阅读说明：本技术 一种锂电池负极析锂含量测试装置 (Lithium battery cathode lithium precipitation content testing device ) 是由 王其钰 张献英 郑杰允 禹习谦 李泓 于 2020-04-20 设计创作，主要内容包括：本发明提供了一种锂电池负极析锂含量的测试装置,包括反应容器、支撑架、封盖、反应物注入装置和气体检测装置。反应容器的内部限定出具有开口的反应腔体；支撑架沿横向设置在反应腔体内；封盖设置在开口处并与反应容器可拆卸连接,封盖上具有注入口和排出口；反应物注入装置与注入口连接；气体检测装置与排出口连接。本发明的测试装置可以将电池负极的某一待研究区域的金属作为待测试件来与反应物进行化学反应,并可以利用气体检测装置测量气体产物的量,进一步推算出该固定区域的金属析出定量分析结果,为电池特定区域的金属析出研究提供数据支持,进一步研究人员可利用本测试装置得出实验数据对电池做出改进。(The invention provides a testing device for lithium analysis content of a lithium battery cathode, which comprises a reaction container, a supporting frame, a sealing cover, a reactant injection device and a gas detection device. The interior of the reaction vessel defines a reaction cavity with an opening; the support frame is arranged in the reaction cavity along the transverse direction; the sealing cover is arranged at the opening and is detachably connected with the reaction container, and the sealing cover is provided with an injection port and a discharge port; the reactant injection device is connected with the injection port; the gas detection device is connected with the discharge port. The testing device can take the metal of a certain area to be researched of the battery cathode as a piece to be tested to carry out chemical reaction with a reactant, and can utilize the gas detection device to measure the amount of a gas product and further calculate the quantitative analysis result of the metal precipitation of the fixed area, thereby providing data support for the research of the metal precipitation of the specific area of the battery, and further utilizing the testing device to obtain experimental data by researchers to improve the battery.)

1. The utility model provides a lithium cell negative pole separates testing arrangement of lithium content which characterized in that includes:

a reaction vessel defining a reaction chamber having an opening therein;

the supporting frame is transversely arranged in the reaction cavity and used for placing a piece to be tested;

the sealing cover is arranged at the opening, is detachably connected with the reaction container and is used for sealing the reaction cavity, and is provided with an injection port and a discharge port which are respectively used for injecting reactants into the reaction cavity and discharging gas products out of the reaction cavity;

the reactant injection device is connected with the injection port and is used for injecting reactants in the reactant injection device into the reaction cavity, reacting with the to-be-tested piece and discharging the gas product; and

and the gas detection device is connected with the discharge port and is used for measuring the volume of the gas product.

2. The testing device of claim 1, wherein the cover further comprises:

two sealing mechanisms provided at the injection port and the discharge port, respectively, and each of the sealing mechanisms includes:

the first sealing sleeve is connected with the sealing cover and is provided with a sealing opening opposite to the injection opening or the discharge opening; and

and the sealing gasket is arranged between the first sealing sleeve and the sealing cover.

3. The test device of claim 1,

the reactant is a mixture comprising deionized water and a plurality of hydroxyl-containing compounds.

4. The testing device of claim 1, wherein the gas detection device comprises:

a gas volume measuring tube having one end connected to the discharge port through a conduit, the gas volume measuring tube having a marker liquid therein, the volume of the gas product being determined by measuring a moving distance of the marker liquid within the gas volume measuring tube under the pressure of the gas product; and

and the second sealing sleeve is sleeved at the end part of the gas volume measuring pipe connected with the conduit and is used for sealing the conduit and the gas volume measuring pipe so as to prevent the gas product from leaking.

5. The testing device of claim 4, further comprising:

the fixing frame is provided with a fixing clamp which is adjustable in height and used for clamping the gas volume measuring pipe, and the gas volume measuring pipe is clamped by the fixing clamp along the transverse direction.

6. The test device of claim 2, wherein the gasket is a rubber gasket.

7. The testing device of claim 1, wherein the support frame is a plexiglas grid.

8. The testing device of claim 1, wherein the reagent injection device is a syringe having graduated lines.

9. The testing device of claim 1, wherein the lid is a stainless steel lid.

10. The testing device of claim 4, wherein the gas volume measuring tube has an inner diameter of 1-4 mm.

Technical Field

The invention relates to a battery technology, in particular to a device for testing lithium precipitation content of a lithium battery cathode.

