CN112229766A - Method for detecting infiltration effect of electrolyte - Google Patents
Method for detecting infiltration effect of electrolyte Download PDFInfo
- Publication number
- CN112229766A CN112229766A CN202011056116.9A CN202011056116A CN112229766A CN 112229766 A CN112229766 A CN 112229766A CN 202011056116 A CN202011056116 A CN 202011056116A CN 112229766 A CN112229766 A CN 112229766A
- Authority
- CN
- China
- Prior art keywords
- electrolyte
- detecting
- detection
- metal salt
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
Abstract
The invention provides a method for detecting the infiltration effect of electrolyte, which comprises the steps of replacing lithium hexafluorophosphate in standard electrolyte components with soluble metal salt to prepare electrolyte for detection; soaking the dry battery cell with detection electrolyte, standing at high temperature for a period of time, and preparing to obtain a soaked battery cell; and drying the infiltrated cell, cutting along the cross section of the infiltrated cell, collecting the cross section image of the sample to be detected, and obtaining the distribution condition of metal elements in the soluble metal salt so as to judge the infiltration effect of the electrolyte. According to the method for detecting the electrolyte infiltration effect, the infiltration effect of the electrolyte can be accurately judged by judging the distribution condition of the metal elements in the soluble metal salt, so that the process time for infiltrating the electrolyte can be accurately set, the performance of the battery can be better ensured, the construction and operation cost of a production line can be minimized, and the method has important significance for reducing the cost of a battery pack.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a method for detecting an electrolyte infiltration effect.
Background
With the development of the new energy automobile market, the demand of the lithium ion power battery is more and more vigorous, and meanwhile, the industry competition and the product competition are more and more intense. In the production process of the lithium ion power battery, the electrolyte infiltration is an important link in the design and production process of the battery. Insufficient electrolyte infiltration can directly affect the performance of the battery, and too long electrolyte infiltration time can cause great increase of production construction and operation cost.
Generally, the electrolyte impregnation is carried out by high temperature standing, and the standing temperature is generally between 40 ℃ and 55 ℃. Because the infiltration degree and the standing time of the pole piece and the battery core are closely related to parameters such as pole piece materials, compaction, pole group thickness, battery size and the like, the standing time of different products is different from dozens of hours to dozens of hours.
However, no effective method is available in the industry at present for accurately detecting the electrolyte infiltration effect, so in order to ensure sufficient infiltration, a conservative manner of prolonging the infiltration time is generally adopted in the industry, and the cost of the battery is increased.
At present, two methods for setting the soaking and standing process time in the industry are mainly adopted: analog estimation and performance testing.
The analog estimation method is also set by directly estimating with reference to the similar products. The infiltration standing process time of the reference product is poor in accuracy, so that the process time estimated after the analogy is also poor in accuracy, and systematic deviation and technical stagnation of a company are caused.
A performance experiment method, namely designing batteries with different soaking and standing times, and judging the soaking effect by disassembling a part of batteries to observe an interface and weighing the weight of a battery core; and the other part is made into a battery, and the electrical property is tested to judge the infiltration effect. The method has the advantages of complex test flow, long period and large error of results due to the limitation of the number of samples and easy influence of process factors.
Disclosure of Invention
In view of the above, the present invention is directed to a method for detecting an electrolyte infiltration effect, so as to relatively accurately determine the electrolyte infiltration effect.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method for detecting the infiltration effect of electrolyte comprises the following preparation steps:
s1 preparation of electrolyte for detection
Replacing lithium hexafluorophosphate in the standard electrolyte component with soluble metal salt to prepare electrolyte for detection;
s2 infiltrating dry electric core
Soaking the dry battery cell with the detection electrolyte, and standing at a high temperature for a period of time;
s3, drying
Taking out the soaked battery cell from the battery shell body and drying;
s4, preparing a sample to be detected
Cutting along the cross section of the infiltration electric core to prepare a sample to be detected;
s5, detection
And collecting a cross section image of the sample to be detected, and obtaining the distribution condition of metal elements in the soluble metal salt so as to judge the infiltration effect of the electrolyte.
Further, in step S1, the concentration of the electrolyte for detection is not less than 1 mol/L.
