A lithium battery test fixture wire connection detection device based on AC signal

Abstract

The present invention provides a lithium battery test fixture line wiring detection device based on AC signals in the field of lithium battery testing technology, comprising a main control module, an AC signal output module, a primary channel switching module, a secondary channel switching module, a primary wiring state judgment module, a secondary wiring state judgment module, and an output switch switching module; the main control module is respectively connected to the AC signal output module, the primary channel switching module, the secondary channel switching module, the primary wiring state judgment module, the secondary wiring state judgment module, and the output switch switching module; the primary channel switching module is respectively connected to the AC signal output module, the primary wiring state judgment module, and the output switch switching module; the secondary channel switching module is connected to the secondary wiring state judgment module and the output switch switching module. The advantage of the present invention is that it realizes automatic detection of the wiring of the lithium battery test fixture line, greatly improving the safety and accuracy of the lithium battery test.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery testing, and in particular to a lithium battery testing fixture line connection detection device based on an alternating current signal. Background Art

[0002] With the rapid development of lithium battery technology, the demand for lithium batteries is increasing, and the demand for batch charge and discharge verification (testing) of lithium batteries is also increasing. Therefore, after the production of lithium batteries, it is necessary to improve the efficiency of lithium battery charge and discharge verification.

[0003] Before performing charge and discharge verification on a lithium battery, you need to connect the four-wire test fixture lines (positive terminal voltage sampling line PS+, negative terminal voltage sampling line PS-, positive terminal current loop line P+, ​​negative terminal current loop line P-) to the lithium battery, that is, PS+ is connected to the positive terminal of the lithium battery, PS- is connected to the negative terminal of the lithium battery, P+ is connected to the positive terminal of the lithium battery, and P- is connected to the negative terminal of the lithium battery.

[0004] In order to improve the efficiency of lithium battery charge and discharge verification, the number of test channels has been increased accordingly, which has led to an increase in the number of test fixture wire harnesses year-on-year. The probability of incorrect wiring has also increased. For example, one or several test wires of a test channel are not correctly identified with the test wires of other test channels and are mixed up. That is, the PS+ of the first test channel is mixed up with the PS+ of the second test channel, or the P- of the first test channel is mixed up with the P- of the third test channel, etc. Therefore, it is necessary to determine whether the test fixture wires of each test channel are correctly connected to the corresponding lithium battery.

[0005] Traditionally, after each test fixture line is connected, a manual check is performed to determine whether the connection is correct. However, when there are many test fixture lines connected, errors are inevitable, which in turn affects the safety and accuracy of lithium battery testing.

[0006] Therefore, how to provide a lithium battery test fixture wire connection detection device based on AC signals to automatically detect the connection of the lithium battery test fixture wires to improve the safety and accuracy of lithium battery testing has become a technical problem that needs to be solved urgently. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a lithium battery test fixture wire connection detection device based on AC signals, which can realize automatic detection of the connection of the lithium battery test fixture wires to ensure the safety and accuracy of lithium battery testing.

[0008] The present invention is implemented as follows: a lithium battery test fixture line connection detection device based on AC signal, including a main control module, an AC signal output module, a first-level channel switching module, a first-level channel switching module, a first-level wiring state judgment module, a first-level wiring state judgment module and an output switch switching module;

[0009] The main control module is respectively connected to the AC signal output module, the first-level channel switching module, the second-level channel switching module, the first-level wiring status judgment module, the second-level wiring status judgment module and the output switch switching module; the first-level channel switching module is respectively connected to the AC signal output module, the first-level wiring status judgment module and the output switch switching module; one end of the second-level channel switching module is connected to the second-level wiring status judgment module, and the other end is connected to the output switch switching module.

