 voltage drop values.

[0128] For each of the voltage intervals and each of the battery characteristics, obtain a number of critical batteries whose initial voltages are in the voltage intervals and whose battery characteristics correspond, calculate the voltage drop values ​​of the critical batteries according to steps 410, 420 and 430, and use the minimum voltage drop value among the critical batteries as the upper limit value of the voltage drop interval. Repeat the above operation to cover each voltage interval between 6V and 14V, and obtain the upper limit value of the voltage drop interval corresponding to each voltage interval and each battery characteristic. For example, for 50 critical batteries with a rated capacity of 0-50Ah, a battery type of AGM, and an initial voltage of 12.75V-12.80V, respectively obtain the voltage drop values ​​according to the above steps 410-430, then the upper limit value of the voltage drop interval corresponding to the initial voltage (12.75V-12.80V) and the battery characteristics (battery rated capacity of 0-50Ah, battery type of AGM) is the minimum value among the 50 voltage drop values.

[0129] Table 1 Preset mapping relationship

[0130]

[0131] It is worth noting that the interval interval can also be other values, such as 0.03V, 0.04V or 0.06V, etc., which can be set manually according to actual experience. The voltage interval can also be other interval values, such as 5V-13V, etc., which can be set manually according to actual conditions. For each voltage interval and each battery characteristic, 40 or 60 new batteries can be sampled, and for each voltage interval and each battery characteristic, 40 or 60 critical batteries can be sampled, and the specific number can be set manually according to actual conditions.

[0132] In order to more intuitively describe the preset mapping relationship and facilitate the determination of the detection result, in some embodiments, the detection area map 500 can be established according to the preset mapping relationship in Table 1, such as Figure 7 As shown, each battery feature has a corresponding detection area map, for example, battery feature C1 corresponds to detection area map (a), battery feature C2 corresponds to detection area map (b), and so on, until the detection area maps corresponding to all battery features are established.

[0133] Taking the detection region diagram (a) of the battery feature C1 pair as an example, the battery feature C1 includes the battery type, and at least one of the rated battery capacity and the rated battery voltage. The horizontal axis of the detection region diagram (a) is the voltage interval [X1, Xn], i.e., the first column in Table 1, and the vertical axis is the voltage drop value. The detection region diagram (a) includes a first curve 501 and a second curve 502. The area G between the first curve 501 and the second curve 502 represents that the battery has sufficient load capacity and does not need to be replaced, and the area R outside the first curve 501 and the second curve 502 represents that the battery has insufficient load capacity and needs to be replaced.

[0134] Among them, the first curve 501 is a linear fitting relationship between the lower limit value of the voltage drop interval and the voltage interval in Table 1, and is a curve composed of the voltage drop value of a new battery whose initial voltage is in the voltage interval and corresponds to the battery feature C1. For example, when the battery feature C1 includes a battery rated capacity of 0-50Ah and a battery type of AGM, the ordinate of the midpoint of the first curve 501 is the lower limit value in the second column of Table 1. The second curve 502 is a linear fitting relationship between the upper limit value of the voltage drop interval and the voltage interval in Table 1, and is a curve composed of the voltage drop value of a critical battery whose initial voltage is in the voltage interval and corresponds to the battery feature C1. For example, when the battery feature C1 includes a battery rated capacity of 0-50Ah and a battery type of AGM, the ordinate of the midpoint of the second curve 502 is the upper limit value in the third column of Table 1.

[0135] For different battery characteristics, the first curve 501 and the second curve 502 have different curve characteristics, and the curve characteristics are functions of the curves in coordinates.

[0136] By establishing a detection area map corresponding to the battery characteristics, an intuitive comparison can be made to facilitate determination of whether the battery to be tested needs to be replaced.

[0137] In this example, see Figure 8 , the step 440 further comprises:

[0138] Step 441b: Determine a voltage drop interval corresponding to the initial voltage and the battery characteristics in the preset mapping relationship.

[0139] Step 442b: Determine whether the voltage drop value falls within the voltage drop interval. If yes, determine that the battery to be tested does not need to be replaced. If no, determine that the battery to be tested needs to be replaced.

