Device and method for detecting current limiting function of lithium battery protection board

Abstract

The invention provides a current-limiting function detection device and method for a lithium battery protection board, and the device comprises an upper computer, and a programmable power supply S1, a programmable power supply S2 and an electronic load which are respectively connected with the upper computer, and the positive and negative electrodes of the programmable power supply S1 are correspondingly connected to a battery end B + wiring terminal and a battery end B-wiring terminal of the lithium battery protection board to be detected. The positive electrode and the negative electrode of the programmable power supply S2 are correspondingly connected to the power supply terminal P + and the power supply terminal P-of the lithium battery protection board to be tested; one end of the electronic load is respectively connected with the positive electrode of the programmable power supply S1 and the battery end B + of the lithium battery protection board to be tested, and the other end of the electronic load is respectively connected with the negative electrode of the programmable power supply S1 and the battery end B-of the lithium battery protection board to be tested; and the upper computer controls the opening or closing of the current limiting function of the lithium battery protection board to be tested, and judges whether the current limiting function of the lithium battery protection board is qualified or not according to the simulated charging current collected before and after current limiting. Therefore, the real lithium battery does not need to be charged in the whole test process, and the test process is high in safety and reliability and high in efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a current limiting function detection device and method for a lithium battery protection board. Background Art

[0002] Because lithium batteries are sensitive to voltage, a higher or lower voltage may affect the battery life or even damage the battery, so lithium batteries must be equipped with a protection board; the lithium battery protection board, also known as the protection module in the battery management system (BMS, Battery Management System), is an indispensable component of the lithium battery pack, generally composed of a main control chip, charge / discharge control circuit, current limiting and short-circuit protection circuit, temperature sensor, etc. It should be noted that the current limiting function of the lithium battery protection board refers to the lithium battery protection board managing the lithium battery charging process. Under normal conditions, it can provide the lithium battery with a charging capacity of the rated current value. When the lithium battery protection board monitors that the lithium battery pack voltage reaches the set voltage value, it limits the charging current to a smaller current value, thereby avoiding the negative impact caused by overcharging the lithium battery.

[0003] At present, the function detection of lithium battery protection board is usually tested on lithium battery string, such as Chinese patent application number CN201410529185.5, which discloses a lithium battery pack protection board detection device and method; when performing charging detection, the battery interface is electrically connected to the lithium battery pack, the charger charges the lithium battery pack through the charging interface, the first current detection module detects the charging current and sends it to the central processing unit, the voltage detection module detects the lithium battery pack voltage and sends it to the central processing unit, and the central processing unit determines whether the overcharge protection function of the protection board is invalid according to the current voltage value detected by the voltage detection module; it can be seen that the above detection device and method not only need to repeatedly charge and discharge the real lithium battery, but also cannot realize the current limiting function detection of the lithium battery protection board.

[0004] It should be noted that when testing the lithium battery protection board, it is usually necessary to repeatedly charge and discharge the real lithium battery to complete the test process of the current limiting function, which not only has low test efficiency but also poses safety hazards.

[0005] Therefore, in order to meet the needs of rapid verification and automatic testing of the production line, it is very necessary to design a device and method that is independent of the real lithium battery and can quickly detect the current limiting function of the lithium battery protection board.

[0006] In order to solve the above problems, people have been seeking an ideal technical solution. Summary of the invention

[0007] Based on this, it is necessary to provide a current limiting function detection device and method for a lithium battery protection board in order to solve the above technical problems.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a current limiting function detection device for a lithium battery protection board, which includes a host computer and a programmable power supply S1, a programmable power supply S2 and an electronic load respectively connected to the host computer, wherein the positive and negative poles of the programmable power supply S1 are correspondingly connected to the battery terminal B+ and B- terminals of the lithium battery protection board to be tested, and the positive and negative poles of the programmable power supply S2 are correspondingly connected to the power terminal P+ and P- terminals of the lithium battery protection board to be tested; One end of the electronic load is respectively connected to the positive electrode of the program-controlled power supply S1 and the battery terminal B+ of the lithium battery protection board to be tested, and the other end of the electronic load is respectively connected to the negative electrode of the program-controlled power supply S1 and the battery terminal B- of the lithium battery protection board to be tested; The host computer controls the opening or closing of the current limiting function of the lithium battery protection board to be tested, and determines whether the current limiting function of the lithium battery protection board is qualified according to the simulated charging current collected before and after the current limiting.

