A system and method for measuring electrical performance parameters of a thermal battery in an unactivated state

Abstract

The present invention discloses a system and method for measuring the electrical performance parameters of a thermal battery in an unactivated state, which solves the problem that the thermal battery has extremely high internal resistance in an unactivated state, and multiple key electrical parameters usually used to judge the battery performance and health status far exceed the measurement range of commonly used battery detection instruments and detection methods, and cannot be accurately measured. The system includes an impedance analyzer, an electrometer, a constant temperature box, an electrical measurement fixture, and a computer data acquisition and analysis device. In the measurement method, impedance matching, environmental noise suppression, temperature fluctuation reduction, and full use of the active characteristics of the thermal battery are used to improve the measurement accuracy and expand the measurement range of the thermal battery electrical parameters. The present invention realizes the accurate measurement of electrical performance parameters such as open circuit voltage, output charge, maximum output current, current-voltage curve, DC resistance, impedance spectrum and capacitance of the thermal battery in an unactivated state, and provides a basis for realizing online detection and reliability evaluation of thermal batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal battery detection, and in particular to a system and method for measuring electrical performance parameters of a thermal battery in an unactivated state. Background Art

[0002] Thermal battery is a primary reserve battery that uses a binary or multi-component molten salt solid solution as the electrolyte. Under normal conditions, the electrolyte is non-conductive and the battery is in a non-working state. When it needs to work, the thermal battery's own heating system will quickly melt the molten salt into an ionic conductor after the outside world gives an activation signal, thereby outputting electrical energy to the outside. Thermal batteries have the characteristics of long storage life, high specific power, short activation time, high reliability, maintenance-free, and ability to withstand extreme environments. They are widely used in various military or civilian equipment systems such as missiles, bombs, torpedoes, space exploration, and emergency escape devices.

[0003] During the production, inspection and storage of thermal batteries, it is necessary to carry out certain tests on thermal batteries in an unactivated state to determine whether their performance meets the requirements for use. At present, the electrical detection methods for thermal batteries in an unactivated state mainly include using a multimeter to measure the resistance of the ignition head, and using an insulating ammeter to measure the insulation resistance between the activation circuit, the working circuit and the outer casing, etc., which are used to characterize the connection of the internal electrical leads of the battery. Since the internal resistance of thermal batteries in an unactivated state is extremely high, the key electrical parameters usually used to judge battery performance and health status, such as open circuit voltage, maximum output current, current-voltage curve, DC resistance, impedance spectrum, etc., far exceed the measurement range of commonly used battery electrical detection instruments and cannot be accurately measured. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the internal resistance of a thermal battery is extremely high in an unactivated state. Key electrical parameters commonly used to judge battery performance and health status, such as open circuit voltage, maximum output current, current-voltage curve, DC resistance, impedance spectrum, etc., far exceed the measurement range of commonly used battery testing instruments and cannot be accurately measured.

[0005] The present invention provides a system and method for measuring the electrical performance parameters of a thermal battery in an unactivated state to solve the above-mentioned problem. By impedance matching, noise suppression and stabilization of ambient temperature, accurate measurement of the open circuit voltage, output charge, maximum output current, current-voltage curve, DC resistance, impedance spectrum and capacitance of a thermal battery with ultra-high internal resistance in an unactivated state is achieved, providing a basis for online detection and reliability evaluation of thermal batteries based on the above electrical parameters.

[0006] The present invention is achieved through the following technical solutions:

[0007] A system for measuring electrical performance parameters of a thermal battery in an unactivated state, comprising an impedance analyzer, an electrometer, a constant temperature box, and an electrical measurement fixture, wherein the electrical measurement fixture is arranged in the constant temperature box, the electrical measurement fixture is electrically connected to the impedance analyzer and the electrometer, and the housing of the electrical measurement fixture is grounded; and a computer data acquisition and analysis device is also included, wherein the computer data acquisition and analysis device is connected to the impedance analyzer and the electrometer through a communication unit;

[0008] The electrical measurement fixture is used to place the thermal battery, and the electrical measurement fixture is used to shield the environmental noise of electromagnetic interference when measuring the electrical performance parameters of the thermal battery in an inactive state;

[0009] The thermostat is used to provide a constant temperature test environment within the range of 0°C to 150°C for the thermal battery, supporting subsequent measurement of electrical performance parameters of the thermal battery in an unactivated state;

[0010] The impedance analyzer is used to measure the impedance spectrum of the thermal battery in an unactivated state and transmit it to a computer data acquisition and analysis device; the electrometer is used to measure the open circuit voltage, output charge, maximum output current, current-voltage curve, and DC impedance of the thermal battery in an unactivated state and transmit them to a computer data acquisition and analysis device;

[0011] The computer data acquisition and analysis device is used to control and collect temperature data of the thermostat, control the impedance analyzer and the electrometer to collect and analyze the electrical performance parameters of the thermal battery in the unactivated state, and can display graphics of various data in real time and realize real-time data storage.

[0012] The working principle is as follows: Since the internal resistance of a thermal battery is extremely high in the unactivated state, key electrical parameters usually used to judge battery performance and health status, such as open circuit voltage, maximum output current, current-voltage curve, DC resistance, impedance spectrum, etc., are far beyond the measurement range of commonly used battery testing instruments and cannot be accurately measured.

