阅读说明：本技术 一种锂离子电池电解液闭口闪点的自动测试系统及方法 (Automatic testing system and method for closed flash point of lithium ion battery electrolyte ) 是由 梁大宇 俞金萍 王涂亮 庞春光 于 2020-08-11 设计创作，主要内容包括：本发明提出的一种锂离子电池电解液闭口闪点的自动测试系统,包括：支架台1、样品杯2、杯盖5、滑轨、电动马达6、控制与显示装置17、直流电源15、高压电供电模块和恒温泵4。本发明,通过控制与显示装置17的设置,实现了直流电源15、气源16、高压电供电模块和恒温泵4的智能化控制,实现了根据测试指令自动进行测试操作并根据实验过程的监控进行实验终止,实现了闪点测试的智能化和自动化。(The invention provides an automatic test system for closed flash point of lithium ion battery electrolyte, which comprises: the device comprises a support table 1, a sample cup 2, a cup cover 5, a slide rail, an electric motor 6, a control and display device 17, a direct-current power supply 15, a high-voltage power supply module and a constant-temperature pump 4. According to the invention, through the arrangement of the control and display device 17, the intelligent control of the direct-current power supply 15, the gas source 16, the high-voltage power supply module and the constant-temperature pump 4 is realized, the automatic test operation according to the test instruction and the termination of the experiment according to the monitoring of the experiment process are realized, and the intelligence and the automation of the flash point test are realized.)

1. The utility model provides an automatic test system of lithium ion battery electrolyte closed flash point which characterized in that includes: the device comprises a support table (1), a sample cup (2), a cup cover (5), a slide rail, an electric motor (6), a control and display device (17), a direct-current power supply (15), a high-voltage power supply module and a constant-temperature pump (4);

the sample cup (2) and the sliding rail are both arranged on the support table (1), and the cup cover (5) is arranged on the sliding rail and positioned above the sample cup (2); the electric motor (6) is connected with the cup cover (5) and is used for driving the cup cover (5) to vertically slide along the sliding rail;

a working electrode (8), a counter electrode (9), a temperature sensor (10), a pressure sensor (11), a spark plug (12) and a photoelectric detector (13) are arranged on the cup cover (5); the working electrode (8) and the counter electrode (9) are both connected with a direct current power supply (15), and the spark plug (12) is connected with a high-voltage power supply module; the control and display device (17) is respectively connected with the temperature sensor (10), the pressure sensor (11) and the photoelectric detector (13);

a gas inlet pipe (14) is also arranged on the cup cover (5), and the gas inlet pipe (14) is connected with a gas source (16);

the cup cover (5) is in sealed combination with the sample cup (2) when positioned at the lowest end of the sliding track, in the state, the working electrode (8) and the counter electrode (9) both extend into the sample cup (2), and the temperature sensor (10), the pressure sensor (11), the spark plug (12) and the photoelectric detector (13) are all positioned in the sample cup (2);

a circulating jacket (3) is coated on the periphery of the sample cup (2), and a heat preservation cavity is formed between the sample cup (2) and the constant-temperature jacket; the circulating jacket (3) is respectively provided with a heat preservation night inflow port connected with an output port of the constant temperature pump (4) and a heat preservation reflux port connected with an input port of the constant temperature pump (4).

2. The system for automatically testing the closed flash point of an electrolyte of a lithium ion battery according to claim 1, wherein the spark plug (12) is arranged adjacent to the photodetector (13) with a distance of 2 cm.

3. The automatic test system for the closed flash point of the lithium ion battery electrolyte according to claim 1, wherein the control and display device (17) is further connected with and controls the operation of the direct current power supply (15), the high voltage power supply module and the gas source (16) respectively.

