A DC signal-based lithium battery test fixture wire connection detection device

Abstract

This invention provides a DC signal-based lithium battery test fixture wire wiring detection device in the field of lithium battery testing technology. It includes a main control module, a primary channel switching module, a primary and secondary channel switching module, a primary wiring status judgment module, a primary and secondary wiring status judgment module, and an output switch switching module. The main control module is connected to each of the primary and secondary channel switching modules. One end of the primary channel switching module is connected to the primary wiring status judgment module, and the other end is connected to the output switch switching module. One end of the secondary channel switching module is connected to the secondary wiring status judgment module, and the other end is connected to the output switch switching module. The advantage of this invention is that it enables automatic detection of the wiring of lithium battery test fixture wires, greatly improving the safety and accuracy of lithium battery testing.

Description

Technical Field

[0001] This invention relates to the field of lithium battery testing technology, and in particular to a lithium battery testing fixture wire connection detection device based on DC signals. Background Technology

[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 charge and discharge verification efficiency of lithium batteries.

[0003] Before verifying the charge and discharge of the lithium battery, the four-wire test fixture wires (positive voltage sampling line PS+, negative voltage sampling line PS-, positive current return line P+, ​​and negative current return line P-) need to be connected 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] To improve the efficiency of lithium battery charge and discharge verification, the number of test channels has been increased accordingly, which has also increased the number of test fixture wire harnesses. This increases the probability of incorrect wiring. For example, one or more test wires of a certain test channel may not be correctly identified and may be mixed up with the test wires of other test channels. That is, the PS+ of the first test channel may be mixed up with the PS+ of the second test channel, or the P- of the first test channel may be mixed up with the P- of the third test channel. 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 the wiring of each test fixture is completed, the correctness of the wiring is judged manually. When there are many test fixture wirings, errors in judgment are inevitable, which will affect the safety and accuracy of lithium battery testing.

[0006] Therefore, how to provide a DC signal-based lithium battery test fixture wiring detection device to automatically detect the wiring of lithium battery test fixtures, thereby improving the safety and accuracy of lithium battery testing, has become an urgent technical problem to be solved. 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 DC signal, so as to realize automatic detection of the connection of lithium battery test fixture wire, thereby improving the safety and accuracy of lithium battery testing.

[0008] The present invention is implemented as follows: a lithium battery test fixture wire connection detection device based on DC signal, comprising a main control module, a primary channel switching module, a primary and secondary channel switching module, a primary connection status judgment module, a primary and secondary connection status judgment module, and an output switch switching module.

[0009] The main control module is connected to 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, respectively. One end of the first-level channel switching module is connected to the first-level wiring status judgment module, and the other end is connected to 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 primary channel switching module includes a multiplexed analog switch U1, a diode D1, and a diode D4;

[0011] Pin 8 of the multiplexed analog switch U1 is connected to the output terminal of diode D1, pin 9 is connected to the input terminal of diode D4, 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; the output terminal of diode D4 is connected to the first-level wiring status judgment module.

[0012] Furthermore, the primary wiring status judgment module includes a voltage comparator U2A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R7, and a capacitor C2.

[0013] One end of resistor R2 is connected to resistor R1 and pin 3 of voltage comparator U2A, and the other end is connected to the first-level channel switching module; resistor R4 is connected in parallel with capacitor C2, one end of which is connected to resistor R3 and pin 2 of voltage comparator U2A, and the other end is grounded; pin 1 of voltage comparator U2A is connected to resistor R7 and the main control module.

[0014] Furthermore, the secondary channel switching module includes a multiplexed analog switch U3, a diode D5, and a diode D6;

[0015] Pin 8 of the multiplexed analog switch U3 is connected to the input terminal of diode D5, pin 9 is connected to the output terminal of diode D6, 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; the output terminal of diode D5 and the input terminal of diode D6 are both connected to the secondary wiring status judgment module.

