Square battery multi-dimensional signal in-situ measurement device and analysis method

Abstract

The invention discloses a square battery multi-dimensional signal in-situ measurement device and an analysis method, and belongs to the technical field of battery testing. The device comprises an outer shell, a top cover, a battery base, a sensor positioning groove, a mechanical arm, a control panel, a valve opening pull ring, a valve opening connecting line, a gas sensor, a temperature sensor, an air pressure sensor and a data acquisition chip. A non-contact square battery internal signal measuring method is adopted, a mechanical arm is controlled to automatically open a pressure release valve of a measured square battery to release internal gas, real-time in-situ monitoring of gas production of a battery cell in the service process is achieved, it is guaranteed that signals are collected through various sensors in the device, external interference is effectively isolated, and the service life of the battery cell is prolonged. And detection data can be transmitted to an external terminal in real time for recording and analysis. According to the invention, through cyclic testing under different working conditions and use of temperature, air pressure and gas sensors, quantitative analysis can be carried out on multiple parameters in the whole life cycle of the battery, and safety early warning of the square battery is facilitated.

Description

Technical Field

[0001] The present invention relates to a multi-dimensional signal in-situ measurement device and analysis method for a square battery, belonging to the technical field of battery testing. Background Art

[0002] Electrochemical energy storage has been widely used as an energy storage method. Among them, the energy battery technology is relatively mature, with the characteristics of long life, pollution-free, and reusable. However, there are still problems such as performance degradation and thermal runaway during the application of energy batteries, resulting in major safety accidents such as the fire of energy storage power stations and the spontaneous combustion of electric vehicles. Due to the unclear battery failure mechanism, it is necessary to develop a method for in-situ real-time monitoring of the evolution of multiple signals inside the battery, establish the correlation between the electrochemical characteristics of the battery and multi-field parameters, reveal the battery degradation mechanism, and guide the optimization design of each component of the battery.

[0003] Taking the most widely used square lithium-ion battery as an example, for the detection of the internal temperature of the battery, implantable testing methods based on temperature thin-film sensors and thermocouple sensors have been developed, realizing the real-time monitoring of the temperature during 500 charge-discharge cycles and during thermal runaway. For the monitoring of the internal air pressure of the battery, a wired air pressure monitoring method for square batteries based on air pressure sensors has been developed, but this method requires opening and resealing the battery case, damaging the structural integrity. For the detection of battery gases, at present, the main research is on the types and concentrations of internal gas spills after battery thermal runaway, and there is no research on in-situ real-time monitoring of the types and concentrations of internal gases in the battery. In addition, the use of fiber optic sensors has now realized the real-time monitoring of the internal temperature, air pressure, and strain parameters of square batteries, but the related detection of gases cannot be realized. However, due to the strong correlation between temperature, air pressure, and gases, it is necessary to synchronously detect the above parameters to achieve the mechanism analysis of the entire life cycle. Moreover, the installation of fiber optic sensors is carried out in the early stage of battery assembly because it needs to be embedded or fixed at specific positions inside the battery, and it is impossible to monitor and analyze the battery after it has served under actual complex working conditions. Summary of the Invention

[0004] In order to solve the problem that the existing methods cannot obtain the internal temperature, air pressure, gases, and electrical parameters of an existing square battery, the purpose of the present invention is to provide a multi-dimensional signal in-situ measurement device and analysis method for a square battery, which can automatically open the pressure relief valve of the measured square battery, release the internal gas, realize the real-time in-situ monitoring of the gas production of the battery core during service, ensure that the signals are collected by various sensors in the device, effectively isolate external interference, and can transmit the detection data to an external terminal in real time for recording and analysis. Through cyclic testing under different working conditions and the use of temperature, air pressure, and gas sensors, the present invention can quantitatively analyze multiple parameters during the entire life cycle of the battery, which is helpful for the safety warning of square batteries.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] The invention discloses a square battery multi-dimensional signal in-situ measuring device, comprising an outer shell, a top cover, a battery base, a sensor positioning slot, a mechanical arm, a control panel, a valve opening pull ring, a valve opening connecting line, a gas sensor, a temperature sensor, an air pressure sensor, and a data acquisition chip.