4. The automatic testing system for the closed flash point of the lithium ion battery electrolyte according to claim 3, characterized in that the control and display device (17) is used for driving the cup cover (5) to move downwards through the electric motor (6) according to an input testing instruction to be combined with the sample cup (2) in a sealing way, and then controlling the direct current power supply (15) and the gas source (16) to work until the interior of the sample cup (2) reaches a positive pressure P; then, the control and display device (17) controls the spark plug (12) to continuously ignite through a high-voltage power supply module, and continuously heats the sample cup (2) through the constant-temperature pump (4); the control and display module is also used for displaying the detection values of the temperature sensor (10) and the pressure sensor (11) in real time;

when the photoelectric sensor detects a flash phenomenon, the control and display module controls the direct-current power supply (15), the high-voltage power supply module, the air source (16) and the constant-temperature pump (4) to stop working, and calculates the flash point temperature of the electrolyte under the standard atmospheric pressure by combining the current detection value and the pressure P of the temperature sensor (10); the value range of P is 0.1-0.5 MPa.

5. The automatic testing system for the closed flash point of the lithium ion battery electrolyte according to claim 1, wherein the lower end of the working electrode (8), the lower end of the counter electrode (9) and the temperature sensor (10) are lower than the pressure sensor (11), the spark plug (12) and the photodetector (13) in a state that the cup cover (5) and the sample cup (2) are hermetically combined.

6. The automatic testing system for the closed flash point of the lithium ion battery electrolyte according to claim 5, wherein the pressure sensor (11), the spark plug (12) and the photoelectric detector (13) are positioned on the same horizontal plane in a state that the cup cover (5) and the sample cup (2) are hermetically combined; the temperature sensor (10) is arranged lower than the three.

7. The automatic test system for the closed flash point of lithium ion battery electrolyte according to claim 1, characterized by further comprising an explosion-proof cover for covering the support stand (1) and the sample cup (2).

8. The system for automatically testing the closed flash point of an electrolyte for a lithium ion battery according to claim 1, wherein the gas stored in the gas source (16) is: the combustible mixed gas in the sample cup (2) accounts for 1-10% of the total volume of the gas in the sample cup (2) when the pressure in the sample cup (2) reaches positive pressure P.

9. An automatic test method for a closed flash point of lithium ion battery electrolyte, which is characterized in that the automatic test system for the closed flash point of the lithium ion battery electrolyte according to any one of claims 1 to 8 is adopted, and the method comprises the following steps:

s1, injecting electrolyte into the sample cup (2), driving the cup cover (5) to be hermetically combined with the sample cup (2), inserting the electrolyte into the temperature sensor (10), and placing the pressure sensor (11), the spark plug (12) and the photoelectric sensor above the liquid level;

s2, applying direct current voltage to the working electrode (8) and the counter electrode (9) through the direct current power supply (15);

s3, controlling a gas source (16) to add gas into the sample cup (2) to keep the sample cup (2) at a positive pressure P;

s4, igniting by a spark plug (12), and heating the sample cup (2) by a constant temperature pump (4);

and S5, when the photoelectric sensor detects the flash phenomenon, the control and display device sends a test stopping instruction, records the temperature value as the observation flash point value of the electrolyte, and then calculates the flash point temperature of the electrolyte under the standard atmospheric pressure by combining the observation flash point value and the pressure P.

Technical Field

The invention relates to the technical field of lithium ion batteries, in particular to an automatic testing system and method for closed flash point of lithium ion battery electrolyte.

Background

The lithium ion battery has the remarkable advantages of high energy density, low self-discharge rate, wide use temperature range, long cycle life, no memory effect and the like, and is widely applied to the fields of 3C digital products, new energy automobiles, energy storage power stations, aerospace and the like.

The electrolyte is an essential important component of the lithium ion battery and has important influence on various performances such as capacity, internal resistance, circulation, multiplying power, safety and the like of the lithium ion battery, however, at present, commercial electrolytes contain a large amount of carbonate organic solvents and have lower flash points, the electrolyte exists in an electric potential field between a positive electrode and a negative electrode, combustible gases such as hydrogen, methane, ethylene and the like can be generated due to oxidative decomposition of the electrolyte in the using process of the lithium ion battery to cause the internal pressure of the battery to rise, and the transition metal oxide positive electrode material can collapse to release oxygen due to unstable structure in the process of releasing and embedding lithium ions, and the factors increase the flammability of the electrolyte, so that how to accurately test the flash point temperature of the lithium ion battery has important significance on developing a safe electrolyte formula and improving the safety of the lithium ion battery.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides an automatic testing system for closed flash point of lithium ion battery electrolyte.