[0013] The present invention provides a system for measuring the electrical performance parameters of a thermal battery in an unactivated state by impedance matching, suppressing noise and stabilizing the ambient temperature. The system mainly comprises an impedance analyzer, an electrostatic meter, a constant temperature box, and an electrical measurement fixture. The electrical measurement fixture is arranged in the constant temperature box, the electrical measurement fixture is electrically connected to the impedance analyzer and the electrostatic meter, and the outer shell of the electrical measurement fixture is grounded. The system also comprises a computer data acquisition and analysis device, which is connected to the impedance analyzer and the electrostatic meter through a communication unit. Based on the system, the present invention provides a method for accurately measuring the open circuit voltage, output charge, and maximum output current of a thermal battery in an unactivated state. The method of measuring current, current-voltage curve, DC resistance, impedance spectrum and capacitance can accurately measure the basic electrical performance parameters of the thermal battery in the unactivated state, such as open circuit voltage, output charge, maximum output current, DC resistance, current-voltage curve, impedance spectrum, capacitance, etc.; during the test, due to the use of a constant temperature box, the measurement temperature range of the above basic electrical performance parameters is 0°C to 150°C; the test environment temperature fluctuation is less than 0.5°C, which effectively reduces the fluctuation of the above measurement results caused by external temperature fluctuations; at the same time, because the adopted measurement fixture can effectively shield environmental noise such as electromagnetic interference, the above test errors are effectively reduced. The present invention provides a basis for realizing online detection and reliability evaluation of thermal batteries based on the above electrical parameters in the unactivated state of thermal batteries.

[0014] Furthermore, the electrical measurement fixture comprises a housing, an upper cover, and an insulating seat, wherein the insulating seat is arranged at the bottom of the housing, the upper cover is arranged at the top of the housing, and the thermal battery is arranged on the insulating seat;

[0015] It also includes a triaxial connector and four BNC connectors, which are fixed on the left side of the outer shell of the electrical measurement fixture from top to bottom, and the horizontal position of the BNC connector is higher than the top of the insulating seat; the four BNC connectors are sequentially recorded as a first BNC connector, a second BNC connector, a third BNC connector, and a fourth BNC connector from top to bottom; the outer shielding layer of the triaxial connector is electrically connected to the outer shell of the electrical measurement fixture, and the shielding layer of the BNC connector is electrically connected to the outer shell of the electrical measurement fixture;

[0016] It also includes 7 internal electrical connection lines, which are used to electrically connect to the thermal battery through the corresponding internal electrical connection lines during measurement; the 7 internal electrical connection lines are recorded as the first internal electrical connection line, the second internal electrical connection line, the third internal electrical connection line, the fourth internal electrical connection line, the fifth internal electrical connection line, the sixth internal electrical connection line, and the seventh internal electrical connection line from top to bottom, the first internal electrical connection line is electrically connected to the inner core of the three coaxial connector, the second internal electrical connection line is electrically connected to the inner shielding layer of the three coaxial connector, the third internal electrical connection line is electrically connected to the inner core of the first BNC connector, the fourth internal electrical connection line is electrically connected to the inner core of the second BNC connector, the fifth internal electrical connection line is electrically connected to the inner core of the third BNC connector, the sixth internal electrical connection line is electrically connected to the inner core of the fourth BNC connector, and the seventh internal electrical connection line is electrically connected to the outer shell of the electrical measurement fixture.

[0017] Furthermore, the three coaxial connector and the three coaxial connector at the electrometer signal input end are connected through a three coaxial test cable, the first BNC connector and the electrometer common end are connected through a coaxial cable, the second BNC connector and the electrometer voltage output end are connected through a coaxial cable, the third BNC connector and the impedance analyzer voltage output end are connected through a coaxial cable, and the fourth BNC connector and the impedance analyzer current input end are connected through a coaxial cable.

[0018] Furthermore, the shell and the upper cover are made of stainless steel.

[0019] Furthermore, the insulating seat is made of high-insulation polytetrafluoroethylene, Teflon, glass or ceramic material.

[0020] Furthermore, the insulating seat is in a U-shape with an opening facing upward, and the thermal battery is arranged in a U-shaped groove of the insulating seat.

[0021] Furthermore, the electrometer is an instrument having voltage source, voltage, current and charge measurement functions simultaneously or separately, and the voltage measurement input impedance is greater than 10 12 Ω, the voltage test range is greater than 10V, and the current measurement limit is less than 10 -12 A, charge measurement limit is less than 10 -12 C, is connected to the computer data acquisition and analysis device through the communication unit GPIB or RS232 interface.

[0022] Furthermore, the impedance analyzer is an AC voltage signal with an output amplitude greater than 0.1V, a frequency range wider than 1mHz to 500kHz, and a test range greater than 10 12 The impedance measuring instrument of Ω is connected to the computer data acquisition and analysis device through the communication unit GPIB, RS232 or USB.

[0023] Furthermore, the constant temperature box includes a temperature control module, and the temperature control module is connected to the computer data acquisition and analysis device through a communication unit; a test hole is provided on the outer shell of the constant temperature box, and all test cables connecting the electrical measurement fixture and the electrometer or impedance analyzer are led out through the test hole; the inner wall of the test hole is made of insulating ceramic, Teflon, glass or polytetrafluoroethylene.

[0024] Furthermore, the computer data acquisition and analysis device is independently developed using the Labview tool to control and collect temperature data of the constant temperature box, control the measurement mode of the electrometer, collect voltage data, current data, and charge data of the electrometer, and collect impedance data of the impedance analyzer. At the same time, it can display graphs of various data in real time and realize real-time data storage. Test options include changes in open circuit voltage of the thermal battery with time or temperature, changes in output current with time or temperature, changes in output charge with time, changes in DC resistance with time or temperature, changes in current with voltage, and changes in impedance and phase with frequency.