Background

In recent years, lithium ion batteries have been widely used in the fields of 3C (Computer, Communication and Consumer Electronics), electric vehicles, energy storage, and the like. During the production and use of the lithium battery, the negative electrode plate is accompanied with the phenomenon of lithium precipitation. The lithium precipitation of the negative electrode material is related to factors such as an electrode structure, the wetting property of an electrolyte, the conductivity, the temperature and the like, for example, the charging rate is too high, the charging temperature is too low, the damage capacity loss of the negative electrode structure after circulation is caused, the pores of a diaphragm are not uniform, and the distance between a positive electrode layer and a negative electrode layer is not uniform.

During the use of commercial lithium ion batteries, the lithium precipitation of the negative electrode can seriously affect the safety, cycle life, low-temperature performance and rapid charging capability of the lithium ion battery, and can cause serious safety accidents. With the rapid development of the related technologies of lithium ion batteries, people hope that future lithium ion batteries have longer service life, more excellent quick charge performance, better low-temperature cycle performance and capacity recovery capability, and unrelenting safety performance, however, all the performances of the lithium ion batteries are closely related to a lithium separation side reaction, and the battery aging process and the negative reaction kinetic change caused by the negative electrode material after lithium separation have great influence on the performances of the batteries.

At present, researchers directly or indirectly experiment lithium deposition side reactions from four aspects of aging characteristics, voltage curves, physical and chemical properties of batteries and physical and chemical properties of electrodes to obtain relevant research data. However, these methods can only prove whether the side reaction of lithium deposition occurs, and cannot perform quantitative analysis, and thus cannot judge whether lithium deposition exists in the lithium content of the negative electrode material.

Disclosure of Invention

The present invention has been made in view of the above problems, and aims to provide a test device for lithium deposition content of a negative electrode of a lithium battery, which overcomes or at least partially solves the above problems.

A further purpose of the invention is that the test device can accurately and quantitatively analyze the metal precipitation content of the battery cathode, and provides accurate data support for researchers.

The invention further aims to reduce the influence of the outside on the experiment and improve the accuracy of experimental data when the test device is used for reaction.

Particularly, the invention provides a device for testing the lithium precipitation content of a negative electrode of a lithium battery, which is characterized by comprising the following components:

a reaction vessel defining a reaction chamber having an opening therein;

the supporting frame is transversely arranged in the reaction cavity and used for placing a piece to be tested;

the sealing cover is arranged at the opening, is detachably connected with the reaction container and is used for sealing the reaction cavity, and is provided with an injection port and a discharge port which are respectively used for injecting reactants into the reaction cavity and discharging gas products out of the reaction cavity;

the reactant injection device is connected with the injection port and is used for injecting reactants in the reactant injection device into the reaction cavity, reacting with the to-be-tested piece and discharging the gas product; and

and the gas detection device is connected with the discharge port and is used for measuring the volume of the gas product.

Further, the cover further comprises:

two sealing mechanisms provided at the injection port and the discharge port, respectively, and each of the sealing mechanisms includes:

the first sealing sleeve is connected with the sealing cover and is provided with a sealing opening opposite to the injection opening or the discharge opening; and

and the sealing gasket is arranged between the first sealing sleeve and the through flow port.

Further, the reactant is a mixture comprising deionized water and a plurality of hydroxyl-containing compounds.

Further, the gas detection apparatus includes:

a gas volume measuring tube having one end connected to the discharge port through a conduit, the gas volume measuring tube having a marker liquid therein, the volume of the gas product being determined by measuring a moving distance of the marker liquid within the gas volume measuring tube under the pressure of the gas product; and

and the second sealing sleeve is sleeved at the end part of the gas volume measuring pipe connected with the conduit and is used for sealing the conduit and the gas volume measuring pipe so as to prevent the gas product from leaking.

Further, the test device further comprises:

the fixing frame is provided with a fixing clamp which is adjustable in height and used for clamping the gas volume measuring pipe, and the gas volume measuring pipe is clamped by the fixing clamp along the transverse direction.

Further, the sealing gasket is a rubber sealing gasket.

Further, the support frame is the organic glass grid.

Further, the reactant injection device is a syringe with graduation lines.

Further, the cover is a stainless steel cover.

Further, the inner diameter of the gas volume measuring pipe is 1-4 mm.

