CN112098238A - Method for measuring ductility of pit punching aluminum-plastic film for power lithium ion battery - Google Patents
Method for measuring ductility of pit punching aluminum-plastic film for power lithium ion battery Download PDFInfo
- Publication number
- CN112098238A CN112098238A CN201910527392.XA CN201910527392A CN112098238A CN 112098238 A CN112098238 A CN 112098238A CN 201910527392 A CN201910527392 A CN 201910527392A CN 112098238 A CN112098238 A CN 112098238A
- Authority
- CN
- China
- Prior art keywords
- aluminum
- plastic film
- reference circle
- deformation
- pit
- 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.)
- Granted
Links
- 239000002985 plastic film Substances 0.000 title claims abstract description 192
- 229920006255 plastic film Polymers 0.000 title claims abstract description 192
- 238000004080 punching Methods 0.000 title claims abstract description 103
- 238000000034 method Methods 0.000 title claims abstract description 46
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 17
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 17
- 229910052782 aluminium Inorganic materials 0.000 claims description 37
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 27
- 239000000463 material Substances 0.000 claims description 9
- 238000003825 pressing Methods 0.000 claims description 8
- 238000009826 distribution Methods 0.000 claims description 7
- 238000010586 diagram Methods 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 claims description 6
- 238000005259 measurement Methods 0.000 abstract description 31
- 238000000691 measurement method Methods 0.000 abstract description 4
- 230000008569 process Effects 0.000 description 15
- 239000012528 membrane Substances 0.000 description 10
- 238000004364 calculation method Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000004033 plastic Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 238000012797 qualification Methods 0.000 description 6
- 230000001447 compensatory effect Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/28—Investigating ductility, e.g. suitability of sheet metal for deep-drawing or spinning
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0298—Manufacturing or preparing specimens
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
A method for measuring ductility of each position of a pit punching aluminum-plastic film for a power lithium ion battery aims to solve the technical problems that the ductility of the pit punching aluminum-plastic film for the power lithium ion battery in the prior art is relatively complex in measurement method and relatively low in measurement precision and measurement reliability. The invention comprises the following steps: printing a plurality of reference circles with the same diameter on the aluminum-plastic film, wherein the reference circles are fully distributed on the aluminum-plastic film, any two adjacent reference circles are tangent, and the diameter of each reference circle is controlled to be 1-5 mm; punching a pit on the aluminum-plastic film; finding out a deformed reference circle on the aluminum-plastic film, and connecting two points of the maximum distance on the deformed reference circle; measuring the deformation of the reference circle of each angular position of the pit-shaped structure on the aluminum-plastic film, and judging the flatness of pit punching equipment and a die by comparing the deformation of the reference circles of the angular positions on the same side; and measuring the length of the mark connecting line on the deformation reference circle, obtaining the distance between the farthest two points on each reference circle after pit punching, and calculating the elongation of each deformation position on the aluminum-plastic film.
Description
Technical Field
The invention relates to the technical field of lithium ion power batteries, in particular to a method for measuring ductility of a pit punching aluminum-plastic film for a power lithium ion battery.
Background
The aluminum-plastic environment-friendly lithium ion battery appeared in the last 90 years of the century becomes one of the most spotlighted vehicle power supplies due to the advantages of high energy density, long cycle life, high working voltage and the like. The service life of the lithium battery for the vehicle is high and generally reaches more than 10 years, and the selection of a proper power battery outer package has a decisive effect on the insulation performance and the service life of the battery. The existing external package of the vehicle battery can be divided into four types, namely a plastic shell, a steel shell, an aluminum shell and an aluminum-plastic composite film, and the aluminum-plastic composite film material becomes one of the main packaging materials of the vehicle lithium battery due to the advantages of wear resistance, corrosion resistance, light weight, good formability and the like. The plastic-aluminum membrane generally divide into the three-layer, and the skin is the nylon material, and the inlayer is the PP material, and the intermediate level is the AL layer, and wherein, the AL layer that is located the intermediate level plays the separation effect, mainly is used for preventing the moisture invasion and isolated oxygen. Before the aluminum plastic film packages the battery electric core, a Pouch bag used for placing the battery electric core is firstly punched out, and the specific operation is as follows: the pressing mechanism fixes the aluminum-plastic film, and then the convex-concave die is matched with the pit punching formation to extend the periphery of the aluminum-plastic film to form a pit-shaped structure with a certain depth. Based on the characteristics of the material, the AL layer cannot be infinitely extended, and the industry engineering standard specifies that the pinhole risk exists in the AL layer when the extension rate of the AL layer (the thickness of the initial AL layer-the thickness of the AL layer after pit punching)/the thickness of the initial AL layer) is more than 50%. Based on the above principle, the ductility of the AL layer has become one of the important indicators for determining the quality of the aluminum-plastic film. Wherein, the pinhole (sputtering point) means that aluminum liquid is sputtered due to poor temperature control or poor position of a wire feeding point in the aluminum plastic film processing process, when the sputtered aluminum liquid contacts with the outer layer and the inner layer of the aluminum plastic film, a small pinhole is formed on the thin film layer, the barrier performance of the aluminum plastic film is reduced due to too many pinholes on the aluminum plastic film, and the number of pinholes on the aluminum plastic film is generally allowed to be 2-3/m2(ii) a In the industry passing judgment method, when the extension rate of the AL layer is more than 50%, the number of pinholes on the aluminum-plastic filmThe probability of over-range is high, and the Al layer is called as the pinhole risk.