[0007] The gas sensor, temperature sensor and air pressure sensor realize wireless data collection through internal and external chips; the top cover and the outer shell are sealed and connected by welding; the battery base is made according to the size of the battery to be tested; the gas sensors detect gases including CO2, CH4, H2, CO, and C2H4; the sensors are all located in the device for in-situ detection; the square battery to be tested is any commercial square battery; the robotic arm is used to open the pressure relief valve of the square battery to be tested.

[0008] The square battery to be tested is placed on the battery base, and the power supply lines of the temperature, air pressure, gas sensor and the robotic arm are connected to the positive and negative electrodes of the square battery to be tested for self-power supply. The top cover and the shell strictly ensure that the square battery multi-dimensional signal in-situ measurement device is sealed. The robotic arm is controlled from the outside to open the pressure relief valve of the square battery to be tested without contact. The pressure relief valve of the square battery to be tested serves as an outlet for gas diffusion flow.

[0009] Furthermore, the robotic arm and the square battery to be tested are respectively reliably fixed on the side wall and the bottom of the square battery multi-dimensional signal in-situ measurement device, the pressure relief valve of the square battery to be tested is rigidly bonded and fixed to one end of the valve opening pull ring, and the robotic arm is in contact with the other end of the valve opening pull ring through the valve opening connecting line. After activating the robotic arm, the robotic arm moves according to the set trajectory, drives the valve opening pull ring through the valve opening connecting line, and thus opens the pressure relief valve.

[0010] Furthermore, the valve opening pull ring can be used separately or simultaneously as needed to save effort in opening the pressure relief valve: ① The bonding part of the valve opening pull ring and the pressure relief valve forms a small lever structure. When the valve opening pull ring is pulled upward, it can first open the weak part of the edge of the pressure relief valve, continue to provide pulling force in the subsequent movement and finally fully open the pressure relief valve. ② The force arm is increased by lengthening the valve opening pull ring, so that the pressure relief valve is locally subjected to greater force and is more easily damaged. ③ For pressure relief valves with a large triggering pressure, the thickness and area are both large. The hydrochloric acid corrosion method is used to thin the pressure relief valve. The corrosion time is determined according to the test, and the corrosion time is 50% to 80% of the complete corrosion time.

[0011] Furthermore, the robot arm is controlled by a control panel, and the control panel switch is an ordinary toggle switch. A strong magnet is glued to the top of the toggle switch, the control panel is fixed to the inner wall of the device, and another magnet is moved outside the square battery multi-dimensional signal in-position measurement device, thereby realizing the external contactless switch control of the robot arm to open the square battery pressure relief valve to be tested.

[0012] Further, for square batteries to be measured with different size types, battery bases with different sizes are used to offset the change in the internal cavity of the device caused by the volume change of the square battery to be measured, and reduce the change range of the air pressure caused by the sudden change of the external space after opening the battery pressure relief valve.

[0013] Further, the data collected by gas sensors, temperature sensors, pressure sensors, etc. are transmitted to the data acquisition chip and then transmitted to the external receiving end wirelessly for data reading; the gas sensors include carbon dioxide gas sensors, methane gas sensors, hydrogen gas sensors, carbon monoxide gas sensors, and ethylene sensors. The temperature sensors include thin-film resistor sensors and thermocouple sensors.

[0014] A method for in-situ measurement and analysis of multi-dimensional signals of a square battery disclosed by the present invention is implemented based on the above-mentioned device for in-situ measurement of multi-dimensional signals of a square battery. The method for in-situ measurement and analysis of multi-dimensional signals of a square battery isolates the square battery to be measured from the external environment. The control board controls the robotic arm to automatically open the pressure relief valve of the square battery to be measured and release the internal gas of the battery to be measured. A variety of gas sensors, pressure sensors, and temperature sensors are used to realize in-situ detection of gas, pressure, and temperature signals for square batteries of different systems and sizes. During the test process, the sensors transmit sensor data through a wireless transmission method. The top cover and the housing are used to achieve airtightness equivalent to that of the square battery to be measured, avoiding the problem of the electrolyte of the internal square battery to be measured continuously volatilizing to the outside and drying out. An electrochemical workstation is externally connected through a wire to realize charge and discharge cycle tests under different working conditions during the entire life cycle of the battery. Curves are plotted according to the current, voltage, temperature, pressure, and the values measured by multi-gas sensors during the battery cycle test to analyze the variation laws of temperature, pressure, and gas concentration with the charge and discharge current and voltage; by detecting the changes in temperature, pressure, and gas concentration under different working conditions, the correlation between the electrochemical performance and multi-parameters of multi-system and multi-type batteries during the entire life cycle is analyzed.