[0016] Furthermore, the secondary wiring status judgment module includes a voltage comparator U2B, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a capacitor C3.

[0017] One end of resistor R10 is connected to one end of resistor R11 and pin 5 of voltage comparator U2B, and the other end is connected to the secondary channel switching module; the other end of resistor R11 is connected to the secondary channel switching module; resistor R14 is connected in parallel with capacitor C3, one end of which is connected to resistor R13 and pin 6 of voltage comparator U2B, and the other end is grounded; pin 7 of voltage comparator U2B is connected to resistor R12 and the main control module.

[0018] Furthermore, the output switch switching module includes a relay K1, a relay K2, a MOSFET Q1, a MOSFET Q2, a diode D2, a diode D3, a resistor R5, a resistor R6, a resistor R8, a resistor R9, and a capacitor C1.

[0019] The relay K1 has pins PS+_TEST and PS-_TEST connected to the first-level channel switching module and the second-level channel switching module, respectively. Its positive terminal is connected to the output terminal of capacitor C1 and diode D2, and its negative terminal is connected to the input terminal of diode D2 and the drain terminal of MOSFET Q1. One end of resistor R5 is connected to the main control module, and the other end is connected to resistor R6 and the gate terminal of MOSFET Q1. The source terminal of MOSFET Q1 is connected to resistor R6 and grounded.

[0020] The relay K2's pins PS+_TEST and PS-_TEST are connected to the first-level channel switching module and the second-level channel switching module, respectively. Its positive terminal is connected to the output terminal of diode D3 and grounded, while its negative terminal is connected to the input terminal of diode D3 and the drain terminal of MOSFET Q2. One end of resistor R8 is connected to the main control module, and the other end is connected to resistor R9 and the gate terminal of MOSFET Q2. The source terminal of MOSFET Q2 is connected to resistor R9 and grounded.

[0021] Furthermore, both MOS transistors Q1 and Q2 are NMOS transistors.

[0022] Furthermore, the main control module includes a microcontroller TU1, a terminal block TJ1, a crystal oscillator Y1, a resistor TR1, a resistor TR2, a resistor TR3, a resistor TR4, a resistor TR5, a resistor TR6, a resistor TR7, a resistor TR8, a capacitor TC1, a capacitor TC2, a capacitor TC3, a capacitor TC4, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, and a capacitor C16.

[0023] Pins 19, 20, and 21 of the microcontroller TU1 are connected to the first-level channel switching module, pin 18 is connected to the first-level wiring status judgment module, pins 23, 24, and 25 are connected to the second-level channel switching module, pin 22 is connected to the second-level wiring status judgment module, pins 31 and 32 are connected to the output switch switching module, and pins 100, 99, 98, 97, and 70 are connected to pins 1, 2, 3, 4, and 5 of the terminal block TJ1, respectively.

[0024] The capacitors C4, C5, C6, C7, C8, C9, C10, C11, C12, and C13 are connected in parallel, with one end connected to pin 122 of the microcontroller TU1 and the other end connected to resistors TR6 and TR8; the capacitors C14, C15, and C16 are connected in parallel, with one end connected to pin 115 of the microcontroller TU1 and the other end grounded.

[0025] The capacitor TC1 is connected to pin 5 of terminal TJ1; the resistor TR1 is connected to pin 5 of terminal TJ1; one end of the capacitor TC2 is connected to the capacitor TC3, and the other end is connected to pin 88 of microcontroller TU1; one end of the resistor TR2 is connected to the capacitor TC3, and the other end is connected to pin 89 of microcontroller TU1; one end of the crystal oscillator Y1 is connected to pin 88 of microcontroller TU1, and the other end is connected to pin 89 of microcontroller TU1; one end of the resistor TR3 is connected to the resistor TR4, and the other end is connected to pin 64 of microcontroller TU1; both the resistor TR4 and the capacitor TC4 are connected to pin 68 of microcontroller TU1; the resistor TR5 is connected to pin 59 of microcontroller TU1; and the resistor TR7 is connected to pin 65 of microcontroller TU1.

