阅读说明：本技术 一种电池内部实时产气量的测试装置及方法 (Device and method for testing real-time gas production rate in battery ) 是由 朱艳丽 王聪杰 卜新雅 陈恒帅 李伟 于 2021-07-20 设计创作，主要内容包括：本发明提供了一种电池内部实时产气量的测试装置及方法,属于锂电池安全技术领域。包括：防爆罐；充气部件包括导管,导管的一端连接有连接装置,导管的另一端与储气罐的出口连接,储气罐的入口通过管路与充气装置连接,导管连接有连接装置的一端伸入防爆罐内；距离测试装置设置于防爆罐内,用于测试电池厚度；触发装置设置于防爆罐底部,用于触发电池。本发明可以在不破坏电池壳体的情况下实现对电池内部产气量的测量,因此可以用来研究电池热失控演化期间的电池膨胀过程；可以实现电池因滥用造成电池发生热失控期间的产气量的在线测量,即可实现锂电池内部因副反应快速产气时,气体量的实时监测。(The invention provides a device and a method for testing real-time gas production in a battery, and belongs to the technical field of lithium battery safety. The method comprises the following steps: an explosion-proof tank; the inflatable component comprises a guide pipe, one end of the guide pipe is connected with a connecting device, the other end of the guide pipe is connected with an outlet of the gas storage tank, an inlet of the gas storage tank is connected with the inflatable device through a pipeline, and one end of the guide pipe, which is connected with the connecting device, extends into the explosion-proof tank; the distance testing device is arranged in the explosion-proof tank and used for testing the thickness of the battery; the trigger device is arranged at the bottom of the explosion-proof tank and used for triggering the battery. The invention can realize the measurement of the gas production in the battery under the condition of not damaging the battery shell, thereby being used for researching the battery expansion process during the thermal runaway evolution of the battery; the online measurement of the gas production amount of the battery during the thermal runaway of the battery caused by abuse can be realized, and the real-time monitoring of the gas amount can be realized when the gas is rapidly produced in the lithium battery due to side reaction.)

1. A testing arrangement of the inside real-time gas production of battery, its characterized in that, testing arrangement includes:

an explosion-proof tank;

the inflatable component comprises a guide pipe, one end of the guide pipe is connected with a connecting device, the other end of the guide pipe is connected with an outlet of a gas storage tank, an inlet of the gas storage tank is connected with the inflatable device through a pipeline, and one end of the guide pipe, which is connected with the connecting device, extends into the explosion-proof tank;

the distance testing device is arranged in the explosion-proof tank and used for testing the distance between the maximum surface and the maximum opposite surface of the battery, namely the thickness of the battery;

and the trigger device is arranged at the bottom of the explosion-proof tank and used for triggering the battery to heat or charge the battery.

2. The device for testing the real-time gas production rate in the battery according to claim 1, wherein the device further comprises a fastening device, the fastening device comprises a supporting plate arranged at the bottom of the explosion-proof tank, two opposite L-shaped clamping plates are arranged on the supporting plate, and the supporting plate and the two L-shaped clamping plates are fixed through screws and nuts.

3. The device for testing the real-time gas production rate in the battery according to claim 1, wherein a first control valve, a first pressure detection device and a fourth control valve are arranged on the guide pipe from the gas storage tank to the connecting device in sequence; the air storage tank is provided with a second pressure intensity detection device, an inlet of the air storage tank is connected with the air charging device through a pipeline, and a second control valve is arranged on the pipeline between the air charging device and the air storage tank.

4. The device for testing the real-time gas production rate in the battery according to claim 1, wherein the distance testing device comprises a ruler body, a first sliding groove and a second sliding groove are respectively connected to two ends of the ruler body in a sliding manner, and the first sliding groove is connected with the second sliding groove through a connecting rod;

the vernier is connected to the ruler body in a sliding mode, a data line interface is arranged on the vernier, and the data line interface is connected with a digital display device through a data line;

a first outer measuring jaw is fixedly arranged on the ruler body, a second outer measuring jaw is fixedly arranged at the bottom of one end, close to the first outer measuring jaw, of the vernier, and the first outer measuring jaw and the second outer measuring jaw are arranged oppositely;

preferably, the first outer measuring claw and the second outer measuring claw are both in a shape of a circular sheet and are directly in friction contact with the center of the surface of the battery or are adhered to the center of the surface of the battery by adopting high-temperature-resistant glue;

preferably, the front surface of the ruler body is provided with scales.

