阅读说明：本技术 电化学元件用分隔件和电化学元件 (Electro chemical elements use separator and electrochemical element ) 是由 井河笃 市村拓己 和田典弘 于 2018-04-10 设计创作，主要内容包括：提供：在维持分隔件的耐短路性、电阻、电解液浸渗性、电解液保持性的均衡性的同时薄层化了的、具有耐热性的电化学元件用分隔件。构成如下电化学元件用分隔件：其为由打浆纤维素系纤维形成的电化学元件用分隔件,连接下述2个中心点的距离的平均值除以该分隔件的厚度而得到的值为0.80～1.35,所述2个中心点为：构成分隔件的纤维素主干纤维的中心点、和最接近于该纤维素主干纤维的其他纤维素主干纤维的中心点。(It provides: in the electro chemical elements use separator balanced while thin layer, with heat resistance for maintaining the resistance to short-circuit of separator, resistance, electrolyte infiltration property, electrolyte retentivity.Constitute following electro chemical elements use separator: it is the electro chemical elements use separator formed by mashing cellulose fibre, connecting value obtained from thickness of the average value of the distance of following 2 central points divided by the separator is 0.80~1.35,2 central points are as follows: constitute the central point of the cellulose trunk fiber of separator and the central point of other cellulose trunk fibers closest to the cellulose trunk fiber.)

1. a kind of electro chemical elements use separator, which is characterized in that it is the electrochemistry member formed by mashing cellulose fibre Part separator,

Connecting value obtained from thickness of the average value of the distance of following 2 central points divided by the separator is 0.80~1.35,

2 central points are as follows:

Constitute separator cellulose trunk fiber central point and

Closest to the central point of other cellulose trunk fibers of the cellulose trunk fiber.

2. electro chemical elements use separator according to claim 1, which is characterized in that formed by the cellulose fibre Separator fibrinogen rate be 7.0~15.0%.

3. according to claim 1 or electro chemical elements use separator as claimed in claim 2, which is characterized in that the cellulose Series fiber is solvent-spun cellulose fibre.

4. a kind of electrochemical element, which is characterized in that using having the right to require 1 to the electrification described in any one of claim 3 Learn element separator.

5. electrochemical element according to claim 4, which is characterized in that it is selected from aluminium electrolutic capacitor, electric double layer electricity Container, lithium-ion capacitor, lithium ion secondary battery, sodium ion secondary battery, sodium-sulfur secondary battery, magnesium ion secondary cell, One of magnesium sulfur rechargeable battery.

Technical field

The present invention relates to electro chemical elements use separator and use the electrochemistry member for having the electro chemical elements use separator Part.

Background technique

As electrochemical element, aluminium electrolutic capacitor (condenser), electroconductive polymer aluminium solid electrolytic can be enumerated Capacitor, electroconductive polymer mixing aluminium electrolutic capacitor, double-layer capacitor (capacitor), lithium-ion capacitor, lithium from Sub- secondary cell, lithium primary battery etc..Moreover, these electrochemical elements are in such as automobile relevant device, digital device, wind-force hair It is used in a large amount of fields of the communication equipments such as renewable energy relevant device, the intelligent electric meters such as electric solar energy power generation etc, Continue purposes it is also contemplated that expanding from now on.

Such as in the case where automobile, using having lithium ion secondary battery, double-layer capacitor in energy regeneration, to various electricity Using there is aluminium electrolutic capacitor in the power supply of sub-control unit.In turn, electric car, the hybrid power being concerned in recent years Using in automobile has as the lithium ion secondary battery of power supply etc., using there is double-layer capacitor in energy regeneration etc., becomes electricity Using there is aluminium in the battery in source, the control of hybrid system, electronic control unit of direct current conversion from external ac power source etc. Electrolytic capacitor.It is bad directly concerning life for electrochemical element used in such automobile, it is therefore desirable to which high can By property.I.e., it is desirable that: be resistant to the vibration of car body, even if for cold district, high temperature area in prolonged use do not generate it is short Road is bad, and in addition the deterioration of performance is also few.

Expectation in circuit substrate used in electronic equipment, to slimming, the miniaturization of the electrochemical element installed It is larger.In addition, electrochemical element used in power supply for portable device, also requirement can be made for a long time with once charging With.

Therefore, for power supply, alternating current to chip, CPU smoothing purpose, to being installed on substrate The electrochemical elements such as aluminium electrolutic capacitor require low back (low back), small-sized.

In addition, for a large amount of lithium ion secondary batteries that the power supply as portable device uses, do not require nothing more than low back and High capacity can use for a long time, also require few to repeat charge and discharge, the deterioration of performance.

With the expansion of such purposes, the high performance of used equipment, for electrochemical element, it is desirable that charge and discharge are special The improvement of the performance of property, power characteristic etc to more than so far, further reliability, miniaturization etc..

As electro chemical elements use separator, using having: cellulose-based separator；Polyolefin microporous membrane, synthesis are fine Tie up the separator etc. that organic/inorganic substance is coated on non-woven fabrics.

Polyolefin microporous membrane separator uses the separator for having polypropylene, polyethylene.

In cellulose-based separator, using having native cellulose fibre, regenerated celulose fibre, regenerated celulose fibre makes With there is solvent-spun cellulose fibre.