[0015] A method for in-situ measurement and analysis of multi-dimensional signals of a square battery disclosed by the present invention specifically includes the following steps:

[0016] Step 1: Fix the valve-opening pull ring on the pressure relief valve of the square battery to be measured with structural adhesive. After curing, fix the square battery to be measured on the inner surface bottom of the in-situ detection device with structural adhesive.

[0017] Step 2: Install the battery base and the robotic arm in sequence.

[0018] Step 3: Connect the robotic arm and the valve-opening pull ring through a valve-opening connecting wire.

[0019] Step 4: Embed the gas sensor, temperature sensor, barometric pressure sensor, data acquisition chip, and control board into the sensor positioning slot, and fill the gaps with sealant.

[0020] Step 5: Install the sensor positioning slot on the top of the square battery to be measured. After connecting the self-powered circuit of the sensor, use laser welding to seal the top cover and plug the liquid injection hole on the top cover.

[0021] Step 6: Control the internal control board non-contact through a magnet from outside the multi-dimensional signal in-situ measurement device of the square battery to activate the robotic arm. The robotic arm moves along the set trajectory and drives the valve-opening pull ring through the valve-opening connecting wire, thereby opening the pressure relief valve;

[0022] Step 7: The positive and negative contacts on the top cover are adaptively connected to the electrochemical workstation, and then connected to the electrochemical test equipment through the positive and negative poles of the top cover. Set the charge and discharge process steps of the measured square battery as needed.

[0023] Step 8: Conduct charge and discharge cycle tests under different working conditions during the entire life cycle of the measured square battery by externally connecting the electrochemical workstation through wires. The different working conditions include different cut-off voltages, cut-off currents, rates, SOC states, overcharge, and over-discharge.

[0024] It further includes Step 9: According to the charge and discharge cycle test results of the measured square battery in Step 8, analyze the performance, evolution behavior, and evolution mechanism of the measured square battery under different working conditions, including the following five analysis methods.

[0025] Analysis Method 1: The measured square battery is a normal mass-produced new battery that has not undergone activation and formation. Analyze the evolution behaviors of CO2, CH4, H2, CO, C2H4, temperature, and barometric pressure during the activation and formation process of the battery.

[0026] Analysis Method 2: The measured square battery is a normal mass-produced new battery that has undergone normal activation and formation. Analyze the evolution behaviors of CO2, CH4, H2, CO, C2H4, temperature, and barometric pressure during the entire life cycle of the battery.

[0027] Analysis Method 3: The measured square battery is a square battery with pre-implanted defects. Analyze the evolution behaviors of CO2, CH4, H2, CO, C2H4, temperature, and barometric pressure during the entire life cycle of the battery, compare the differences with normal batteries, and further analyze the deep mechanism causing such differences.

[0028] Analysis Method 4: The measured square battery is a square battery in a critical aging state. Analyze the evolution behaviors of CO2, CH4, H2, CO, C2H4, temperature, and barometric pressure during the process from critical aging to capacity drop and even thermal runaway of the battery, and further analyze the deep mechanism of the evolution at the critical moment of the battery's service life.

[0029] Analysis method five: In the above four working conditions, electrochemical impedance spectroscopy tests are carried out simultaneously as needed to increase the signal dimension and analyze the internal signals and evolution laws of the square battery under test.

[0030] During the charge and discharge process of the square battery cell, there is the following relationship among temperature, air pressure, and gas variables: PV = nRT, where P is the total gas pressure in the detection device, V is the volume of the empty space at the top of the detection device, n is the total number of moles of gas generated, T is the temperature in the detection device, R is the gas molar constant, and the total number of moles of gas is obtained by accumulating various gases, that is, n = Σn i The actual gas concentration generated by the battery is calculated in the following way: the mass-volume concentration of the gas b = cM gas / V m The mass of the gas m = bV, and the actual gas concentration c1 = mV m / V 电池 M gas where c is the concentration detected by the gas sensor, M gas is the molar mass of the gas, V m is the molar volume, V is the volume of the in-situ device, V 电池 is the volume of the wound battery cell, and c1 is the actual gas concentration generated by the battery.

