阅读说明：本技术 锂离子电池电解液离子电导率测试电解池及其测试方法 (Electrolytic cell for testing ionic conductivity of lithium ion battery electrolyte and testing method thereof ) 是由 孟繁慧 姜伟 高凡 朱莎 伍绍中 周江 于 2020-12-18 设计创作，主要内容包括：本发明涉及一种锂离子电池电解液离子电导率测试电解池,包括工作电极结构件和对电极结构件,工作电极结构件通过绝缘垫片与对电极结构件连接构成电导率测试电解池结构。电导率测试方法,配制电解液；采用原位聚合法制备凝胶电解液、半固态电解液和固态电解质、聚合物电解质单体溶液；将体积为V的电解液注入电解池中；将电解池加热处理,引发电解液中聚合物单体聚合,电解池中进行原位制备凝胶电解液、半固态电解液和固态电解质；采用电化学阻抗测试法,测试电解池的电化学阻抗谱图,计算离子电导率。有益效果：本发明通过限定测试厚度和测试面积,对包括锂离子电池液态电解液、凝胶电解液和半固态电解液进行离子电导率的测试,一致性和准确性好。(The invention relates to an electrolytic cell for testing ionic conductivity of lithium ion battery electrolyte, which comprises a working electrode structural member and a counter electrode structural member, wherein the working electrode structural member is connected with the counter electrode structural member through an insulating gasket to form a conductivity testing electrolytic cell structure. A conductivity test method, preparing electrolyte; preparing gel electrolyte, semi-solid electrolyte, solid electrolyte and polymer electrolyte monomer solution by adopting an in-situ polymerization method; injecting electrolyte with the volume V into the electrolytic cell; heating the electrolytic cell to initiate polymerization of polymer monomers in the electrolyte, and preparing gel electrolyte, semi-solid electrolyte and solid electrolyte in situ in the electrolytic cell; and testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity. Has the advantages that: the invention carries out the test of the ionic conductivity of the liquid electrolyte, the gel electrolyte and the semi-solid electrolyte of the lithium ion battery by limiting the test thickness and the test area, and has good consistency and accuracy.)

1. The utility model provides a lithium ion battery electrolyte ionic conductivity test electrolytic cell which characterized by: the device comprises a working electrode structural member and a counter electrode structural member, wherein the working electrode structural member is in threaded connection with the counter electrode structural member through an insulating gasket to form an integral conductivity test electrolytic cell structure.

2. The lithium ion battery electrolyte ionic conductivity test cell of claim 1, wherein: the shape of the insulating gasket is circular, a central hole is formed in the insulating gasket, and the shape of the central hole is circular, triangular, square or rhombic.

3. The lithium ion battery electrolyte ionic conductivity test cell of claim 1, wherein: the insulating gasket comprises a three-layer sandwich structure formed by a sealing layer, a structure supporting layer and a sealing layer which are sequentially connected, wherein the thickness of the structure supporting layer is 8-1 mm, the thickness of the sealing layer is 1-500 μm, and the total thickness of the insulating gasket is 10-2 mm.

4. The lithium ion battery electrolyte ionic conductivity test cell of claim 1, wherein: the structural supporting layer of the insulating gasket is a porous circular plastic sheet made of PE, PP, PVDF, PTFE or PET; the sealing layer is made of a rubber layer.

5. The lithium ion battery electrolyte ionic conductivity test cell of claim 1, wherein: the working electrode structure comprises a working electrode seat, a spring, a current collecting column, a limiting column, a working electrode and an insulating sleeve, wherein a stepped central hole is formed in the working electrode seat, the spring is sleeved at the front end of the current collecting column, the rear end of the current collecting column is connected with the limiting column in a sliding mode, the front end of the current collecting column penetrates through the central hole of the working electrode seat, the rear end of the current collecting column penetrates through the limiting column and then is connected with a working electrode in a threaded mode, the limiting column is connected with the working electrode seat in a threaded mode to form a cylindrical working electrode structure, the shape of the counter electrode structure is cylindrical, the center of the counter electrode structure is provided with a stepped hole, an insulating lining is arranged in the stepped hole, and the bottom.

6. The lithium ion battery electrolyte ionic conductivity test cell of claim 1, wherein: the insulating ring is made of PE, PP, PVDF, PTFE, PET or rubber, the thickness is 0.5mm-2mm, the height is 5mm-20mm, the insulating lining is made of PTFE and PET, and the thickness is 1mm-3 mm.