In the separator for coating organic/inorganic substance on non-woven fabrics of synthetic fiber, proposes following scheme: being coated on non-woven fabrics Inorganic powder, the non-woven fabrics are that the synthetic fibers as polyester fiber have been carried out the nothing of sheet material by wet type copy paper method Woven fabric.

The main function of separator in electrochemical element are as follows: isolation a pair of electrodes and holding electrolyte.In order to be isolated one To electrode, to the demanding shielding of separator.Moreover, in order to improve shielding, it is desirable that the densification of separator.

In addition, also being required for the purpose that the miniaturization (path and/or low back) of electrochemical element, capacity improve Keep separator further thin layer.

Thin layer for electro chemical elements use separator, its film must be more thinned in polyolefin microporous membrane separator Thickness proposes coating alumina for the reduced purpose for preventing the heat resistance necessarily led to due to filming, resistance to short-circuit The scheme of equal inorganic powders.

On the other hand, cellulose-based separator is in order to thin layer, and use following method: thinned separator (is copied when manufacturing When paper) thickness and copy paper, or with based on pressurization line press be thinned copy paper after separator.

In order to improve the performance of separator, such as disclose the technology of patent document 1 to patent document 5.

Summary of the invention

Problems to be solved by the invention

In patent document 1, polyolefin microporous membrane separator is proposed.Polyolefin microporous membrane is with oriented film etc. Method and make, therefore, compared with by accumulating the non-woven fabrics that is formed of fiber, be easy filming.However, polypropylene, It shrinks, micropore closed pore, interferes under temperature environment more than fusing point possessed by the polyolefin-based resins of polyethylene etc Movement of the electrolyte inside electrochemical element.In addition, microporous membrane institute different from by accumulating the non-woven fabrics that fiber is formed The hole having is mostly to penetrate through from a face to the hole in another face.Therefore, if the thickness of separator, resistance to short-circuit is thinned It reduces.Moreover, polyolefin-based resins used in such microporous membrane lack the compatibility of raw material itself and electrolyte, because This, the infiltration of electrolyte is low, and the retentivity of electrolyte is also low.

As described in Patent Document 2, in order to improve the thermal contraction of polyolefin microporous membrane, resistance to short-circuit, it is also proposed that one Kind separator, is obtained from film surface coated inorganic powder, heat-resistant resin particle.However, being unable to improve electrolyte Infiltration, electrolyte retentivity to the polyolefin microporous membrane as substrate.In turn, coated inorganic powder etc. on substrate Etc preparation method on, it is thin layer to become difficult.

In patent document 3, a kind of separator formed by the solvent-spun cellulose fibre through being beaten is proposed.Cellulose fiber The heat resistance of dimension, the compatibility height with electrolyte, are best suited for the former material of the constituent material as electro chemical elements use separator Material.In order to which the separator for maintaining cellulose fiber is thin layer, it is miniaturize the cellulose fibre as raw material, thickness is thinned when copy paper Spend and copy paper in the case where, the upper limit for constituting the filling rate that the fiber of separator can use is restricted, it is difficult to freely be controlled point The density of spacing body.Fiber is beaten and generates fibrinogen, is formed in highdensity situation to improve apparent filling rate, resistance meeting It gets higher.On the other hand, if becoming low-density, resistance to short-circuit is poor.Herein, also as disclosed in embodiment 4 of patent document 2 etc. Like that, it is based not only on the mashing of cellulose fibre, also there are as below methods: is added by carrying out thickness adjusting to cellulose-based separator Work (calendering processing) is to thickness thinning, but in this method, even if resistance to short-circuit improves, resistance also becomes larger or the leaching of electrolyte Infiltration property, retention property are deteriorated.

In patent document 4, the separator formed by cellulose fiber peacekeeping synthetic fibers is proposed.Disclose following technology: By using the separator, to inhibit the fluctuation of the flash-over characteristic of lithium ion secondary battery, keep cycle characteristics excellent.

However, synthetic fibers are compared with cellulose fibre, and it is low with the compatibility of electrolyte, therefore, in the grade of patent document 2 Disclosed cellulose-based separator is compared, and the infiltration of electrolyte, retention property are poor.

In addition, therefore the fibre diameter of the synthetic fibers for copy paper, makes fiber accumulations and makes greatly to a certain degree It is thin layer to become difficult in non-woven fabrics.It is assumed that after copy paper want by heating, compression keep separator thin layer when, synthetic fibers that This crimping, the crimping position become film-form, and therefore, the resistance of separator increases.

In patent document 5, a kind of separator is proposed, by being coated with nothing on the non-woven fabrics formed by polyester fiber Machine powder and form inorganic layer.For the reason identical as the separator of patent document 4, such non-woven fabrics is difficult to thin layer. Herein, even if assuring resistance to short-circuit with inorganic layer (coating layer), (accumulating amount for reducing fiber) nonwoven layer (substrate layer) is thinned To the limit, substrate layer is also added with the thickness of coating layer, accordingly, it is difficult to thin layer.In addition, the separator of coating inorganic layer is also Have following worry: since separator surface is by friction and inorganic particles fall off.

As above-mentioned, in order to make electrolytics miniaturization of components, it is difficult to provide: maintaining the resistance to of electro chemical elements use separator Short-circuit, resistance, electrolyte infiltrate the thin separator that is balanced while having heat resistance of property, electrolyte retentivity.