In the technical field of lithium ion power batteries, the conventional method for measuring the elongation of an AL layer mainly comprises the following two methods:
(1) micrometer measurement: adopting a micrometer to punch the thickness of each area position of the aluminum-plastic film Pouch bag after the pit punching, and obtaining the thickness of the aluminum-plastic film Pouch bag through a formula: calculating the extension rate of the aluminum-plastic film at each position according to the initial aluminum-plastic film thickness-the post-pit punching aluminum-plastic film thickness)/the initial aluminum-plastic film thickness, and judging whether the AL layer has a pinhole risk or not according to the extension rate index;
(2) slice AL layer thickness analysis: adopting section equipment, slicing each region position of the aluminum-plastic film Pouch bag after pit punching, observing each position section morphology of the Pouch bag through an electron microscope, and testing the thickness of an aluminum layer through a formula: and calculating the extension rate of the aluminum-plastic film at each position according to the initial AL layer thickness-the AL layer thickness after pit punching)/the initial AL layer thickness, and judging whether the AL layer has the pinhole risk or not according to the extension rate index.
Chinese patent application No. CN 201610742743.5 discloses a method for testing aluminum layer thickness of an aluminum plastic film, which comprises the following steps: (1) the slicing machine is built and comprises a base and a sliding part which slides on the base in a reciprocating mode, the rear end of a cutter holder is fixed on the sliding part, a handle is arranged on the cutter holder, a cutter blade is fixed at the front end of the cutter holder, a clamping device is arranged below the cutter blade, and the clamping device is fixed on the base; (2) cutting off the part of the aluminum-plastic film, which needs to measure the thickness of the aluminum layer, and clamping the part into two plastic hard sheets to form a sample sheet; (3) fixing the sample wafer in a clamping device; (4) adjusting the position of the blade, aligning the sharp position of the blade to the aluminum-plastic film part of the sample wafer needing to measure the thickness of the aluminum layer, and pushing the cutter holder to and fro by utilizing the handle to slice the sample wafer; (5) the coupon was removed and placed under a microscope through the cut portion to measure the thickness of the aluminum layer in the aluminum plastic film.
The method measures the thickness of the AL layer by a slicing method, and then calculates to obtain the ductility of the AL layer, has the advantages of rapid measuring process, simple operation, accurate data and no radiation to human body, and can bring more reliable data basis to the research and development field of the aluminum plastic film; however, slicing equipment and an electron microscope are expensive, and a slicer cutter needs to be imported abroad, so that maintenance is troublesome; in addition, the mode of fixing the clamp during sample preparation, cutter wearing and tearing all easily make section plastic-aluminum membrane take place to warp, cause the measuring result deviation great, and the sample is difficult for preserving after the measurement.
Chinese patent application No. CN 201610887206.X discloses an aluminum-plastic film pit depth measuring device and a measuring method thereof, which comprises a thickness gauge platform and a thickness gauge, wherein the thickness gauge platform is provided with a die hole corresponding to an aluminum-plastic film pit, the bottom surface of the thickness gauge platform is slidably connected with a positioning ruler for fixing an aluminum-plastic film, the thickness gauge comprises a transparent main ruler fixed on the edge of the die hole, an accommodating cavity is arranged at the axis of the transparent main ruler, an auxiliary ruler is slidably connected in the accommodating cavity, an air pump is arranged at the top of the transparent main ruler, the air pump is communicated with the accommodating cavity through an air pipe, and a contact is arranged at the bottom of the auxiliary ruler; the axis department of vice chi and butt contact runs through and is provided with the air flue, and the air flue is close to butt head bottom edge and is provided with the buffering air cushion, and the butt head side is provided with a plurality of exhaust hole, and the exhaust hole is linked together with the air flue.
Above-mentioned patent promotes the automatic measure who realizes the aluminium-plastic film dashing the hole degree of depth through atmospheric pressure, and its measuring process is actually automatic with micrometer measurement, though can reduce measuring error, but, because dash hole aluminium-plastic film Pouch bag angular position form is irregular, micrometer measurement reference face, the measurement of can't accurate laminating, the error is great, and through indirect measurement finite point aluminium-plastic film thickness's change, reflect whole aluminium-plastic film extension condition, the reliability is lower.
Disclosure of Invention
The invention provides a method for measuring the ductility of a pit punching aluminum-plastic film for a power lithium ion battery, aiming at overcoming the technical problems of complex measuring method and low measuring precision and measuring reliability of the pit punching aluminum-plastic film for the power lithium ion battery in the prior art.
In order to achieve the above object, the present invention adopts the following technical solutions.