[0031] The battery types include but are not limited to lithium-ion batteries, aluminum-ion batteries, sodium-ion batteries, potassium-ion batteries, and other aqueous (acidic) and non-aqueous batteries (acidic organic electrolyte, ionic liquid electrolyte).

[0032] Beneficial effects:

[0033] 1. For a square battery multi-dimensional signal in-situ measurement device and analysis method disclosed in the present invention, the gas sensor, temperature sensor, and air pressure sensor realize wireless data acquisition through internal and external chips, and adopt a non-contact method for measuring the internal signals of the square battery, avoiding the shortcoming that other battery testing methods cannot in-situ measure internal gas signals or introducing too many external factors to affect the battery and resulting in inaccurate measurement results, and improving the in-situ measurement accuracy of internal gas signals.

[0034] 2. For a square battery multi-dimensional signal in-situ measurement device and analysis method disclosed in the present invention, the pressure relief valve is opened through the built-in robotic arm valve opening device, reducing the complexity and danger of manual operation, and helping to realize non-contact measurement of the internal signals of the square battery; in addition, three measures to make it easier to open the pressure relief valve are designed according to needs.

[0035] 3. A multi-dimensional signal in-situ measurement device and analysis method for a square battery disclosed by the present invention create an equivalent internal and external environment in a small space outside the battery to be measured, non-contact open the pressure relief valves provided in all square batteries, create a channel for internal and external material flow, have wide applicability, have almost no requirements for the state of the battery to be measured, can perform in-situ measurement on fresh square batteries or critically aged square batteries, and have little impact on the battery to be measured itself.

[0036] 4. A multi-dimensional signal in-situ measurement device and analysis method for a square battery disclosed by the present invention achieve equivalent airtightness with the square battery to be measured by designing fixed bases and fillers for battery cores of different types, avoid the problem of continuous evaporation of the electrolyte of the square battery to be measured inside to the outside and drying out, and ensure good consistency between the battery service environment inside the device and the commercial battery service environment.

[0037] 5. A multi-dimensional signal in-situ measurement device and analysis method for a square battery disclosed by the present invention perform cyclic tests under different working conditions and use temperature, pressure, and gas sensors, combined with wireless transmission technology, to synchronously collect the internal temperature, pressure, gas, and electrical properties of the battery core, establish the correlation between electrochemical properties and multiple parameters, quantitatively analyze multiple parameters during the entire life cycle of the battery, contribute to the optimization of battery materials, and achieve the function of battery safety warning.

[0038] 6. A multi-dimensional signal in-situ measurement device and analysis method for a square battery disclosed by the present invention use the basic configuration pressure relief valve of the square battery as a channel for transmitting internal signals of the battery core to the sensor, can be applied to batteries with common square casings, are suitable for real-time monitoring of temperature, pressure, gas, and electrical properties during the cycling process of multiple systems (such as lithium-ion batteries, aluminum-ion batteries, sodium-ion batteries, potassium-ion batteries, etc.) and multiple structural types (such as laminated and wound battery cores), so as to analyze the degradation mechanism of each system battery during service and provide data support for the development of high-performance batteries.

[0039] 7. A multi-dimensional signal in-situ measurement device and analysis method for a square battery disclosed by the present invention uses a device casing with the same structure as the square battery casing. Compared with special-shaped devices, it has better compatibility and applicability with conventional battery testing instruments, reduces the testing and debugging process, and thus improves efficiency. Description of the Drawings

[0040] Figure 1 It is a schematic diagram of a multi-dimensional signal in-situ measurement device for a square battery of the present invention.

[0041] Figure 2 is Figure 1 an exploded view.

[0042] Figure 3 It is a schematic diagram of a sensor positioning groove.

[0043] Figure 4 Schematic diagram of the valve opening system (robotic arm + valve opening pull ring + valve opening connection wire + pressure relief valve).

[0044] Figure 5 Schematic diagram of the self-powered wiring of the sensors (gas sensor + air pressure sensor + temperature sensor) and the control board.

[0045] Wherein: 1 - top cover, 2 - sensor positioning groove, 3 - control board, 4 - robotic arm, 5 - gas sensor, 6 - temperature sensor, 7 - air pressure sensor, 8 - data acquisition chip, 9 - valve opening pull ring, 10 - valve opening connection wire, 11 - square battery to be measured, 11.1 - pressure relief valve, 12 - battery base, 13 - outer housing. Specific implementation mode

[0046] The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification, and the implementation modes of the present invention are not limited thereto.