7. A method for testing the ionic conductivity of the lithium ion battery electrolyte by applying the electrolytic battery is characterized by comprising the following steps: the method comprises the following steps:

step 1, preparing electrolyte to be tested according to test requirements; preparing a polymer electrolyte monomer solution according to the formula requirements aiming at gel electrolyte, semi-solid electrolyte and solid electrolyte prepared by an in-situ polymerization method;

step 2, preparing an ion conductivity test electrolytic cell, and calculating the volume V, V-d pi r of electrolyte to be injected²Setting the thickness of the insulating gasket as d and the inner diameter of the insulating ring as 2r, and injecting electrolyte with the volume of V into the electrolytic cell;

step 3, assembling the electrolytic cell and sealing; heating the electrolytic cell at 30-80 deg.C to initiate polymerization of polymer monomer in the electrolyte, and in-situ preparing gel electrolyte, semi-solid electrolyte and solid electrolyte;

and 4, testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity.

8. The conductivity test method according to claim 7, wherein: the electrolyte comprises liquid electrolyte of a lithium ion battery or gel electrolyte suitable for in-situ polymerization, semi-solid electrolyte and solid electrolyte.

Technical Field

The invention belongs to a lithium battery electrolyte testing technology, and particularly relates to an electrolytic cell for testing ionic conductivity of lithium ion battery electrolyte and a testing method thereof

Background

During the working process of the lithium ion battery, the lithium ion battery is internally accompanied with the transmission of lithium ions and electrons. Inside the lithium ion battery, the electron transmission is mainly conducted to the active material particle/electrolyte interface through the solid particles of the conductive network, especially the three-dimensional network formed by the conductive agent, to participate in the redox reaction of the electrode. The transmission of lithium ions is performed through electrolyte filled in electrode pores, and the performance of the lithium ion battery is affected by the conduction characteristics of the lithium ions, including the rate characteristic, the internal resistance, the heat generation performance of the battery and the like of the lithium ion battery. Therefore, the performance of the lithium ion battery can be predicted through the test of the ionic conductivity of the lithium ion battery electrolyte.

Generally, the ionic conductivity test of the liquid electrolyte is realized by using a conductive electrode, and the conductive electrode is generally two parallel electrode plates with the area A and the distance L determined, and corresponds to an electrode conductivity constant K. The resistance R is measured by electrochemical AC impedance, and the conductivity is measured

For the test of the ionic conductivity of the inorganic electrolyte, a sheet sample with the conductivity similar to the bulk conductivity can be obtained by cold pressing under certain pressure or sintering at lower temperature. The ionic conductivity of the inorganic electrolyte needs to be tested by an alternating current impedance method under the condition of keeping higher pressure so as to ensure that the electrolyte is in good contact with the mould.

The polymer electrolyte is typically tested by assembling the button cell with a punched polymer film sandwiched between stainless steel sheets. Determination of the geometry of the test apparatus is a difficult point in the conductivity test of polymers. The diameter of the polymer film is larger than that of the stainless steel sheet, so that the area of the polymer film is the area of the stainless steel sheet; its thickness is thin and the actual thickness varies to a large extent due to pressure when assembling the button cell.

At present, gel electrolytes and semi-solid electrolytes do not have the characteristics of liquid electrolyte flowability and high mechanical strength of solid electrolytes, and no fixed method is available for testing the ionic conductivity of the gel electrolytes and the semi-solid electrolytes.

Disclosure of Invention

The invention aims to overcome the defects of the technology and provides the lithium ion battery electrolyte ionic conductivity test electrolytic cell and the test method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme: the utility model provides a lithium ion battery electrolyte ionic conductivity test electrolytic cell which characterized by: the device comprises a working electrode structural member and a counter electrode structural member, wherein the working electrode structural member is in threaded connection with the counter electrode structural member through an insulating gasket to form an integral conductivity test electrolytic cell structure.

The shape of the insulating gasket is circular, a central hole is formed in the insulating gasket, and the shape of the central hole is circular, triangular, square or rhombic.

The insulating gasket comprises a three-layer sandwich structure formed by a sealing layer, a structure supporting layer and a sealing layer which are sequentially connected, wherein the thickness of the structure supporting layer is 8-1 mm, the thickness of the sealing layer is 1-500 μm, and the total thickness of the insulating gasket is 10-2 mm.

The structural supporting layer of the insulating gasket is a porous circular plastic sheet made of PE, PP, PVDF, PTFE or PET; the sealing layer is made of a rubber layer.