[0025] Furthermore, the system is applied to the preliminary detection of the number and assembly direction of thermal battery cells; specifically, according to the thermal battery open circuit voltage V measured by the system 100 , and measuring the open circuit voltage V0 of the thermal battery single cell, wherein the average value of the open circuit voltages corresponding to a plurality of thermal battery single cells is taken as the single cell open circuit voltage reference value V0;

[0026] According to the formula V 100 =V0×(n1-n2), where n1 is the number of single battery cells with the correct assembly direction, and n2 is the number of single battery cells with the wrong assembly direction. The calculation result is (n1-n2)=ROUND(V 100 / V0), where ROUND is the rounding function;

[0027] Compare (n1-n2) and n 100 The numerical relationship between 100 is the number of single cells in the thermal battery required by the process. If n1-n2≠n 100 , then there is an error in the number of single battery cells or the assembly direction.

[0028] On the other hand, the present invention also provides a method for measuring electrical performance parameters of a thermal battery in an unactivated state, the method supports the system for measuring electrical performance parameters of a thermal battery in an unactivated state, and the method comprises the following steps:

[0029] S10, turn on the computer data acquisition and analysis device, electrometer, impedance analyzer, and thermostat, set the thermostat temperature to the target temperature T0, and preheat each measuring instrument for 10 to 30 minutes;

[0030] S20, connecting the triaxial connector on the electrical measurement fixture and the triaxial connector on the signal input end of the electrometer through a triaxial test cable, connecting the first BNC connector on the electrical measurement fixture and the common end of the electrometer through a coaxial cable, connecting the second BNC connector on the electrical measurement fixture and the voltage output end of the electrometer through a coaxial cable, connecting the third BNC connector on the electrical measurement fixture and the voltage output end of the impedance analyzer through a coaxial cable, and connecting the fourth BNC connector on the electrical measurement fixture and the current input end of the impedance analyzer through a coaxial cable;

[0031] S30: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the thermal battery positive electrode, the thermal battery negative electrode and the thermal battery shell to the first internal electrical connection line, the third internal electrical connection line and the second internal electrical connection line in the electrical measurement fixture respectively, cover the upper cover of the electrical measurement fixture, close the thermostat door, select the voltage-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the open circuit voltage V of the thermal battery in the unactivated state oc ;

[0032] S40: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the positive electrode of the thermal battery to the first internal electrical connection line, connect the negative electrode of the thermal battery to the second internal electrical connection line and the seventh internal electrical connection line, cover the upper cover of the electrical measurement fixture, close the door of the thermostat, select the charge-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the output charge Q of the thermal battery in the inactive state;

[0033] S50: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the positive electrode of the thermal battery to the first internal electrical connection line, connect the negative electrode of the thermal battery to the second internal electrical connection line and the seventh internal electrical connection line, cover the upper cover of the measurement fixture, close the door of the thermostat, select the current-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the maximum output current I of the thermal battery in the inactive state SC ;

[0034] S60: setting the temperature of the thermostat to the target temperature T0, placing the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, waiting for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connecting the positive electrode of the thermal battery to the first internal electrical connection line, connecting the negative electrode of the thermal battery to the fourth internal electrical connection line, connecting the outer shell of the thermal battery to the second internal electrical connection line, covering the upper cover of the measurement fixture, closing the hatch of the thermostat, selecting the current-voltage measurement option on the computer data acquisition and analysis device, setting the current test range and the voltage scanning range, and measuring the current-voltage curve of the thermal battery in the inactive state;

[0035] S70: According to the current-voltage curve measured in step S60, the resistance R of the thermal battery in an unactivated state at temperature T0 is calculated according to the formula R=△V / △I;

[0036] S80: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the positive electrode of the thermal battery to the fifth internal electrical connection line, connect the negative electrode of the thermal battery to the sixth internal electrical connection line, cover the upper cover of the measurement fixture, close the door of the thermostat, select the impedance spectrum measurement option on the computer data acquisition and analysis device, set the frequency (ω) scanning range, excitation voltage, current test range, bias voltage and data storage path and other parameters, and measure the impedance spectrum Z(ω) of the thermal battery in the unactivated state;

[0037] S90: According to the impedance spectrum Z(ω) of the thermal battery in the unactivated state measured in step S80, a linear fit is performed on the logarithm of the impedance log(Z) and the logarithm of the frequency Log(ω) in the frequency range of 1 kHz to 500 kHz. According to log(Z)=-log(ω)-log(C), the intercept obtained is -log(C), and the capacitance C of the thermal battery in the unactivated state is further calculated.

[0038] Furthermore, the maximum output current I of the thermal battery in the inactive state in step S50 is SC It can also be calculated by the output charge Q, measuring the output charge Q(t) within time t, and the maximum output current is given by I SC =Q(t) / t is calculated.

[0039] Furthermore, the thermal battery inactive state resistance R in step S70 may also be determined based on the V measured in step S30. oc , the I measured in step S50 sc , according to the formula R = V oc / I sc Calculate R.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] 1. The present invention can accurately measure the basic electrical performance parameters of the thermal battery in an unactivated state, such as open circuit voltage, output charge, maximum output current, DC resistance, current-voltage curve, impedance spectrum, capacitance, etc.;

[0042] 2. The present invention uses a constant temperature box, and the temperature range of the above basic electrical performance parameters is 0°C to 150°C. The test environment temperature fluctuation is less than 0.5°C, which effectively reduces the fluctuation of the above measurement results caused by the fluctuation of the external temperature;

[0043] 3. The electrical measurement fixture used in the present invention can effectively shield environmental noise such as electromagnetic interference and effectively improve the test accuracy;

[0044] 4. The lower limit of the impedance spectrum measurement frequency of the thermal battery in the unactivated state of the present invention can be as low as 1mHz;

[0045] 5. The excitation voltage for measuring the impedance spectrum of the thermal battery in the unactivated state of the present invention can be as low as 0.1V, and the DC resistance measurement of the thermal battery in the unactivated state does not require an external excitation voltage, thereby achieving non-destructive measurement of the thermal battery;

[0046] 6. During the test process, the computer data acquisition and analysis device of the present invention collects basic electrical performance measurement data such as open circuit voltage, output charge, maximum output current, DC resistance, current-voltage curve, impedance spectrum, capacitance, and environmental data such as temperature, and displays and stores them in real time, which can prevent data loss caused by accidental software shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0048] Figure 1 The present invention is a schematic diagram of the structure of a system for measuring electrical performance parameters of a thermal battery in an unactivated state.