[0010] Furthermore, the AC signal output module includes an operational amplifier U4A, a resistor R2, a resistor R3, a resistor R4, a resistor R7, a resistor R15, a capacitor C2, a capacitor C18 and a capacitor C19;

[0011] One end of the resistor R2 is connected to the main control module, and the other end is connected to the capacitor C2 and the capacitor C18; one end of the resistor R3 is connected to the first-level channel switching module, and the other end is connected to pin 1 of the operational amplifier U4A; after the capacitor C19 is connected in parallel with the resistor R7, one end is grounded, and the other end is connected to the resistor R15 and the pin 2 of the operational amplifier U4A; the pin 3 of the operational amplifier U4A is connected to the capacitor C2 and the resistor R4.

[0012] Furthermore, the first-level channel switching module includes a multiplexing analog switch U1 and a capacitor C17;

[0013] One end of the capacitor C17 is connected to the AC signal output module, and the other end is connected to pin 8 of the multiplexing analog switch U1; pin 9 of the multiplexing analog switch U1 is connected to the first-level wiring status judgment module, pins 4, 5, 6, 7, 10, 11, 12, and 13 are connected to the output switch switching module, and pins 1, 2, and 16 are connected to the main control module.

[0014] Furthermore, the first-level wiring state judgment module includes a MOS tube Q3, a resistor R16, a resistor R17, a resistor R18, a resistor R20, a capacitor C20 and a diode D1;

[0015] The G pole of the MOS tube Q3 is connected to the resistor R18 and the resistor R20, the S pole is connected to the resistor R18 and grounded, and the D pole is connected to the resistor R16 and the main control module; the input end of the diode D1 is connected to the resistor R17 and the capacitor C20, and the output end is connected to the resistor R20; the capacitor C20 is connected to the primary channel switching module.

[0016] Furthermore, the MOS transistor Q3 is an NMOS transistor.

[0017] Furthermore, the secondary channel switching module includes a multiplexing analog switch U3, a diode D5 and a diode D6;

[0018] The output end of the diode D5 is connected to the secondary wiring status judgment module, and the input end is connected to pin 8 of the multiplexing analog switch U3; the input end of the diode D6 is connected to the secondary wiring status judgment module, and the input end is connected to pin 9 of the multiplexing analog switch U3; pins 4, 5, 6, 7, 10, 11, 12, and 13 of the multiplexing analog switch U3 are connected to the output switch switching module, and pins 1, 2, and 16 are connected to the main control module.

[0019] Furthermore, the secondary wiring state judgment module includes an operational amplifier U4B, a MOS tube Q4, a resistor R1, a resistor R10, a resistor R11, a resistor R13, a resistor R14, a resistor R19, a resistor R21, a capacitor C3 and a diode D4;

[0020] The G pole of the MOS tube Q4 is connected to the resistor R19 and the resistor R21, the S pole is connected to the resistor R19 and grounded, and the D pole is connected to the resistor R1 and the main control module; the input end of the diode D4 is connected to the pin 7 of the operational amplifier U4B, and the output end is connected to the resistor R21; after the resistor R14 is connected in parallel with the capacitor C3, one end is connected to the resistor R13 and the pin 5 of the operational amplifier U4B, and the other end is grounded; one end of the resistor R10 is connected to the resistor R11 and the lead frame 6 of the operational amplifier U4B, and the other end is connected to the secondary channel switching module; the resistor R11 is connected to the secondary channel switching module.

[0021] Furthermore, the MOS transistor Q4 is an NMOS transistor.

[0022] Furthermore, the output switch switching module includes a relay K1, a relay K2, a MOS transistor Q1, a MOS transistor Q2, a resistor R5, a resistor R6, a resistor R8, a resistor R9, a capacitor C1, a diode D2 and a diode D3;

[0023] Pins PS+ and PS- of the relay K1 are connected to the primary channel switching module, pins PS+_TEST and PS-_TEST are connected to the secondary channel switching module, the positive electrode is connected to the capacitor C1 and the output end of the diode D2, and the negative electrode is connected to the input end of the diode D2 and the D electrode of the MOS tube Q1; one end of the resistor R5 is connected to the main control module, and the other end is connected to the resistor R6 and the G electrode of the MOS tube Q1; the S electrode of the MOS tube Q1 is connected to the resistor R6 and grounded;