Further, in step S1, the lithium hexafluorophosphate and the soluble metal salt are equal in mass.
Further, in step S1, the soluble metal salt includes a sodium salt.
Further, the sodium salt includes sodium hexafluorophosphate.
Further, in step S3, the soaked battery cell is dried by a freeze-drying process until all the solvent in the detection electrolyte salt on the soaked battery cell is sublimated.
Further, in step S4, the sample to be detected is taken from the middle of the soaked battery cell.
Further, in step S4, the cross section of the sample to be detected is processed by a polishing process.
Further, in step S5, a cross-sectional image of the sample to be detected is acquired by using a scanning electron microscope.
Further, in step S5, an electron microscope image of the metal elements in the soluble metal salt is obtained, and the infiltration effect is determined according to the uniformity of the distribution of the metal elements.
Compared with the prior art, the invention has the following advantages:
according to the method for detecting the electrolyte infiltration effect, lithium hexafluorophosphate in the standard electrolyte component is replaced by the soluble metal salt, and the distribution condition of metal elements in the soluble metal salt is judged, so that the infiltration effect of the electrolyte can be accurately judged, the process time for infiltrating the electrolyte can be accurately set, the performance of the battery can be better ensured, the construction and operation cost of a production line can be minimized, and the method has important significance for reducing the cost of a battery pack.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be described in detail with reference to examples.
The embodiment relates to an electrolyte infiltration effect detection method which mainly comprises the following preparation steps of preparing electrolyte for detection, infiltrating a dry battery cell, drying, preparing a sample to be detected and detecting by an electron microscope.
In order to better understand the present embodiment, the structure of the battery pack and the manufacturing process of the battery pack will be briefly described below.
The structure of the battery pack is briefly described, and the battery pack mainly comprises a battery pack shell, wherein a containing cavity is formed in the battery pack shell, and a battery core is arranged in the containing cavity. The battery cell mainly comprises a positive electrode, a diaphragm and a negative electrode, and the outer surfaces of the positive electrode and the negative electrode are respectively coated with a coating. During actual preparation, the diaphragm, the anode, the diaphragm and the cathode are sequentially and circularly arranged in sequence to prepare the dry cell.
The production process of the battery pack mainly comprises the following steps of respectively preparing a dry battery core, electrolyte and a battery pack shell, installing the dry battery core into a containing cavity of the battery pack shell, then injecting the electrolyte into the containing cavity, and standing for a period of time at a high temperature of generally 40-55 ℃ to ensure that the electrolyte fully infiltrates coatings on the surfaces of a positive electrode and a negative electrode so as to ensure that the battery pack has excellent performance. Because different dry cells have different parameters such as pole piece materials, compaction, pole group thickness, battery size and the like, the required soaking time is different.
Next, the method for detecting the electrolyte infiltration effect of this embodiment will be described in detail, which includes the following steps:
s1 preparation of electrolyte for detection
And replacing lithium hexafluorophosphate in the standard electrolyte component with soluble metal salt to prepare the electrolyte for detection. It should be noted that the standard electrolyte is a conventional electrolyte applied to the production of a battery pack, and specific components of the standard electrolyte can refer to the prior art, but the main difference between the electrolyte for detection and the standard electrolyte in this embodiment is that only lithium hexafluorophosphate in the components of the standard electrolyte is replaced by a soluble metal salt, so as to facilitate the observation of the distribution of the metal salt in the subsequent step by using an electron microscope.
Because the main component elements of the standard electrolyte, such as C, H, O, F, P, Li, are coincided with the electrode material elements and cannot track the infiltration diffusion of the electrolyte, soluble metal salt needs to be selected and needs to have certain solubility in the electrolyte, so that the soluble metal salt is adopted to replace lithium hexafluorophosphate in the embodiment, and the prepared electrolyte for detection simulates the standard electrolyte to detect the infiltration effect.