[0047] As Figure 1 、 2 shown, a square battery multi-dimensional signal in-situ measurement device disclosed in this embodiment mainly consists of a top cover 1, a sensor positioning groove 2, a control board 3, a robotic arm 4, a gas sensor 5, a temperature sensor 6, an air pressure sensor 7, a data acquisition chip 8, a valve opening pull ring 9, a valve opening connection wire 10, a pressure relief valve 11.1, a battery base 12, and an outer housing 13. Among them, the robotic arm 4, the valve opening pull ring 9, the valve opening connection wire 10, and the pressure relief valve 11.1 constitute a valve opening system.

[0048] The valve opening pull ring 9, the square battery 11 to be measured, and the robotic arm 4 are all fixed by bonding with structural adhesive and completely cured.

[0049] Among them, the valve opening connection wire 10 has high rigidity and tensile resistance;

[0050] Among them, both the top cover 1 and the outer housing 13 can use the mature square battery housings in the market, and the mature laser welding process can not only improve the efficiency but also ensure the encapsulation quality.

[0051] Among them, the gas sensor 5, the temperature sensor 6, and the air pressure sensor 7 collect data and transmit it to the data acquisition chip 8, and then transmit it to the external receiving end wirelessly to read the actual gas concentration, temperature value, and air pressure value.

[0052] Among them, the external magnet controls the internal control board 3 without contact because a magnet is installed on the ordinary toggle switch of the control board 3 in advance. After the external magnet and the internal magnet attract each other with opposite polarities, moving the external magnet causes the internal magnet to move, and then toggles the switch.

[0053] The sensor positioning groove is as Figure 3As shown, each notch is made according to the actual sizes of the control board 3, gas sensor 5, temperature sensor 6, barometric pressure sensor 7, and data acquisition chip 8. After the above components are embedded, the gaps are filled with sealant to reduce the size of the internal cavity of the device and prevent corrosion. There are wire holes on the back of each notch, and the power supply wires of the above components are uniformly arranged through the wire holes to the back of the positioning groove and connected to the self-powered circuit.

[0054] The valve opening system (robotic arm 4 + valve opening pull ring 9 + valve opening connection wire 10 + pressure relief valve 11.1) is as Figure 4 shown. The valve opening system is the key to the device of this patent. It can open the square battery 11 to be tested and release internal multi-dimensional signals in a sealed in-situ detection device with equivalent internal and external environments, isolating the internal and external atmospheric mass exchange.

[0055] The schematic diagram of the self-powered wiring of the sensors (gas sensor 5 + barometric pressure sensor 6 + temperature sensor 7) and the control board 3 is as Figure 5 shown. The positive and negative electrodes of the square battery 11 to be tested are respectively connected to the positive and negative electrodes of the in-situ measurement device using wires, and are connected in parallel with the positive and negative electrodes of the sensors (gas sensor 5 + barometric pressure sensor 6 + temperature sensor 7) and the control board 3 on the back of the sensor positioning groove 2, thus completing self-power supply.

[0056] The volume ratio of the filling object conforming to the battery cell in the in-situ detection device is 95%, and the service environment of the square battery inside the device is the same as that of the commercial square battery.

[0057] Among them, a power supply or transformer component can be separately set inside the in-situ measurement device to meet the power supply requirements of different components.

[0058] A method for on-site measurement and analysis of multi-dimensional signals of a square battery disclosed in this embodiment is specifically implemented as follows:

[0059] Step 1: Fix the valve opening pull ring 9 on the pressure relief valve 11.1 of the square battery 11 to be tested using structural adhesive. After curing, fix the square battery 11 to be tested to the bottom inner surface of the in-situ detection device using structural adhesive.

[0060] Step 2: Then install the battery base 12 and robotic arm 4 in sequence.

[0061] Step 3: Connect the robotic arm 4 and the valve opening pull ring 9 through the valve opening connection wire 10.

[0062] Step 4: Embed the gas sensor 5, temperature sensor 6, barometric pressure sensor 7, data acquisition chip 8, and control board 3 into the sensor positioning groove 2, and fill the gaps with sealant.

[0063] Step 5: Install the sensor positioning groove 2 on the top of the battery to be tested. After connecting the internal self-power supply line, use laser welding to seal the top cover 1 and block the liquid injection hole on the top cover 1.