The invention provides an automatic test system for closed flash point of lithium ion battery electrolyte, which comprises: the device comprises a support table, a sample cup, a cup cover, a slide rail, an electric motor, a control and display device, a direct-current power supply, a high-voltage power supply module and a constant-temperature pump;

the sample cup and the sliding rail are both arranged on the bracket platform, and the cup cover is arranged on the sliding rail and positioned above the sample cup; the electric motor is connected with the cup cover and is used for driving the cup cover to vertically slide along the slide rail;

the cup cover is provided with a working electrode, a counter electrode, a temperature sensor, a pressure sensor, a spark plug and a photoelectric detector; the working electrode and the counter electrode are both connected with a direct current power supply, and the spark plug is connected with the high-voltage power supply module; the control and display device is respectively connected with the temperature sensor, the pressure sensor and the photoelectric detector;

the cup cover is also provided with a gas inlet pipe which is connected with a gas source;

when the cup cover is positioned at the lowest end of the sliding track, the cup cover is combined with the sample cup in a sealing way, in this state, the working electrode and the counter electrode all extend into the sample cup, and the temperature sensor, the pressure sensor, the spark plug and the photoelectric detector are all positioned in the sample cup;

a circulating jacket is coated on the periphery of the sample cup, and a heat preservation cavity is formed between the sample cup and the constant temperature jacket; the circulating jacket is respectively provided with a heat preservation night inflow port connected with the output port of the constant temperature pump and a heat preservation reflux port connected with the input port of the constant temperature pump.

Preferably, the spark plug is disposed adjacent to the photodetector with a distance of 2cm therebetween.

Preferably, the control and display device is also respectively connected with the direct-current power supply, the high-voltage power supply module and the air source and controls the work of the direct-current power supply, the high-voltage power supply module and the air source.

Preferably, the control and display device is used for driving the cup cover to move downwards to be combined with the sample cup in a sealing mode through the electric motor according to an input test instruction, and then controlling the direct-current power supply and the gas source to work until the interior of the sample cup reaches positive pressure P; then, the control and display device controls the spark plug to continuously ignite through the high-voltage power supply module, and continuously heats the sample cup through the constant-temperature pump; the control and display module is also used for displaying the detection values of the temperature sensor and the pressure sensor in real time;

when the photoelectric sensor detects a flash phenomenon, the control and display module controls the direct-current power supply, the high-voltage power supply module, the air source and the constant-temperature pump to stop working, and calculates the flash point temperature of the electrolyte under the standard atmospheric pressure by combining the current detection value and the pressure P of the temperature sensor; the value range of P is 0.1-0.5 MPa.

Preferably, the lower end of the working electrode, the lower end of the counter electrode and the temperature sensor are lower than the pressure sensor, the spark plug and the photoelectric detector under the state that the cup cover and the sample cup are in sealed combination.

Preferably, the pressure sensor, the spark plug and the photoelectric detector are positioned on the same horizontal plane when the cup cover and the sample cup are in a sealing combination state; the temperature sensor is lower than the three.

Preferably, an explosion-proof cover is further included for covering the holder table and the sample cup.

Preferably, the gas stored in the gas source is: and the combustible mixed gas in the sample cup accounts for 1-10% of the total volume of the gas in the sample cup when the pressure in the sample cup reaches the positive pressure P.