The solution to the problem

The present invention has been made in view of the above problems, provides: in resistance to short-circuit, resistance, the electrolyte for maintaining separator Balanced while thin layer electro chemical elements use separator with heat resistance of infiltration property, electrolyte retentivity.Separately Outside, it provides: by using the electro chemical elements use separator to path, the electrochemical element of low back.

The present invention specifically has composition below.

That is, electro chemical elements use separator of the invention is characterized in that, formed by mashing cellulose fibre Electro chemical elements use separator connects obtained from thickness of the average value of the distance of following 2 central points divided by the separator Value be 0.80~1.35,2 central points are as follows: constitute the cellulose trunk fiber of separator central point and closest to The central point of other cellulose trunk fibers of the cellulose trunk fiber.

And then it is characterized in that, preferably the fibrinogen rate of the above-mentioned separator formed by cellulose fibre for 7.0~ 15.0%.

And it is characterized in that, it is preferred that above-mentioned cellulose fibre is solvent-spun cellulose fibre.

Electrochemical element of the invention is the composition using the electro chemical elements use separator for having aforementioned present invention.

In addition, electrochemical element of the invention can be selected from aluminium electrolutic capacitor, double-layer capacitor, lithium-ion capacitance Device, lithium ion secondary battery, sodium ion secondary battery, sodium-sulfur secondary battery, magnesium ion secondary cell, magnesium sulfur rechargeable battery.

The effect of invention

According to aforementioned present invention, property, the feelings of electrolyte retentivity can be infiltrated in resistance, the electrolyte for not damaging separator Improve resistance to short-circuit under condition, is also able to achieve thin layer.

In addition, by using separator of the invention, so that the miniaturization of electrochemical element can also be conducive to.

Detailed description of the invention

Fig. 1 is the figure being illustrated between the measuring method of the distance the central point of cellulose trunk fiber.

Specific embodiment

The separator that electro chemical elements use separator of the invention is preferably formed by cellulose fibre.Cellulose fibre In, from the viewpoint of the low resistance of separator, more preferable solvent-spun cellulose fibre.If it is cellulose fibre, It is desired fibrinogen incidence that fiber etc., which can be beaten, and form desired fibre diameter, control.

By synthetic fibers rather than in the case that cellulose fibre is used for separator, the thin layer difficulty of separator is Thin layer and carry out in the case that thickness adjusts processing, fiber itself is compressed, and fiber is fused to each other, and have that resistance increases can It can property.In addition, synthetic fibers is low with the compatibility of electrolyte, therefore, have the tendency that electrolyte infiltration property, retentivity are poor.

For electro chemical elements use separator of the invention, connect the average value of the distance of following 2 central points divided by point Value obtained from the thickness of spacing body is 0.80~1.35 range, more preferable 0.85~1.25 range, 2 central points Are as follows: constitute the central point of the cellulose trunk fiber of separator and other celluloses closest to the cellulose trunk fiber The central point of trunk fiber.

If value obtained from thickness of the average value of the distance of the central point of cellulose trunk fiber divided by separator is low In 0.80, then trunk fiber is each crimping, and resistance becomes larger or the infiltration of electrolyte is deteriorated.

On the other hand, obtained from thickness of the average value of the distance of the central point of cellulose trunk fiber divided by separator Value is if it exceeds 1.35, then trunk fiber becomes to separate each other, resistance to short-circuit is poor or the retentivity of electrolyte occur through when it is bad Change.

It should be noted that so-called trunk fiber refers to herein, in the cellulose fibre through being beaten, the fibre of non-protofibre Dimension is 1 μm of fibre diameter or more of fiber.In addition, fibrinogen refers to, in the cellulose fibre through being beaten, fibre diameter be lower than 1 μm fiber.

The composition of the electro chemical elements use separator of aforementioned present invention can for example manufacture as follows: cellulose fibre is beaten It starches after making sheet material, thickness adjusting is carried out by soft calendering, so as to manufacture.

Soft calendering (is compressed) using the combined pressurization of resin roll and metallic roll, when carrying out pressurization compression, resin roll It seldom deforms, becomes face pressure contracting.Since for the compression at face, accordingly, there exist the fibers in pressurized plane can relatively freely Ground is mobile, and trunk fiber can also be slightly to movement other than thickness direction.In addition, there is the freedom of fiber itself by face pressure contracting Degree is therefore, few to deformation, the pressurization deterioration of the fiber itself for constituting separator.

On the other hand, for previous used hard calendering (being compressed using the mutual pressurization of metallic roll), metallic roll is not sent out Change shape, therefore, becomes wire compression, and the fiber for constituting separator only has the freedom degree of thickness direction, to the fibre for constituting separator Deformation, the pressurization deterioration for tieing up itself are big.

It is resistance to short even if causing the movement of trunk fiber by compression of pressurizeing when the fibrinogen rate of separator is lower than 7.0% Road property is also poor, and has the tendency that the retentivity of electrolyte is also deteriorated.

On the other hand, fibrinogen rate is then not easy to cause the movement of trunk fiber, there is trunk fiber if it exceeds 15.0% It crimps each other, the case where resistance increases, the case where infiltration of electrolyte, retentivity reduce.

The range of the fibrinogen rate preferably 7.0~15.0% of separator as a result,.

In turn, preferably 400~2500 seconds ranges of the smoothness of the sheet material of separator, more preferable 2000 seconds or less.

If the smoothness of sheet material is lower than 400 seconds, the puncture resistance of sheet surface is lower, and resistance to short-circuit is lower.