A method for measuring ductility of a pit punching aluminum-plastic film for a power lithium ion battery comprises the following steps of:
the method comprises the following steps: printing a plurality of reference circles with the diameter D on the aluminum-plastic film;
step two: fixing the aluminum-plastic film printed with the reference circle in the step I by the material pressing mechanism, punching the aluminum-plastic film by matching of a concave-convex mold, and extending the aluminum-plastic film to form a cubic pit structure;
step three: finding out a deformed reference circle on the aluminum-plastic film in the step II, and marking two points which are connected with the maximum distance L on the deformed reference circle;
step IV: measuring the deformation of a reference circle at the angular position of the middle pit structure, respectively marking two angular positions on the same side of the pit structure as A and B, and judging that the flatness of pit punching equipment and a die is qualified when the deformation of the reference circle at the angular position A is equal to the deformation of the reference circle at the angular position B; when the deformation of the reference circle at the angular position A is not equal to the deformation of the reference circle at the angular position B, judging that the flatness of the pit punching equipment and the die is unqualified, and storing the aluminum-plastic film with the judged flatness of the pit punching equipment and the die separately;
step five: taking the aluminum-plastic film with qualified flatness of the pit punching equipment and the die, measuring the length of the mark connecting line on the deformed reference circle in the aluminum-plastic film, obtaining the distance L between the farthest two points on the reference circle after pit punching, and obtaining the distance L through a formula: (L-D)/D, and calculating the elongation of each deformation position on the aluminum plastic film.
The existing aluminum plastic film pit punching process mainly comprises two modes: (1) and (3) extending and drawing depth: the blank holder has larger pressure to the aluminum-plastic film, the edge part of the aluminum-plastic film is fixed, the fixed part does not deform, the deep part is difficult to compensate, the edge part is completely compensated by the bottom during forming, the punching depth is shallow, the adjustability is poor, and the number of the blank holders is small at present; (2) compensatory punching depth: the pressure of the blank holder on the aluminum-plastic film is adjustable, the deep part of the aluminum-plastic film can be compensated by the materials at the edge and the bottom, the aluminum-plastic film moves and deforms integrally, the thickness is uniform, and the deep punching capability is strong. In order to ensure the quality of the aluminum-plastic film, the invention adopts compensatory deep punching, as the second step, in the pit punching process of the aluminum-plastic film, the pressing mechanism fixes the aluminum-plastic film, the concave-convex mold is matched to punch the pit of the aluminum-plastic film, and the aluminum-plastic film forms a pit-shaped structure with certain depth after being stretched. After the aluminum-plastic film is processed by punching the pits, the area of the aluminum-plastic film is greatly increased compared with that before the aluminum-plastic film is processed, so that the thickness of the aluminum-plastic film is reduced compared with that before the aluminum-plastic film is processed, when the extensibility of the aluminum-plastic film is more than 50%, because the AL layer and the aluminum-plastic film are synchronously extended, the extensibility of the AL layer is also more than 50%, and at the moment, the AL layer has the risk of pinholes. Based on the principle and considering the measurement convenience, the elongation rate measurement of the AL layer is assimilated into the elongation rate measurement of the aluminum plastic film.
Printing a plurality of reference circles with the diameter of D on the aluminum-plastic film, wherein the reference circles are fully distributed on the aluminum-plastic film, and any two adjacent reference circles are tangent; before the aluminum-plastic film is not stretched, the diameters of the reference circles are equal; after the aluminum-plastic film is stretched, the diameter of a reference circle at the position, which is not stretched, on the aluminum-plastic film is unchanged; and the radial length of the aluminum-plastic film at the position corresponding to the reference circle is synchronously changed, wherein the distance between the farthest two points on the corresponding reference circle reflects the maximum elongation rate of the aluminum-plastic film at the position.
And comprehensively integrating the steps from the first step to the fourth step, finding out a deformed reference circle on the aluminum-plastic film after the aluminum-plastic film is subjected to pit punching processing, marking two points with the maximum distance on the deformed reference circle, measuring the deformation amount of the reference circle of each angular position of a pit-shaped structure formed by the pit punching processing on the aluminum-plastic film, and judging the flatness of pit punching equipment and a mold by comparing the deformation amounts of the reference circles of the angular positions on the same side. When the flatness of the pit punching equipment and the flatness of the die are qualified, the deformation of each angular reference circle of the pit punching on the aluminum-plastic film are basically consistent, and the deformation of each corresponding position reference circle on two opposite side walls of the pit punching are basically consistent; when the flatness of the pit punching equipment and the flatness of the die are unqualified, the deformation of the reference circle at each corner position of the pit punching on the aluminum-plastic film is not completely consistent, or the deformation of the reference circle at each corresponding position on two opposite side walls of the pit punching is not completely consistent. At the relatively poor position of the roughness of dashing hole equipment and mould, dashing the unable quilt of hole in-process plastic-aluminum membrane and compressing tightly completely, the percentage of elongation of plastic-aluminum membrane is lower, because the whole percentage of elongation of plastic-aluminum membrane is certain, dashing the qualified position of the roughness of hole equipment and mould, the percentage of elongation of plastic-aluminum membrane is forced to increase, and then the AL layer that leads to this position has the pinhole risk. Through above-mentioned judgement standard, adjust the roughness of dashing hole equipment and mould, and then start from the processing equipment, reduce the pinhole on AL layer and have the risk. The existing battery core is usually in a cubic shape, and in the invention, the aluminum plastic film pit punching structure is processed into the cubic shape, so that the aluminum plastic film pit punching structure can be matched with the battery core. Marking two angular positions on the same side in the pit punching structure as an angular position A and an angular position B respectively, and judging that the flatness of pit punching equipment and a mould is qualified when the deformation of the reference circle at the angular position A is equal to the deformation of the reference circle at the angular position B; and when the deformation of the reference circle at the angular position A is not equal to the deformation of the reference circle at the angular position B, judging that the flatness of the pit punching equipment and the flatness of the die are unqualified. In the pit punching process, if the flatness of pit punching equipment and a die is qualified, the die and the aluminum-plastic film are completely attached, in the process of pressing down the die, the acting forces of two angular positions on the same side of the die on the aluminum-plastic film are basically the same, and the deformation of a reference circle at the two angular positions on the same side in the pit punching structure of the aluminum-plastic film is basically the same after the pit punching process is finished; otherwise, the reverse is true.