In a preferred embodiment, sodium salt is used as the soluble metal salt, and sodium hexafluorophosphate is preferred as the sodium salt in this embodiment, and the addition amounts of lithium hexafluorophosphate and sodium hexafluorophosphate are equal, so as not to affect the infiltration speed due to too large difference of the addition amounts. Therefore, in the method for detecting the electrolyte infiltration effect of the embodiment, although the components of the detection electrolyte and the standard electrolyte are different, the infiltration speed is not greatly affected, and therefore the detection electrolyte can be used to replace the standard electrolyte to determine the infiltration effect.
In order to clearly observe the infiltration effect, the metal elements in the soluble metal salt need to reach a certain component ratio so as to be conveniently scanned and displayed by an electron microscope. Therefore, in the present embodiment, the concentration of the electrolyte solution for detection is not less than 1mol/L, so as to meet the requirement of the electron microscope for testing accuracy. The coating on the common positive plate adopts nickel cobalt lithium manganate or lithium iron phosphate, and the porosity of the nickel cobalt lithium manganate is more than 20%, and the porosity of the lithium iron phosphate is more than 30%, so that the lithium iron phosphate can fully soak the positive plate according to the measurement of 1mol/L of the salt concentration of the common standard electrolyte, the mass ratio of the soluble metal salt in the electrolyte after the drying of the positive plate in the nickel cobalt lithium manganate coating is about 1%, and the mass ratio in the lithium iron phosphate coating is about 2%, so that the requirement of the test precision of an electron microscope can be met.
S2 infiltrating dry electric core
When the dry electric core is actually soaked, a liquid injection hole is reserved on a common battery pack shell, electrolyte for detection is injected into the battery pack shell containing the dry electric core to block the liquid injection hole, and the battery pack shell is stood at a high temperature for a period of time. In the step, the dry electric cores are produced according to the conventional production process of the battery pack, the standing temperature is generally 40-55 ℃, and the standing time can be estimated according to the dry electric cores of the infiltration time to be judged. It should be noted that, the dry battery core is placed in the battery case body when the dry battery core is soaked, so as to truly simulate the actual production process of the battery case, and in the process, the dry battery core can be placed in the battery case body for soaking, and certainly, the dry battery core can be placed in other containers capable of containing the dry battery core and electrolyte for soaking.
S3, drying
Disassembling the battery pack, taking out the soaked battery cell from the battery pack shell, and drying the taken out battery cell; in this step, the infiltrated cell is preferably dried by a freeze-drying process until all the solvent in the electrolyte salt for detection is sublimated, so as to avoid affecting the detection of the electron microscope.
In this step, the reason why the freeze drying process is adopted is that the normal drying is heating drying, and the heating process accelerates the diffusion of the electrolyte, and changes the initial state of the electrolyte infiltration in the sample to be detected, thereby greatly affecting the infiltration effect. Therefore, in this embodiment, the freeze-drying technology is adopted to rapidly freeze the sample to be detected, which can effectively prevent the electrolyte from continuously diffusing, thereby maintaining the initial state of the electrolyte infiltration in the sample to be detected.
The freeze drying process can refer to the prior art, in the freeze drying step, the electrolyte salt and the solvent are crystallized and solidified in sequence, then the electrolyte solvent is sublimated, and then the dried battery cell is prepared, and the diffusion state of metal elements or other molecules of soluble metal salt in the electrolyte for detection can be well maintained.
S4, preparing a sample to be detected
And cutting along the cross section of the infiltrated cell to obtain a sample to be detected. In the step, the sample to be detected is preferably taken from the middle part of the infiltrated battery cell, and because the middle part of the battery cell is the part which is most difficult to infiltrate by the electrolyte, the infiltration degree of the whole battery cell can be judged by observing the infiltration degree of the middle part. In order to facilitate clear observation of the infiltration effect, the cross section of the sample to be detected can be treated by adopting a polishing process, and particularly, an argon ion polishing machine can be adopted for polishing.
S5, detection
Scanning the sample to be detected under an electron microscope to acquire a cross section image of the sample to be detected, and acquiring the distribution condition of metal elements in the soluble metal salt to judge the electrolyte infiltration effect. In this step, the scanning electron microscope is preferably adopted as the electron microscope, and the scanning electron microscope can scan and obtain distribution images of various elements, so that an electron microscope image of metal elements in the soluble metal salt can also be obtained, for example, an electron microscope image of sodium element distribution in this embodiment, and whether the infiltration effect is sufficient can be determined by observing whether the distribution of sodium elements is uniform.