[0024] Pins P+ and P- of the relay K2 are connected to the primary channel switching module, pins P+_TEST and P-_TEST are connected to the secondary channel switching module, the positive electrode is connected to the output end of the diode D3, and the negative electrode is connected to the input end of the diode D3 and the D pole of the MOS tube Q2; one end of the resistor R8 is connected to the main control module, and the other end is connected to the resistor R9 and the G pole of the MOS tube Q2; the S pole of the MOS tube Q2 is connected to the resistor R9 and grounded.

[0025] Furthermore, the MOS transistor Q1 and the MOS transistor Q2 are both NMOS transistors.

[0026] The advantages of the present invention are:

[0027] By setting a main control module, an AC signal output module, a primary channel switching module, a secondary channel switching module, a primary wiring state judgment module, a secondary wiring state judgment module and an output switch switching module; the main control module outputs a PWM signal to the AC signal output module to control the channel switching of the primary channel switching module and the secondary channel switching module, and controls the electrical connection between the output switch switching module and the external signal wiring; the AC signal output module converts the PWM signal into an AC signal and outputs it to the primary channel switching module as the signal source required for detection; the main control module judges the wiring state of the channel selected by the primary channel switching module through the primary wiring state judgment module, and judges the wiring state of the channel selected by the secondary channel switching module through the secondary wiring state judgment module, that is, whether the input signal frequency is consistent with the PWM signal frequency, and whether the wiring is correct, that is, automatic detection of the wiring of the lithium battery test fixture line is achieved. In the case of incorrect wiring, the wiring error information can be promptly identified and fed back, avoiding the lithium battery test being performed under the incorrect wiring state, thereby greatly improving the safety and accuracy of the lithium battery test. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 The present invention is a circuit principle block diagram of a lithium battery test fixture line connection detection device based on AC signals.

[0030] Figure 2 It is a circuit diagram of the AC signal output module, the first-level channel switching module and the first-level wiring state judgment module of the present invention.

[0031] Figure 3 It is a circuit diagram of the secondary channel switching module and the secondary wiring state judgment module of the present invention.

[0032] Figure 4 It is a circuit diagram of the output switch switching module of the present invention.

[0033] Figure 5 It is a circuit diagram of the main control module of the present invention. DETAILED DESCRIPTION

[0034] Please refer to Figures 1 to 5 As shown, a preferred embodiment of the present invention is a lithium battery test fixture line connection detection device based on AC signal, including a main control module, an AC signal output module, a first-level channel switching module, a second-level channel switching module, a first-level wiring state judgment module, a first-level wiring state judgment module and an output switch switching module;

[0035] The chip of the main control module is preferably an ARM microprocessor TM4C1294NCPDT, which is used to provide PWM signal output to the AC signal output module, control the channel switching and channel switching enable control in the primary channel switching module, receive the status judgment signal returned by the primary wiring status judgment module, control the channel switching and channel switching enable control in the secondary channel switching module, receive the status judgment signal returned by the secondary wiring status judgment module, and perform switching control on the output switch switching module.

[0036] The AC signal output module is used to convert the PWM signal provided by the main control module into an AC signal, and output it to the first-level channel switching module to be used as a signal source for testing.

[0037] The primary channel switching module is used to switch the connection channel selection with the primary wiring status judgment module according to the control signal of the main control module.

[0038] The first-level wiring status judgment is used to judge the wiring status of the first-level channel switching module after the channel is switched, and the judgment result is returned to the main control module in the form of a PWM signal that matches the frequency output by the main control module to the AC signal output module.

[0039] The secondary channel switching module is used to switch the connection channel selection with the secondary wiring status judgment module according to the control signal of the main control module.