And integrating the steps from the first step to the fifth step, after the flatness of the pit punching equipment and the mold is judged, accurately measuring the length of the mark connecting line on the deformation reference circle to obtain the distance L between the farthest points on each reference circle after pit punching, and calculating the extension rate of each deformation position on the aluminum-plastic film. At the position where the aluminum-plastic film extends, the stress of the aluminum-plastic film is anisotropic, and the extension rates in different directions are different; however, when the elongation of the aluminum-plastic film is used as a judgment basis for judging whether the AL layer has the pinholes or not and further the qualification rate of the aluminum-plastic film after pit punching is detected, the maximum elongation of the elongation position of the aluminum-plastic film is ensured to be within the qualification range; therefore, in the present invention, by the formula (L-D)/D: and measuring the elongation rate of the aluminum-plastic film, and calculating to obtain the maximum elongation rate of the aluminum-plastic film at the corresponding position only by measuring the distance between the farthest two points on each reference circle after pit punching, so as to judge whether the AL layer has a pinhole risk. By the method, invalid variables are screened out, only one datum is measured for the same deformation datum circle, the measuring method is greatly simplified, and the measuring efficiency is effectively improved.
Preferably, the diameter of the reference circle in the step (r) is controlled to be 1-5 mm.
The diameter of the reference circle is controlled to be 1-5 mm; when the diameter of the reference circle is too large, the same reference circle may cover a plurality of extension positions on the aluminum-plastic film at the same time, and the extension changes of the plurality of extension positions interfere with each other, so that the reference circle cannot accurately reflect the extension rate of a certain deformation position; when the diameter of the reference circle is too small, a plurality of reference circles may exist at the same deformation position on the aluminum-plastic film, the extension deformation of the aluminum-plastic film is divided by the plurality of reference circles, a single reference circle cannot reflect the deformation condition of the aluminum-plastic film at the position, the deformation of the plurality of reference circles needs to be integrated in the calculation of the extension rate of the aluminum-plastic film at the position, the calculation process is extremely complex, and the efficiency requirement of production quality inspection cannot be met. Through multiple times of test determination, the diameter of the reference circle is controlled within the range of 1-5mm, the situation that a single deformation position corresponds to a plurality of reference circles or a single reference circle covers a plurality of deformation positions can be avoided, on one hand, the measurement precision of the elongation rate of the aluminum-plastic film is greatly improved, on the other hand, the measurement efficiency can be improved, and the requirement of production quality inspection is met.
Preferably, the reference circles in step (r) are arranged in a rectangular array.
The reference circles are arranged in a rectangular array; the processing position of the aluminum-plastic film pit is generally in the middle of the aluminum-plastic film, the number of reference circles tangent to the reference circles in the circumferential direction of each reference circle is fixed, the reference circles are four, and the reference circles tangent in the circumferential direction are uniformly distributed at intervals; above-mentioned mode of arranging can guarantee on the one hand that the benchmark circle fully covers the plastic-aluminum membrane, each extension deformation position on the plastic-aluminum membrane is brought into to the maximize, prevents to miss to survey and whether have the pinhole to produce the erroneous judgement to the AL layer because of the extension position, and on the other hand is based on the strong regularity of mode of arranging, and the benchmark circle warp back and peripheral not warp benchmark circle and form the contrast to can fix a position fast deformation benchmark circle, and then promote measurement of efficiency.
Preferably, the marked connecting line of each deformation reference circle in the step three is extended to obtain a force field distribution diagram of the deformation position on the aluminum-plastic film.
And c, performing the extension process of the aluminum-plastic film under the driving of external force, wherein the marked connecting line between two points with the maximum distance on the deformed reference circle in the step c represents the deformation path of the aluminum-plastic film at the deformation position under the driving of the maximum external force, and the marked connecting line of each deformed reference circle is taken as an extension line to form a force field distribution diagram, so that the stress condition of each deformation position on the aluminum-plastic film can be roughly analyzed.