[0026] The advantages of this invention are:

[0027] By configuring a main control module, a primary channel switching module, a secondary channel switching module, a primary wiring status judgment module, a secondary wiring status judgment module, and an output switch switching module, the main control module controls the channel switching of the primary and secondary channel switching modules via DC signals, and controls the electrical connection between the output switch switching module and external signals. The main control module judges the wiring status of the selected channel of the primary channel switching module through the primary wiring status judgment module, and judges the wiring status of the selected channel of the secondary channel switching module through the secondary wiring status judgment module. This achieves automatic detection of the wiring of the lithium battery test fixture wires, and can promptly identify and provide feedback on wiring errors, preventing lithium battery testing from being performed under incorrect wiring conditions, thereby greatly improving the safety and accuracy of lithium battery testing. Attached Figure Description

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

[0029] Figure 1 This is a circuit block diagram of a lithium battery test fixture wire connection detection device based on DC signal according to the present invention.

[0030] Figure 2 This is a circuit diagram of the primary channel switching module and the primary wiring status judgment module of the present invention.

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

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

[0033] Figure 5 This is the circuit diagram of the main control module of this invention. Detailed Implementation

[0034] Please refer to Figures 1 to 5 As shown, a preferred embodiment of the lithium battery test fixture wire connection detection device based on DC signal of the present invention includes a main control module, a primary channel switching module, a primary and secondary channel switching module, a primary wiring status judgment module, a primary and secondary wiring status judgment module, and an output switch switching module.

[0035] The main control module is used to control 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 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 primary channel switching module is used to switch the connection channel selection of the primary wiring status judgment module according to the control signal of the main control module.

[0037] The primary wiring status judgment module judges the wiring status of the selected channel after the primary channel switching module switches between different channels, and sends the judgment result back to the main control module in the form of high and low level signals.

[0038] The secondary channel switching module is used to switch the connection channel selection of the secondary wiring status judgment module according to the control signal of the main control module.

[0039] The secondary wiring status judgment module judges the wiring status of the selected channel after the secondary channel switching module switches between different channels, and sends the judgment result back to the main control module in the form of high and low level signals.

[0040] The output switch switching module controls the connection and disconnection of the electrical wiring between the test signal and the external signal through the switching signal of the main control module.

[0041] This invention increases the reliability of wiring identification results by using a two-stage judgment of the test fixture wires through the switching path selection of a multiplexed analog switch; it uses relays to connect and disconnect test signals from external signals, avoiding interference with the normal charge and discharge test circuit of the lithium battery; it avoids mutual interference between the two stages of analog switches by controlling the enable pins of the two stages; and it uses the unidirectional conduction characteristic of diodes to identify the wiring status while avoiding the impact of wiring errors on the internal test circuit.

[0042] The main control module is connected to 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, respectively. One end of the first-level channel switching module is connected to the first-level wiring status judgment module, and the other end is connected to 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.

[0043] The primary channel switching module includes a multiplexed analog switch U1, a diode D1, and a diode D4; the multiplexed analog switch U1 is preferably a MUX509.

[0044] Pin 8 of the multiplexed analog switch U1 is connected to the output terminal of diode D1, pin 9 is connected to the input terminal of diode D4, 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; the output terminal of diode D4 is connected to the first-level wiring status judgment module.

[0045] The primary wiring status judgment module includes a voltage comparator U2A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R7, and a capacitor C2; the preferred model of the voltage comparator U2A is LM2903.

[0046] One end of resistor R2 is connected to resistor R1 and pin 3 of voltage comparator U2A, and the other end is connected to the first-level channel switching module; resistor R4 is connected in parallel with capacitor C2, one end of which is connected to resistor R3 and pin 2 of voltage comparator U2A, and the other end is grounded; pin 1 of voltage comparator U2A is connected to resistor R7 and the main control module.