[0040] The secondary wiring status judgment module is used to judge the wiring status after the secondary channel switching module is switched, and transmit the judgment result back to the main control module in the form of high and low level signals.

[0041] The output switch switching module controls the connection and disconnection between the test signal and the external signal wiring electrical system through the switching signal of the main control module.

[0042] The present invention converts the PWM signal output by the main control module into an AC signal for testing, and determines the wiring status by checking whether the frequency of the output is consistent with that of the test feedback signal. By selecting the switching path of a multiplexed analog switch, a two-stage judgment is performed on the wiring identification of the test fixture line, thereby increasing the reliability of the wiring judgment result. A relay is used to connect and disconnect the test signal with the external signal, thereby avoiding affecting the normal charge and discharge test circuit of the lithium battery. By controlling the enable pins of the two-stage analog switch, mutual influence between the two-stage analog switches is avoided. The AC signal is safely applied to the NPN-type MOS tube through the unidirectional conduction characteristic of the diode.

[0043] The main control module is respectively connected to the AC signal output module, the first-level channel switching module, the second-level channel switching module, the first-level wiring status judgment module, the second-level wiring status judgment module and the output switch switching module; the first-level channel switching module is respectively connected to the AC signal output module, the first-level wiring status judgment module and the output switch switching module; one end of the second-level channel switching module is connected to the second-level wiring status judgment module, and the other end is connected to the output switch switching module.

[0044] The AC signal output module includes an operational amplifier U4A, a resistor R2, a resistor R3, a resistor R4, a resistor R7, a resistor R15, a capacitor C2, a capacitor C18, and a capacitor C19; the model of the operational amplifier U4A is preferably OPA2188;

[0045] One end of the resistor R2 is connected to the main control module, and the other end is connected to the capacitor C2 and the capacitor C18; one end of the resistor R3 is connected to the first-level channel switching module, and the other end is connected to pin 1 of the operational amplifier U4A; after the capacitor C19 is connected in parallel with the resistor R7, one end is grounded, and the other end is connected to the resistor R15 and the pin 2 of the operational amplifier U4A; the pin 3 of the operational amplifier U4A is connected to the capacitor C2 and the resistor R4.

[0046] The first-level channel switching module includes a multiplexing analog switch U1 and a capacitor C17; the model of the multiplexing analog switch U1 is preferably MUX509;

[0047] One end of the capacitor C17 is connected to the AC signal output module, and the other end is connected to pin 8 of the multiplexing analog switch U1; pin 9 of the multiplexing analog switch U1 is connected to the first-level wiring status judgment module, pins 4, 5, 6, 7, 10, 11, 12, and 13 are connected to the output switch switching module, and pins 1, 2, and 16 are connected to the main control module.

[0048] The first-level wiring status judgment module includes a MOS tube Q3, a resistor R16, a resistor R17, a resistor R18, a resistor R20, a capacitor C20 and a diode D1;

[0049] The G pole of the MOS tube Q3 is connected to the resistor R18 and the resistor R20, the S pole is connected to the resistor R18 and grounded, and the D pole is connected to the resistor R16 and the main control module; the input end of the diode D1 is connected to the resistor R17 and the capacitor C20, and the output end is connected to the resistor R20; the capacitor C20 is connected to the primary channel switching module.

[0050] The MOS transistor Q3 is an NMOS transistor.

[0051] The secondary channel switching module includes a multiplexing analog switch U3, a diode D5 and a diode D6; the model of the multiplexing analog switch U3 is preferably MUX509;

[0052] The output end of the diode D5 is connected to the secondary wiring status judgment module, and the input end is connected to pin 8 of the multiplexing analog switch U3; the input end of the diode D6 is connected to the secondary wiring status judgment module, and the input end is connected to pin 9 of the multiplexing analog switch U3; pins 4, 5, 6, 7, 10, 11, 12, and 13 of the multiplexing analog switch U3 are connected to the output switch switching module, and pins 1, 2, and 16 are connected to the main control module.