On the other hand, the smoothness of sheet material is if it exceeds 2500 seconds, then separator surface flicks liquid as film Tendency is got higher, and electrolyte infiltration property is deteriorated.

It should be noted that fluctuation (the standard of the mutual distance of central point of the trunk fiber of connection cellulose fibre Deviation) preferably 12.0 or less.

The fluctuation of the mutual distance of central point of trunk fiber is connected if it exceeds 12.0, then it represents that trunk fiber is mutual Unevenly exist apart from close position, separate position, resistance to short-circuit, electrolyte infiltration property, the electrolyte of separator are kept Property difference position become to be locally present.

The density of separator of the invention is not limited, can be used for any density.As long as density be 0.45~ 1.00g/cm³Left and right, does not just interfere effect of the invention.Consider resistance to short-circuit, resistance, it is believed that substantial 0.50~0.85g/cm³ The range of left and right is good.

As long as with the function as separator and between mean center point of the invention, distance is worth divided by obtained from thickness It meets the above range, just also the thickness of separator is not particularly limited, it is excellent from the viewpoint of the miniaturization of electrochemical element It selects relatively thin.Consider resistance to short-circuit, resistance, it is believed that substantial 5~35 μm or so of range is good.

Hereinafter, to electro chemical elements use separator of the invention and having the electrochemistry of the electro chemical elements use separator The specific various embodiments of element, comparative example etc. are described in detail.

It should be noted that whole separators are formed by copy paper method in the embodiment of this implementation, but as long as connection is following The range that value is 0.80~1.35 obtained from thickness of the average distance of 2 central points divided by the separator, described 2 Central point are as follows: constitute the central point of the cellulose trunk fiber of separator and other closest to the cellulose trunk fiber The central point of cellulose trunk fiber, the forming method of separator are not limited to copy paper method.For example, fiber is divided by casting etc. Also there is no problem for the method for dispersion liquid sheet material.

(evaluation method of separator and electrochemical element)

The evaluation of the specific characteristic of separator and electrochemical element is carried out with condition below and method.

(thickness)

Using use " JIS C 2300-2 ' electrically use cellulose paper-the 2: test method ' 5.1 thickness " specified in, The mircrometer gauge of " 5.1.1 analyzer and measuring method using on the outside of a the case where mircrometer gauge ", is folded into that " 5.1.3 fan-fold paper simultaneously measures 10 methods of the case where thickness ", measure the thickness of separator.

(density)

It utilizes and is provided in the B method of " JIS C 2300-2 ' is electrically with cellulose paper-the 2: test method ' 7.0A density " Method, measure the density of the separator of absolute dry condition.

(standard deviation of distance between distance, central point between mean center point)

Separator is cut off in the width direction (direction CD), is separated with scanning electron microscope with 1500 times of shootings of multiplying power The section of part.Then, the center of cellulose trunk fiber and other celluloses closest to the cellulose trunk fiber are measured The distance at the center of trunk fiber.For it, cellulose trunk fiber 200 amounts are measured, using average value as mean center point Between distance.

Later, the standard deviation of distance between the central point being measured to is found out.

Herein, the measuring method of the distance the central point of cellulose trunk fiber is illustrated.

As shown in Figure 1, the inside of separator 10 includes a large amount of cellulose trunk fiber 11 and fibrinogen 12.Fig. 1 In, mark 1 to 7 number respectively to each cellulose trunk fiber 11.

There are 2 to 5 cellulose trunk fibers around the 1 of Fig. 1 cellulose trunk fiber.Wherein, measurement away from Central point from nearest 2 cellulose trunk fiber, at a distance from the central point of 1 cellulose trunk fiber.For whole Cellulose trunk fiber (being 1 to 7 cellulose trunk fiber in Fig. 1) carries out the measurement.Cellulose trunk fiber 200 are measured Same measurement is repeated, using the average value of whole measured values as distance between mean center point.

It should be noted that being set as center of gravity by the center of the cellulose trunk fiber of the deformations such as pressurization compression.

(the fibrinogen rate of separator)

Use " the long measuring method of fiber of the JIS P 8226-2 ' paper pulp-based on optical autoanalyzer method-the 2: non- Change method (ISO16065-2) ' " specified in analyzer, dissociate separator sheet material and disperse, measurement gained fiber.

Specifically, using the value for " Fibrillation " for using " Kajaani Fiber Lab.4 " measurement.

It should be noted that " Fibrillation " refers to, measurement is scattered in the area of the fiber of water, and then, measurement is former The area of fiber.With the area of the fibrinogen divided by the numerical value (%) of the cartographic represenation of area of fiber.

(surface smoothness of separator)

According to " the smoothness test method of JIS P 8119 ' paper and paperboard-based on Bekk smoothness testing machine ' ", measurement The surface smoothness of separator.

(electrochemical element)

It is located in separator between two electrode materials and winds, to make element volume.

Each electrochemical element is by enclosing to shell and obtaining element volume and electrolyte.Specifically, with below Method make aluminium electrolutic capacitor, double-layer capacitor, lithium ion secondary battery each electrochemical element.

(production method of aluminium electrolutic capacitor)

Make separator sandwiched and winds the anode aluminium foil and cathode aluminium for having carried out etching process and having aoxidized overlay film formation processing Foil obtains capacitor element volume.So that electrolyte is infiltrated in element volume, and sealed after being put into shell, makes diameter 10mm, height The aluminium electrolutic capacitor of 20mm, voltage rating 63V, 120 μ F of rated capacity.