[0064] Step 6: Control the internal control board 3 non-contact through a magnet from outside the in-situ detection device to activate the robotic arm 4. The robotic arm 4 moves along a set trajectory, drives the valve-opening pull ring 9 through the valve-opening connecting line 10, and thus opens the pressure relief valve 11.1.

[0065] Step 7: The positive and negative contacts on the device top cover 1 are adaptively connected to the electrochemical workstation, and the charge and discharge process steps can be set as needed.

[0066] Step 8: Achieve charge and discharge cycle tests of the square battery to be tested under different working conditions during the entire life cycle through an external wire connected to the electrochemical workstation; the different working conditions include different cut-off voltages, cut-off currents, rates, SOC states, overcharge and over-discharge.

[0067] Step 9: According to the charge and discharge cycle test results of the square battery to be tested in Step 8, analyze the performance, evolution behavior and evolution mechanism of the square battery to be tested under different working conditions, including the following five analysis methods;

[0068] Analysis method 1: The square battery to be tested is a normal mass-produced fresh battery that has not undergone activation and formation. Study the evolution behavior of CO2, CH4, H2, CO, C2H4, temperature and air pressure during the activation and formation process of the battery.

[0069] Analysis method 2: The square battery to be tested is a normal mass-produced fresh battery that has undergone normal activation and formation. Study the evolution behavior of CO2, CH4, H2, CO, C2H4, temperature and air pressure during the entire life cycle of the battery.

[0070] Analysis method 3: The square battery to be tested is a square battery with pre-implanted defects. Study the evolution behavior of CO2, CH4, H2, CO, C2H4, temperature and air pressure during the entire life cycle of this battery, compare the differences with normal batteries, and further study the deep mechanism causing such differences.

[0071] Analysis method 4: The square battery to be tested is a square battery in a critical aging state. Study the evolution behavior of CO2, CH4, H2, CO, C2H4, temperature and air pressure during the process from critical aging to capacity plunge and even thermal runaway of this battery, and further study the deep mechanism of the evolution at the critical moment of the battery's service life.

[0072] Analysis method 5: During the above actual working process, electrochemical impedance spectroscopy tests can be carried out simultaneously as needed to increase the signal dimension and comprehensively explore the internal signals of the battery to be tested. The outer shell of the in-situ detection device adopts the outer shell of a common square battery and can adapt to various electrochemical testing methods.

[0073] During the charging and discharging process of the battery cell, there is approximately the following relationship among temperature, air pressure, and gas variables: PV = nRT, where P is the total gas pressure in the detection device, V is the volume of the empty space at the top of the detection device, n is the total number of moles of gas generated, T is the temperature in the detection device, R is the gas molar constant, and the total number of moles of gas is obtained by accumulating various gases, that is, n = Σn i The gas concentration actually generated by the battery is calculated in the following way: the mass-volume concentration of the gas b = cM gas / V m The mass of the gas m = bV, and the actual concentration of the gas c1 = mV m / V 电池 M gas where c is the concentration detected by the gas sensor, M gas is the molar mass of the gas, V m is the molar volume, V is the volume of the in-situ device, V 电池 is the volume of the wound cell, and c1 is the concentration of the gas actually generated by the battery.

[0074] According to the above specification, the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Referring to the above embodiments, the present invention is described in detail. Those skilled in the art can still modify or equivalently replace the specific implementation manners of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention is within the scope of the claims pending for approval. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

[0075] The above specific description further details the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A square battery multi-dimensional signal in-situ measurement device, characterized in that: It includes an outer shell, a top cover, a battery base, a sensor positioning slot, a mechanical arm, a control panel, a valve opening pull ring, a valve opening connecting line, a gas sensor, a temperature sensor, an air pressure sensor, and a data acquisition chip; The gas sensor, temperature sensor and air pressure sensor realize wireless data collection through internal and external chips; the top cover and the outer shell are sealed and connected by welding; the battery base is made according to the size of the battery to be tested; the gas sensors detect gases including CO2, CH4, H2, CO, and C2H4; the sensors are all located in the device for in-situ detection; the square battery to be tested is any commercial square battery; the mechanical arm is used to open the pressure relief valve of the square battery to be tested; The square battery to be tested is placed on the battery base, and the power supply lines of the temperature, air pressure, gas sensors and the robotic arm are connected to the positive and negative electrodes of the square battery to be tested for self-power supply; the sealing of the square battery multi-dimensional signal in-situ measurement device is strictly ensured through the top cover and the shell; the device sealing can use the square battery vacuum sealing method to achieve an environment equivalent to the internal environment of the battery to be tested; the external contactless control robotic arm opens the pressure relief valve of the square battery to be tested; the pressure relief valve of the square battery to be tested serves as an outlet for gas diffusion flow.