The working electrode structure comprises a working electrode seat, a spring, a current collecting column, a limiting column, a working electrode and an insulating sleeve, wherein a stepped central hole is formed in the working electrode seat, the spring is sleeved at the front end of the current collecting column, the rear end of the current collecting column is connected with the limiting column in a sliding mode, the front end of the current collecting column penetrates through the central hole of the working electrode seat, the rear end of the current collecting column penetrates through the limiting column and then is connected with a working electrode in a threaded mode, the limiting column is connected with the working electrode seat in a threaded mode to form a cylindrical working electrode structure, the shape of the counter electrode structure is cylindrical, the center of the counter electrode structure is provided with a stepped hole, an insulating lining is arranged in the stepped hole, and the bottom.

The insulating ring is made of PE, PP, PVDF, PTFE, PET or rubber, the thickness is 0.5mm-2mm, the height is 5mm-20mm, the insulating lining is made of PTFE and PET, and the thickness is 1mm-3 mm.

A method for testing the ionic conductivity of the lithium ion battery electrolyte by applying the electrolytic battery is characterized by comprising the following steps: the method comprises the following steps:

step 1, preparing electrolyte to be tested according to test requirements; preparing a polymer electrolyte monomer solution according to the formula requirements aiming at gel electrolyte, semi-solid electrolyte and solid electrolyte prepared by an in-situ polymerization method;

step 2, preparing an ion conductivity test electrolytic cell, and calculating the volume V, V-d pi r of electrolyte to be injected²Setting the thickness of the insulating gasket as d and the inner diameter of the insulating ring as 2r, and injecting electrolyte with the volume of V into the electrolytic cell;

step 3, assembling the electrolytic cell and sealing; heating the electrolytic cell at 30-80 deg.C to initiate polymerization of polymer monomer in the electrolyte, and in-situ preparing gel electrolyte, semi-solid electrolyte and solid electrolyte;

and 4, testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity.

The electrolyte comprises liquid electrolyte of a lithium ion battery or gel electrolyte suitable for in-situ polymerization, semi-solid electrolyte and solid electrolyte.

Has the advantages that: compared with the prior art, the method provided by the invention has the advantages that the ionic conductivity of the liquid electrolyte, the gel electrolyte and the semi-solid electrolyte of the lithium ion battery is tested by limiting the test thickness and the test area, and the consistency and the accuracy are good. The gel electrolyte, the semi-solid electrolyte and the solid electrolyte prepared by the in-situ polymerization method can be nondestructively tested without a diaphragm or other treatments. The method for testing the ionic conductivity of the lithium ion battery electrolyte has wide coverage range of test objects and is easy to apply and popularize.

Drawings

FIG. 1 is a structural isometric view of a lithium ion battery electrolyte ionic conductivity test cell;

FIG. 2 is an assembled view of the structure of FIG. 1;

FIG. 3 is an electrochemical impedance curve tested in example 1;

FIG. 4 is a plot of the electrochemical impedance measured in example 2;

figure 5 is an electrochemical impedance curve tested in example 3.

In the figure: 1. working electrode seat, 2, spring, 3, current collecting column, 4, spacing column, 5, working electrode, 6, insulating cover, 7, insulating gasket, 8, counter electrode structure, 9, insulating inside lining.

Detailed Description

So that the manner in which the above recited objects, features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. In addition, the embodiments and features of the embodiments of the present application may be combined with each other without conflict. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention, and the described embodiments are merely a subset of the embodiments of the present invention, rather than a complete embodiment. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In various embodiments of the present invention, for convenience in description and not in limitation, the term "coupled" as used in the specification and claims of the present application is not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.

Referring to fig. 1 and 2 in detail, the embodiment provides an electrolytic cell for testing ionic conductivity of electrolyte of a lithium ion battery, which includes a working electrode structural member and a counter electrode structural member, wherein the working electrode structural member is in threaded connection with the counter electrode structural member through an insulating gasket 7 to form an overall conductivity testing electrolytic cell structure. The working electrode structure comprises a working electrode seat 1, a spring 2, a flow collecting column 3, a limiting column 4, a working electrode 5 and an insulating sleeve 6, wherein a stepped central hole is formed in the working electrode seat, the spring is sleeved at the front end of the flow collecting column, the rear end of the flow collecting column is in sliding connection with the limiting column, the front end of the flow collecting column penetrates through the central hole of the working electrode seat, the rear end of the flow collecting column penetrates through the limiting column and then is in threaded connection with the working electrode, the limiting column is in threaded connection with the inner thread of the working electrode seat to form a cylindrical working electrode structure, the shape of the counter electrode structure is cylindrical, a stepped hole is formed in the center of the counter electrode structure, an insulating lining 9 is formed in the stepped hole, and an insulating sleeve is arranged at.