[0140] By matching the initial test voltage and battery characteristics, find the voltage drop interval corresponding to the initial voltage and the battery characteristics in the preset mapping relationship. For example, if the initial voltage of the battery to be tested is 6.12V, the rated capacity of the battery is 40Ah, the battery type is AGM, and the voltage drop value is V0, first, locate the voltage interval [6.10V, 6.15V) from the initial voltage of 6.12V, that is, the third row in Table 1, locate the battery rated capacity of 40Ah to the rated capacity of 0-50Ah, and locate the battery type AGM to the second and third columns in Table 1. The lower limit value V1 in the second column and the lower limit value V2 in the third column are the corresponding voltage drop intervals.

[0141] Through the preset mapping relationship, it is determined whether the voltage drop value falls within the voltage drop interval. For example, in the example of step 441b, the voltage drop value V0 is compared with the voltage drop interval [V1, V2]. When V1≤V0≤V2, the voltage drop value V0 falls within the voltage drop interval [V1, V2], and it is determined that the battery to be tested does not need to be replaced. If V0<V1 or V0>V2, the voltage drop value V0 is not within the voltage drop interval [V1, V2], and it is determined that the battery to be tested needs to be replaced.

[0142] In some embodiments, the corresponding detection area map can also be determined by the battery characteristics. For example, the battery characteristics (battery rated capacity is 40Ah, battery type is AGM) can be determined to belong to battery characteristics C1 (battery rated capacity is 0-50Ah, battery type is AGM), and the corresponding detection area map (a) is determined. In the detection area map (a), the coordinates of the battery to be tested are determined according to the initial voltage and voltage drop value of the battery to be tested. When the coordinates of the battery to be tested fall into area G, it is determined that the load capacity of the battery to be tested is sufficient and does not need to be replaced. When the coordinates of the battery to be tested fall into area R, it is determined that the load capacity of the battery to be tested is insufficient and needs to be replaced.

[0143] In this embodiment, by controlling the battery to be tested to discharge under preset discharge conditions to obtain a voltage drop value, it is possible to determine whether the battery to be tested needs to be replaced based on the voltage drop value, the battery characteristics of the battery to be tested, the initial voltage, and the preset mapping relationship, thereby making the detection fast and accurate and improving the detection efficiency.

[0144] It should be noted that the detection method of the embodiment of the present invention utilizes the voltage drop value of the battery to confirm whether the battery needs to be replaced, and is therefore applicable to any suitable circuit that can detect the battery voltage drop. The battery detection device described in any embodiment of the present invention is only one of the implementation methods.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vehicle battery detection method, characterized in that: include: Acquire an initial voltage of a battery to be tested and a battery characteristic of the battery to be tested, wherein the initial voltage is the voltage across both ends of the battery to be tested when the battery to be tested is not discharged; Obtaining a discharge voltage of the battery to be tested when discharged under a preset discharge condition; Calculating the voltage drop value of the battery to be tested as the difference between the initial voltage and the discharge voltage; Determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and a preset mapping relationship, wherein the preset mapping relationship includes a correspondence between the initial voltage and the battery characteristics and the voltage drop interval; The step of determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and the preset mapping relationship includes: Determining a voltage drop interval corresponding to the initial voltage and the battery characteristic in the preset mapping relationship; Determine whether the voltage drop value falls within the voltage drop interval, if yes, determine that the battery to be tested does not need to be replaced, if no, determine that the battery to be tested needs to be replaced; Among them, the lower limit value of the voltage drop range is determined by the voltage drop value obtained by the new battery according to the preset discharge condition, and the upper limit value of the voltage drop range is determined by the voltage drop value obtained by the critical battery according to the preset discharge condition, and the critical battery is a battery with a battery capacity of 80% of the rated capacity.

2. The method according to claim 1, characterized in that The battery characteristics include a battery type, and at least one of a rated battery capacity and a rated battery voltage.

3. The method according to claim 1, characterized in that The preset discharge condition includes discharging the battery to be tested according to a preset discharge current for a preset time period.

4. The method according to claim 1, characterized in that: The step of obtaining a discharge voltage of the battery to be tested when the battery is discharged under a preset discharge condition comprises: During a period of time including a cut-off time point in the preset time length, a plurality of voltages of the battery to be tested discharged are collected at a preset sampling rate; The discharge voltage is determined as an average value of the plurality of voltages.