An automatic test method for a closed flash point of lithium ion battery electrolyte, which adopts the automatic test system for the closed flash point of the lithium ion battery electrolyte as claimed in any one of claims 1 to 8, and is characterized by comprising the following steps:

s1, injecting electrolyte into the sample cup, driving the cup cover to be hermetically combined with the sample cup, inserting the temperature sensor into the electrolyte, and placing the pressure sensor, the spark plug and the photoelectric sensor above the liquid level;

s2, applying direct current voltage to the working electrode and the counter electrode through a direct current power supply;

s3, controlling an air source to add air into the sample cup, and keeping the sample cup at a positive pressure P;

s4, igniting by a spark plug, and heating the sample cup by a constant temperature pump;

and S5, when the photoelectric sensor detects the flash phenomenon, the control and display device sends a test stopping instruction, records the temperature value as the observation flash point value of the electrolyte, and then calculates the flash point temperature of the electrolyte under the standard atmospheric pressure by combining the observation flash point value and the pressure P.

When the automatic testing system for the closed flash point of the lithium ion battery electrolyte provided by the invention is used for testing the flash point of the electrolyte, the electrolyte is injected into the sample cup under the condition that the cup cover is separated from the sample cup, and then the cup cover is moved down to seal the sample cup, so that the working electrode and the counter electrode are inserted into the electrolyte; then starting a direct current power supply to charge the working electrode and the counter electrode, and starting an air pump to fill the sample cup with air to regulate the pressure environment to meet the test requirement; then, a high-voltage power supply module is started to ignite the ignition piston, the temperature of the sample cup is adjusted through a constant-temperature pump, a photoelectric sensor detects a flash combustion phenomenon in real time, and a temperature sensor detects the temperature. When the flash-off phenomenon is detected, the direct-current power supply and the high-voltage power supply module are closed, the test is finished, and the flash point of the electrolyte under the standard atmospheric pressure is calculated according to the current temperature detected by the temperature sensor

According to the invention, through the arrangement of the control and display device, the intelligent control of the direct-current power supply, the gas source, the high-voltage power supply module and the constant-temperature pump is realized, the automatic test operation according to the test instruction and the termination of the experiment according to the monitoring of the experiment process are realized, and the intelligence and the automation of the flash point test are realized.

Drawings

Fig. 1 is a structural diagram of an automatic testing system for closed flash point of lithium ion battery electrolyte according to the present invention.

The figure is as follows: 1 is a support platform, 2 is a sample cup, 3 is a circulating jacket, 4 is a constant temperature pump, 5 is a cup cover, 6 is an electric motor, 7 is a vertical slide rail, 8 is a working electrode, 9 is a counter electrode, 10 is a temperature sensor, 11 is a pressure sensor, 12 is a spark plug, 13 is a photoelectric detector, 14 is a gas inlet pipe, 15 is a direct current power supply, 16 is a gas source, 17 is a control and display device, 18 is an explosion-proof box

Detailed Description

Referring to fig. 1, the automatic testing system for closed flash point of lithium ion battery electrolyte provided by the invention comprises: the device comprises a support table 1, a sample cup 2, a cup cover 5, a slide rail, an electric motor 6, a control and display device 17, a direct-current power supply 15, a high-voltage power supply module and a constant-temperature pump 4.

Sample cup 2 and slide rail are all installed on a support platform 1, and a cup cover 5 is installed on the slide rail and is located above the sample cup 2. The electric motor 6 is connected with the cup cover 5 and used for driving the cup cover 5 to vertically slide along the slide rail.

The cup cover 5 is provided with a working electrode 8, a counter electrode 9, a temperature sensor 10, a pressure sensor 11, a spark plug 12 and a photoelectric detector 13. The working electrode 8 and the counter electrode 9 are both connected with a direct current power supply 15, and the spark plug 12 is connected with a high-voltage power supply module. The control and display device 17 is respectively connected with the temperature sensor 10, the pressure sensor 11 and the photoelectric detector 13 so as to receive and display the detection results of the temperature sensor 10, the pressure sensor 11 and the photoelectric detector 13.

The cup cover 5 is also provided with a gas inlet pipe 14, and the gas inlet pipe 14 is connected with a gas source 16, so that when the cup cover 5 seals the sample cup 2, the sample cup 2 is inflated by the gas source 16 to adjust the pressure environment of the test.