(production method of double-layer capacitor)

Activated carbon electrodes and separator are wound, double-layer capacitor element volume is obtained.The element retracting bottom has been contained in In cylindric aluminum enclosure, it is infused in the electricity dissolved with the tetraethyl ammonium tetrafluoroborate as electrolyte in polypropylene carbonate ester solvent After solving liquid and carrying out vacuum infiltration, with sealing rubber seal.In this way, production voltage rating 2.5V, capacity 300F, diameter 35mm, The double-layer capacitor of height 60mm.

(production method of lithium ion secondary battery)

The cobalt acid lithium electrode for using lithium ion secondary battery to use uses graphite electrode as cathode material as positive electrode Material, it is wound together with separator, obtains lithium ion secondary battery element volume.Element retracting is contained in bottomed cylindrical In shell, the in the mixed solvent of ethylene carbonate and diethyl carbonate is infused in dissolved with the lithium lithium phosphate as electrolyte Electrolyte, sealed with pressuring machine.In this way, production voltage rating 3.7V, rated capacity 3000mAh, diameter 18mm, height 65mm Lithium ion secondary battery.

Characteristic is measured by the following method for each electrochemical element made.It should be noted that for each Example makes 1000 each electrochemical elements, is used for evaluating characteristics below.

(infiltration property)

With the element volume made, infiltration speed is measured by the following method.

When electrolyte being made to be infiltrated in each element volume, measurement is from injection electrolyte or element is made to be impregnated in electrolyte up to reaching Time until the 80% of specified static capacity or nominal discharge capacity, the evaluation as infiltration property.

The measurement is as follows: when production element volume, each element volume being carried out 20 times, using its average value as the infiltration time. It should be noted that being measured without decompression etc. when infiltration.

In aluminium electrolutic capacitor, infiltration the case where being within 4 minutes time it will be denoted as "○", more than 4 minutes and be 6 minutes Within the case where be denoted as " △ ", more than 6 minutes the case where be denoted as "×".

In addition, in double-layer capacitor and lithium ion secondary battery, the case where will the infiltration time being within 10 minutes, is denoted as "○", more than 10 minutes and within 15 minutes the case where be denoted as " △ ", more than 15 minutes the case where be denoted as "×".

(poor short circuit rate)

The poor short circuit rate of electrochemical element is as follows: the case where charging voltage is increased less than voltage rating as it is short-circuit not Good, these become the number of the electrochemical element of poor short circuit divided by the electrochemical element number measured for static capacity, take hundred Divide rate as poor short circuit rate.

(impedance)

The impedance of aluminium electrolutic capacitor is as follows: using LCR table, measures with 20 DEG C, under the frequency of 1kHz.

(internal resistance)

The internal resistance of double-layer capacitor by " the fixed double-layer capacitor-the 1 of JIS C 5160-1 ' electronic equipment: General norm ' " specified in, exchange (a.c.) electric-resistivity method of " 4.6 internal resistance " and measure.

In addition, lithium ion secondary battery internal resistance according to " monocell of JIS C 8715-1 ' industry lithium secondary battery and Battery system-the first: performance requirement item ' " specified in, " 8.6.3 AC internal Resistance " and measure.

(Capacitance Shift Rate caused by heating)

Capacitance Shift Rate caused by the heating of aluminium electrolutic capacitor is found out by the following method.

By specified in " JIS C5101-1 ' electronic equipment is with fixed capacitor-the 1: general norm ' ", " 4.7 is quiet The method of capacitance " measures initial static capacity.

Then, it after aluminium electrolutic capacitor being stood to (heat treatment) under 160 DEG C of environment 250 hours, surveys in aforementioned manners Static capacity after fixed heat treatment.Then, heating institute is calculated according to formula 1 below with the static capacity of heat treatment front and back The Capacitance Shift Rate of generation.

Formula 1:C={ 1- (C1-C2)/C1 } × 100

C: Capacitance Shift Rate (%) caused by heating

C1: initial capacity (F or mA)

C2: the capacity (F or mA) after heating

Capacitance Shift Rate caused by the heating of double-layer capacitor is found out by the following method.

By specified in " JIS C 5160-1 ' electronic equipment with fixed double-layer capacitor ' ", " 4.5 static capacity " Constant current electric discharge, measure initial static capacity.

Then, it after double-layer capacitor being stood to (heat treatment) under 150 DEG C of environment 1 hour, measures in aforementioned manners Static capacity after heat treatment.Then, it with the static capacity of heat treatment front and back, is calculated according to formula 1 and is held caused by heating Quantitative change rate.

Capacitance Shift Rate caused by the heating of lithium ion secondary battery is found out by the following method.

According to " monocell of JIS C 8715-1 ' industry lithium secondary battery and battery system-the first: performance requirement Item ' " specified in, " test of 8.4.1 discharge performance ", measure initial discharge capacity.

Then, it after lithium ion secondary battery being stood to (heat treatment) under 150 DEG C of environment 1 hour, surveys in aforementioned manners Discharge capacity after fixed heat treatment.Then, it with the discharge capacity of heat treatment front and back, is calculated according to formula 1 caused by heating Capacitance Shift Rate.