5. The device for testing the real-time gas production rate in the battery according to claim 1, wherein the trigger device is a heating device or a charging device, the heating device is a heating plate or a heating sheet, and the battery is heated by contacting with the battery; the charging device is a charger and is directly connected with the anode and the cathode of the battery through leads.

6. A method for testing gas production by adopting the device for testing gas production in real time in the battery of any one of claims 1 to 5 is characterized by comprising the following steps:

step 1, fixing a second battery in an explosion-proof tank, communicating the second battery with a conduit, inflating a battery cavity of the second battery by using an inflating component, collecting a plurality of inflation quantity values and battery thickness increment values, drawing a curve relation, and fitting to obtain a functional relation f of inflation quantity n and thickness d, wherein n is f (d);

step 2, removing the battery II, fixing the battery I in an explosion-proof tank, triggering the battery through a triggering device to generate thermal runaway, recording heating or charging time and surface temperature of the battery I, and monitoring a series of thicknesses d of the battery I during the thermal runaway evolution through a distance testing device^*D is mixing^*Substituting the function f obtained in the step 1 to calculate a series of n^*With time or temperature as abscissa, n^*And obtaining a change curve of the gas production rate in the battery during the thermal runaway evolution by the ordinate.

7. The method according to claim 6, wherein step 1 is specifically: the battery cavity of the battery II is inflated through the inflation component and the guide pipe to obtain the inflation quantity n in the battery cavity, the thickness d of the shell of the battery II after being inflated is monitored through the distance testing device, a series of corresponding thicknesses d are obtained by changing the inflation quantity n, and therefore a series of numerical values n are finally obtained₁、d₁，n₂、d₂，…，n_i、d_iLet the initial thickness of the second battery be d₀The amount of inflation n and the increment of cell thickness (d-d) are plotted by the obtained values₀) Fitting the curve to obtain the functional relationship f of the air inflation n and the thickness d, namely n ═ f (d).

8. The method of claim 7, wherein the operation of inflating the battery cavity of the second battery through the inflation component and the conduit comprises:

(1) first the air in the conduit is displaced and a first pressure value P is ensured₁And a second pressure value P₂Initial value P of₁₀And P₂₀Equal to local atmospheric pressure, wherein the first pressure value P₁The real-time pressure value detected by the first pressure detection device, the second pressure value P₂A real-time pressure value detected by the second pressure detection means;

(2) closing the first control valve, opening the second control valve, inflating the gas storage tank through the inflating device, closing the second control valve after the inflation is finished, and recording a second pressure value P₂₁；

(3) Opening the first control valve, the third control valve and the fourth control valve, inflating the battery cavity through the gas storage tank, after the inflation is stable, closing the first control valve, and recording a first pressure value P₁₂And a second pressure value P₂₂The method for checking the stability of the inflation comprises the following steps: if P₁₂＝P₂₂The aeration is stable; then closing the third control valve and the fourth control valve;

(4) repeating the steps (2) and (3), wherein the inflation is increased once every time the steps (2) and (3) are executed, the gas in the battery cavity of the battery II is continuously increased, the battery is finally broken, and the inflation is stopped after the battery is broken; each time steps (2) and (3) are performed, an array m ═ P is obtained₂₁，P₁₂，P₂₂Get it writtenFor the set of values recorded when steps (2) and (3) were performed the ith time, i.e. m_iObtained at the i-th inflationThe set of values of (1).

9. The method of claim 8, wherein the operation of obtaining the amount of inflation n within the cell cavity comprises:

inflation amount for the 1 st time:

in the formula, V₁Is the volume of the gas storage tank, V₂Is the internal volume of the conduit, R is the ideal gas constant, T is the ambient temperature, V₂The inner diameter and the length of the conduit are calculated;

total inflation after the 2 nd inflation:

the second inflation is performed on the basis of the first inflation, so that the total inflation amount after the second inflation includes the inflation amount during the first inflation;

total inflation amount after the t-th inflation (2< t ≤ i):

10. the method of claim 8, wherein the step (1) of displacing air from the conduit comprises:

closing the first control valve, the third control valve and the fourth control valve, opening the second control valve, inflating the gas storage tank through the inflating device, and when the second pressure value P is₂When the pressure is higher than the atmospheric pressure, the second control valve is closed;

and opening the connecting device, the first control valve and the fourth control valve in sequence, closing the fourth control valve and the first control valve in sequence after discharging the air in the guide pipe, and screwing on the connecting device.