And after the flatness of the pit punching equipment and the die is judged, accurately measuring the length of the mark connecting line on the deformation reference circle to obtain the distance between the farthest two points on each reference circle after pit punching, and calculating the elongation of each deformation position on the aluminum-plastic film. At the position where the aluminum-plastic film extends, the stress of the aluminum-plastic film is anisotropic, and the extension rates in different directions are different; however, when the elongation of the aluminum-plastic film is used as a judgment basis for judging whether the AL layer has the pinholes or not and further the qualification rate of the aluminum-plastic film after pit punching is detected, the maximum elongation of the elongation position of the aluminum-plastic film is ensured to be within the qualification range; therefore, in the invention, the elongation of the aluminum-plastic film is measured, and the maximum elongation of the aluminum-plastic film at the corresponding position can be calculated by measuring the distance between the farthest two points on each reference circle after pit punching, so as to judge whether the AL layer has a pinhole. Based on the principle, the calculation formula of the elongation of the aluminum-plastic film at the position of each deformation reference circle is as follows: (distance between two farthest points on the reference circle after pit punching-diameter of the reference circle before pit punching)/diameter of the reference circle before pit punching. And when the elongation is more than 50%, judging that the AL layer has a pinhole risk, and judging that the quality of the aluminum-plastic film processed by punching the pits is unqualified. In the method, the extensibility of the aluminum-plastic film is obtained through actual measurement instead of indirect conversion of thickness measurement, and the measurement method has high measurement precision and measurement reliability.
Preferably, the maximum radial distance of each reference circle after the pit flushing in the fifth step is measured under an electron microscope.
Because the diameter of the reference circle before extension is controlled within the range of 1-5mm, the length unit is small, and the calculation of the extension rate can be seriously influenced by the extremely small measurement error in the traditional manual measurement after the length unit is amplified; according to the invention, the maximum radial distance of each reference circle after pit punching is measured under an electron microscope, so that the measurement precision can be improved, and the reliability of the calculation of the elongation rate is further improved.
In conclusion, the invention has the following beneficial effects: (1) by adopting a finite element idea, the strain conditions of each position of the pit are actually simulated and displayed through the grids, so that the reliability of the elongation data is ensured; (2) the extensibility of the aluminum-plastic film is obtained through actual measurement, not indirect conversion of thickness measurement, and the measurement precision and the measurement reliability of the measurement method are high; (3) the measuring method is simple and convenient, low in cost and short in testing time.
Drawings
FIG. 1 is a schematic view of an aluminum plastic film printed with a reference circle according to the present invention.
Fig. 2 is a schematic view of the aluminum-plastic film after the pits are punched in the invention.
FIG. 3 is a schematic view of a reference circle after the aluminum plastic film is deformed according to the present invention.
FIG. 4 is a force field distribution diagram of a deformation position on the aluminum-plastic film in the invention.
In the figure:
1. 2, a reference circle, 3, a pit structure, 4, an angular position A, 5, an angular position B, 6 and a stress trajectory line;
d, the diameter of the reference circle;
l is the distance between the farthest points on the reference circle after pit punching.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example (b):
a method for measuring ductility of a pit punching aluminum-plastic film for a power lithium ion battery comprises the following steps of:
the method comprises the following steps: printing a plurality of reference circles 2 with the diameter D on the aluminum-plastic film 1;
step two: the pressing mechanism fixes the aluminum-plastic film printed with the reference circle in the step I, the concave-convex mold is matched to punch the aluminum-plastic film, and the aluminum-plastic film forms a cubic pit structure 3 after being stretched;
step three: finding out a deformed reference circle on the aluminum-plastic film in the step II, and marking two points which are connected with the maximum distance L on the deformed reference circle;
step IV: measuring the deformation of a reference circle at the angular position of the middle pit structure, respectively marking two angular positions on the same side of the pit structure as A and B, and judging that the flatness of pit punching equipment and a die is qualified when the deformation of the reference circle at the angular position A is equal to the deformation of the reference circle at the angular position B; when the deformation of the reference circle at the angular position A is not equal to the deformation of the reference circle at the angular position B, judging that the flatness of the pit punching equipment and the flatness of the die are unqualified;
step five: taking the aluminum-plastic film with qualified flatness of the pit punching equipment and the die, measuring the length of the mark connecting line on the deformed reference circle in the aluminum-plastic film, obtaining the distance L between the farthest two points on the reference circle after pit punching, and obtaining the distance L through a formula: (L-D)/D, and calculating the elongation of each deformation position on the aluminum plastic film.
The diameter of a reference circle in the step I is controlled to be 1-5 mm; arranging reference circles in the step I according to a rectangular array; making extension lines for the marked connecting lines of the deformation reference circles in the step three to obtain a force field distribution diagram of the deformation position on the aluminum-plastic film; and (6) measuring the distance L in the step (v) under an electron microscope.
As shown in fig. 1 to 3:
step 1: and a reference circle pattern is printed on the coil aluminum-plastic film, the diameter of the reference circle is 3.0mm, and the circles are arranged in a transverse and longitudinal tangent mode. In the reference circle pattern, reference circles are arranged in a rectangular array; the processing position of the aluminum-plastic film pit is generally in the middle of the aluminum-plastic film, the number of reference circles tangent to the reference circles in the circumferential direction of each reference circle is fixed, the reference circles are four, and the reference circles tangent in the circumferential direction are uniformly distributed at intervals; above-mentioned mode of arranging can guarantee on the one hand that the benchmark circle fully covers the plastic-aluminum membrane, each extension deformation position on the plastic-aluminum membrane is brought into to the maximize, prevents to miss to survey and whether have the pinhole to produce the erroneous judgement to the AL layer because of the extension position, and on the other hand is based on the strong regularity of mode of arranging, and the benchmark circle warp back and peripheral not warp benchmark circle and form the contrast to can fix a position fast deformation benchmark circle, and then promote measurement of efficiency.