[0047] The secondary channel switching module includes a multiplexed analog switch U3, a diode D5, and a diode D6; the multiplexed analog switch U3 is preferably a MUX509.

[0048] Pin 8 of the multiplexed analog switch U3 is connected to the input terminal of diode D5, pin 9 is connected to the output terminal of diode D6, 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; the output terminal of diode D5 and the input terminal of diode D6 are both connected to the secondary wiring status judgment module.

[0049] The secondary wiring status judgment module includes a voltage comparator U2B, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a capacitor C3; the voltage comparator U2B is preferably an LM2903.

[0050] One end of resistor R10 is connected to one end of resistor R11 and pin 5 of voltage comparator U2B, and the other end is connected to the secondary channel switching module; the other end of resistor R11 is connected to the secondary channel switching module; resistor R14 is connected in parallel with capacitor C3, one end of which is connected to resistor R13 and pin 6 of voltage comparator U2B, and the other end is grounded; pin 7 of voltage comparator U2B is connected to resistor R12 and the main control module.

[0051] The output switch switching module includes a relay K1, a relay K2, a MOSFET Q1, a MOSFET Q2, a diode D2, a diode D3, a resistor R5, a resistor R6, a resistor R8, a resistor R9, and a capacitor C1; the preferred models of the relays K1 and K2 are HFD4 / 12-SR.

[0052] The relay K1 has pins PS+_TEST and PS-_TEST connected to the first-level channel switching module and the second-level channel switching module, respectively. Its positive terminal is connected to the output terminal of capacitor C1 and diode D2, and its negative terminal is connected to the input terminal of diode D2 and the drain terminal of MOSFET Q1. One end of resistor R5 is connected to the main control module, and the other end is connected to resistor R6 and the gate terminal of MOSFET Q1. The source terminal of MOSFET Q1 is connected to resistor R6 and grounded.

[0053] The relay K2's pins PS+_TEST and PS-_TEST are connected to the first-level channel switching module and the second-level channel switching module, respectively. Its positive terminal is connected to the output terminal of diode D3 and grounded, while its negative terminal is connected to the input terminal of diode D3 and the drain terminal of MOSFET Q2. One end of resistor R8 is connected to the main control module, and the other end is connected to resistor R9 and the gate terminal of MOSFET Q2. The source terminal of MOSFET Q2 is connected to resistor R9 and grounded.

[0054] Both MOS transistors Q1 and Q2 are NMOS transistors.

[0055] The main control module includes a microcontroller TU1, a terminal block TJ1, a crystal oscillator Y1, resistors TR1, TR2, TR3, TR4, TR5, TR6, TR7, and TR8, and capacitors TC1, TC2, TC3, TC4, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, and C16; the microcontroller TU1 is preferably an ARM microprocessor TM4C1294NCPDT.

[0056] Pins 19, 20, and 21 of the microcontroller TU1 are connected to the first-level channel switching module, pin 18 is connected to the first-level wiring status judgment module, pins 23, 24, and 25 are connected to the second-level channel switching module, pin 22 is connected to the second-level wiring status judgment module, pins 31 and 32 are connected to the output switch switching module, and pins 100, 99, 98, 97, and 70 are connected to pins 1, 2, 3, 4, and 5 of the terminal block TJ1, respectively.

[0057] The capacitors C4, C5, C6, C7, C8, C9, C10, C11, C12, and C13 are connected in parallel, with one end connected to pin 122 of the microcontroller TU1 and the other end connected to resistors TR6 and TR8; the capacitors C14, C15, and C16 are connected in parallel, with one end connected to pin 115 of the microcontroller TU1 and the other end grounded.