[0009] In order to achieve the above-mentioned purpose, the second aspect of the present invention provides a method for detecting the current limiting function of a lithium battery protection board, using the above-mentioned device for detecting the current limiting function of a lithium battery protection board; The current limiting function detection method comprises: Determine the charging voltage drop Vf and current limit value I of the lithium battery protection board to be tested L , the minimum operating voltage Vmin of the lithium battery protection board to be tested and the maximum charging voltage Vmax of the lithium battery protection board to be tested; The output voltage of the programmable power supply S1 is set to the minimum working voltage Vmin of the lithium battery protection board to be tested, and the output voltage of the programmable power supply S2 is set to the maximum charging voltage Vmax of the lithium battery protection board to be tested; the resistance value of the electronic load is adjusted to R0, R0 < (maximum charging voltage Vmax of the lithium battery protection board to be tested - charging voltage drop Vf of the lithium battery protection board to be tested) / current limiting value I L ; When the current limiting function of the lithium battery protection board to be tested is in a closed state, a first simulated charging current I1 is obtained through an electronic load; When the current limiting function of the lithium battery protection board to be tested is in an on state, a second simulated charging current I2 is obtained through an electronic load; If the current limit value I L <The first simulated charging current I1, and the second simulated charging current I2 = current limit value I L , it is determined that the current limiting function of the lithium battery protection board to be tested is qualified; If the second simulated charging current I2 = the first simulated charging current I1, or the second simulated charging current I2 < the preset current limit value I L , it is determined that the current limiting function of the lithium battery protection board under test is unqualified.

[0010] The beneficial effects of the present invention are: The present invention utilizes a host computer, a programmable power supply S1, a programmable power supply S2 and an electronic load to build a current limiting function simulation test platform, predetermines relevant parameters of the programmable power supply S1, the programmable power supply S2 and the electronic load, and controls the turning on or off of the current limiting function of the lithium battery protection board to be tested. Whether the current limiting function of the lithium battery protection board to be tested is qualified is judged according to the detected simulated charging current, and the test process of the current limiting function can be completed. The entire test process is separated from the real lithium battery and the real load. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of a current limiting function detection device of a lithium battery protection board of the present invention; Figure 2 It is a flow chart of a method for detecting the current limiting function of a lithium battery protection board of the present invention. DETAILED DESCRIPTION

[0012] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0013] For ease of understanding, the interactive parties and / or terms and / or custom words involved in the present invention are first described in conjunction with the technical solution of the present invention: Lithium battery protection board: refers to a lithium battery protection board with current limiting function, which is the product to be tested; in the current limiting mode, a qualified product to be tested can limit the charging current within a certain current range.

[0014] Programmable power supply S1: It is a programmable power supply used to simulate a lithium battery pack. During the current limiting test, it replaces the lithium battery required for the previous current limiting test and provides working power for the lithium battery protection board to be tested. Its voltage meets the minimum working voltage requirement of the lithium battery protection board.

[0015] Programmable power supply S2: It is a programmable power supply used to simulate the lithium battery charging power supply. It replaces the real charging power supply during the current limiting test. Its output voltage meets the charging power and voltage requirements of the lithium battery protection board.

[0016] Electronic load: It replaces the real load during the current limiting test and is used to make the lithium battery protection board generate simulated charging current. It can measure the voltage and current values ​​in the load circuit.

[0017] Host computer: As the system master control PC, its functions include: 1) According to the user-set parameters, send parameter setting instructions to the programmable power supply S1 and the programmable power supply S2 respectively, set the output voltage of the programmable power supply S1 to the minimum working voltage Vmin of the lithium battery protection board to be tested, and set the output voltage of the programmable power supply S2 to the maximum charging voltage Vmax of the lithium battery protection board to be tested; 2) Send instructions to the electronic load to set the electronic load to resistance mode, and set its resistance value to R0, R0<(Vmax-Vf) / I L ; 3) Send a start command to the programmable power supply S1, so that the programmable power supply S1 outputs voltage, and the lithium battery protection board to be tested starts working. At this time, the lithium battery protection board is in normal working mode; 4) Send a start command to the programmable power supply S2, so that the programmable power supply S2 outputs voltage, and the lithium battery protection board charges and outputs to the electronic load; 5) Send a current limiting function start command to the lithium battery protection board to be tested to control the lithium battery protection board to enter the current limiting mode.