The testing device can take the metal of a certain area to be researched of the battery cathode as a piece to be tested to carry out chemical reaction with the reactant, and can measure the amount of the gas product. And a quantitative analysis result of metal precipitation of the fixed area is further calculated, data support is provided for metal precipitation research of a specific area of the battery, and further researchers can use the testing device to obtain experimental data to improve the battery.

Furthermore, the sealing mechanism can realize the sealing of the injection port and the discharge port, avoid the influence of external factors during the experiment and ensure the air tightness of the testing device. And the closing cap can be stainless steel, and the stainless steel can be processed into the closing cap of high accuracy, has further guaranteed this testing arrangement's gas tightness.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic view of a test apparatus according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of a closure according to an embodiment of the present invention.

Detailed Description

Referring to fig. 1 and 2, fig. 1 is a schematic diagram of a testing device according to an embodiment of the invention, and fig. 2 is a cross-sectional view of a cap according to an embodiment of the invention. The lithium battery negative electrode metal precipitation content testing device 10 comprises a reaction container 100, a support frame 120, a sealing cover 200, a reactant injection device 300, a gas detection device and the like.

The interior of the reaction vessel 100 defines a reaction chamber 110 having an opening. The support frame 120 is disposed in the reaction chamber 110 along the transverse direction for placing the test piece 130. The cover 200 is disposed at the opening and detachably connected to the reaction container 100 for sealing the reaction chamber 110, and the cover 200 has an inlet 230 and an outlet 240 for injecting a reactant into the reaction chamber 110 and discharging a gas product out of the reaction chamber 110. The reactant injection device 300 is connected to the injection port 230, and is used for injecting the reactant therein into the reaction cavity 110, reacting with the test piece 130, and discharging the gas product. A gas detection device is connected to the exhaust port 240 for measuring the volume of the gas product.

In this embodiment, the reaction vessel 100 may be used as the reaction vessel 100 for an experiment for measuring the metal deposition content of the battery negative electrode. The support frame 120 places the to-be-tested piece 130 on the support frame 120, the support frame 120 is placed in the reaction cavity 110, the to-be-tested piece 130 reacts with the reactant, and the metal precipitation amount of the to-be-tested piece 130 can be quantitatively calculated by utilizing the relation between the hydrogen content in the gas product and the reactant.

Wherein the test piece 130 may be a negative electrode material of a certain area to be studied on a lithium battery. In the production and use processes of the batteries, the negative electrode material is possibly affected by factors such as electrode structure, wetting of electrolyte, conductivity, temperature and the like, and is accompanied by metal precipitation, so that the service life and the use safety of the batteries are affected. At present, the existing research carries out direct or indirect experiments on lithium deposition side reactions from four angles of aging characteristics, voltage curves, physical and chemical properties of batteries and physical and chemical properties of electrodes, but quantitative analysis cannot be carried out, and whether lithium deposition exists in the lithium content of the negative electrode material cannot be judged.

Of course, after knowing the technical solution of the present application, the skilled person can also apply the testing apparatus to other primary battery negative electrode content testing experiments, such as sodium batteries, and the like, which will not be described herein.

In this embodiment, a metal in a certain region to be studied of the negative electrode of the battery may be used as the test object 130 to perform a related experiment, so as to obtain a quantitative result of metal precipitation in the region, provide data support for metal precipitation research in a specific region of the battery, and further enable a researcher to improve the battery by using the test device 10 to obtain experimental data.

In other embodiments of this application, reaction vessel 100 can also adopt the organic glass processing to form for reaction vessel 100 has the sufficient intensity and guarantees going on of reaction, and organic glass has the transparency simultaneously, is convenient for observe the reaction process.

The supporting frame 120 is used as a support for the test object 130 to be tested in the testing apparatus 10, and is disposed in the reaction chamber 110 along the transverse direction. And the structure of the support frame 120 can increase the contact area between the test piece 130 to be tested and the reactant, which is beneficial to the full and rapid reaction.

In other embodiments of this application, support frame 120 can be the organic glass grid, and organic glass still has certain chemical stability, has reduced the influence of external factor to the experiment again when providing sufficient area of contact for the reaction to be convenient for wash, guarantee that this testing arrangement 10 can recycle.