Hereinafter, being illustrated to specific embodiment of the invention, comparative example and conventional example.

It should be noted that the separator of each embodiment is as follows: using solvent-spun cellulose fibre as cellulose-based fibre Dimension, obtains separator using the copy paper method based on paper machine.

(embodiment 1)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 10.0 μm of thickness, density 0.75g/cm³Separator.

It is 7.1 that distance, which is the standard deviation of distance between 12.8 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 1.28, fibrinogen rate be 8.3%, Bekk it is smooth Degree is 1984.2 seconds.

(embodiment 2)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 20.0 μm of thickness, density 0.75g/cm³Separator.

It is 8.7 that distance, which is the standard deviation of distance between 16.6 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 0.83, fibrinogen rate be 7.2%, Bekk it is smooth Degree is 1031.2 seconds.

(embodiment 3)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out cylinder copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 20.0 μm of thickness, density 0.60g/cm³Separator.

It is 11.8 that distance, which is the standard deviation of distance between 24.2 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 1.21, fibrinogen rate be 14.8%, Bekk it is flat Slippery is 596.1 seconds.

(embodiment 4)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 20.0 μm of thickness, density 0.55g/cm³Separator.

It is 6.8 that distance, which is the standard deviation of distance between 17.2 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 0.86, fibrinogen rate be 10.6%, Bekk it is flat Slippery is 445.1 seconds.

(reference example 1)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 8.0 μm of thickness, density 0.75g/cm³Separator.

It is 6.1 that distance, which is the standard deviation of distance between 10.2 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 1.28, fibrinogen rate be 11.5%, Bekk it is flat Slippery is 2449.7 seconds.

(reference example 2)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 25.0 μm of thickness, density 0.55g/cm³Separator.

It is 11.9 that distance, which is the standard deviation of distance between 26.5 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 1.06, fibrinogen rate be 9.6%, Bekk it is smooth Degree is 380.9 seconds.

(comparative example 1)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 10.0 μm of thickness, density 1.05g/cm³Separator.

It is 5.5 that distance, which is the standard deviation of distance between 7.5 μm, central point, between the mean center point of the separator.In addition, should Between the mean center point of separator distance divided by value obtained from thickness be 0.75, fibrinogen rate be 12.6%, Bekk it is smooth Degree is 1833.9 seconds.

(comparative example 2)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 30.0 μm of thickness, density 0.48g/cm³Separator.

It is 26.3 that distance, which is the standard deviation of distance between 41.7 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 1.39, fibrinogen rate be 13.2%, Bekk it is flat Slippery is 421.1 seconds.

(comparative example 3)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 15.0 μm of thickness, density 0.85g/cm³Separator.

It is 12.9 that distance, which is the standard deviation of distance between 16.6 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 1.11, fibrinogen rate be 15.7%, Bekk it is flat Slippery is 1789.5 seconds.

(comparative example 4)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by soft calendering, obtains 25.0 μm of thickness, density 0.60g/cm³Separator.

It is 13.0 that distance, which is the standard deviation of distance between 22.5 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 0.90, fibrinogen rate be 6.5%, Bekk it is smooth Degree is 558.0 seconds.

(conventional example 1)

Solvent as cellulose fibre is spun into the mashing of rayon fiber height, and carries out fourdrinier wire copy paper, to obtain 20.0 μm of thickness, density 0.55g/cm³Separator.

It is 13.1 that distance, which is the standard deviation of distance between 18.3 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 0.92, fibrinogen rate be 15.3%, Bekk it is flat Slippery is 321.1 seconds.

It should be noted that the separator is only formed by copy paper, thickness adjusting processing is not carried out.

(conventional example 2)

Solvent as cellulose fibre is spun into rayon fiber mashing, and carries out fourdrinier wire copy paper, to obtain sheet material. Thickness adjusting is carried out to the sheet material by rolling firmly, obtains 10.0 μm of thickness, density 1.05g/cm³Separator.

It is 4.3 that distance, which is the standard deviation of distance between 5.5 μm, central point, between the mean center point of the separator.In addition, should It is 8.0% that distance, which is 0.55, fibrinogen rate divided by value obtained from thickness, between the mean center point of separator.

The separator is as follows: the fiber for constituting separator is bonded each other with film-form, and part filming has occurred.The film The position changed slightly is shunk, and fine fold is generated in sheet material, therefore, it is impossible to accurately measure Bekk smoothness.

(conventional example 3)

By 25.0 μm of thickness, mass area ratio 16g/m²Polyethylene microporous film as separator.

The separator is not by fibroplastic separator, therefore, it is impossible to measure distance between mean center point, use central point Between distance calculate value and fibrinogen rate.It should be noted that Bekk smoothness is 6530.9 seconds.

(conventional example 4)

The solvent as cellulose fibre of 70 mass % is spun into rayon fiber mashing, with 30 mass %, fiber The pet fiber mixing of 3 μm of diameter, length 2mm, and fourdrinier wire copy paper is carried out, to obtain sheet material.It is logical It crosses soft calendering and thickness adjusting is carried out to the sheet material, obtain 25.0 μm of thickness, density 0.60g/cm³Separator.

It is 12.1 that distance, which is the standard deviation of distance between 18.0 μm, central point, between the mean center point of the separator.In addition, Between the mean center point of the separator distance divided by value obtained from thickness be 0.72, fibrinogen rate be 8.2%, Bekk it is smooth Degree is 615.0 seconds.