5. A battery testing device, characterized in that: The battery testing device comprises: A first connection terminal, a second connection terminal, a third connection terminal and a fourth connection terminal, wherein the first connection terminal, the second connection terminal, the third connection terminal and the fourth connection terminal are respectively used to connect to a battery to be tested; a discharge circuit, electrically connected to the battery to be tested via the first connection terminal and the fourth connection terminal, and used for triggering the battery to be tested to discharge under a preset discharge condition; a voltage sampling circuit, electrically connected to the battery to be tested via the second connection terminal and the third connection terminal, and used for detecting the voltage at both ends of the battery to be tested; A controller is electrically connected to the discharge circuit and the voltage sampling circuit respectively, and the controller is used for: Acquiring the initial voltage of the battery to be tested through the voltage sampling circuit, wherein the initial voltage is the voltage across both ends of the battery to be tested when the battery to be tested is not discharged; Controlling the discharge circuit so that the discharge circuit triggers the storage battery to be tested to discharge under a preset discharge condition; Acquiring, by means of the voltage sampling circuit, a discharge voltage of the battery to be tested when discharged under the preset discharge condition; Calculating the voltage drop value of the battery to be tested as the difference between the initial voltage and the discharge voltage; Determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and a preset mapping relationship, wherein the preset mapping relationship includes a correspondence between the initial voltage and the battery characteristics and the voltage drop interval; The step of determining whether the battery to be tested needs to be replaced according to the voltage drop value, the battery characteristics and the preset mapping relationship includes: Determining a voltage drop interval corresponding to the initial voltage and the battery characteristic in the preset mapping relationship; Determine whether the voltage drop value falls within the voltage drop interval, if yes, determine that the battery to be tested does not need to be replaced, if no, determine that the battery to be tested needs to be replaced; Among them, the lower limit value of the voltage drop range is determined by the voltage drop value obtained by the new battery according to the preset discharge condition, and the upper limit value of the voltage drop range is determined by the voltage drop value obtained by the critical battery according to the preset discharge condition, and the critical battery is a battery with a battery capacity of 80% of the rated capacity.

6. The battery testing device according to claim 5, characterized in that: The discharge circuit includes a switch circuit, a load and a current sampling circuit: The first end of the switch circuit is connected to the first connection end, the second end of the switch circuit is connected to the controller, and the third end of the switch circuit is connected to the fourth connection end through the load; The first end of the current sampling circuit is connected to the controller, the second end of the current sampling circuit is connected to the load, and the current sampling circuit is used to detect the discharge current of the battery to be tested; The controller is specifically used for: The switch circuit is adjusted according to the discharge current detected by the current sampling circuit to discharge the battery under test under the preset discharge condition, wherein the preset discharge condition includes discharging the battery under test for a preset time according to the preset discharge current.

7. The battery testing device according to claim 6, characterized in that: The controller is specifically used for: During a period of time including a cut-off time point in the preset time length, a plurality of voltages of the battery to be tested discharged are collected at a preset sampling rate; The discharge voltage is determined as an average value of the plurality of voltages.

8. The battery testing device according to claim 6, characterized in that: The switch circuit includes a MOS tube and a first operational amplifier; The non-inverting input terminal of the first operational amplifier is connected to the controller, the inverting input terminal of the first operational amplifier is connected to the source of the MOS tube, the output terminal of the first operational amplifier is connected to the gate of the MOS tube, the source of the MOS tube is connected to the first end of the load, and the drain of the MOS tube is connected to the first connection terminal.

9. The battery testing device according to claim 8, characterized in that: The discharge circuit further includes a diode, a first end of the diode is connected to the first connection end, and a second end of the diode is connected to the drain of the MOS tube.

10. The battery testing device according to any one of claims 6 to 9, characterized in that: The current sampling circuit includes a second operational amplifier, a non-inverting input terminal of the second operational amplifier is connected to the first terminal of the load, an inverting input terminal of the second operational amplifier is connected to the second terminal of the load, and an output terminal of the second operational amplifier is connected to the controller.

11. The battery testing device according to any one of claims 5 to 9, characterized in that: The voltage sampling circuit comprises: A third operational amplifier, wherein the non-inverting input terminal of the third operational amplifier is connected to the second connection terminal, the inverting input terminal of the third operational amplifier is connected to the third connection terminal, and the output terminal of the third operational amplifier is connected to the controller.

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