The closing cap 200 sets up at the opening part, can seal reaction cavity 110 when utilizing this testing arrangement 10 to carry out the experiment for whole experiment can be gone on under the environment inclosed relatively, gets rid of the influence of external factor to this experiment, makes data have certain reliability.

The cover 200 can be detachably connected to the reaction vessel 100, such as by screwing, clipping, etc., which are not listed here.

The reagent injecting device 300 is connected to the injection port 230, and the reagent injecting device 300 can be inserted from the injection port 230 during the experiment, and the reagent in the reagent injecting device is injected into the reaction cavity 110 to react with the test piece 130.

In other embodiments of the present application, the reactant injection device 300 may be a syringe having graduation marks. In the experiment, the needle of the syringe is inserted into the injection port 230 and the reactant sucked into the reaction chamber 110 is injected. And the graduation mark can control the reactant quantitatively, so that the reaction is sufficient.

A gas detection device is connected to the exhaust port 240 for measuring the volume of the gas product. In this embodiment, the test piece 130 and the reactant may be chemically reacted to generate gas, and the data related to the metal deposition of the battery negative electrode may be obtained according to the gas product.

In some embodiments of the present application, the closure 200 further comprises two sealing mechanisms. Two sealing mechanisms are provided at the injection port 230 and the exhaust port 240, respectively, and each sealing mechanism includes a first sealing boot 210 and a sealing gasket 220. A first sealing boot 210 is connected to the cover 200 and the first sealing boot 210 is provided with a sealing port 212 opposite to the injection port 230 or the discharge port 240. A gasket 220 is disposed between first seal gland 210 and closure 200. In this embodiment, the sealing mechanism may be used to seal the inlet 230 and the outlet 240, so as to reduce the influence of the inlet 230 and the outlet 240 on the testing device 10 and improve the air tightness of the testing device 10.

In some embodiments of the present application, the cover 200 may be stainless steel, which may be machined into the cover 200 with high precision, further ensuring the air tightness of the testing device 10.

In some embodiments, the gasket 220 is a rubber gasket, which can perform an insulation sealing between the cap 200 and the reaction vessel 100.

In some embodiments of the present application, the reactant is a mixture comprising deionized water and a plurality of hydroxyl containing compounds. In the present embodiment, the hydroxyl group-containing compound may include high-purity ethanol, ethylene glycol, and the like. The reactant is capable of chemically reacting with the metal of the test piece 130 to generate hydrogen gas. Quantitative data of the test piece 130 can be estimated from the relationship of the present chemical reaction in combination with the amount of hydrogen.

In other embodiments of the present application, the reactant is excessively disposed with respect to the negative electrode metal of the test piece 130 based on the above chemical reaction, so that the negative electrode metal of the test piece 130 can be completely reacted to measure an accurate amount of the negative electrode metal.

In some embodiments of the present application, the gas detection apparatus includes a gas volumetric measurement tube 400 and a second gland 410. One end of the gas volume measuring tube 400 is connected to the discharge port 240 through a pipe 420, and the inside of the gas volume measuring tube 400 is provided with a marking liquid 430, and the volume of the gas product is determined by measuring the moving distance of the marking liquid 430 in the gas volume measuring tube 400 under the pressure of the gas product. A second gland 410 is fitted over the end of the gas volumetric measuring tube 400 connected to the conduit 420 for sealing the conduit 420 and the gas volumetric measuring tube 400 against leakage of gaseous products.

In the present embodiment, the gas volume measuring tube 400 is connected to the discharge port 240 through the guide tube 420, and when the reaction proceeds, the gas product generated inside the reaction vessel 100 may enter the gas volume measuring tube 400 through the guide tube 420 under pressure and push the marking liquid 430 to move within the gas volume measuring tube 400. The researcher can calculate the amount of gas product produced during the reaction by recording the distance traveled by the marker liquid 430 before and after the reaction, and by combining the inner diameter of the gas volumetric measuring tube 400.

In the present embodiment, the marking liquid 430 may be a substance that is visually distinguished from the gas product and the gas volume measuring tube 400 and cannot chemically react with the gas product, and there is no wall built up in the gas volume measuring tube 400 during the movement of the marking liquid 430, so as to reduce the error of the measurement of the gas product. The skilled person can select a suitable substance as the marking liquid 430 by combining the above features, and the category of the marking liquid 430 is not particularly limited in the present application.