[0053] The secondary wiring status judgment module includes an operational amplifier U4B, a MOS transistor Q4, a resistor R1, a resistor R10, a resistor R11, a resistor R13, a resistor R14, a resistor R19, a resistor R21, a capacitor C3 and a diode D4; the model of the operational amplifier U4B is preferably OPA2188;

[0054] The G pole of the MOS tube Q4 is connected to the resistor R19 and the resistor R21, the S pole is connected to the resistor R19 and grounded, and the D pole is connected to the resistor R1 and the main control module; the input end of the diode D4 is connected to the pin 7 of the operational amplifier U4B, and the output end is connected to the resistor R21; after the resistor R14 is connected in parallel with the capacitor C3, one end is connected to the resistor R13 and the pin 5 of the operational amplifier U4B, and the other end is grounded; one end of the resistor R10 is connected to the resistor R11 and the lead frame 6 of the operational amplifier U4B, and the other end is connected to the secondary channel switching module; the resistor R11 is connected to the secondary channel switching module.

[0055] The MOS transistor Q4 is an NMOS transistor.

[0056] The output switch module includes a relay K1, a relay K2, a MOS transistor Q1, a MOS transistor Q2, a resistor R5, a resistor R6, a resistor R8, a resistor R9, a capacitor C1, a diode D2, and a diode D3; the relay K1 and the relay K2 are preferably HFD4 / 12-SR models;

[0057] Pins PS+ and PS- of the relay K1 are connected to the primary channel switching module, pins PS+_TEST and PS-_TEST are connected to the secondary channel switching module, the positive electrode is connected to the capacitor C1 and the output end of the diode D2, and the negative electrode is connected to the input end of the diode D2 and the D electrode of the MOS tube Q1; one end of the resistor R5 is connected to the main control module, and the other end is connected to the resistor R6 and the G electrode of the MOS tube Q1; the S electrode of the MOS tube Q1 is connected to the resistor R6 and grounded;

[0058] Pins P+ and P- of the relay K2 are connected to the primary channel switching module, pins P+_TEST and P-_TEST are connected to the secondary channel switching module, the positive electrode is connected to the output end of the diode D3, and the negative electrode is connected to the input end of the diode D3 and the D pole of the MOS tube Q2; one end of the resistor R8 is connected to the main control module, and the other end is connected to the resistor R9 and the G pole of the MOS tube Q2; the S pole of the MOS tube Q2 is connected to the resistor R9 and grounded.

[0059] The MOS transistor Q1 and the MOS transistor Q2 are both NMOS transistors.

[0060] Working principle of the present invention:

[0061] The main control module controls the enable pin EN (corresponding to network number EN-2) of multiplexer analog switch U3 to a low level, disconnecting the electrical connection link between the two channels of multiplexer analog switch U3 and preventing any connection to any path, thereby preventing any impact on the subsequent first-level test. The main control module controls relays K1 and K2. During testing, by controlling network numbers REL_K1 and REL_K2, the main control module controls the relays to connect network numbers PS+_TEST to PS+, PS-_TEST to PS-, P+_TEST to P+, and P-_TEST to P-, respectively.

[0062] After the master control module controls the enable signal EN (corresponding to network number EN-1) of the multiplexed analog switch U1 to a high level, it performs different test connection combinations on the channel switching signals corresponding to network numbers A0-1 and A1-1. The current first-level channel switching module design provides four combination tests: 1. PS+_TEST and P+_TEST combination test; 2. PS+_TEST and PS-_TEST combination test; 3. P+_TEST and P-_TEST combination test; 4. PS-_TEST and P-_TEST combination test.