When the cup cover 5 is positioned at the lowest end of the sliding track, the cup cover and the sample cup 2 are combined in a sealing mode, in this state, the working electrode 8 and the counter electrode 9 both extend into the sample cup 2, and the temperature sensor 10, the pressure sensor 11, the spark plug 12 and the photoelectric detector 13 are all positioned in the sample cup 2. In this way, the working electrode 8 and the counter electrode 9 can be inserted into the electrolyte by controlling the liquid level of the electrolyte in the sample cup 2, and the temperature sensor 10, the pressure sensor 11, the spark plug 12 and the photodetector 13 can perform corresponding detection in the sample cup 2 as required.

The periphery of the sample cup 2 is coated with a circulating jacket 3, and a heat preservation cavity is formed between the sample cup 2 and the constant temperature jacket. The circulating jacket 3 is respectively provided with a heat preservation night inflow port connected with an output port of the constant temperature pump 4 and a heat preservation reflux port connected with an input port of the constant temperature pump 4. Therefore, through the circulation temperature control of the constant temperature pump 4, the temperature regulation of the heat preservation in the heat preservation cavity at night is facilitated, and the temperature regulation of the electrolyte in the sample cup 2 is realized.

When the automatic test system for the closed flash point of the lithium ion battery electrolyte provided by the embodiment is used for carrying out flash point test on the electrolyte, the electrolyte is injected into the sample cup 2 under the condition that the cup cover 5 is separated from the sample cup 2, then the cup cover 5 is moved down to seal the sample cup 2, and the working electrode 8 and the counter electrode 9 are inserted into the electrolyte; then, the direct-current power supply 15 is started to charge the working electrode 8 and the counter electrode 9, and the air pump is started to fill the sample cup 2 with air to regulate the pressure environment to meet the test requirement; then, a high-voltage power supply module is started to ignite the ignition piston, the temperature of the sample cup 2 is adjusted through the constant-temperature pump 4, the photoelectric sensor detects a flash combustion phenomenon in real time, and the temperature sensor 10 detects the temperature. When the flash-off phenomenon is detected, the direct-current power supply 15 and the high-voltage power supply module are closed, the test is finished, the flash point of the electrolyte under the standard atmospheric pressure is calculated according to the current temperature detected by the temperature sensor 10, and the calculation formula is as follows:

Tc＝T₀+0.25101.3-P wherein: tc represents the flash point, in units of ℃; t is₀The unit is that the temperature sensor 10 detects the flash point, namely the flash phenomenon, and the unit is; p represents the pressure value in kPa inside the sample cup 2 at the time of the test.

In this embodiment, the spark plug 12 and the photodetector 13 are disposed adjacent to each other, and the distance between the spark plug and the photodetector 13 is 2cm, so as to ensure that the photosensor detects a flash phenomenon in real time, thereby ending the test in real time and avoiding explosion.

In this embodiment, the control and display device 17 is further connected to and controls the dc power supply 15, the high voltage power supply module, and the air source 16, respectively, so as to improve the automation degree of the test.

Specifically, the control and display device 17 is used for driving the cup cover 5 to move downwards through the electric motor 6 according to an input test instruction to be combined with the sample cup 2 in a sealing manner, and then controlling the direct-current power supply 15 and the air source 16 to work until the interior of the sample cup 2 reaches a positive pressure P, and then closing the air source 16. Then, the control and display device 17 controls the spark plug 12 to continuously ignite through the high-voltage power supply module, and continuously heats the sample cup 2 through the constant-temperature pump 4. The control and display module is also used for displaying the detection values of the temperature sensor 10 and the pressure sensor 11 in real time.

In this embodiment, when the photoelectric sensor detects a flash phenomenon, the control and display module controls the dc power supply 15, the high voltage power supply module, the air source 16 and the constant temperature pump 4 to stop working, and calculates the flash point temperature of the electrolyte under the standard atmospheric pressure by combining the current detection value of the temperature sensor 10 and the pressure P. The value range of P is 0.1-0.5 MPa.