[0049] Figure 2 The open circuit voltage of the thermal battery in an unactivated state measured at room temperature according to the present invention changes with time.

[0050] Figure 3 The short-circuit current of the thermal battery in an unactivated state measured at room temperature varies with time.

[0051] Figure 4 The curve of the charge outputted by the thermal battery in an unactivated state measured at room temperature versus time is shown in the figure.

[0052] Figure 5 This is the current-voltage curve of the thermal battery in an unactivated state measured at room temperature according to the present invention.

[0053] Figure 6 The impedance curve of the thermal battery in the unactivated state measured at room temperature according to the present invention varies with frequency.

[0054] Marks and corresponding parts names in the attached drawings:

[0055] 1-first internal electrical connection line, 2-second internal electrical connection line, 3-third internal electrical connection line, 4-fourth internal electrical connection line, 5-fifth internal electrical connection line, 6-sixth internal electrical connection line, 7-seventh internal electrical connection line, 8-impedance analyzer, 9-electrostatic meter, 10-computer data acquisition and analysis device, 11-upper cover, 12-housing, 13-thermal battery, 14-insulating seat, 15-constant temperature box, 16-positive electrode of thermal battery, 17-negative electrode of thermal battery, 18-housing of thermal battery, 19-three coaxial connector, 20-first BNC connector, 21-second BNC connector, 22-third BNC connector, 23-fourth BNC connector, 24-three coaxial connector of electrometer signal input terminal, 25-common terminal of electrometer, 26-voltage output terminal of electrometer, 27-voltage output terminal of impedance analyzer, 28-current input terminal of impedance analyzer. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0057] Example 1

[0058] like Figure 1 As shown, the present invention provides a system for measuring electrical performance parameters of a thermal battery in an unactivated state, comprising an impedance analyzer 8, an electrometer 9, a constant temperature box 15, and an electrical measurement fixture, wherein the electrical measurement fixture is arranged in the constant temperature box 15, the electrical measurement fixture is electrically connected to the impedance analyzer 8 and the electrometer 9, and the housing of the electrical measurement fixture is grounded; and further comprising a computer data acquisition and analysis device 10, wherein the computer data acquisition and analysis device 10 is connected to the impedance analyzer 8 and the electrometer 9 through a communication unit;

[0059] The electrical measurement fixture is used to place the thermal battery 13, and the electrical measurement fixture is used to shield the environmental noise of electromagnetic interference when the electrical performance parameters of the thermal battery 13 are measured in an inactive state;

[0060] The thermostat 15 is used to provide a constant temperature test environment within a range of 0° C. to 150° C. for the thermal battery 13 , and to support subsequent measurement of electrical performance parameters of the thermal battery 13 in an unactivated state;

[0061] The impedance analyzer 8 is used to measure the impedance spectrum of the thermal battery 13 in an unactivated state, and transmit it to the computer data acquisition and analysis device 10; the electrometer 9 is used to measure the open circuit voltage, output charge, maximum output current, current-voltage curve, and DC impedance of the thermal battery 13 in an unactivated state, and transmit it to the computer data acquisition and analysis device 10;

[0062] The computer data acquisition and analysis device 10 is used to control and collect temperature data of the constant temperature box 15, control the impedance analyzer 8 and the electrometer 9 to collect and analyze the electrical performance parameters of the thermal battery 13 in the unactivated state, and can also display various data graphs in real time and realize real-time data storage.

[0063] Specifically, the electrical measurement fixture includes a housing 12, an upper cover 11, and an insulating seat 14, wherein the insulating seat 14 is disposed at the bottom of the housing 12, the upper cover 11 is disposed at the top of the housing 12, and the thermal battery 13 is disposed on the insulating seat 14;

[0064] It also includes a triaxial connector 19 and four BNC connectors, which are fixed on the left side of the housing 12 of the electrical measurement fixture in sequence from top to bottom, and the horizontal position of the BNC connector is higher than the top of the insulating seat 14; the four BNC connectors are sequentially recorded as a first BNC connector 20, a second BNC connector 21, a third BNC connector 22, and a fourth BNC connector 23 from top to bottom; the outer shielding layer of the triaxial connector 19 is electrically connected to the housing 12 of the electrical measurement fixture, and the shielding layer of the BNC connector is electrically connected to the housing 12 of the electrical measurement fixture;

[0065] It also includes 7 internal electrical connection lines, which are used to electrically connect to the thermal battery 13 through the corresponding internal electrical connection lines during measurement; the 7 internal electrical connection lines are recorded as the first internal electrical connection line 1, the second internal electrical connection line 2, the third internal electrical connection line 3, the fourth internal electrical connection line 4, the fifth internal electrical connection line 5, the sixth internal electrical connection line 6, and the seventh internal electrical connection line 7 from top to bottom, the first internal electrical connection line 1 is electrically connected to the inner core of the three coaxial connector 19, the second internal electrical connection line 2 is electrically connected to the inner shielding layer of the three coaxial connector 19, the third internal electrical connection line 3 is electrically connected to the inner core of the first BNC connector 20, the fourth internal electrical connection line 4 is electrically connected to the inner core of the second BNC connector 21, the fifth internal electrical connection line 5 is electrically connected to the inner core of the third BNC connector 22, the sixth internal electrical connection line 6 is electrically connected to the inner core of the fourth BNC connector 23, and the seventh internal electrical connection line 7 is electrically connected to the outer shell of the electrical measurement fixture.