[0063] The AC signal output module passes the PWM signal provided by the main control module through a low-pass filter composed of resistor R2 and capacitor C18, and then through a high-pass filter composed of capacitor C2 and resistor R4, and then inputs it to pin 3 of the operational amplifier U4A. The voltage value of pin 2 of the operational amplifier U4A is designed by the resistance value of resistor R15 and resistor R7. After comparing the voltage of pin 3 and pin 2 of the operational amplifier U4A, an AC signal is output at pin 1 of the operational amplifier U4A. The AC signal passes through resistor R3 and capacitor C17 and is connected to pin 8 of the multiplexed analog switch U1 in the first-level channel switching module (that is, the selection pin for switching input and output of one of the channels of the analog switch). The AC signal used for the test is output to the corresponding fixture line through channel selection.

[0064] The test judgment signal in the primary wiring status judgment module is transmitted through pin 9 of the multiplexing analog switch U1 (i.e., the selection pin for switching input and output of one of the channels of the analog switch). The corresponding AC signal in the loop passes through capacitor C20 and resistor R17. The AC voltage (the voltage of network number AC-IN to ground) finally formed on resistor R17 passes through diode D1 and resistor R20 to control MOS transistor Q3. Under the influence of the unidirectional conductivity of diode D1, after the AC signal AC-IN acts on MOS transistor Q3, it will form a PWM signal corresponding to the frequency of network number PWM-IN on network number OUT-1.

[0065] The signal from network number OUT-1 is transmitted to the main control module for identification. When the wiring is correct, that is, when there is no mixed connection with other channels in this state, the entire test link can form a closed loop with the lithium battery under test. If there is a mixed connection with other channels, the mixed lines will not be able to form a closed loop with the lithium battery under test. Therefore, the corresponding result relationship can be obtained from network number OUT-1: when the signal frequency output by network number OUT-1 is inconsistent with the signal frequency of network number PWM-IN, it indicates that the channel group identification wiring selected by the currently selected multiplexer analog switch U1 is abnormal. When the signal frequency output by network number OUT-1 is consistent with the signal frequency of network number PWM-IN, it indicates that the channel group identification wiring selected by the currently selected multiplexer analog switch U1 is normal.

[0066] After the first-level judgment is completed, the second-level judgment begins to determine whether the test wiring is connected to the corresponding positive and negative positions of the lithium battery according to the corresponding correct positive and negative pole connection method. Before the test, the main control module sets the enable control pin 2 (corresponding to network number EN-1) of the multiplexed analog switch U1 to a low level, thereby avoiding affecting the secondary channel switching module and the secondary wiring status judgment module.

[0067] After the main control module controls the enable signal EN (corresponding to network number EN-2) of the multiplexed analog switch U3 to a high level, different test connection combinations are performed on the channel switching signals corresponding to network numbers A0-2 and A1-2. The current design can achieve four different combinations, and form a loop with diode D5, diode D6, resistor R10, and resistor R11: 1. Combined test of PS+_TEST and PS-_TEST; 2. Combined test of PS+_TEST and P-_TEST; 3. Combined test of P+_TEST and PS-_TEST; 4. Combined test of P+_TEST and P-_TEST.

[0068] The secondary wiring status judgment module judges whether the current wiring is connected to the positive and negative poles of the battery in the correct way by selecting different paths of the current multiplexing analog switch U3. By designing the corresponding resistance values ​​of resistors R10, R11, R13 and R14, when the wiring is correct, the positive and negative poles of the lithium battery form a loop with the forward conductivity of diodes D5 and D6 and resistors R10 and R11, and obtain a voltage value relative to the ground level on network number VS1; when the positive and negative poles of the wiring are incorrect, the positive and negative poles of the lithium battery cannot form a normal current flow loop with resistors R10 and R11 through the reverse cutoff characteristics of diodes D5 and D6. Network number VS1 will not form a voltage value relative to the ground level due to the external lithium battery. At this time, the VS1 voltage amplitude is basically the ground level value. The voltage value of network VS2 is obtained by the resistance value design of resistors R13 and R14. Therefore, pin 7 of op amp U4B The output signal of OUT-2 acts on the MOS tube Q4 after passing through the diode D4 and the resistor R21. Under the action of the pull-up resistor R1, the corresponding result relationship can be obtained on the network number OUT-2: when the ground level of the network number OUT-2 is low for the main control module, it indicates that the channel group identification wiring selected by the currently selected multiplexing analog switch U3 is abnormal; when the voltage of the network number OUT-2 to the ground level is high for the main control module, it indicates that the channel group identification wiring selected by the currently selected multiplexing analog switch U3 is normal; after the test is completed, the main control module controls the relay K1 and the relay K2, and controls the network numbers REL_K1 and REL_K2 to control the relays to disconnect the network numbers PS+_TEST from PS+, PS-_TEST from PS-, P+_TEST from P+, and P-_TEST from P-, thereby avoiding affecting the subsequent lithium battery charge and discharge tests.