The preferable scheme of this embodiment is that the insulating gasket is circular, and the insulating gasket is equipped with the centre bore, and the shape of centre bore is circular, triangle-shaped, square or rhombus.

The preferable scheme of this embodiment is that the insulating gasket comprises a three-layer sandwich structure formed by a sealing layer, a structure supporting layer and a sealing layer which are connected in sequence, the thickness of the structure supporting layer is 8 μm-1mm, the thickness of the sealing layer is 1 μm-500 μm, and the total thickness of the insulating gasket is 10 μm-2 mm.

In a preferred embodiment of this embodiment, the structural support layer of the insulating gasket is a porous circular plastic sheet made of PE, PP, PVDF, PTFE or PET; the sealing layer is made of a rubber layer.

The preferable scheme of this embodiment is that the material of insulating ring is PE, PP, PVDF, PTFE, PET or rubber, and thickness is 0.5mm-2mm, and highly is 5mm-20mm, the material of insulating inside lining is PTFE and PET, and thickness is 1mm-3 mm.

A method for testing the ionic conductivity of the lithium ion battery electrolyte by applying the electrolytic battery is characterized by comprising the following steps: the method comprises the following steps:

step 1, preparing electrolyte to be tested according to test requirements; preparing a polymer electrolyte monomer solution according to the formula requirements aiming at gel electrolyte, semi-solid electrolyte and solid electrolyte prepared by an in-situ polymerization method;

step 2, preparing an ion conductivity test electrolytic cell, and calculating the volume V, V-d pi r of electrolyte to be injected²Setting the thickness of the insulating gasket as d and the inner diameter of the insulating ring as 2r, and injecting electrolyte with the volume of V into the electrolytic cell;

step 3, assembling the electrolytic cell and sealing; heating the electrolytic cell at 30-80 deg.C to initiate polymerization of polymer monomer in the electrolyte, and in-situ preparing gel electrolyte, semi-solid electrolyte and solid electrolyte;

and 4, testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity.

The electrolyte comprises liquid electrolyte of a lithium ion battery or gel electrolyte suitable for in-situ polymerization, semi-solid electrolyte and solid electrolyte.

The structure and operation of the present embodiment will be further explained with reference to the accompanying drawings

The electrolytic cell for testing ionic conductivity comprises a working electrode structural member, a counter electrode structural member and an insulating ring, and particularly comprises a permeable insulating gasket for supporting an electrolyte structure and isolating the working electrode and the counter electrode. The ionic conductivity test electrolytic cell can be used for testing the ionic conductivity of the lithium ion battery electrolyte for liquid electrolyte, gel electrolyte and semi-solid electrolyte of the lithium ion battery. The shape of the through insulating gasket is a circular gasket, and holes are formed in the gasket, wherein the shapes of the holes include one or more than one of a circle, a triangle, a square, a diamond and other polygons. The transparent insulating gasket is of a three-layer sandwich structure of a sealing layer/a structural support/a sealing layer, the structural support layer is arranged in the middle, the total thickness of the gasket is 10-2 mm, the thickness of the structural support layer is 8-1 mm, and the thickness of the sealing layer is 1-500 μm. In the sealing layer/structure support/sealing layer structure of the permeable insulating gasket, the structure support layer is a porous circular plastic sheet made of polymers with small deformation such as PE, PP, PVDF, PTFE, PET and the like; the sealing layer is made of a rubber layer and can deform to play a sealing role. The working electrode structural part and the counter electrode structural part are made of stainless steel materials and are connected by adopting a bolt/cap nut structure. The working electrode structural member, the insulating ring and the permeable insulating gasket are assembled to form an electrolytic cell with insulated working electrode and counter electrode. The working electrode structural part adopts a bolt structure, and the counter electrode structural part adopts a cap nut structure. The working electrode structure comprises a stainless steel electrode column, a stainless steel current collecting column, a stainless steel spring, a limiting column, a working electrode and an insulating sleeve, wherein the stainless steel spring is connected with the stainless steel electrode column and the stainless steel current collecting column, and the working electrode is ensured to be in contact with a test substance in the test process. The counter electrode structural member adopts a cover-shaped nut which is a stainless steel casting and is internally provided with an insulating lining to avoid the direct contact between the working electrode and the counter electrode. In the electrolytic cell for testing the ionic conductivity, the insulating ring is made of polymers such as PE, PP, PVDF, PTFE, PET, rubber and the like, the thickness is 0.5mm-2mm, and the height is 5mm-20 mm. The insulating lining of the counter electrode structural member is made of polymer materials with small deformation such as PTFE, PET and the like, and the thickness is 1mm-3 mm.