2. A square battery multi-dimensional signal in-situ measurement device as claimed in claim 1, characterized in that: The robotic arm and the square battery to be tested are respectively reliably fixed on the side wall and the bottom of the square battery multi-dimensional signal in-situ measurement device; the pressure relief valve of the square battery to be tested is rigidly bonded and fixed to one end of the valve opening pull ring; the robotic arm is in contact with the other end of the valve opening pull ring through the valve opening connecting line; after activating the robotic arm, the robotic arm moves according to the set trajectory, drives the valve opening pull ring through the valve opening connecting line, and thus opens the pressure relief valve.

3. A square battery multi-dimensional signal in-situ measurement device as claimed in claim 2, characterized in that: The valve opening pull ring can be used separately or simultaneously as needed to save effort in opening the pressure relief valve: ① The bonding part of the valve opening pull ring and the pressure relief valve forms a small lever structure. When the valve opening pull ring is pulled upward, it can first open the weak part of the edge of the pressure relief valve, continue to provide pulling force in subsequent movements and finally fully open the pressure relief valve; ② The force arm is increased by lengthening the valve opening pull ring, so that the pressure relief valve is locally subjected to greater force and is easier to be damaged; ③ For pressure relief valves with a large triggering pressure, their thickness and area are both large. The hydrochloric acid corrosion method is used to thin the pressure relief valve. The corrosion time is determined according to the test, and the corrosion time is 50% to 80% of the complete corrosion time.

4. A square battery multi-dimensional signal in-situ measurement device as claimed in claim 1, characterized in that: The robotic arm is controlled by a control panel, and the switch on the control panel is an ordinary toggle switch; a strong magnet is glued to the top of the toggle switch, the control panel is fixed to the inner wall of the device, and another magnet is moved outside the square battery multi-dimensional signal in-position measurement device, thereby realizing external contactless switch control of the robotic arm to open the square battery pressure relief valve to be tested.

5. A square battery multi-dimensional signal in-situ measurement device as claimed in claim 1, characterized in that: For square batteries of different sizes and types to be tested, battery bases of different sizes are used to offset the changes in the internal cavity of the device caused by the volume changes of the square batteries to be tested, and reduce the amplitude of the change in air pressure caused by the sudden change in the external space after opening the battery pressure relief valve.

6. A square battery multi-dimensional signal in-situ measurement device and analysis method as claimed in claim 1, characterized in that: The data collected by gas sensors, temperature sensors, air pressure sensors, etc. are transmitted to the data acquisition chip, and then wirelessly transmitted to the external receiving end to read the data; the gas sensors include carbon dioxide gas sensors, methane gas sensors, hydrogen gas sensors, carbon monoxide gas sensors, and ethylene sensors; the temperature sensors include thin film resistive sensors and thermocouple sensors.

7. A square battery multi-dimensional signal in-situ measurement and analysis method, based on a square battery multi-dimensional signal in-situ measurement device as claimed in claim 1, 2, 3, 4, 5 or 6, characterized in that: The square battery to be tested is isolated from the external environment. The control board controls the robotic arm to automatically open the pressure relief valve of the square battery to be tested to release the gas inside the battery to be tested. A variety of gas sensors, air pressure sensors, and temperature sensors are used to realize in-situ detection of gas, air pressure, and temperature signals for square batteries of different systems and sizes. During the test, the sensor realizes sensor data transmission through wireless transmission; the top cover and the shell are used to achieve airtightness equivalent to that of the square battery to be tested, so as to avoid the problem of continuous evaporation of the electrolyte of the internal square battery to be tested to the outside and causing drying; the electrochemical workstation is connected to the outside through wires to realize charge and discharge cycle testing under different working conditions throughout the life cycle of the battery; curves are drawn according to the current, voltage, temperature, air pressure, and values ​​measured by multiple gas sensors during the battery cycle test, and the changes in temperature, air pressure, and gas concentration with charge and discharge current and voltage are analyzed; the changes in temperature, air pressure, and gas concentration under different working conditions are detected to analyze the correlation between electrochemical performance and multiple parameters of multiple systems and multiple types of batteries throughout the life cycle.