Technical Field

The invention belongs to the technical field of lithium battery safety, and particularly relates to a device and a method for testing real-time gas production in a battery.

Background

The motorization of the automobile is rapidly developed, however, the safety of the battery becomes one of the key factors for rapidly expanding the market of the electric automobile. Therefore, research on the safety of the battery is increasing, and research on the thermal runaway mechanism of the battery has been a hot spot. Under abusive conditions, side reactions occur inside the battery and a large amount of gas is generated, causing the battery case to undergo swelling deformation, further possibly causing the battery to undergo combustion explosion. The online measurement of the internal gas production during the thermal runaway evolution of the lithium battery is helpful for deeply understanding the thermal runaway mechanism of the lithium battery, and can provide data support for the structure and strength design of the lithium battery shell, reduce the explosion risk of the battery and improve the safety of the battery.

The existing test of the gas production rate in the lithium battery mainly aims at the expansion gas production of the battery under the conventional use condition, the gas production rate is low, the gas production rate is small, the test environment is relatively static, and the measurement of the rapid gas production during the abuse period of the lithium battery is difficult to meet. In addition, the existing testing method mainly leads out the gas in the battery, breaks the sealing structure of the battery, influences the evolution process of abuse induced thermal runaway of the battery, and is not beneficial to the research on the thermal runaway mechanism of the battery.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a device and a method for testing the gas production rate in the battery in real time, which can realize the measurement of the gas production rate in the battery under the condition of not damaging a battery shell.

The invention is realized by the following technical scheme:

in a first aspect of the present invention, a device for testing real-time gas production in a battery is provided, which includes:

an explosion-proof tank;

the gas charging component comprises a guide pipe, one end of the guide pipe is connected with a connecting device, the other end of the guide pipe is connected with an outlet of the gas storage tank, an inlet of the gas storage tank is connected with the gas charging device through a pipeline, and one end of the guide pipe, which is connected with the connecting device, extends into the explosion-proof tank;

the distance testing device is arranged in the explosion-proof tank and used for testing the distance between the maximum surface and the maximum opposite surface of the battery, namely the thickness of the battery;

and the trigger device is arranged at the bottom of the explosion-proof tank and used for triggering the battery to heat or charge the battery.

The invention is further improved in that:

the test device further comprises a fastening device, the fastening device comprises a supporting plate arranged at the bottom of the explosion-proof tank, two opposite L-shaped clamping plates are arranged on the supporting plate, and the supporting plate and the two L-shaped clamping plates are fixed through screws and nuts.

The invention is further improved in that:

a first control valve, a first pressure detection device and a fourth control valve are sequentially arranged on the guide pipe from the gas storage tank to the connecting device; the second pressure intensity detection device is arranged on the gas storage tank, the inlet of the gas storage tank is connected with the air charging device through a pipeline, and a second control valve is arranged on the pipeline between the air charging device and the gas storage tank.

The invention is further improved in that:

the distance testing device comprises a ruler body, wherein a first sliding chute and a second sliding chute are respectively connected to two ends of the ruler body in a sliding manner, and the first sliding chute and the second sliding chute are connected through a connecting rod;

the vernier is connected to the ruler body in a sliding mode, a data line interface is arranged on the vernier, and the data line interface is connected with the digital display device through a data line;

a first outer measuring jaw is fixedly arranged on the ruler body, a second outer measuring jaw is fixedly arranged at the bottom of one end, close to the first outer measuring jaw, of the vernier, and the first outer measuring jaw and the second outer measuring jaw are arranged oppositely;

preferably, the first outer measuring claw and the second outer measuring claw are both in a shape of a circular sheet and are directly in friction contact with the center of the surface of the battery or are adhered to the center of the surface of the battery by adopting high-temperature-resistant glue;

preferably, the front surface of the ruler body is provided with scales.

The invention is further improved in that:

the trigger device is a heating device or a charging device, the heating device is a heating plate or a heating sheet, and the heating device heats the battery by contacting the battery; the charging device is a charger and is directly connected with the anode and the cathode of the battery through leads.