In order to eliminate the influence of other gases generated by the reaction on the test result, in other embodiments of the present application, the content of the gases generated by the reaction is measured by using the gas volume measuring tube 400, then 1-2ml of gas products are collected in the reaction cavity by using an injector as a sample, the sample is subjected to ratio measurement by using gas chromatography-mass spectrometry to determine the proportion of hydrogen in the sample, and finally, the accurate content of hydrogen is determined by the content of the gases generated by the reaction and the proportion of hydrogen, so that the test accuracy is improved.

In some embodiments of the present application, the present testing device 10 further comprises a fixture 500. The fixing frame 500 is provided with a fixing clip 510 which is height-adjustable and is used for clamping the gas volume measuring tube 400, and the gas volume measuring tube 400 is clamped by the fixing clip 510 in the transverse direction.

The workflow of the test apparatus 10 in some embodiments of the present application is:

step one, cleaning and drying the testing device 10;

transferring the reaction cavity 120, the sealing device 200, the first sealing sleeve 210, the sealing gasket 220 and the support frame 120 into an inert atmosphere glove box, and weighing the to-be-tested piece 130 in the to-be-researched area on the negative electrode of the to-be-tested battery;

placing the to-be-tested piece 130 on the support frame 120, placing the support frame 120 and the to-be-tested piece 130 in the reaction cavity 110, installing the sealing cover 200, the first sealing sleeve 210 and the sealing gasket 220, and taking out the to-be-tested piece 130 from the inert atmosphere glove box after the installation is finished;

step four, connecting the reactant injection device 300 with the injection port 230, and connecting the gas volume measuring tube 400 with the discharge port 240 through the conduit 420;

step five, recording a first position of the marking liquid 430 in the gas volume measuring tube 400;

sixthly, injecting the reactant to be injected into the reactant injection device 300 into the reaction cavity 110 for chemical reaction;

seventhly, recording the second position when the liquid 430 to be marked moves from the first position to the second position and is kept at the second position;

step eight, calculating the volume of the gas product by combining the inner diameter of the gas volume measuring tube 400 through the distance between the first position and the second position;

step nine, pulling out the reactant injection device 300, inserting the reactant injection device into the reaction cavity 110 through a syringe 220, taking out 1-2ml of gas sample, and measuring the volume ratio of hydrogen through gas chromatography. Calculating to obtain the total amount of the internally generated hydrogen by combining the volume of the gas product;

the amount of the metal of the test piece 130 is calculated according to the chemical reaction formula of the reactant and the metal of the test piece 130 and the total amount of the hydrogen gas of the gas product.

Wherein, step two and step three in the above-mentioned flow are carried out under inert atmosphere, in order to avoid the air to cause the influence on the experiment, improve the accuracy of this testing arrangement 10.

When the testing device 10 is used for measuring the metal precipitation content of the negative electrode of the battery, the battery can be a lithium battery or a sodium battery, wherein the battery to be tested can be a certain area on the negative electrode of the lithium battery or a certain area on the negative electrode of the sodium battery.

It should be noted that the above-mentioned work flow is only a specific experiment based on the present testing device 10, but those skilled in the art can also apply the present testing device 10 to other related testing experiments, such as experiments that need to calculate the amount of fixed or even liquid reactant by gas product, and will not be described herein.

In some embodiments of the present disclosure, the inner diameter of the reaction vessel 100 is 15 to 22mm, the wall thickness of the reaction vessel 100 is 2 to 5mm, the height of the reaction vessel 100 is 400 to 500mm, and the outer diameter of the reaction vessel 100 is 20 to 30 mm.

The outer diameter of the sealing cover 200 is 32-40 mm, and the height of the first sealing sleeve 210 is 2-5 mm; the diameter of the sealing gasket 220 is 5-8 mm.

The outer diameter of the second sealing sleeve 410 is 3-8 mm, the inner diameter of the second sealing sleeve 410 is 3-8 mm, and the height of the second sealing sleeve 410 is 3-8 mm; the external diameter of gaseous volumetric survey buret 400 is 3 ~ 8mm, and the internal diameter of gaseous volumetric survey buret 400 is 1 ~ 4mm, and the length of gaseous volumetric survey buret 400 is 150 ~ 250mm, and gaseous volumetric survey buret 400 adopts less diameter, the volume of ability accurate measurement gas product.

The height of the fixing clip 510 is not less than 80 mm.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.