[0058] The capacitor TC1 is connected to pin 5 of terminal TJ1; the resistor TR1 is connected to pin 5 of terminal TJ1; one end of the capacitor TC2 is connected to the capacitor TC3, and the other end is connected to pin 88 of microcontroller TU1; one end of the resistor TR2 is connected to the capacitor TC3, and the other end is connected to pin 89 of microcontroller TU1; one end of the crystal oscillator Y1 is connected to pin 88 of microcontroller TU1, and the other end is connected to pin 89 of microcontroller TU1; one end of the resistor TR3 is connected to the resistor TR4, and the other end is connected to pin 64 of microcontroller TU1; both the resistor TR4 and the capacitor TC4 are connected to pin 68 of microcontroller TU1; the resistor TR5 is connected to pin 59 of microcontroller TU1; and the resistor TR7 is connected to pin 65 of microcontroller TU1.

[0059] Working principle of this invention:

[0060] The main control module controls the enable pin EN (corresponding to network number EN-2) of the multiplexed analog switch U3 in the secondary channel switching module to be low, so that the electrical connection link between the two channels of the multiplexed analog switch U3 is disconnected and not connected to either path, so as to avoid affecting the first-level test to be carried out.

[0061] The main control module controls relays K1 and K2. During testing, it controls network numbers REL_K1 and REL_K2, thereby controlling 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 main control module controls the multiplexed analog switch U1 to have its enable signal EN (corresponding to network number EN-1) high, 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 is designed with 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 test voltage signal (corresponding to network number V+_+15V) in the first-level wiring status judgment module is connected to pin 8 of the multiplexed analog switch U1 (i.e., the selection pin for switching input and output of one channel of the analog switch) through diode D1. The DC signal used for testing is output to the corresponding fixture line through channel selection. The test judgment signal in the first-level wiring status judgment module is transmitted through pin 9 of the multiplexed analog switch U1 (i.e., the selection pin for switching input and output of one channel of the analog switch) to the corresponding signal in the circuit through diode D4, and then through resistors R2 and R1. Finally, the voltage formed on resistor R1 (network number VS1 voltage to ground) and the voltage on resistor R4 (network number VS2 voltage to ground) are compared by voltage comparator U2A. The judgment result is transmitted to the main control module for identification in the form of high and low levels through network number OUT-1 through pin 1 of voltage comparator U2A under the action of pull-up resistor R7.

[0064] By designing the corresponding resistance values ​​for resistors R1, R2, R3, and R4, when the wiring is correct (i.e., there is no mixing with other channels), the entire test link can form a closed loop with the lithium battery under test. When mixing with other channels occurs, the mixed wires may not 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 voltage of network number OUT-1 relative to ground is low for the main control module, it indicates that the channel group identification wiring selected by the currently selected multiplexer analog switch U1 is abnormal; when the voltage of network number OUT-1 relative to ground is high, it indicates that the channel group identification wiring selected by the currently selected multiplexer analog switch U1 is normal.

[0065] 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 terminals of the lithium battery according to the correct positive and negative 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, so as to avoid affecting the secondary channel switching module and the secondary wiring status judgment module.

[0066] After the main control module controls the multiplexed analog switch U3 to have its enable signal EN (corresponding to network number EN-2) high, it performs different test connection combinations on the channel switching signals corresponding to network numbers A0-2 and A1-2, respectively. The current design can realize four different combinations, forming a circuit 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.