Step 2: and (3) placing the aluminum-plastic film with the reference circle on equipment for sample preparation, fixing the aluminum-plastic film printed with the reference circle in the step (1) by a material pressing mechanism, punching the aluminum-plastic film by matching of a concave-convex mold, and extending the aluminum-plastic film to form a pit-shaped structure with a certain depth. The existing aluminum plastic film pit punching process mainly comprises two modes: (1) and (3) extending and drawing depth: the blank holder has larger pressure to the aluminum-plastic film, the edge part of the aluminum-plastic film is fixed, the fixed part does not deform, the deep part is difficult to compensate, the edge part is completely compensated by the bottom during forming, the punching depth is shallow, the adjustability is poor, and the number of the blank holders is small at present; (2) compensatory punching depth: the pressure of the blank holder on the aluminum-plastic film is adjustable, the deep punching position of the aluminum-plastic film can be compensated by the materials at the edge and the bottom, the aluminum-plastic film moves and deforms integrally, the thickness is uniform, and the deep punching capability is strong; in order to ensure the quality of the aluminum-plastic film, the embodiment adopts compensatory deep drawing.
And step 3: and (4) carrying out stress analysis on the sample after pit punching, connecting the farthest two points on the deformation reference circle by using a Mark pen, and judging the stress condition of the aluminum-plastic film during pit punching according to the extension line. The extension process of the aluminum-plastic film is carried out under the driving of external force, a connecting line is marked between two points with the maximum distance on the deformed reference circle, the connecting line represents the deformation path of the aluminum-plastic film at the deformation position under the driving of the maximum external force, the marking connecting line of each deformed reference circle is extended to form a force field distribution diagram, and the stress condition of each deformation position on the aluminum-plastic film can be roughly analyzed.
And 4, step 4: and judging the flatness conditions of pit punching equipment and a die according to the extension condition of the reference circle of each angular position of the pit punching of the aluminum-plastic film Pouch bag. Marking two angular positions on the same side in the pit punching structure as an angular position A and an angular position B respectively, and judging that the flatness of pit punching equipment and a mould is qualified when the deformation of the reference circle at the angular position A is equal to the deformation of the reference circle at the angular position B; and when the deformation of the reference circle at the angular position A is not equal to the deformation of the reference circle at the angular position B, judging that the flatness of the pit punching equipment and the flatness of the die are unqualified. In the pit punching process, if the flatness of pit punching equipment and a die is qualified, the die and the aluminum-plastic film are completely attached, in the process of pressing down the die, the acting forces of two angular positions on the same side of the die on the aluminum-plastic film are basically the same, and the deformation of a reference circle at the two angular positions on the same side in the pit punching structure of the aluminum-plastic film is basically the same after the pit punching process is finished; otherwise, the reverse is true.
And 5: testing the elongation rate of each position of the Pouch bag, testing the elongation rate of a reference circle of each position under an electron microscope, and obtaining the elongation rate of the reference circle of each position through a formula: (the distance between the farthest points on the reference circle after pit punching-the diameter of the reference circle before pit punching)/the diameter of the reference circle before pit punching, and calculating the elongation of the aluminum-plastic film at the position of each deformed reference circle. And after the flatness of the pit punching equipment and the die is judged, accurately measuring the length of the mark connecting line on the deformation reference circle to obtain the distance between the farthest two points on each reference circle after pit punching, and calculating the elongation of each deformation position on the aluminum-plastic film. At the position where the aluminum-plastic film extends, the stress of the aluminum-plastic film is anisotropic, and the extension rates in different directions are different; however, when the elongation of the aluminum-plastic film is used as a judgment basis for judging whether the AL layer has the pinholes or not and further the qualification rate of the aluminum-plastic film after pit punching is detected, the maximum elongation of the elongation position of the aluminum-plastic film is ensured to be within the qualification range; therefore, in the invention, the elongation of the aluminum-plastic film is measured, and the maximum elongation of the aluminum-plastic film at the corresponding position can be calculated by measuring the distance between the farthest two points on each reference circle after pit punching, so as to judge whether the AL layer has a pinhole. Based on the principle, the calculation formula of the elongation of the aluminum-plastic film at the position of each deformation reference circle is as follows: (distance between two farthest points on the reference circle after pit punching-diameter of the reference circle before pit punching)/diameter of the reference circle before pit punching. And when the elongation is more than 50%, judging that the AL layer has a pinhole risk, and judging that the quality of the aluminum-plastic film processed by punching the pits is unqualified. In the method, the extensibility of the aluminum-plastic film is obtained through actual measurement instead of indirect conversion of thickness measurement, and the measurement method has high measurement precision and measurement reliability.
The method is simple and convenient, has lower cost and shorter test time; in addition, the method actually measures the elongation rate, and the elongation rate is not converted indirectly through measuring the thickness, so that the measurement accuracy and the reliability are high; finally, the measuring method adopts a similar finite element mode, and the strain conditions of all positions of the pit punching are actually simulated and displayed through the grids, so that support is provided for the reliability of the elongation rate calculation.