In practical application, the electrolyte wetting effect detection method of this embodiment may prepare a plurality of dry battery cells for which the wetting time needs to be determined, and the other process conditions and parameters are not changed, and only preset a plurality of wetting times, and perform detection according to the above steps, for example, preset wetting times are 24 hours, 36 hours, and 48 hours, and may sequentially take out the wetted battery cells according to the set wetting times to perform drying, and then determine according to subsequent steps.
If the battery cell is soaked for a certain preset soaking time, for example, the battery cell is taken out for 24 hours, the Na ions are uniformly distributed under the observation of an electron microscope after the battery cell is treated according to the steps of the method, if the Na ions are uniformly distributed, the subsequent test with the preset time is not needed, and the battery pack can be fully soaked by the electrolyte according to the soaking time during production.
According to the method for detecting the electrolyte infiltration effect, lithium hexafluorophosphate in the standard electrolyte component is replaced by the soluble metal salt, and the distribution condition of metal elements in the soluble metal salt is judged, so that the infiltration effect of the electrolyte can be accurately judged, the process time for infiltrating the electrolyte can be accurately set, the battery performance is well guaranteed, the construction and operation cost of a production line can be minimized, and the method has important significance for reducing the cost of a battery pack.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. The method for detecting the infiltration effect of the electrolyte is characterized by comprising the following preparation steps of:
s1 preparation of electrolyte for detection
Replacing lithium hexafluorophosphate in the standard electrolyte component with soluble metal salt to prepare electrolyte for detection;
s2 infiltrating dry electric core
Injecting the electrolyte for detection into the infiltrated dry battery cell, and standing at high temperature for a period of time;
s3, drying
Taking out the soaked battery cell from the battery shell body and drying;
s4, preparing a sample to be detected
Cutting along the cross section of the infiltration electric core to prepare a sample to be detected;
s5, detection
And collecting a cross section image of the sample to be detected, and obtaining the distribution condition of metal elements in the soluble metal salt so as to judge the infiltration effect of the electrolyte.
2. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S1, the concentration of the detection electrolyte is not less than 1 mol/L.
3. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S1, the lithium hexafluorophosphate and the soluble metal salt are equal in mass.
4. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S1, the soluble metal salt includes a sodium salt.
5. The method for detecting the wetting effect of the electrolyte according to claim 4, wherein: the sodium salt comprises sodium hexafluorophosphate.
6. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S3, the infiltrated electrical core is dried by a freeze-drying process until all the solvent in the detection electrolyte salt on the infiltrated electrical core is sublimated.
7. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S4, the sample to be detected is taken from the middle of the infiltrated cell.
8. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S4, the cross section of the sample to be detected is processed by a polishing process.
9. The method for detecting the wetting effect of the electrolyte according to claim 1, wherein: in step S5, a cross-sectional image of the sample to be detected is acquired using a scanning electron microscope.