[0067] The secondary wiring status judgment module uses the different path selections of the current multiplexed analog switch U3 to determine whether the current wiring is correctly connected to the positive and negative terminals of the battery. By designing the corresponding resistance values ​​for resistors R10, R11, R13, and R14, when the wiring is correct, the positive and negative terminals of the lithium battery form a circuit with resistors R10 and R11 through the forward conduction of diodes D5 and D6, resulting in a voltage value relative to ground on network VS3. When the wiring is incorrect, the positive and negative terminals of the lithium battery cannot form a normal current flow circuit with resistors R10 and R11 due to the reverse cutoff characteristics of diodes D5 and D6. Therefore, network VS3 will not generate a voltage value relative to ground due to the external lithium battery connection; the voltage amplitude of VS3 in this case is essentially ground level. The voltage value of network VS4 is then determined by resistors R13 and R14. The resistance value of R14 is designed accordingly. Therefore, the corresponding result relationship can be obtained from network number OUT-2: when the voltage level of network number OUT-2 relative to ground is low for the main control module, it indicates that the channel group identification wiring selected by the currently selected multiplexed analog switch U3 is abnormal; when the voltage level of network number OUT-2 relative to ground is high for the main control module, it indicates that the channel group identification wiring selected by the currently selected multiplexed analog switch U3 is normal. After the test is completed, the main control module controls relays K1 and K2. After the test is completed, by controlling network numbers REL_K1 and REL_K2, the relays are controlled to disconnect network numbers PS+_TEST from PS+, PS-_TEST from PS-, P+_TEST from P+, and P-_TEST from P-, respectively, thus avoiding any impact on the subsequent lithium battery charge and discharge tests.

[0068] In summary, the advantages of this invention are as follows:

[0069] By configuring a main control module, a primary channel switching module, a secondary channel switching module, a primary wiring status judgment module, a secondary wiring status judgment module, and an output switch switching module, the main control module controls the channel switching of the primary and secondary channel switching modules via DC signals, and controls the electrical connection between the output switch switching module and external signals. The main control module judges the wiring status of the selected channel of the primary channel switching module through the primary wiring status judgment module, and judges the wiring status of the selected channel of the secondary channel switching module through the secondary wiring status judgment module. This achieves automatic detection of the wiring of the lithium battery test fixture wires, and can promptly identify and provide feedback on wiring errors, preventing lithium battery testing from being performed under incorrect wiring conditions, thereby greatly improving the safety and accuracy of lithium battery testing.

[0070] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered 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 DC signal, characterized in that: It includes a main control module, a primary channel switching module, a primary and secondary channel switching module, a primary wiring status judgment module, a primary and secondary wiring status judgment module, and an output switch switching module; The main control module is connected to 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, respectively; one end of the first-level channel switching module is connected to the first-level wiring status judgment module, and the other end is connected to 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. The primary wiring status determination module includes a voltage comparator U2A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R7, and a capacitor C2. One end of resistor R2 is connected to resistor R1 and pin 3 of voltage comparator U2A, and the other end is connected to the first-level channel switching module; resistor R4 is connected in parallel with capacitor C2, one end of which is connected to resistor R3 and pin 2 of voltage comparator U2A, and the other end is grounded; pin 1 of voltage comparator U2A is connected to resistor R7 and the main control module. The secondary wiring status judgment module includes a voltage comparator U2B, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a capacitor C3. One end of resistor R10 is connected to one end of resistor R11 and pin 5 of voltage comparator U2B, and the other end is connected to the secondary channel switching module; the other end of resistor R11 is connected to the secondary channel switching module; resistor R14 is connected in parallel with capacitor C3, one end of which is connected to resistor R13 and pin 6 of voltage comparator U2B, and the other end is grounded; pin 7 of voltage comparator U2B is connected to resistor R12 and the main control module.

2. The lithium battery test fixture wire connection detection device based on DC signal as described in claim 1, characterized in that: The primary channel switching module includes a multiplexed analog switch U1, a diode D1, and a diode D4. Pin 8 of the multiplexed analog switch U1 is connected to the output terminal of diode D1, pin 9 is connected to the input terminal of diode D4, 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; the output terminal of diode D4 is connected to the first-level wiring status judgment module.