As shown in fig. 4, three complete reference circles in the dashed rectangle frame in the drawing are deformed under the extension driving of the aluminum-plastic film, two points with the largest distance on the deformed reference circle are connected by an arc solid line, two ends of the arc solid line are extended to the edge position of the aluminum-plastic film by a virtual arc line, and the whole formed by the arc solid line and the arc dashed line approximately represents a stress trajectory line 6 of the deformed reference circle; when the reference circle and the aluminum-plastic film are deformed integrally, the aluminum-plastic film at the position of the deformed reference circle can be subjected to anisotropic external force, and because the deformation of the aluminum-plastic film is in positive correlation with the external force applied to the aluminum-plastic film, the maximum force action in the external force is expressed as that the deformation of the reference circle along a certain direction is maximum when the aluminum-plastic film passes through the reference circle, and the direction of the maximum external force is approximately reflected by the extending direction of the stress trajectory line. The density degree of the intervals between the different stress trajectory lines can be used for simply judging the probability of the deformation of the aluminum-plastic film at the position; when the aluminum-plastic film at a certain position does not extend, the reference circle at the position does not expand and deform, so that the axial center distance between the adjacent reference circles is smaller, the distribution of the stress trajectory lines is denser, and vice versa. As shown in the figure, the stress trajectory line at the position of the deformation reference circle is distributed loosely, while the stress trajectory line at the position of the non-deformation reference circle is dense.
Claims (5)
1. A method for measuring ductility of a pit punching aluminum-plastic film for a power lithium ion battery is characterized by comprising the following steps of:
the method comprises the following steps: printing a plurality of reference circles with the diameter D on the aluminum-plastic film;
step two: fixing the aluminum-plastic film printed with the reference circle in the step I by the material pressing mechanism, punching the aluminum-plastic film by matching of a concave-convex mold, and extending the aluminum-plastic film to form a cubic pit structure;
step three: finding out a deformed reference circle on the aluminum-plastic film in the step II, and marking two points which are connected with the maximum distance L on the deformed reference circle;
step IV: measuring the deformation of a reference circle at the angular position of the middle pit structure, respectively marking two angular positions on the same side of the pit structure as A and B, and judging that the flatness of pit punching equipment and a die is qualified when the deformation of the reference circle at the angular position A is equal to the deformation of the reference circle at the angular position B; when the deformation of the reference circle at the angular position A is not equal to the deformation of the reference circle at the angular position B, judging that the flatness of the pit punching equipment and the die is unqualified, and storing the aluminum-plastic film with the judged flatness of the pit punching equipment and the die separately;
step five: taking the aluminum-plastic film with qualified flatness of the pit punching equipment and the die, measuring the length of the mark connecting line on the deformed reference circle in the aluminum-plastic film, obtaining the distance L between the farthest two points on the reference circle after pit punching, and obtaining the distance L through a formula: (L-D)/D, and calculating the elongation of each deformation position on the aluminum plastic film.
2. The method for measuring the ductility of the pit punching aluminum-plastic film for the power lithium ion battery as claimed in claim 1, wherein the diameter of the reference circle in the step (r) is controlled to be 1-5 mm.
3. The method for measuring the ductility of the pit punching aluminum-plastic film for the power lithium ion battery as claimed in claim 1, wherein the reference circles in the step (i) are arranged in a rectangular array.
4. The method for measuring the ductility of the punched aluminum-plastic film for the power lithium ion battery as claimed in claim 1, wherein the force field distribution diagram of the deformation position on the aluminum-plastic film is obtained by extending the marked connecting line of each deformation reference circle in the step (iii).
5. The method for measuring the ductility of the pit punching aluminum-plastic film for the power lithium ion battery as claimed in claim 1, wherein the distance L in the fifth step is measured under an electron microscope.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910527392.XA CN112098238B (en) | 2019-06-18 | 2019-06-18 | Pit punching aluminum plastic film ductility measuring method for power lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910527392.XA CN112098238B (en) | 2019-06-18 | 2019-06-18 | Pit punching aluminum plastic film ductility measuring method for power lithium ion battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112098238A true CN112098238A (en) | 2020-12-18 |
| CN112098238B CN112098238B (en) | 2024-03-05 |
Family
ID=73749411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910527392.XA Active CN112098238B (en) | 2019-06-18 | 2019-06-18 | Pit punching aluminum plastic film ductility measuring method for power lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112098238B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113764819A (en) * | 2021-08-26 | 2021-12-07 | 汤路华 | Diaphragm ductility test coating equipment for lithium battery |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202503037U (en) * | 2012-02-13 | 2012-10-24 | 深圳格林德能源有限公司 | Flexible package polymer lithium cell and aluminum plastic film pit structure thereof |