(conventional example 5)

Using the separator of embodiment 4 as substrate, alumina powder is coated on substrate two sides and drying, to obtain thickness Spend 25.0 μm, density 0.82g/cm³Separator.It should be noted that in order to make alumina powder be held in substrate, using having Polyvinylidene fluoride binder.

For the separator of embodiment 4, for the separator equipped with inorganic layer, therefore, it is impossible to measure mean center point spacing From, with the value and fibrinogen rate calculated with a distance between central point.In table 1, the value of embodiment 4 is continued to use.In addition, inorganic in measurement Powder slowly falls off, and Bekk smoothness can not be measured accurately.

(conventional example 6)

Using the separator of conventional example 3 as substrate, alumina powder is coated on substrate two sides and drying, to obtain thickness Spend 30.0 μm, density 0.85g/cm³Separator.It should be noted that in order to make alumina powder be held in substrate, using having Polyvinylidene fluoride binder.

For the separator of conventional example 3, for the separator equipped with inorganic layer, therefore, it is impossible to measure mean center point spacing From, with the value and fibrinogen rate calculated with a distance between central point.In addition, inorganic powder slowly falls off in measurement, Bekk smoothness It can not accurately be measured.

By each embodiment, comparative example, conventional example separator evaluation result is shown in table 1.

In addition, by the electrochemical element for using the separator of each example to make evaluation result is shown in table 2.

[table 1]

[table 2]

As known to table 2, in the electrochemical element of each embodiment, poor short circuit does not occur.In addition, the electrochemistry with conventional example Element is compared, and impedance, internal resistance can also be reduced.Moreover, all "○" of infiltration property, in turn, the alminium electrolytic condenser of each embodiment The sustainment rate (100%- change rate) of the static capacity of device and double-layer capacitor is also 80% or more, lithium ion secondary battery The sustainment rate (100%- change rate) of discharge capacity is also 70% or more, is good.

For the separator of comparative example 1, distance is 0.75 divided by value obtained from thickness between mean center point.Moreover, making With the impedance of each electrochemical element of the separator of comparative example 1, internal resistance, lower than fiber, part is integrated with film-form bonding each other Electrochemical element changed, conventional example 2, but be the level being equal with each conventional example.In addition, the electrochemical element of comparative example 1 Infiltration be "×".It is thought that since distance is divided by obtained from thickness between the mean center point of the separator of comparative example 1 Value is lower than 0.80, and cellulose trunk fiber crimps each other, and as a result separator resistance increases, in addition, the infiltration of electrolyte is also dropped It is low.

For the separator of comparative example 2, distance is 1.39 divided by value obtained from thickness between mean center point.Moreover, making In each electrochemical element with the separator of comparative example 2, poor short circuit has occurred.In addition, the aluminium electrolutic capacitor of comparative example 2 and Capacitance Shift Rate after the heating of double-layer capacitor is more than 20%, and the Capacitance Shift Rate after the heating of lithium ion secondary battery is super Cross 30%.It is thought that since distance is more than divided by value obtained from thickness between the mean center point of the separator of comparative example 2 1.35, trunk fiber is separated from each other, and therefore, resistance to short-circuit reduces.In addition, the big reason of Capacitance Shift Rate think the reason is that, The electrolyte retentivity of separator is reduced and is evapotranspired by heat treatment electrolyte.

By each embodiment it is found that distance is divided by thickness between the mean center point of separator compared with comparative example 1 and comparative example 2 It is worth preferably 0.80~1.35 range obtained from degree.

In addition, when being compared to embodiment 1 and embodiment 3, the aluminium electrolutic capacitor and Electric double-layer capacitor of embodiment 1 Capacitance Shift Rate after the heating of device is 10% or more, the Capacitance Shift Rate after the heating of lithium ion secondary battery be 20% with On, the aluminium electrolutic capacitor of embodiment 3 and the static capacity sustainment rate of double-layer capacitor are 10% hereinafter, lithium ion secondary The discharge capacity sustainment rate of battery is 20% or less.Moreover, when being compared to embodiment 2 and embodiment 4, the resistance of embodiment 2 Anti-, internal resistance low 10% or more.

As knowen from these results, between the mean center point of separator distance divided by value obtained from thickness it is more preferable 0.85~ 1.25 range.

For the separator of comparative example 3, fibrinogen rate is 15.7%.Moreover, each electricity of the separator using comparative example 3 For chemical component compared with fibrinogen rate is close to 15.3% value, conventional example 1 electrochemical element, impedance, internal resistance are high. In addition, the infiltration of the electrochemical element of comparative example 3 is "×".Moreover, the aluminium electrolutic capacitor and Electric double-layer capacitor of comparative example 3 Capacitance Shift Rate after the heating of device is 20% or more, the discharge capacity sustainment rate up to 30% or more of lithium ion secondary battery. Think therefore, to be not easy to cause the shifting of trunk fiber the reason is that the fibrinogen rate of the separator of comparative example 3 is more than 15% Dynamic, the standard deviation of distance also becomes larger between central point, and as a result trunk fiber crimps each other and separator resistance increases, electrolyte Infiltration property, retentivity also reduce.In the lithium ion secondary battery of comparative example 3, poor short circuit has occurred, it is believed that the reason is that The standard deviation of distance becomes larger between central point, and as a result the homogenieity of separator slightly reduces.