[0066] Specifically, the three-coaxial connector 19 and the three-coaxial connector 24 at the electrometer signal input terminal are connected through a three-coaxial test cable, the first BNC connector 20 and the electrometer common terminal 25 are connected through a coaxial cable, the second BNC connector 21 and the electrometer voltage output terminal 26 are connected through a coaxial cable, the third BNC connector 22 and the impedance analyzer voltage output terminal 27 are connected through a coaxial cable, and the fourth BNC connector 23 and the impedance analyzer current input terminal 28 are connected through a coaxial cable.

[0067] Specifically, the shell 12 and the upper cover 11 are made of stainless steel.

[0068] Specifically, the insulating seat 14 is made of high-insulation polytetrafluoroethylene, Teflon, glass or ceramic material.

[0069] Specifically, the insulating seat 14 is in a U-shape with an opening upward, and the thermal battery 13 is placed in a U-shaped groove of the insulating seat 14 .

[0070] Specifically, the electrometer 9 is an instrument having voltage source, voltage, current and charge measurement functions simultaneously or separately, and the voltage measurement input impedance is greater than 10 12 Ω, the voltage test range is greater than 10V, and the current measurement limit is less than 10 -12 A, charge measurement limit is less than 10 -12 C, communicates with the computer data acquisition and analysis device 10 through the communication unit GPIB or RS232 interface.

[0071] Specifically, the impedance analyzer 8 is an AC voltage signal with an output amplitude greater than 0.1V, a frequency range wider than 1mHz to 500kHz, and a test range greater than 10 12 The impedance measuring instrument of Ω is connected to the computer data acquisition and analysis device 10 through the communication unit GPIB, RS232 or USB.

[0072] Specifically, the computer data acquisition and analysis device 10 is independently developed using the Labview tool to control and collect temperature data of the constant temperature box 15, control the measurement mode of the electrometer 9, collect voltage data, current data, and charge data of the electrometer 9, and collect impedance data of the impedance analyzer 8. At the same time, it can display graphs of various data in real time and realize real-time data storage. Test options include changes in open circuit voltage of the thermal battery with time or temperature, changes in output current with time or temperature, changes in output charge with time, changes in DC resistance with time or temperature, changes in current with voltage, and changes in impedance and phase with frequency.

[0073] During implementation: The present invention provides a system for measuring the electrical performance parameters of a thermal battery in an unactivated state by impedance matching, suppressing noise and stabilizing the ambient temperature. The system mainly includes an impedance analyzer, an electrostatic meter, a constant temperature box, and an electrical measurement fixture. The electrical measurement fixture is arranged in the constant temperature box. The electrical measurement fixture is electrically connected to the impedance analyzer and the electrostatic meter. The outer shell of the electrical measurement fixture is grounded. The system also includes a computer data acquisition and analysis device. The computer data acquisition and analysis device is connected to the impedance analyzer and the electrostatic meter through a communication unit. Based on the system, the present invention provides a method for accurately measuring the open circuit voltage, output charge, and maximum output of a thermal battery in an unactivated state. The method of measuring the output current, current-voltage curve, DC resistance, impedance spectrum and capacitance can accurately measure the basic electrical performance parameters of the thermal battery in the unactivated state, such as the open circuit voltage, output charge, maximum output current, DC resistance, current-voltage curve, impedance spectrum, capacitance, etc.; during the test, due to the use of a constant temperature box, the measurement temperature range of the above basic electrical performance parameters is 0°C to 150°C; the test environment temperature fluctuation is less than 0.5°C, which effectively reduces the fluctuation of the above measurement results due to the fluctuation of the external temperature; at the same time, because the measurement fixture used can effectively shield environmental noise such as electromagnetic interference, the above test errors are effectively reduced. The present invention provides a basis for realizing online detection and reliability evaluation of thermal batteries based on the above electrical parameters in the unactivated state of thermal batteries.

[0074] Example 2

[0075] like Figure 1 As shown, the difference between this embodiment and embodiment 1 is that the constant temperature box 15 includes a temperature control module, and the temperature control module is connected to the computer data acquisition and analysis device 10 through a communication unit; a test hole is provided on the shell of the constant temperature box 15, and all test cables connecting the electrical measurement fixture and the electrometer or impedance analyzer are led out through the test hole, and the inner wall of the test hole is made of insulating ceramic, Teflon, glass or polytetrafluoroethylene.

[0076] The temperature control module is connected to the computer data acquisition and analysis device through a USB or RS485 interface.

[0077] Example 3

[0078] like Figure 1 As shown, this embodiment provides a method for measuring electrical performance parameters of a thermal battery in an unactivated state. The method is a system for measuring electrical performance parameters of a thermal battery in an unactivated state in Embodiment 1 or Embodiment 2, and the method comprises the following steps:

[0079] S10, turn on the computer data acquisition and analysis device 10, the electrometer 9, the impedance analyzer 8, and the thermostat 15, set the temperature of the thermostat 15 to the target temperature T0, and preheat each measuring instrument for 10 to 30 minutes;

[0080] S20, connecting the triaxial connector 19 on the electrical measurement fixture and the triaxial connector 24 at the signal input end of the electrometer through a triaxial test cable, connecting the first BNC connector 20 on the electrical measurement fixture and the common end 25 of the electrometer through a coaxial cable, connecting the second BNC connector 21 on the electrical measurement fixture and the voltage output end 26 of the electrometer through a coaxial cable, connecting the third BNC connector 22 on the electrical measurement fixture and the voltage output end 27 of the impedance analyzer through a coaxial cable, and connecting the fourth BNC connector 23 on the electrical measurement fixture and the current input end 28 of the impedance analyzer through a coaxial cable;

[0081] S30: Set the temperature of the thermostat 15 to the target temperature T0, place the thermal battery 13 on the insulating seat 14 of the electrical measurement fixture in the thermostat 15, wait for 1 hour to make the internal temperature of the thermal battery 13 consistent with the temperature of the thermostat 15, connect the thermal battery positive electrode 16, the thermal battery negative electrode 17 and the thermal battery shell 18 to the first internal electrical connection line 1, the third internal electrical connection line 3 and the second internal electrical connection line 2 in the electrical measurement fixture respectively, cover the upper cover 11 of the electrical measurement fixture, close the hatch of the thermostat 15, select the voltage-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the open circuit voltage V of the thermal battery 13 in the inactive state oc .