[0018] Example 1 As attached Figure 1 As shown, this embodiment provides a specific implementation of a current limiting function detection device for a lithium battery protection board; The current limiting function detection device includes a host computer and a programmable power supply S1, a programmable power supply S2 and an electronic load respectively connected to the host computer, wherein the positive and negative poles of the programmable power supply S1 are correspondingly connected to the battery terminal B+ and B- terminals of the lithium battery protection board to be tested, and the positive and negative poles of the programmable power supply S2 are correspondingly connected to the power terminal P+ and P- terminals of the lithium battery protection board to be tested; wherein the programmable power supply S1 is used as a lithium battery simulation power supply to provide a working power supply for the lithium battery protection board to be tested; and the programmable power supply S2 is used as a lithium battery charging power supply; One end of the electronic load is respectively connected to the positive electrode of the programmable power supply S1 and the battery terminal B+ of the lithium battery protection board to be tested, and the other end of the electronic load is respectively connected to the negative electrode of the programmable power supply S1 and the battery terminal B- of the lithium battery protection board to be tested; wherein the electronic load is used to make the lithium battery protection board generate a simulated charging current, and detect the simulated charging current corresponding to the lithium battery protection board to be tested; The host computer controls the opening or closing of the current limiting function of the lithium battery protection board to be tested, and determines whether the current limiting function of the lithium battery protection board is qualified according to the simulated charging current collected before and after the current limiting.

[0019] It should be noted that when the current limiting function of the protection board of the lithium battery to be tested is turned off, the simulated charging current detected by the host computer is the first simulated charging current I1; after the current limiting function of the protection board of the lithium battery to be tested is turned on, the simulated charging current detected by the host computer is the second simulated charging current I2; If the current limit value I L<The first simulated charging current I1, and the second simulated charging current I2 = the preset current limit value I L , it is determined that the current limiting function of the lithium battery protection board to be tested is qualified; If the second simulated charging current I2 = the first simulated charging current I1, or the second simulated charging current I2 < the preset current limit value I L , it is determined that the current limiting function of the lithium battery protection board under test is unqualified.

[0020] It should also be noted that this embodiment uses a current limiting function detection device to detect the current limiting function of the lithium battery protection board to be tested. No real lithium battery is required, and automatic detection of the charging current limiting function of the lithium battery protection board can be achieved, which can meet the needs of batch rapid verification and automatic testing of the production line.

[0021] It should also be noted that the programmable power supply S1 and the programmable power supply S2 are also interconnected with the host computer through communication lines, and the programmable power supply S1 and the programmable power supply S2 support Modbus RTU communication; the host computer uses Modbus communication instructions to adjust the output voltage value and output control of the programmable power supply S1 and the programmable power supply S2.

[0022] It should also be noted that the output voltage of the programmable power supply S1 must meet the minimum operating voltage requirement of the lithium battery protection board to be tested and provide working power for the lithium battery protection board; the output voltage of the programmable power supply S2 must meet the charging power and voltage requirements of the lithium battery protection board to be tested.

[0023] It should also be noted that the electronic load is interconnected with the host computer through a communication line, and the host computer sets its working mode to the resistance mode and sets the resistance value.

[0024] It should also be noted that, as Figure 1 As shown, the communication method between the host computer and the programmable power supply S1, the programmable power supply S2, the electronic load and the lithium battery protection board to be tested includes but is not limited to serial communication, Ethernet communication and USB communication, and the communication format and communication instructions are communicated according to the specific instrument communication protocol.

[0025] It can be understood that the programmable power supply S1, the programmable power supply S2 and the electronic load can adopt devices with the above functions, and this embodiment does not limit the specific models of the programmable power supply S1, the programmable power supply S2 and the electronic load.