3. The lithium battery test fixture wire connection detection device based on DC signal as described in claim 1, characterized in that: The secondary channel switching module includes a multiplexed analog switch U3, a diode D5, and a diode D6. Pin 8 of the multiplexed analog switch U3 is connected to the input terminal of diode D5, pin 9 is connected to the output terminal of diode D6, 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; the output terminal of diode D5 and the input terminal of diode D6 are both connected to the secondary wiring status judgment module.

4. The lithium battery test fixture wire connection detection device based on DC signal as described in claim 1, characterized in that: The output switch switching module includes a relay K1, a relay K2, a MOSFET Q1, a MOSFET Q2, a diode D2, a diode D3, a resistor R5, a resistor R6, a resistor R8, a resistor R9, and a capacitor C1. The relay K1 has pins PS+_TEST and PS-_TEST connected to the first-level channel switching module and the second-level channel switching module, respectively. Its positive terminal is connected to the output terminal of capacitor C1 and diode D2, and its negative terminal is connected to the input terminal of diode D2 and the drain terminal of MOSFET Q1. One end of resistor R5 is connected to the main control module, and the other end is connected to resistor R6 and the gate terminal of MOSFET Q1. The source terminal of MOSFET Q1 is connected to resistor R6 and grounded. The relay K2's pins PS+_TEST and PS-_TEST are connected to the first-level channel switching module and the second-level channel switching module, respectively. Its positive terminal is connected to the output terminal of diode D3 and grounded, while its negative terminal is connected to the input terminal of diode D3 and the drain terminal of MOSFET Q2. One end of resistor R8 is connected to the main control module, and the other end is connected to resistor R9 and the gate terminal of MOSFET Q2. The source terminal of MOSFET Q2 is connected to resistor R9 and grounded.

5. The lithium battery test fixture wire connection detection device based on DC signal as described in claim 4, characterized in that: Both MOS transistors Q1 and Q2 are NMOS transistors.

6. The lithium battery test fixture wire connection detection device based on DC signal as described in claim 1, characterized in that: The main control module includes a microcontroller TU1, a terminal block TJ1, a crystal oscillator Y1, a resistor TR1, a resistor TR2, a resistor TR3, a resistor TR4, a resistor TR5, a resistor TR6, a resistor TR7, a resistor TR8, a capacitor TC1, a capacitor TC2, a capacitor TC3, a capacitor TC4, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, and a capacitor C16. Pins 19, 20, and 21 of the microcontroller TU1 are connected to the first-level channel switching module, pin 18 is connected to the first-level wiring status judgment module, pins 23, 24, and 25 are connected to the second-level channel switching module, pin 22 is connected to the second-level wiring status judgment module, pins 31 and 32 are connected to the output switch switching module, and pins 100, 99, 98, 97, and 70 are connected to pins 1, 2, 3, 4, and 5 of the terminal block TJ1, respectively. The capacitors C4, C5, C6, C7, C8, C9, C10, C11, C12, and C13 are connected in parallel, with one end connected to pin 122 of the microcontroller TU1 and the other end connected to resistors TR6 and TR8; the capacitors C14, C15, and C16 are connected in parallel, with one end connected to pin 115 of the microcontroller TU1 and the other end grounded. The capacitor TC1 is connected to pin 5 of terminal TJ1; the resistor TR1 is connected to pin 5 of terminal TJ1; one end of the capacitor TC2 is connected to the capacitor TC3, and the other end is connected to pin 88 of microcontroller TU1; one end of the resistor TR2 is connected to the capacitor TC3, and the other end is connected to pin 89 of microcontroller TU1; one end of the crystal oscillator Y1 is connected to pin 88 of microcontroller TU1, and the other end is connected to pin 89 of microcontroller TU1; one end of the resistor TR3 is connected to the resistor TR4, and the other end is connected to pin 64 of microcontroller TU1; both the resistor TR4 and the capacitor TC4 are connected to pin 68 of microcontroller TU1; the resistor TR5 is connected to pin 59 of microcontroller TU1; and the resistor TR7 is connected to pin 65 of microcontroller TU1.

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