The second aspect of the invention provides a method for testing the real-time gas production rate in a battery, which specifically comprises the following steps:

step 1, fixing a second battery in an explosion-proof tank, communicating the second battery with a conduit, inflating a battery cavity of the second battery by using an inflating component, collecting a plurality of inflation quantity values and battery thickness increment values, drawing a curve relation, and fitting to obtain a functional relation f of inflation quantity n and thickness d, wherein n is f (d);

step 2, removing the battery II, fixing the battery I in an explosion-proof tank, triggering the battery through a triggering device to generate thermal runaway, recording heating or charging time and surface temperature of the battery I, and monitoring a series of thicknesses d of the battery I during the thermal runaway evolution through a distance testing device^*D is mixing^*Substituting the function f obtained in the step 2 to calculate a series of n^*With time or temperature as abscissa, n^*And obtaining a change curve of the gas production rate in the battery during the thermal runaway evolution by the ordinate.

The invention is further improved in that:

the step 1 specifically comprises the following steps: the battery cavity of the battery II is inflated through the inflation component and the guide pipe to obtain the inflation quantity n in the battery cavity, the thickness d of the shell of the battery II after being inflated is monitored through the distance testing device, a series of corresponding thicknesses d are obtained by changing the inflation quantity n, and therefore a series of numerical values n are finally obtained₁、d₁，n₂、d₂，…，n_i、d_iLet the initial thickness of the second battery be d₀The amount of inflation n and the increment of cell thickness (d-d) are plotted by the obtained values₀) Fitting the curve to obtain the functional relationship f of the air inflation n and the thickness d, namely n ═ f (d).

The invention is further improved in that:

the operation of inflating the battery cavity of the second battery through the inflating component and the guide pipe comprises the following steps:

(1) first of all in the catheterAir and ensures a first pressure value P₁And a second pressure value P₂Initial value P of₁₀And P₂₀Equal to local atmospheric pressure, wherein the first pressure value P₁The real-time pressure value detected by the first pressure detection device, the second pressure value P₂A real-time pressure value detected by the second pressure detection means;

(2) closing the first control valve, opening the second control valve, inflating the gas storage tank through the inflating device, closing the second control valve after the inflation is finished, and recording a second pressure value P₂₁；

(3) Opening the first control valve, the third control valve and the fourth control valve, inflating the battery cavity through the gas storage tank, after the inflation is stable, closing the first control valve, and recording a first pressure value P₁₂And a second pressure value P₂₂The method for checking the stability of the inflation comprises the following steps: if P₁₂＝P₂₂The aeration is stable; then closing the third control valve and the fourth control valve;

(4) repeating the steps (2) and (3), wherein the inflation is increased once every time the steps (2) and (3) are executed, the gas in the battery cavity of the battery II is continuously increased, the battery is finally broken, and the inflation is stopped after the battery is broken; each time steps (2) and (3) are performed, an array m ═ P is obtained₂₁，P₁₂，P₂₂Get it writtenFor the set of values recorded when steps (2) and (3) were performed the ith time, i.e. m_iThe value set obtained for the ith inflation.

The invention is further improved in that:

the operation of acquiring the inflation quantity n in the battery cavity comprises the following steps:

inflation amount for the 1 st time:

in the formula, V₁Is the volume of the gas storage tank, V₂R is the ideal gas for the internal volume of the conduitConstant, T is the ambient temperature, V₂The inner diameter and the length of the conduit are calculated;

total inflation after the 2 nd inflation:

the second inflation is performed on the basis of the first inflation, so that the total inflation amount after the second inflation includes the inflation amount during the first inflation;

total inflation amount after the t-th inflation (2< t ≤ i):

the invention is further improved in that:

the operation of replacing air in the conduit in the step (1) comprises the following steps:

closing the first control valve, the third control valve and the fourth control valve, opening the second control valve, inflating the gas storage tank through the inflating device, and when the second pressure value P is₂When the pressure is higher than the atmospheric pressure, the second control valve is closed;

and opening the connecting device, the first control valve and the fourth control valve in sequence, closing the fourth control valve and the first control valve in sequence after discharging the air in the guide pipe, and screwing on the connecting device.

Compared with the prior art, the invention has the beneficial effects that:

(1) the method can realize measurement of the gas production in the battery under the condition of not damaging the battery shell, and therefore, the method can be used for researching the expansion process of the battery during the thermal runaway evolution of the battery.