[0082] S40: Set the temperature of the thermostat to the target temperature T0, place the thermal battery 13 on the insulating seat 14 of the electrical measurement fixture in the thermostat 15, wait for 1 hour to make the internal temperature of the thermal battery 13 consistent with the temperature of the thermostat 15, connect the thermal battery positive electrode 16 to the first internal electrical connection line 1, connect the thermal battery negative electrode 17 to the second internal electrical connection line 2 and the seventh internal electrical connection line 7, cover the electrical measurement fixture cover 11, close the hatch of the thermostat 15, select the charge-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the output charge Q of the thermal battery 13 in the inactive state.

[0083] S50: Set the temperature of the thermostat 15 to the target temperature T0, place the thermal battery 13 on the insulating seat 14 of the electrical measurement fixture in the thermostat 15, wait for 1 hour to make the internal temperature of the thermal battery 13 consistent with the temperature of the thermostat 15, connect the thermal battery positive electrode 16 to the first internal electrical connection line 1, connect the thermal battery negative electrode 17 to the second internal electrical connection line 2 and the seventh internal electrical connection line 7, cover the measurement fixture cover 11, close the hatch of the thermostat 15, select the current-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the maximum output current I of the thermal battery 13 in the inactive state SC .

[0084] S60: Set the temperature of the thermostat 15 to the target temperature T0, place the thermal battery 13 on the insulating seat 14 of the electrical measurement fixture in the thermostat 15, wait for 1 hour to make the internal temperature of the thermal battery 13 consistent with the temperature of the thermostat 15, connect the thermal battery positive electrode 16 to the first internal electrical connection line 1, connect the thermal battery negative electrode 17 to the fourth internal electrical connection line 4, connect the thermal battery shell 18 to the second internal electrical connection line 2, cover the measurement fixture cover 11, close the hatch of the thermostat 15, select the current-voltage measurement option on the computer data acquisition and analysis device, set the current test range and voltage scanning range, and measure the current-voltage curve of the thermal battery 13 in the unactivated state.

[0085] S70: According to the current-voltage curve measured in step S60, the resistance R of the thermal battery 13 in the inactive state at the temperature T0 is calculated according to the formula R=△V / △I;

[0086] S80: Set the temperature of the thermostat 15 to the target temperature T0, place the thermal battery 13 on the insulating seat 14 of the electrical measurement fixture in the thermostat 15, wait for 1 hour to make the internal temperature of the thermal battery 13 consistent with the temperature of the thermostat 15, connect the thermal battery positive electrode 16 to the fifth internal electrical connection line 4, connect the thermal battery negative electrode 17 to the sixth internal electrical connection line 5, cover the measurement fixture cover 11, close the hatch of the thermostat 15, select the impedance spectrum measurement option on the computer data acquisition and analysis device, set the frequency (ω) scanning range, excitation voltage, current test range, bias voltage and data storage path and other parameters, and measure the impedance spectrum Z(ω) of the thermal battery 13 in the unactivated state.

[0087] S90: According to the impedance spectrum Z(ω) of the thermal battery 13 in the unactivated state measured above, a linear fit is performed on the logarithm of the impedance log(Z) and the logarithm of the frequency Log(ω) in the frequency range of 1 kHz to 500 kHz. According to log(Z)=-log(ω)-log(C), the intercept obtained is -log(C), and the capacitance C of the thermal battery 13 in the unactivated state is further calculated.

[0088] According to this method, the open circuit voltage, short circuit current and output charge of a certain thermal battery sample measured at room temperature in the unactivated state are shown in Figure 2 to 3. Figure 4 As shown, the current-voltage curve is Figure 5 As shown in the measurement results, the open circuit voltage of the thermal battery in the unactivated state at room temperature is 38.2V, and the short circuit current is 3.35×10 -11 A, can continuously output charge, the maximum output charge within 300s is 9.95×10 -9 C, the resistance in the unactivated state is 1.08×10 12 Ω; impedance spectrum such as Figure 6 As shown, the impedance at 1mHz is as high as 1.02×1012 Ω, the capacitance C is obtained by fitting = 9.8×10 -11 F. The method of the present invention can accurately measure the relevant basic electrical performance parameters of the thermal battery in the unactivated state.

[0089] Example 4

[0090] like Figures 1 to 6 As shown, the difference between this embodiment and embodiment 3 is that the maximum output current I of the thermal battery in the unactivated state in step S50 is SC The output charge Q is used for calculation, and the charge output in time t is measured. Q(t), the maximum output current is given by I SC =Q(t) / t is calculated. Figure 4 As shown, the output charge in 300s is 9.95×10 -9 C, according to I SC =Q(t) / t, I SC =9.95×10 -9 / 300=3.32×10 -11 A.

[0091] Example 5

[0092] like Figures 1 to 6 As shown, the difference between this embodiment and embodiment 3 is that the thermal battery inactive state resistance R in step S70 is based on the V measured in step S30. oc , the I measured in step S50 sc , according to the formula R = V oc / I sc Calculate R. Figure 2 and Figure 3 As shown in the figure, Voc = 38.2 V, Isc = 3.35 × 10 -11 A, according to R = V oc / I sc Calculated, R = 38.2 / (3.35×10 -11 )=1.14×10 12 Ω.