10. The method for detecting the wetting effect of the electrolyte according to any one of claims 1 to 9, wherein: in step S5, an electron microscope image of the metal elements in the soluble metal salt is obtained, and the infiltration effect is determined according to the uniformity of the distribution of the metal elements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011056116.9A CN112229766A (en) | 2020-09-30 | 2020-09-30 | Method for detecting infiltration effect of electrolyte |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011056116.9A CN112229766A (en) | 2020-09-30 | 2020-09-30 | Method for detecting infiltration effect of electrolyte |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112229766A true CN112229766A (en) | 2021-01-15 |
Family
ID=74119704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011056116.9A Withdrawn CN112229766A (en) | 2020-09-30 | 2020-09-30 | Method for detecting infiltration effect of electrolyte |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112229766A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112903537A (en) * | 2021-01-26 | 2021-06-04 | 湖北亿纬动力有限公司 | Method for testing battery cell wettability |
| CN113237792A (en) * | 2021-03-25 | 2021-08-10 | 蜂巢能源科技有限公司 | Characterization method of wettability of electrolyte |
| CN113324876A (en) * | 2021-05-31 | 2021-08-31 | 蜂巢能源科技有限公司 | Method for detecting infiltration effect of electrolyte |
| CN113866155A (en) * | 2021-09-16 | 2021-12-31 | 江苏中兴派能电池有限公司 | Lithium ion battery electrolyte infiltration judgment method |
| CN114993888A (en) * | 2022-07-29 | 2022-09-02 | 苏州宇量电池有限公司 | Method for testing wettability of battery electrolyte |
-
2020
- 2020-09-30 CN CN202011056116.9A patent/CN112229766A/en not_active Withdrawn
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112903537A (en) * | 2021-01-26 | 2021-06-04 | 湖北亿纬动力有限公司 | Method for testing battery cell wettability |
| CN113237792A (en) * | 2021-03-25 | 2021-08-10 | 蜂巢能源科技有限公司 | Characterization method of wettability of electrolyte |
| CN113324876A (en) * | 2021-05-31 | 2021-08-31 | 蜂巢能源科技有限公司 | Method for detecting infiltration effect of electrolyte |
| CN113866155A (en) * | 2021-09-16 | 2021-12-31 | 江苏中兴派能电池有限公司 | Lithium ion battery electrolyte infiltration judgment method |
| CN114993888A (en) * | 2022-07-29 | 2022-09-02 | 苏州宇量电池有限公司 | Method for testing wettability of battery electrolyte |
| CN114993888B (en) * | 2022-07-29 | 2022-11-15 | 苏州宇量电池有限公司 | Method for testing wettability of battery electrolyte |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112229766A (en) | Method for detecting infiltration effect of electrolyte | |
| Zhang et al. | Unraveling the intra and intercycle interfacial evolution of Li6PS5Cl‐based all‐solid‐state lithium batteries | |
| Wandt et al. | Operando electron paramagnetic resonance spectroscopy–formation of mossy lithium on lithium anodes during charge–discharge cycling | |
| Zheng et al. | Effects of state of charge on the degradation of LiFePO4/graphite batteries during accelerated storage test | |
| Hu et al. | Unrevealing the effects of low temperature on cycling life of 21700-type cylindrical Li-ion batteries | |
| Jagger et al. | Solid electrolyte interphases in lithium metal batteries | |
| CN111721674A (en) | Testing method and testing device for pole piece infiltration state | |
| CN109814042A (en) | A kind of analysis method of lithium ion battery in charge and discharge process middle impedance variation tendency | |
| CN113324876A (en) | Method for detecting infiltration effect of electrolyte | |
| CN112903537A (en) | Method for testing battery cell wettability | |
| CN113991198A (en) | Lithium ion battery electrolyte infiltration detection method | |
| Tian et al. | Reversible lithium plating on working anodes enhances fast charging capability in low-temperature lithium-ion batteries | |
| CN111551523A (en) | Method for rapidly evaluating dispersion performance of positive and negative electrode slurry of battery | |
| Duan et al. | Quantitative Understanding of Lithium Deposition‐Stripping Process on Graphite Anodes of Lithium‐Ion Batteries | |
| Fang et al. | Quantifying lithium lost to plating and formation of the solid-electrolyte interphase in graphite and commercial battery components | |
| CN113945676B (en) | Method for analyzing distribution state of electrolyte in battery cell and application thereof | |
| CN114094043A (en) | Method for evaluating cycle performance of lithium battery positive electrode material | |
| CN107039668B (en) | Method for testing durability acceleration of gas diffusion layer of proton exchange membrane fuel cell | |
| CN110556588B (en) | Activation process of lithium ion battery | |
| CN111579412A (en) | Method for evaluating performance of negative electrode binder | |
| CN101315415B (en) | Judgment method for quality of battery pole piece to be tested | |
| CN113642153B (en) | Reference electrode measurement error calibration method and computer equipment | |
| Berthault et al. | Lithium isotope tracing in silicon-based electrodes using solid-state MAS NMR: a powerful comprehensive tool for the characterization of lithium batteries | |
| CN113866311A (en) | Method for testing content and consumption of electrolyte in battery | |
| CN114221038A (en) | Preparation method of polymer solid electrolyte based on lithium metal battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20210115 |