Example 1

A method for testing ionic conductivity of lithium ion battery electrolyte comprises the following steps:

1) first, in a glove box (moisture)<0.1ppm, oxygen content<0.1ppm) to prepare a lithium ion battery gel electrolyte with a formula mass ratio of LiPF₆: ECA: EC: EMC: VC: PS: azobisisobutyronitrile (AIBN) ═ 16%: 20%: 30%: 30%: 2%: 1%: 1 percent;

2) in a glove box (moisture)<0.1ppm, oxygen content<0.1ppm), preparing an ion conductivity test electrolytic cell which comprises a working electrode structural member, a counter electrode structural member, an insulating ring and an insulating gasket; the diameter of the insulating sheet is 1.8cm, the thickness is 1mm, and the hole area is 0.7693cm²And 0.25mL of electrolyte is injected into the electrolytic cell;

3) assembling an electrolytic cell in a glove box (the water content is less than 0.1ppm and the oxygen content is less than 0.1ppm), sealing, standing the electrolytic cell for 1 hour at normal temperature, and measuring;

4) and testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity.

Example 2

A method for testing ionic conductivity of lithium ion battery electrolyte comprises the following steps:

1) first, in a glove box (moisture)<0.1ppm, oxygen content<0.1ppm) to prepare a lithium ion battery gel electrolyte with a formula mass ratio of LiPF₆: DMC: EC: EMC: VC: PS: 1, 3-Dioxolane (DOL): azobisisobutyronitrile (AIBN) ═ 16%: 29%: 20%: 20%: 2%: 2%: 10%: 1 percent.

2) In a glove box (moisture)<0.1ppm, oxygen content<0.1ppm), preparing an ion conductivity test electrolytic cell which comprises a working electrode structural member, a counter electrode structural member, an insulating ring and an insulating gasket; the insulating sheet has a diameter of 1.8cm, a thickness of 500 μm, and a hole area of 0.3846cm²And 0.13mL of electrolyte was injected into the cell.

3) Assembling an electrolytic cell in a glove box (the water content is less than 0.1ppm and the oxygen content is less than 0.1ppm), sealing, standing the electrolytic cell for 12 hours at 60 ℃, and measuring.

4) And testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity.

Example 3

A method for testing ionic conductivity of lithium ion battery electrolyte comprises the following steps:

1) first, in a glove box (moisture)<0.1ppm, oxygen content<0.1ppm) to prepare lithium ionsThe battery semi-solid electrolyte has a formula mass ratio of LiPF₆: PPC: EC: EMC: VC: PS: pentaerythritol tetraacrylate (PET 4A): AIBN 16%: 15%: 30%: 30%: 2%: 2%: 4%: 1 percent.

2) In a glove box (moisture)<0.1ppm, oxygen content<0.1ppm), preparing an ion conductivity test electrolytic cell which comprises a working electrode structural member, a counter electrode structural member, an insulating ring and an insulating gasket; the insulating sheet has a diameter of 1.8cm, a thickness of 200 μm, and a hole area of 0.1538cm²And 0.05mL of the electrolyte was injected into the electrolytic cell.

3) Assembling an electrolytic cell in a glove box (the water content is less than 0.1ppm and the oxygen content is less than 0.1ppm), sealing, standing the electrolytic cell for 12 hours at 60 ℃, and measuring.

4) And testing the electrochemical impedance spectrogram of the electrolytic cell by adopting an electrochemical impedance testing method, and calculating the ionic conductivity.

According to the formula:the ionic conductivity of the electrolyte was calculated as follows:

the above detailed description of the lithium ion battery electrolyte ionic conductivity test cell and the test method thereof with reference to the embodiments is illustrative and not restrictive, and several embodiments can be enumerated within the scope of the limitations, so that variations and modifications thereof are within the scope of the present invention without departing from the general concept of the present invention.