(2) The online measurement of the gas yield of the battery during the thermal runaway of the battery caused by abuse of the battery can be realized, namely, the real-time monitoring of the gas yield can be realized when the gas is rapidly produced due to side reaction in the lithium battery; the prior art can not realize the measurement of the gas production under two conditions of 'quick gas production' and 'real-time monitoring' at the same time.

Drawings

Fig. 1 is a schematic view of a square-casing battery provided in the present invention;

FIG. 2 is a diagram of a device for testing the real-time gas production rate inside a battery according to the present invention;

FIG. 3 is a schematic view of a battery fastening device according to the present invention;

FIG. 4 is a schematic view of a distance measuring device;

FIG. 5 is a flow chart of a method for testing the real-time gas production rate inside a battery according to the present invention.

In the drawing, 10, a battery, 100, a battery chamber, 101, a maximum surface, 102, a maximum facing surface, 103, a side surface, 104, a side facing surface, 105, an upper end cap, 106, a lower surface, 110, a guide tube, 120, a K-type thermocouple, 20, a fastening means, 210, an explosion-proof can, 220, a support plate, 230, a nut, 240, a screw, 250, an L-shaped clamp plate, 30, a distance measuring means, 310, a blade, 320, the pressure measuring device comprises a cursor 330, a first outer measuring jaw 340, a second outer measuring jaw 350, a connecting rod 360, a first sliding groove 370, a second sliding groove 380, a data line 390, a digital display device 40, a trigger device 510, a first pressure detecting device 520, a second pressure detecting device 530, a first control valve 540, a second control valve 550, a third control valve 560, a fourth control valve 570, a connecting device 580, an inflating device 590, an air storage tank 60 and a control device.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

the invention provides a device and a method for testing the real-time gas production in a battery.A battery II is inflated to obtain a functional relation f between the inflation quantity n and the thickness d, namely n ═ f (d); triggering (heating or charging) the battery through a triggering device to generate thermal runaway, recording heating or charging time and surface temperature of the battery, and simultaneously monitoring a series of thicknesses d of the battery during the thermal runaway evolution^*D is mixing^*Calculating a series of n by substituting the function f^*With time or temperature as abscissa, n^*And obtaining a change curve of the gas production rate in the battery during the thermal runaway evolution by the ordinate.

The first battery at least comprises a shell and a battery core arranged in the shell. And preparing a second battery, wherein the internal material properties and the shell properties of the second battery are the same as those of the first battery.

For convenience of description of the common parts of the first battery and the second battery, the first battery and the second battery are collectively referred to as the battery 10, and as shown in fig. 1, the main body of the battery 10 has six surfaces: a maximum surface 101, a maximum opposing surface 102, an upper end cap 105, a lower surface 106, a side surface 103, a side opposing surface 104. Wherein, the maximum surface 101 and the maximum opposite surface 102 are two maximum surfaces of the battery, and the deformation of the maximum surface 101 and the maximum opposite surface 102 is the largest when the internal pressure of the battery is increased. (three invisible surfaces are shown by dotted lines in FIG. 1)

The upper end cover 105 of the second battery is provided with a hole, the lower end of the conduit 110 is connected with the hole, the conduit 110 is communicated with the battery cavity 100, and the battery cavity 100 can be inflated through the conduit 110.

Example 1

The embodiment of the invention discloses a device for testing real-time gas production in a battery, as shown in figure 2, the structure of the device specifically comprises:

an explosion-proof can 210;

the inflatable part comprises a guide pipe 110, one end of the guide pipe 110 is connected with a connecting device 570, the other end of the guide pipe 110 is connected with an outlet of the air storage tank 590, an inlet of the air storage tank 590 is connected with an inflatable device 580 through a pipeline, and one end of the guide pipe 110, which is connected with the connecting device 570, extends into the anti-explosion tank 210;

a distance measuring device 30 disposed in the explosion-proof can 210 for measuring a distance between the maximum surface and the maximum pair of surfaces of the battery, i.e., the thickness of the battery;

and the triggering device 40 is arranged at the bottom of the explosion-proof tank 210 and is used for triggering the battery to heat or charge the battery.

Further preferably, the structure of the explosion-proof tank 210 can be referred to in the patent application No. 201610375908.X, the connection between the conduit 110 and the explosion-proof tank 210 is sealed, the explosion-proof tank mainly ensures the safety of the test, and no special requirement is imposed on the shape of the tank.