[0069] In summary, the advantages of the present invention are:

[0070] By setting a main control module, an AC signal output module, a primary channel switching module, a secondary channel switching module, a primary wiring state judgment module, a secondary wiring state judgment module and an output switch switching module; the main control module outputs a PWM signal to the AC signal output module to control the channel switching of the primary channel switching module and the secondary channel switching module, and controls the electrical connection between the output switch switching module and the external signal wiring; the AC signal output module converts the PWM signal into an AC signal and outputs it to the primary channel switching module as the signal source required for detection; the main control module judges the wiring state of the channel selected by the primary channel switching module through the primary wiring state judgment module, and judges the wiring state of the channel selected by the secondary channel switching module through the secondary wiring state judgment module, that is, whether the input signal frequency is consistent with the PWM signal frequency, and whether the wiring is correct, that is, automatic detection of the wiring of the lithium battery test fixture line is achieved. In the case of incorrect wiring, the wiring error information can be promptly identified and fed back, avoiding the lithium battery test being performed under the incorrect wiring state, thereby greatly improving the safety and accuracy of the lithium battery test.

[0071] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A lithium battery test fixture wire connection detection device based on AC signals, characterized by: It includes a main control module, an AC signal output module, a first-level channel switching module, a first-level channel switching module, a first-level wiring state judgment module, a first-level wiring state judgment module and an output switch switching module; The main control module is respectively connected to the AC signal output module, the primary channel switching module, the secondary channel switching module, the primary wiring state judgment module, the secondary wiring state judgment module and the output switch switching module; the primary channel switching module is respectively connected to the AC signal output module, the primary wiring state judgment module and the output switch switching module; one end of the secondary channel switching module is connected to the secondary wiring state judgment module, and the other end is connected to the output switch switching module; The first-level wiring status judgment module includes a MOS tube Q3, a resistor R16, a resistor R17, a resistor R18, a resistor R20, a capacitor C20 and a diode D1; The G pole of the MOS transistor Q3 is connected to the resistor R18 and the resistor R20, the S pole is connected to the resistor R18 and grounded, and the D pole is connected to the resistor R16 and the main control module; the input end of the diode D1 is connected to the resistor R17 and the capacitor C20, and the output end is connected to the resistor R20; the capacitor C20 is connected to the primary channel switching module; The secondary wiring state judgment module includes an operational amplifier U4B, a MOS tube Q4, a resistor R1, a resistor R10, a resistor R11, a resistor R13, a resistor R14, a resistor R19, a resistor R21, a capacitor C3 and a diode D4; The G pole of the MOS tube Q4 is connected to the resistor R19 and the resistor R21, the S pole is connected to the resistor R19 and grounded, and the D pole is connected to the resistor R1 and the main control module; the input end of the diode D4 is connected to the pin 7 of the operational amplifier U4B, and the output end is connected to the resistor R21; after the resistor R14 is connected in parallel with the capacitor C3, one end is connected to the resistor R13 and the pin 5 of the operational amplifier U4B, and the other end is grounded; one end of the resistor R10 is connected to the resistor R11 and the lead frame 6 of the operational amplifier U4B, and the other end is connected to the secondary channel switching module; the resistor R11 is connected to the secondary channel switching module.