8. A square battery multi-dimensional signal in-situ measurement and analysis method as claimed in claim 7, characterized in that: The steps include: Step 1: Use structural adhesive to fix the valve opening pull ring on the pressure relief valve of the square battery to be tested. After curing, fix the square battery to be tested on the bottom of the inner surface of the in-situ detection device through the structural adhesive; Step 2: Install the battery base and robotic arm in sequence; Step 3: Connect the robot arm to the valve opening pull ring through the valve opening connection line; Step 4: Embed the gas sensor, temperature sensor, air pressure sensor, data acquisition chip, and control board into the sensor positioning groove, and fill the gap with sealant; Step 5: Install the sensor positioning slot to the top of the square battery to be tested, connect the sensor self-power supply line, use laser welding to close the top cover, and seal the injection hole on the top cover; Step 6: The internal control board is non-contactly controlled by a magnet from the outside of the square battery multi-dimensional signal in-situ measurement device to activate the robotic arm, which moves according to the set trajectory and drives the valve opening pull ring through the valve opening connection line to open the pressure relief valve; Step 7: The positive and negative contacts on the top cover are connected to the electrochemical workstation through the adapter, and then connected to the electrochemical test equipment through the positive and negative electrodes of the top cover, and the charging and discharging steps of the square battery to be tested are set according to the needs; Step 8: Use wires to connect an external electrochemical workstation to implement charge and discharge cycle testing under different operating conditions throughout the life cycle of the square battery under test; the different operating conditions include different cut-off voltages, cut-off currents, rates, SOC states, overcharge and over-discharge.

9. A square battery multi-dimensional signal in-situ measurement and analysis method as claimed in claim 8, characterized in that: The method further includes step nine: analyzing the performance, evolution behavior and evolution mechanism of the square battery under different working conditions according to the charge and discharge cycle test results of the square battery under test in step eight, including the following five analysis methods: Analysis method 1: The square battery under test is a normal mass-produced new battery that has not been activated and capacity divided. The evolution behavior of CO2, CH4, H2, CO, C2H4, temperature and gas pressure of the battery during the activation and capacity division process is analyzed; Analysis method 2: The square battery under test is a new mass-produced battery that has been activated and divided normally. The evolution behavior of CO2, CH4, H2, CO, C2H4, temperature and pressure in the battery during its entire life cycle is analyzed; Analysis method three: The square battery under test is a square battery with defects implanted in advance. The evolution behaviors of CO2, CH4, H2, CO, C2H4, temperature and gas pressure of the battery during its entire life cycle are analyzed, and the differences are compared with those of normal batteries, and then the deep mechanism causing such differences is analyzed; Analysis method 4: The square battery under test is a square battery in a critical aging state. The evolution behaviors of CO2, CH4, H2, CO, C2H4, temperature and gas pressure of the battery during the process of critical aging to capacity drop and even thermal runaway are analyzed, and then the deep mechanism of battery evolution at the critical moment of service is analyzed; Analysis method five: In the above four working conditions, electrochemical impedance spectroscopy tests are carried out simultaneously as needed to increase the signal dimension and analyze the internal signals and evolution laws of the square battery under test.

10. The method for in-situ measurement and analysis of multi-dimensional signals of a square battery as claimed in claim 9, characterized in that: The relationship between the temperature, air pressure and gas variables of the square battery cell during the charging and discharging process is as follows: PV = nRT, where P is the total pressure of the gas in the detection device, V is the volume of the top free space in the detection device, n is the total number of moles of gas generated, T is the temperature in the detection device, R is the gas molar constant, and the total number of moles of gas is obtained by accumulating each gas, that is, n = Σn i , the actual gas concentration generated by the battery is calculated as follows: gas mass volume concentration b = cM gas / V m , gas mass m = bV, actual gas concentration c1 = mV m / V 电池 M gas , where c is the gas sensor detection concentration, M gas is the gas molar mass, V m is the molar volume, V is the volume of the in-situ device, V 电池 is the volume of the wound battery cell, and c1 is the concentration of the gas actually generated by the battery.

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