[0093] Example 6

[0094] like Figures 1 to 6 As shown, the difference between this embodiment and embodiment 3 is that the maximum output current I of the thermal battery in the unactivated state in step S50 is SC The output charge Q is used for calculation, and the charge output in time t is measured. Q(t), the maximum output current is given by I SC =Q(t) / t is calculated; Figure 4 As shown, the output charge in 300s is 9.95nC. SC=Q(t) / t, I SC =9.95×10 -9 / 300=3.32×10 -11 A.

[0095] The thermal battery inactive state resistance R in step S70 is based on the V measured in step S30. oc , the I measured in step S50 sc , according to the formula R = V oc / I sc Calculate R, such as Figure 2 and Figure 3 As shown in oc =38.2V, I sc =3.32×10 - 11 A, according to R = V oc / I sc Calculated, R = 38.2 / (3.32×10 -11 )=1.15×10 12 Ω.

[0096] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for measuring electrical performance parameters of a thermal battery in an unactivated state, characterized in that: The invention comprises an impedance analyzer (8), an electrometer (9), a constant temperature box (15), and an electrical measurement fixture, wherein the electrical measurement fixture is arranged in the constant temperature box (15), the electrical measurement fixture is electrically connected to the impedance analyzer (8) and the electrometer (9), and the housing of the electrical measurement fixture is grounded; and further comprises a computer data acquisition and analysis device (10), wherein the computer data acquisition and analysis device (10) is connected to the impedance analyzer (8) and the electrometer (9) via a communication unit; The electrical measurement fixture is used to place the thermal battery (13) therein, and the electrical measurement fixture is used to shield the electromagnetic interference environmental noise received when the electrical performance parameters of the thermal battery (13) are measured in an inactive state; The thermostatic box (15) is used to provide a constant temperature test environment within a range of 0° C. to 150° C. for the thermal battery (13), and to support subsequent measurement of electrical performance parameters of the thermal battery (13) in an unactivated state; The impedance analyzer (8) is used to measure the impedance spectrum of the thermal battery (13) in an unactivated state, and transmit the spectrum to the computer data acquisition and analysis device (10); the electrometer (9) is used to measure the open circuit voltage, output charge, maximum output current, current-voltage curve, and DC impedance of the thermal battery (13) in an unactivated state, and transmit the spectrum to the computer data acquisition and analysis device (10); The computer data acquisition and analysis device (10) is used to control and acquire temperature data of the thermostatic box (15), control the impedance analyzer (8) and the electrometer (9) to acquire and analyze electrical performance parameters of the thermal battery (13) in an unactivated state, and can display graphics of various data in real time and realize real-time data storage; The electrical measurement fixture comprises a housing (12), an upper cover (11), and an insulating seat (14); the insulating seat (14) is arranged at the bottom of the housing (12), the upper cover (11) is arranged at the top of the housing (12), and the thermal battery (13) is arranged on the insulating seat (14); It also includes a triaxial connector (19) and four BNC connectors, the triaxial connector (19) and the BNC connector are fixed on the left side of the housing (12) of the electrical measurement fixture in sequence from top to bottom, and the horizontal position of the BNC connector is higher than the top of the insulating seat (14); the four BNC connectors are sequentially recorded as a first BNC connector (20), a second BNC connector (21), a third BNC connector (22), and a fourth BNC connector (23) from top to bottom; the outer shielding layer of the triaxial connector (19) is electrically connected to the housing (12) of the electrical measurement fixture, and the shielding layer of the BNC connector is electrically connected to the housing (12) of the electrical measurement fixture; It also includes 7 internal electrical connection lines, which are used to electrically connect to the thermal battery (13) through the corresponding internal electrical connection lines during measurement; the 7 internal electrical connection lines are recorded from top to bottom as a first internal electrical connection line (1), a second internal electrical connection line (2), a third internal electrical connection line (3), a fourth internal electrical connection line (4), a fifth internal electrical connection line (5), a sixth internal electrical connection line (6), and a seventh internal electrical connection line (7); the first internal electrical connection line (1) is electrically connected to the inner core of the triaxial connector (19), and the second internal electrical connection line (10) is electrically connected to the inner core of the triaxial connector (19). The wire (2) is electrically connected to the inner shielding layer of the triaxial connector (19), the third internal electrical connection wire (3) is electrically connected to the inner core of the first BNC connector (20), the fourth internal electrical connection wire (4) is electrically connected to the inner core of the second BNC connector (21), the fifth internal electrical connection wire (5) is electrically connected to the inner core of the third BNC connector (22), the sixth internal electrical connection wire (6) is electrically connected to the inner core of the fourth BNC connector (23), and the seventh internal electrical connection wire (7) is electrically connected to the outer shell of the electrical measurement fixture; The triaxial connector (19) and the triaxial connector (24) at the electrometer signal input end are connected via a triaxial test cable, the first BNC connector (20) and the electrometer common end (25) are connected via a coaxial cable, the second BNC connector (21) and the electrometer voltage output end (26) are connected via a coaxial cable, the third BNC connector (22) and the impedance analyzer voltage output end (27) are connected via a coaxial cable, and the fourth BNC connector (23) and the impedance analyzer current input end (28) are connected via a coaxial cable; The electrometer (9) is an instrument having voltage source, voltage, current and charge measurement functions simultaneously or separately, and the voltage measurement input impedance is greater than 10 12 Ω, the voltage test range is greater than 10V, and the current measurement limit is less than 10 -12 A, charge measurement limit is less than 10 -12 C, communicating with the computer data acquisition and analysis device (10) via a communication unit GPIB or RS232 interface; The impedance analyzer (8) is an AC voltage signal with an output amplitude greater than 0.1V, a frequency range wider than 1mHz to 500kHz, and a test range greater than 10 12 An impedance measuring instrument of Ω, which is connected to the computer data acquisition and analysis device (10) through a communication unit GPIB, RS232 or USB; The constant temperature box (15) comprises a temperature control module, and the temperature control module is connected to the computer data acquisition and analysis device (10) via a communication unit.