2. The AC signal-based lithium battery test fixture wire connection detection device according to claim 1, characterized in that: The AC signal output module includes an operational amplifier U4A, a resistor R2, a resistor R3, a resistor R4, a resistor R7, a resistor R15, a capacitor C2, a capacitor C18, and a capacitor C19; One end of the resistor R2 is connected to the main control module, and the other end is connected to the capacitor C2 and the capacitor C18; one end of the resistor R3 is connected to the first-level channel switching module, and the other end is connected to pin 1 of the operational amplifier U4A; after the capacitor C19 is connected in parallel with the resistor R7, one end is grounded, and the other end is connected to the resistor R15 and the pin 2 of the operational amplifier U4A; the pin 3 of the operational amplifier U4A is connected to the capacitor C2 and the resistor R4.

3. The AC signal-based lithium battery test fixture wire connection detection device according to claim 1, characterized in that: The first-level channel switching module includes a multiplexing analog switch U1 and a capacitor C17; One end of the capacitor C17 is connected to the AC signal output module, and the other end is connected to pin 8 of the multiplexing analog switch U1; pin 9 of the multiplexing analog switch U1 is connected to the first-level wiring status judgment module, pins 4, 5, 6, 7, 10, 11, 12, and 13 are connected to the output switch switching module, and pins 1, 2, and 16 are connected to the main control module.

4. The AC signal-based lithium battery test fixture wire connection detection device according to claim 1, characterized in that: The MOS transistor Q3 is an NMOS transistor.

5. The AC signal-based lithium battery test fixture wire connection detection device according to claim 1, characterized in that: The secondary channel switching module includes a multiplexing analog switch U3, a diode D5 and a diode D6; The output end of the diode D5 is connected to the secondary wiring status judgment module, and the input end is connected to pin 8 of the multiplexing analog switch U3; the input end of the diode D6 is connected to the secondary wiring status judgment module, and the input end is connected to pin 9 of the multiplexing analog switch U3; pins 4, 5, 6, 7, 10, 11, 12, and 13 of the multiplexing analog switch U3 are connected to the output switch switching module, and pins 1, 2, and 16 are connected to the main control module.

6. The AC signal-based lithium battery test fixture wire connection detection device according to claim 1, characterized in that: The MOS transistor Q4 is an NMOS transistor.

7. The AC signal-based lithium battery test fixture wire connection detection device according to claim 1, characterized in that: The output switch module includes a relay K1, a relay K2, a MOS transistor Q1, a MOS transistor Q2, a resistor R5, a resistor R6, a resistor R8, a resistor R9, a capacitor C1, a diode D2 and a diode D3; Pins PS+ and PS- of the relay K1 are connected to the primary channel switching module, pins PS+_TEST and PS-_TEST are connected to the secondary channel switching module, the positive electrode is connected to the capacitor C1 and the output end of the diode D2, and the negative electrode is connected to the input end of the diode D2 and the D electrode of the MOS tube Q1; one end of the resistor R5 is connected to the main control module, and the other end is connected to the resistor R6 and the G electrode of the MOS tube Q1; the S electrode of the MOS tube Q1 is connected to the resistor R6 and grounded; Pins P+ and P- of the relay K2 are connected to the primary channel switching module, pins P+_TEST and P-_TEST are connected to the secondary channel switching module, the positive electrode is connected to the output end of the diode D3, and the negative electrode is connected to the input end of the diode D3 and the D pole of the MOS tube Q2; one end of the resistor R8 is connected to the main control module, and the other end is connected to the resistor R9 and the G pole of the MOS tube Q2; the S pole of the MOS tube Q2 is connected to the resistor R9 and grounded.

8. The AC signal-based lithium battery test fixture wire connection detection device according to claim 7, characterized in that: The MOS transistor Q1 and the MOS transistor Q2 are both NMOS transistors.

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