Further preferably, the testing device further comprises a fastening device 20, the battery is fixed in the explosion-proof tank 210 through the fastening device 20, the fastening device 20 is structured as shown in fig. 3, and comprises a supporting plate 220 arranged at the bottom of the explosion-proof tank 210, two L-shaped clamping plates 250 arranged oppositely are arranged on the supporting plate 220, the two L-shaped clamping plates 250 are used for clamping the side surface 103 and the measuring surface 104 of the battery, and the supporting plate 220 and the two L-shaped clamping plates 250 are fixed through a screw 240 and a nut 230.

Further preferably, the conduit 110 is provided with a first control valve 530, a first pressure detecting device 510 and a fourth control valve 560 in sequence from the gas storage tank 590 to the connecting device 570; the gas storage tank 590 is provided with a second pressure detection device 520, an inlet of the gas storage tank 590 is connected with an inflator 580 through a pipeline, and a second control valve 540 is arranged on the pipeline between the inflator 580 and the gas storage tank 590.

The inflator 580 (an inflator is an existing product, as long as the inflator is an inflatable device) inflates the gas storage tank 590 through the second control valve 540, and the second pressure detection device 520 is configured to detect the internal pressure of the gas storage tank 590. The gas storage 590 charges the battery chamber 100 through the first control valve 530, and the first pressure detection device 510 is used for detecting the pressure of the battery chamber 100 and the pressure of the conduit 110.

The gas filled by the gas filling device 580 should not react with the internal material of the battery and is non-flammable and non-explosive. Preferably, the gas is argon.

It is further preferable that a connection pipe is connected to the opening of the upper end cap 105 of the battery, the other end of the connection pipe is connected to the connection device 570, the connection pipe is provided with a third control valve 550, and the connection pipe is configured to: facilitating the replacement of air in the conduit 110. Because the air in the conduit 110 needs to be replaced when the air reservoir 590 is used to fill the battery chamber, the connection tube and the connection device 570 (the connection device 570 may be an existing joint for connecting two tubes) are provided, and the air in the conduit 110 can be exhausted from the connection device 570, i.e., from the lower end of the conduit 110, by opening the connection device 570. It should be noted that the air in the connecting tube between the connecting device 570 and the battery cavity 100 is not replaced, but is ignored, so the length of the connecting tube should be as short as possible.

Further preferably, as shown in fig. 4, the distance measuring device 30 includes a blade 310, a cursor 320, a first outer measuring jaw 330, a second outer measuring jaw 340, a connecting rod 350, a first sliding groove 360, a second sliding groove 370, a data line 380 and a digital display device 390.

The front of the ruler body 310 is provided with scales, the two ends of the ruler body 310 are respectively connected with a first sliding chute 360 and a second sliding chute 370 in a sliding manner, the first sliding chute 360 and the second sliding chute 370 are connected through a connecting rod 350, and the ruler body 310 can slide on the first sliding chute 360 and the second sliding chute 370; the ruler body 310 is connected with a vernier 320 in a sliding manner, the vernier 320 can slide on the ruler body 310, the vernier 320 is provided with a data line interface, the data line interface is connected with a digital display device 390 through a data line 380, preferably, the digital display device 390 can be a notebook computer, and distance data measured by the vernier 320 is transmitted to the digital display device 390 through the data line 380; the first outer measuring claw 330 is fixedly arranged on the ruler body 310, the second outer measuring claw 340 is fixedly arranged at the end part of the vernier 320 close to one end of the first outer measuring claw 330, the second outer measuring claw 340 can slide along with the sliding of the vernier 320, the first outer measuring claw 330 and the second outer measuring claw 340 are oppositely arranged, the first outer measuring claw 330 and the second outer measuring claw 340 are both in a disc shape, the material is high-temperature-resistant metal, such as a copper sheet or a steel sheet, and the material is directly in friction contact with the center of the surface of the battery or is adhered to the center of the surface of the battery by using high-temperature-resistant glue.