2. A system for measuring electrical performance parameters of a thermal battery in an unactivated state according to claim 1, characterized in that: The shell (12) and the upper cover (11) are made of stainless steel, and the insulating seat (14) is made of highly insulating polytetrafluoroethylene, Teflon, glass or ceramic.

3. A system for measuring electrical performance parameters of a thermal battery in an unactivated state according to claim 1, characterized in that: The insulating seat (14) is in a U-shape with an opening upward, and the thermal battery (13) is arranged in the U-shaped groove of the insulating seat (14).

4. A system for measuring electrical performance parameters of a thermal battery in an unactivated state according to claim 1, characterized in that: A test hole is provided on the shell of the thermostatic box (15), and the inner wall of the test hole is made of insulating ceramic, Teflon, glass or polytetrafluoroethylene.

5. A system for measuring electrical performance parameters of a thermal battery in an unactivated state according to claim 1, characterized in that: The system is used for preliminary detection of the number and assembly direction of thermal battery cells.

6. A method for measuring electrical performance parameters of a thermal battery in an unactivated state, characterized in that: The method supports a system for measuring electrical performance parameters of a thermal battery in an unactivated state as claimed in any one of claims 1 to 5, and the method comprises the following steps: S10, turn on the computer data acquisition and analysis device, electrometer, impedance analyzer, and thermostat, set the thermostat temperature to the target temperature T0, and preheat each measuring instrument for 10 to 30 minutes; S20, connecting the triaxial connector on the electrical measurement fixture and the triaxial connector on the signal input end of the electrometer through a triaxial test cable, connecting the first BNC connector on the electrical measurement fixture and the common end of the electrometer through a coaxial cable, connecting the second BNC connector on the electrical measurement fixture and the voltage output end of the electrometer through a coaxial cable, connecting the third BNC connector on the electrical measurement fixture and the voltage output end of the impedance analyzer through a coaxial cable, and connecting the fourth BNC connector on the electrical measurement fixture and the current input end of the impedance analyzer through a coaxial cable; S30: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the thermal battery positive electrode, the thermal battery negative electrode and the thermal battery shell to the first internal electrical connection line, the third internal electrical connection line and the second internal electrical connection line in the electrical measurement fixture respectively, cover the upper cover of the electrical measurement fixture, close the thermostat door, select the voltage-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the open circuit voltage V of the thermal battery in the unactivated state oc ; S40: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the positive electrode of the thermal battery to the first internal electrical connection line, connect the negative electrode of the thermal battery to the second internal electrical connection line and the seventh internal electrical connection line, cover the upper cover of the electrical measurement fixture, close the door of the thermostat, select the charge-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the output charge Q of the thermal battery in the inactive state; S50: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the positive electrode of the thermal battery to the first internal electrical connection line, connect the negative electrode of the thermal battery to the second internal electrical connection line and the seventh internal electrical connection line, cover the upper cover of the measurement fixture, close the door of the thermostat, select the current-time measurement option on the computer data acquisition and analysis device, set the test range, test time, sampling rate and data storage path, and measure the maximum output current I of the thermal battery in the inactive state SC ; S60: setting the temperature of the thermostat to the target temperature, placing the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, waiting for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connecting the positive electrode of the thermal battery to the first internal electrical connection line, connecting the negative electrode of the thermal battery to the fourth internal electrical connection line, connecting the outer shell of the thermal battery to the second internal electrical connection line, covering the upper cover of the measurement fixture, closing the hatch of the thermostat, selecting the current-voltage measurement option on the computer data acquisition and analysis device, setting the current test range and the voltage scanning range, and measuring the current-voltage curve of the thermal battery in the inactive state; S70: According to the current-voltage curve measured in step S60, according to the formula R=△V / △I, the resistance R of the thermal battery in the inactive state when the temperature is T0 is calculated; S80: Set the temperature of the thermostat to the target temperature T0, place the thermal battery on the insulating seat of the electrical measurement fixture in the thermostat, wait for 1 hour to make the internal temperature of the thermal battery consistent with the temperature of the thermostat, connect the positive electrode of the thermal battery to the fifth internal electrical connection line, connect the negative electrode of the thermal battery to the sixth internal electrical connection line, cover the upper cover of the measurement fixture, close the door of the thermostat, select the impedance spectrum measurement option on the computer data acquisition and analysis device, set the frequency (ω) scanning range, excitation voltage, current test range, bias voltage and data storage path parameters, and measure the impedance spectrum Z(ω) of the thermal battery in the unactivated state; S90: According to the impedance spectrum Z(ω) of the thermal battery in the unactivated state measured in step S80, a linear fit is performed on the logarithm of the impedance log(Z) and the logarithm of the frequency log(ω) in the frequency range of 1 kHz to 500 kHz. According to log(Z)=-log(ω)-log(C), the intercept obtained is -log(C), and the capacitance C of the thermal battery in the unactivated state is further calculated.

7. A method for measuring electrical performance parameters of a thermal battery in an unactivated state according to claim 6, characterized in that: The maximum output current I of the thermal battery in the inactive state in step S50 SC It can also be calculated by the output charge Q, measuring the output charge Q(t) within time t, and the maximum output current is given by I SC =Q(t) / t is calculated.

8. The method for measuring the electrical performance parameters of a thermal battery in an unactivated state according to claim 6, characterized in that: The thermal battery inactive state resistance R in step S70 can also be based on the V measured in step S30. oc , the I measured in step S50 sc , according to the formula R = V oc / I sc Calculate R.

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