For the separator of comparative example 4, fibrinogen rate is 6.5%.In addition, the standard deviation of distance is also big between central point To 13.0.Moreover, poor short circuit has occurred in each electrochemical element using the separator of comparative example 4.In addition, comparative example 4 Capacitance Shift Rate up to 20% or more after the heating of the static capacity sustainment rate and double-layer capacitor of aluminium electrolutic capacitor, Capacitance Shift Rate up to 30% or more after the heating of lithium ion secondary battery.It is thought that due to the separator of comparative example 4 Fibrinogen rate is lower than 7%, even if causing the movement of trunk fiber, the fluctuation of distance is also big between central point, is as a result unable to improve Resistance to short-circuit, and the retentivity of electrolyte also reduces.

By each embodiment compared with comparative example 3 and comparative example 4 it is found that the fibrinogen rate preferably 7.0 of separator~ 15.0% range.In addition we know, the standard deviation of distance preferably 12.0 or less between central point.

For the separator of reference example 1, Bekk smoothness is 2449.7 seconds.Moreover, using reference example 1 separator it is each In electrochemical element, poor short circuit does not occur.Impedance, the internal resistance of each electrochemical element are slightly larger compared with embodiment, but can compare The horizontal of conventional example reduces.Capacitance Shift Rate after the heating of each electrochemical element is also high compared with each embodiment, not ask The level of topic.

On the other hand, the Bekk smoothness of the separator of conventional example 3 very up to 6530.9 seconds, use the electricity of the separator Impedance, the internal resistance of chemical component are also big.

By reference example 1 it is found that Bekk smoothness preferably 2500 seconds or less, more preferably compared with each embodiment, conventional example 2000 seconds or less.

For the separator of reference example 2, Bekk smoothness is 380.9 seconds.Using the separator aluminium electrolutic capacitor and In double-layer capacitor, poor short circuit does not occur, in addition, impedance and internal resistance and embodiment are also equivalent horizontal, it is good.So And using in the lithium ion secondary battery of the separator, although poor short circuit slightly has occurred very much.

It, can be further by reference example 2 it is found that Bekk smoothness was if it is 400 seconds or more compared with each embodiment Improve the resistance to short-circuit of separator.

For the separator of conventional example 1, thickness is not carried out and adjusts processing, but in order to improve compactness, keeps fiber height micro- Refinement, the fibrinogen rate of separator are 15.3%.Moreover, the trunk fiber for constituting the separator does not move.

By conventional example 1 it is found that by using separator of the invention, so as to realize electrification compared with each embodiment Learn the reduction of poor short circuit rate, low resistance, the improvement of infiltration property, the reduction of Capacitance Shift Rate of element.

For the separator of conventional example 2, distance is 0.55 divided by value obtained from thickness between mean center.This is because, The fiber of separator is constituted each other by excessive compression and partially with film-form bonding and integration, the electrification of conventional example 2 Learn the impedance of element, internal resistance with each embodiment, comparative example 1 electrochemical element compared with it is also high.In addition, the electrochemistry of conventional example 2 The infiltration of element is "×".

The separator of conventional example 3 and conventional example 6 is polyethylene microporous film.For the separator of conventional example 6, to existing The separator of example 3 implements inorganic coating and improves heat resistance, but conventional example 3, the Capacitance Shift Rate of conventional example 6 after the heating After test, functioned not as electrochemical element.On the other hand, visible heat treatment in the electrochemical element of each embodiment Generated a small amount of capacity is reduced, but there is no problem ground work.

It follows that by using the separator of the invention formed by cellulose fibre, so as to improve electrification Learn the heat resistance of element.

In addition, the separator of conventional example 4 contains synthetic fibers.By conventional example 4 it is found that by making compared with each embodiment With the separator of the invention formed by cellulose fibre, so as to improve the infiltration of electrolyte, in addition, improving electrolyte Retentivity, so that the Capacitance Shift Rate of electrochemical element can also be reduced.

For the separator for being coated with inorganic powder of conventional example 5 and conventional example 6, inorganic powder in the measurement of Bekk smoothness End slowly falls off, therefore, it is impossible to accurately measure.

When such separator is used for electrochemical element as separator as a result, also there is the worry of inorganic shed powder.

In addition, the separator thickness below that the separator of each embodiment is a large amount of conventional examples does not occur although thin Poor short circuit.

As a result, by using separator of the invention, so that the thin layer and then electrochemistry of separator can also be conducive to The miniaturization of element.

As described above, by using separator of the invention, so as in resistance, the electrolyte for not damaging separator Improve resistance to short-circuit in the case where infiltration property, electrolyte retentivity, is also able to achieve thin layer.

More than, the separator of present embodiment is used aluminium electrolutic capacitor, double-layer capacitor, lithium ion secondary battery Example be illustrated.

In electrochemical element of the invention, for electrode material and electrolyte material, other components etc., without especially limit It is fixed, a variety of materials can be used.

In addition, electro chemical elements use separator of the invention can be used for the electricity other than illustrating in present embodiment example Chemical component, such as lithium-ion capacitor, lithium primary battery, sodium ion secondary battery, sodium-sulfur secondary battery, the secondary electricity of magnesium ion The electrochemical element in pond, magnesium sulfur rechargeable battery etc.

Description of symbols

10 separators, 11 cellulose trunk fibers, 12 fibrinogens