When measuring the distance, the connecting rod 350 is fixed in the explosion-proof tank 210 (which may be fixed by any means, such as bolts, etc.), and therefore, the first sliding groove 360 and the second sliding groove 370 are also fixed. When the maximum surface 101 and the maximum opposing surface 102 are deformed due to the expansion of the battery chamber 100, the first outer measuring jaw 330 and the second outer measuring jaw 340 can be always kept in close contact with the centers of the maximum surface 101 and the maximum opposing surface 102, respectively. When the battery expands and deforms, on one hand, the first outer measuring claw 330 can slide along the first sliding groove 360 and the second sliding groove 370 together with the ruler body 310, and on the other hand, the second outer measuring claw 340 can slide along the ruler body 310 together with the vernier 320, so that the vernier 320 can record the thickness of the battery in real time and continuously transmit the data of the thickness of the battery to the digital display device 390 through the data line 380.

As shown in fig. 2, a triggering device 40 is further disposed in the explosion-proof tank, and the triggering device 40 may be a heating device or a charging device, wherein the heating device is a heating plate or a heating sheet, and heats the battery by contacting with the battery, and preferably, the heating device may be directly placed at the bottom of the battery and directly contacts with the bottom of the battery; the charging device is a charger and is directly connected with the anode and the cathode of the battery through leads to charge the battery.

The first control valve 530, the second control valve 540, the third control valve 550, the fourth control valve 560 and the trigger device 40 are all connected with the control device 60 and are all electrically connected, and the on-off of the first control valve 530, the second control valve 540, the third control valve 550 and the fourth control valve 560 is controlled by the control device 60; the control device 60 controls the triggering device 40 to heat or charge the battery.

The embodiment of the invention provides a device for testing the real-time gas production rate in a battery, which has the working principle that:

firstly, fixing a second battery in an explosion-proof tank 210 through a fastening device 20, extending a guide pipe 110 into the explosion-proof tank 210 and sealing well, connecting a connecting pipe at an opening of an upper end cover 105 of the second battery with a connecting device 570 at one end of the guide pipe 110, inflating a battery cavity 100 of the second battery through an inflating part to obtain an inflating quantity n in the battery cavity 100, monitoring a thickness d of a shell of the second battery after the shell is inflated through a distance testing device 30, and obtaining a series of corresponding thicknesses d by changing the inflating quantity n, thereby finally obtaining a series of numerical values n₁、d₁，n₂、d₂，…，n_i、d_iLet the secondary initial thickness of the battery be d₀The amount of inflation n and the increment of cell thickness (d-d) are plotted by the obtained values₀) Fitting the curve to obtain a functional relation f of the inflation quantity n and the thickness d, namely n ═ f (d);

removing the second battery, fixing the first battery in the explosion-proof tank 210 through the fastening device 20, triggering the first battery to generate thermal runaway through the triggering device 40 in a heating or charging mode, recording heating or charging time, and using the K-type thermocouple 120 monitoring the surface temperature of a cell, while monitoring a series of thicknesses d of the cell during thermal runaway evolution by means of a distance measuring device 30^*D is mixing^*Calculating a series of n by substituting the function f^*，With time or temperature as abscissa, n^*And obtaining a variation curve of the gas production rate in the battery during the thermal runaway evolution as a vertical coordinate.

It should be noted that the K-type thermocouple 120 can be adhered to any surface of the battery through a high temperature resistant adhesive tape, preferably, as shown in fig. 2, since the deformation of the side surface 103 and the measurement surface 104 is small, the K-type thermocouple 120 is adhered to the center of the side surface 103 or the center of the measurement surface 104, and can be clamped by the L-shaped clamping plate 250, so that the K-type thermocouple 120 is not easy to fall off.

Example 2

The embodiment of the invention discloses a method for testing the real-time gas production in a battery, which has a specific flow shown in figure 4 and specifically comprises the following steps:

step 1, fixing a second battery in an explosion-proof tank 210, communicating the second battery with a conduit 110, inflating a battery cavity 100 of the second battery by using an inflating part, collecting a plurality of inflation quantity values and battery thickness increment values, drawing a curve relation, and fitting to obtain a functional relation f between inflation quantity n and thickness d, wherein n is f (d);

specifically, the battery cavity 100 of the second battery is inflated through the inflation component and the conduit 110 to obtain the inflation quantity n in the battery cavity 100, the thickness d of the casing of the second battery expanded due to inflation is monitored through the distance testing device 30, and a series of corresponding thicknesses d are obtained by changing the inflation quantity n, so that a series of numerical values n are finally obtained₁、d₁，n₂、d₂，…，n_i、d_iLet the initial thickness of the second battery be d₀The amount of inflation n and the increment of cell thickness (d-d) are plotted by the obtained values₀) Fitting the curve to obtain the functional relationship f of the air inflation n and the thickness d, namely n ═ f (d).

Preferably, the specific process of inflating the battery II is as follows:

(1) first displacing air from the conduit 110 and ensuringFirst pressure value P₁And a second pressure value P₂Initial value P of₁₀And P₂₀Equal to local atmospheric pressure, wherein the first pressure value P₁The real-time pressure value detected by the first pressure detecting means 510, the second pressure value P₂The real-time pressure value detected by the second pressure detecting means 520;

preferably, the method of displacing air in the conduit 110 is:

the first control valve 530, the third control valve 550 and the fourth control valve 560 are closed, the second control valve 540 is opened, the air storage tank 590 is charged by the air charging device 580, and when the second pressure value P is₂Slightly above atmospheric pressure, the second control valve 540 is closed;

the connection device 570, the first control valve 530 and the fourth control valve 560 are opened in sequence, air in the conduit 110 is exhausted due to the fact that the pressure in the air storage tank 590 is higher than the ambient atmospheric pressure (the air is exhausted from the connection device 570, namely from the lower end of the conduit 110, because the connection device 570 is already opened), after the air in the conduit 110 is exhausted, the fourth control valve 560 and the first control valve 530 are closed in sequence, and then the connection device 570 is screwed on.

(2) Closing the first control valve 530, opening the second control valve 540, inflating the air storage tank 590 by an inflation device 580, closing the second control valve 540 after the inflation is finished, and recording a second pressure value P₂₁；

(3) Opening the first control valve 530, the third control valve 550 and the fourth control valve 560, filling air into the battery cavity 100 through the air storage tank, after the air filling is stable, closing the first control valve 530, and recording a first pressure value P₁₂And a second pressure value P₂₂The method for checking the stability of the inflation comprises the following steps: if P₁₂＝P₂₂The aeration is stable; then the third control valve 550, the fourth control valve 560 are closed;

(4) repeating the steps (2) and (3), wherein the inflation is increased once every time the steps (2) and (3) are executed, the gas in the battery cavity 100 of the battery II is continuously increased, the battery is finally cracked, and the inflation is stopped after the battery is cracked; each time steps (2) and (3) are performed, an array m ═ P is obtained₂₁，P₁₂，P₂₂Get it writtenFor the set of values recorded when steps (2) and (3) were performed the ith time, i.e. m_iThe value set obtained for the ith inflation.

In the method, the calculation method of the air inflation amount n comprises the following steps:

inflation amount for the 1 st time:

in the formula, V₁Is the volume, V, of the gas reservoir 590₂For the internal volume of conduit 110, R is the ideal gas constant, T is the ambient temperature, V₂Can be calculated from the inner diameter and length of the catheter 110. The first term on the right of the equation represents the total charge provided by the reservoir 590 to the battery chamber 100 and the associated conduit 110, and the second term on the right of the equation represents the charge provided by the reservoir 590 to the conduit 110;

total inflation after the 2 nd inflation:

the second inflation is performed on the basis of the first inflation, so that the total inflation amount after the second inflation includes the inflation amount during the first inflation;

total inflation amount after the t-th inflation (2< t ≤ i):

step 2, removing the battery II, fixing the battery I in the explosion-proof tank 210 (the battery I does not need to be provided with a hole connected with the guide pipe 110 on the upper end cover, when the step 2 is carried out, the guide pipe 110 and the connecting device 570 can not be placed in the explosion-proof tank 210), and triggering the battery to generate thermal runaway through the triggering device 40Recording heating or charging time, monitoring surface temperature of the battery by a K-type thermocouple 120, and monitoring a series of thicknesses d of the battery during thermal runaway evolution by a distance measuring device 30^*D is mixing^*Substituting the function f obtained in the step 1 to calculate a series of n^*With time or temperature as abscissa, n^*And obtaining a change curve of the gas production rate in the battery during the thermal runaway evolution by the ordinate.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Finally, it should be noted that the above-mentioned technical solution is only one embodiment of the present invention, and it will be apparent to those skilled in the art that various modifications and variations can be easily made based on the application method and principle of the present invention disclosed, and the method is not limited to the above-mentioned specific embodiment of the present invention, so that the above-mentioned embodiment is only preferred, and not restrictive.