[0026] Example 2 Based on Example 1, this example provides a specific implementation method of a current limiting function detection method for a lithium battery protection board, as shown in the attached Figure 2 As shown; The method for detecting the current limiting function of the lithium battery protection board adopts the current limiting function detection device of the lithium battery protection board in Example 1; The current limiting function detection method includes a preparation stage and a detection stage; The preparation stage includes the following steps: determine the charging voltage drop Vf and current limit value I of the lithium battery protection board to be tested. L , the minimum operating voltage Vmin of the lithium battery protection board to be tested and the maximum charging voltage Vmax of the lithium battery protection board to be tested; The output voltage of the programmable power supply S1 is set to the minimum working voltage Vmin of the lithium battery protection board to be tested, and the output voltage of the programmable power supply S2 is set to the maximum charging voltage Vmax of the lithium battery protection board to be tested; the resistance value of the electronic load is adjusted to R0, R0 < (maximum charging voltage Vmax of the lithium battery protection board to be tested - charging voltage drop Vf of the lithium battery protection board to be tested) / current limiting value I L ; The detection phase includes the following steps: When the current limiting function of the lithium battery protection board to be tested is in a closed state, a first simulated charging current I1 is obtained through an electronic load; When the current limiting function of the lithium battery protection board to be tested is in an on state, a second simulated charging current I2 is obtained through an electronic load; If the current limit value I L <The first simulated charging current I1, and the second simulated charging current I2 = current limit value I L , it is determined that the current limiting function of the lithium battery protection board to be tested is qualified; If the second simulated charging current I2 = the first simulated charging current I1, or the second simulated charging current I2 < the preset current limit value I L , it is determined that the current limiting function of the lithium battery protection board under test is unqualified.

[0027] It should be noted that when the current limiting function of the lithium battery protection board to be tested is in the off state and the program-controlled power supply S1 and the program-controlled power supply S2 are started, the lithium battery protection board to be tested enters the normal working mode and its current limiting function is in the off state. At this time, the current limiting function of the lithium battery protection board to be tested does not work; When the current limiting function of the lithium battery protection board to be tested is in an on state and the program-controlled power supply S1 and the program-controlled power supply S2 are started, the lithium battery protection board to be tested enters a current limiting mode.

[0028] It should also be noted that before the current limiting function test, the user shall complete the minimum working voltage Vmin, the maximum charging voltage Vmax, and the current limiting value I of the lithium battery protection board to be tested according to the product characteristics. L And the setting of parameters such as charging voltage drop Vf of the lithium battery protection board to be tested; These parameters are set to satisfy the following condition: (Vmax-Vf)>Vmin.

[0029] It should also be noted that the resistance value R0 of the electronic load meets the following conditions: (1) In order to make the first simulated charging current I1 (corresponding to the qualified product) greater than the current limit value I L , R0<(maximum charging voltage Vmax of the lithium battery protection board to be tested - charging voltage drop Vf of the lithium battery protection board to be tested) / current limiting value I L ; (2) I L * R0> the minimum operating voltage Vmin of the lithium battery protection board to be tested (the set voltage of S1), so that the output voltages of B+ and B- of the lithium battery protection board to be tested are greater than the set voltage of the programmable power supply S1, so that it can be confirmed that the current value measured by the electronic load is the output current value of the lithium battery protection board to be tested, thereby completing the current limiting function test verification of the lithium battery protection board.

[0030] In a specific implementation manner, the detection process of the current limiting function is described by way of example; 1) If Figure 1 As shown, connect the test harness; The charging voltage drop Vf of the lithium battery protection board to be tested is 7V (the components in the lithium battery protection board will produce a certain voltage drop, which varies from manufacturer to manufacturer). L The current is 10A, the minimum working voltage Vmin of the lithium battery protection board to be tested is DC30V, and the maximum charging voltage Vmax of the lithium battery protection board to be tested is DC67V; 2) The output voltage of the program-controlled power supply S1 is set to DC30V, and the output voltage of the program-controlled power supply S2 is set to DC67V; Adjust the resistance value of the electronic load to 4 ohms; 3) When the lithium battery protection board to be tested works in normal mode, the B+ and B- terminals of the lithium battery protection board to be tested will form a DC voltage of about 60V, and the simulated charging current measured by the electronic load is 15A; That is, the first simulated charging current I1 = 60V / 4 ohms = 15A; at this time, the first simulated charging current I1> the preset current limit value I L , indicating that the lithium battery protection board is working normally, otherwise the charging output of the lithium battery protection board is abnormal; 4) The upper computer controls the lithium battery protection board to be tested to start the current limiting function, and the lithium battery protection board to be tested enters the current limiting mode; at this time, the simulated charging current measured by the electronic load is reduced to 10A; that is, the second simulated charging current I2 is 10A, at this time, the second simulated charging current I2 = the preset current limiting value I L, indicating that the current limiting function of the lithium battery protection board is normal; At this time, the voltage between B+ and B- of the lithium battery protection board to be tested is 10A*4 ohms, that is, 40V. Its value is greater than the set voltage of 30V of the lithium battery simulation voltage S1, which can be determined that the current measured by the electronic load is provided by the lithium battery protection board. When the current limiting function of the lithium battery protection board to be tested is turned on, the output current is 10A (less than 15A), indicating that the current limiting function of the lithium battery protection board to be tested is working normally.

[0031] 5) Complete the current limiting function test of one lithium battery protection board, record the product test process data, and proceed to the next test.

[0032] It should be noted that if the current limiting function of the lithium battery protection board to be tested is abnormal, the output current value measured by the electronic load will not be 10A; there are two types of errors: Case 1: the current limiting function of the lithium battery protection board to be tested does not work, and the current value measured by the electronic load is still 15A (the second simulated charging current I2 = the first simulated charging current I1); Case 2: The protection board of the lithium battery to be tested is closed after current limiting, and the current measured by the electronic load is 30V / 4 ohms = 7.5A (the second simulated charging current I2 < the preset current limit value I L ).

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A current limiting function detection device for a lithium battery protection board, characterized in that: It includes a host computer and a programmable power supply S1, a programmable power supply S2 and an electronic load respectively connected to the host computer, wherein the positive and negative poles of the programmable power supply S1 are correspondingly connected to the battery terminal B+ and B- terminals of the lithium battery protection board to be tested, and the positive and negative poles of the programmable power supply S2 are correspondingly connected to the power terminal P+ and P- terminals of the lithium battery protection board to be tested; One end of the electronic load is respectively connected to the positive electrode of the program-controlled power supply S1 and the battery terminal B+ of the lithium battery protection board to be tested, and the other end of the electronic load is respectively connected to the negative electrode of the program-controlled power supply S1 and the battery terminal B- of the lithium battery protection board to be tested; The host computer controls the opening or closing of the current limiting function of the lithium battery protection board to be tested, and determines whether the current limiting function of the lithium battery protection board is qualified according to the simulated charging current collected before and after the current limiting.

2. A method for detecting the current limiting function of a lithium battery protection board, characterized in that: A current limiting function detection device for a lithium battery protection board according to claim 1; The current limiting function detection method comprises: Determine the charging voltage drop Vf and current limit value I of the lithium battery protection board to be tested L , the minimum operating voltage Vmin of the lithium battery protection board to be tested and the maximum charging voltage Vmax of the lithium battery protection board to be tested; The output voltage of the programmable power supply S1 is set to the minimum working voltage Vmin of the lithium battery protection board to be tested, and the output voltage of the programmable power supply S2 is set to the maximum charging voltage Vmax of the lithium battery protection board to be tested; the resistance value of the electronic load is adjusted to R0, R0 < (maximum charging voltage Vmax of the lithium battery protection board to be tested - charging voltage drop Vf of the lithium battery protection board to be tested) / current limiting value I L ; When the current limiting function of the lithium battery protection board to be tested is in a closed state, a first simulated charging current I1 is obtained through an electronic load; When the current limiting function of the lithium battery protection board to be tested is in an on state, a second simulated charging current I2 is obtained through an electronic load; If the current limit value I L <The first simulated charging current I1, and the second simulated charging current I2 = current limit value I L , it is determined that the current limiting function of the lithium battery protection board to be tested is qualified; If the second simulated charging current I2 = the first simulated charging current I1, or the second simulated charging current I2 < the preset current limit value I L , it is determined that the current limiting function of the lithium battery protection board under test is unqualified.

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