Thus, in the embodiment, the intelligent control of the direct-current power supply 15, the gas source 16, the high-voltage power supply module and the constant-temperature pump 4 is realized, the automatic test operation according to the test instruction and the termination of the experiment according to the monitoring of the experiment process are realized, and the intelligent and automatic flash point test is realized.

In this embodiment, in the state of sealing and combining the cup cover 5 and the sample cup 2, the lower end of the working electrode 8, the lower end of the counter electrode 9 and the temperature sensor 10 are lower than the pressure sensor 11, the spark plug 12 and the photoelectric detector 13, so as to ensure that the working electrode 8 and the counter electrode 9 are inserted into the electrolyte, and the pressure sensor 11, the spark plug 12 and the photoelectric detector 13 are located above the electrolyte, so as to ensure that the flash point test is performed smoothly.

In the embodiment, the pressure sensor 11, the spark plug 12 and the photoelectric detector 13 are positioned on the same horizontal plane when the cup cover 5 and the sample cup 2 are in a sealed combined state; the temperature sensor 10 is arranged lower than the three so that the temperature sensor 10 can be in close contact with the electrolyte liquid level or directly inserted into the electrolyte liquid level for temperature detection according to the test requirement.

In this embodiment, the test device further comprises an explosion-proof cover for covering the support stand 1 and the sample cup 2, so that the explosion-proof cover can be used for spatial separation during the test process, and the diffusion of flash combustion explosion can be avoided.

In this embodiment, the gases stored in the gas source 16 are: the combustible mixed gas in the sample cup 2 accounts for 1% -10% of the total volume of the gas in the sample cup 2 under the condition that the pressure in the sample cup 2 reaches positive pressure P, so as to ensure the test condition.

The invention also provides an automatic test method of the closed flash point of the lithium ion battery electrolyte, and the method adopts the automatic test system of the closed flash point of the lithium ion battery electrolyte. The method comprises the following steps:

s1, injecting electrolyte into the sample cup 2, driving the cup cover 5 to be hermetically combined with the sample cup 2, inserting the working electrode 8, the counter electrode 9 and the temperature sensor 10 into the electrolyte, and placing the pressure sensor 11, the spark plug 12 and the photoelectric sensor above the liquid level.

And S2, applying direct current voltage to the working electrode 8 and the counter electrode 9 through the direct current power supply 15, wherein the specific value of the applied direct current voltage is 3.0-5.0V.

S3, controlling the gas source 16 to add gas into the sample cup 2, and keeping the sample cup 2 in positive pressure P, wherein the range of P is 0.1-0.5 MPa.

S4, igniting the spark plug 12, and heating the sample cup 2 through the constant temperature pump 4. Specifically, the initial temperature of the electrolyte can be set to be 20-30 ℃ below the estimated flash point value, and then the sample cup 2 is heated at a heating test rate of 2 ℃/min.

And S5, when the photoelectric sensor detects the flash phenomenon, the control and display device sends a test stopping instruction, records the temperature value as the observation flash point value of the electrolyte, and then calculates the flash point temperature of the electrolyte under the standard atmospheric pressure by combining the observation flash point value and the pressure P.

If when the flash phenomenon happens, the resistance value of the thermal resistor of the photoelectric detector can be changed under the action of flame temperature, the resistance value of the photoelectric detector is changed into the change of voltage and is fed back to the control and display device, after the voltage change signal is received, the control and display device sends out a test stopping instruction, the temperature value when the voltage is changed is recorded, and the numerical value is used as the observed flash point value of the electrolyte sample

Specifically, in this embodiment, when the electrolyte solution volatilizes vapor and the mixed gas is introduced for flash combustion, the temperature detected by the photodetector 13 when the voltage change time lasts for 5 to 10 seconds is determined as the observation flash point value.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention are equivalent to or changed within the technical scope of the present invention.