| CN103240763A (en) * | 2013-05-13 | 2013-08-14 | 东莞市比比克电子科技有限公司 | Lithium ion battery aluminum plastic film forming punch and method |
| CN103386694A (en) * | 2012-05-11 | 2013-11-13 | 万向电动汽车有限公司 | Aluminum plastic film deep pit punching device and pit punching method |
| KR101642047B1 (en) * | 2015-04-02 | 2016-07-22 | 무진기공주식회사 | Apparatus and method for measuring plastic strain of mold products |
| CN106370115A (en) * | 2016-08-26 | 2017-02-01 | 上海紫江新材料科技有限公司 | Aluminum-plastic film aluminum layer thickness detection method |
| CN106468532A (en) * | 2016-10-11 | 2017-03-01 | 浙江超威创元实业有限公司 | A kind of aluminum plastic film scour hole depth measuring apparatus and its measuring method |
| CN108695482A (en) * | 2018-05-17 | 2018-10-23 | 四川众联航泰科技有限公司 | Encapsulating structure suitable for high current soft-package battery group |
| CN208753375U (en) * | 2018-09-20 | 2019-04-16 | 东莞维科电池有限公司 | A kind of aluminum plastic film and rush pit device |
-
2019
- 2019-06-18 CN CN201910527392.XA patent/CN112098238B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202503037U (en) * | 2012-02-13 | 2012-10-24 | 深圳格林德能源有限公司 | Flexible package polymer lithium cell and aluminum plastic film pit structure thereof |
| CN103386694A (en) * | 2012-05-11 | 2013-11-13 | 万向电动汽车有限公司 | Aluminum plastic film deep pit punching device and pit punching method |
| CN103240763A (en) * | 2013-05-13 | 2013-08-14 | 东莞市比比克电子科技有限公司 | Lithium ion battery aluminum plastic film forming punch and method |
| KR101642047B1 (en) * | 2015-04-02 | 2016-07-22 | 무진기공주식회사 | Apparatus and method for measuring plastic strain of mold products |
| CN106370115A (en) * | 2016-08-26 | 2017-02-01 | 上海紫江新材料科技有限公司 | Aluminum-plastic film aluminum layer thickness detection method |
| CN106468532A (en) * | 2016-10-11 | 2017-03-01 | 浙江超威创元实业有限公司 | A kind of aluminum plastic film scour hole depth measuring apparatus and its measuring method |
| CN108695482A (en) * | 2018-05-17 | 2018-10-23 | 四川众联航泰科技有限公司 | Encapsulating structure suitable for high current soft-package battery group |
| CN208753375U (en) * | 2018-09-20 | 2019-04-16 | 东莞维科电池有限公司 | A kind of aluminum plastic film and rush pit device |
Non-Patent Citations (1)
| Title |
|---|
| 赵越;肖艳春;崔佳;于盼;关玉明;: "锂离子电池电芯铝塑膜外壳冲压成形工艺", 锻压技术, no. 07 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113764819A (en) * | 2021-08-26 | 2021-12-07 | 汤路华 | Diaphragm ductility test coating equipment for lithium battery |
| CN113764819B (en) * | 2021-08-26 | 2023-08-04 | 汕头市曜辉新能源有限公司 | Separator ductility test coating equipment for lithium battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112098238B (en) | 2024-03-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106370115A (en) | Aluminum-plastic film aluminum layer thickness detection method | |
| CN105115464B (en) | Plate-type heat exchanger slab mould gap measuring method | |
| CN112098238A (en) | Method for measuring ductility of pit punching aluminum-plastic film for power lithium ion battery | |
| CN110232388A (en) | A method of identifying honeycomb side from honeycomb core surface measurement data | |
| EP3543641B1 (en) | Gage and method for detecting diameter of bolt hole back socket | |
| CN211373437U (en) | Device for measuring integral thickness of aluminum plastic film at corner of lithium ion battery shell | |
| CN216348300U (en) | Utensil is examined to car shift fork centre-to-centre spacing | |
| CN110987261A (en) | Method for testing residual stress of steel rail | |
| CN216206204U (en) | Taper measuring mechanism | |
| KR102611967B1 (en) | Measuring Apparatus For Outer Diameter Of Jelly-roll And Measuring Method For Outer Diameter Of Jelly-roll | |
| CN112098178B (en) | Test method for detecting thickness of aluminum layer at corner of aluminum plastic film after pit punching | |
| CN213321929U (en) | Inorganic non-metal mold | |
| CN210570345U (en) | Simple surface difference detection mechanism | |
| CN110806356B (en) | Method for detecting extension amount of positive plate | |
| CN211516279U (en) | Aluminum alloy C shape nick diaphragm engraving frock | |
| CN112665548B (en) | Method for quantitatively determining flatness of battery core | |
| CN210400224U (en) | Groove detection device of composite reamer | |
| CN207592527U (en) | A kind of on-Line Monitor Device of press machine | |
| CN220602421U (en) | New energy automobile battery shell module regional flatness examines utensil | |
| CN111780650B (en) | Band saw blade transverse straightness detector and detection method thereof | |
| CN220541890U (en) | Simple gauge for judging qualification of burrs at edges of automobile steel plates | |
| CN206057073U (en) | A kind of device for electrokinetic cell module side plate tension test | |
| CN213902146U (en) | Interim frock convenient to short-term test deformation | |
| CN220472540U (en) | Symmetry inspection tool for connecting rod forging blank | |
| CN213580148U (en) | Lithium battery pole piece sample sampler |
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 | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20211110 Address after: 311215 No. 855, Jianshe Second Road, economic and Technological Development Zone, Xiaoshan District, Hangzhou City, Zhejiang Province Applicant after: Wanxiang A123 Co.,Ltd. Address before: 311215 No. 855, Jianshe Second Road, Xiaoshan Economic and Technological Development Zone, Xiaoshan District, Hangzhou City, Zhejiang Province Applicant before: Wanxiang A123 Co.,Ltd. Applicant before: WANXIANG GROUP Co.,Ltd. |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |