CN1728439A - Lithium ion secondary cell - Google Patents
Lithium ion secondary cell Download PDFInfo
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- CN1728439A CN1728439A CNA2005100978829A CN200510097882A CN1728439A CN 1728439 A CN1728439 A CN 1728439A CN A2005100978829 A CNA2005100978829 A CN A2005100978829A CN 200510097882 A CN200510097882 A CN 200510097882A CN 1728439 A CN1728439 A CN 1728439A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The present invention provides a lithium ion secondary battery including: an electrode group including a belt-like positive electrode and a belt-like negative electrode that are wound with a separator interposed therebetween; and a can with a bottom for accommodating the electrode group, wherein the positive electrode has a positive electrode current collector and a positive electrode mixture layer carried on the positive electrode current collector, the negative electrode has a negative electrode current collector and a negative electrode mixture layer carried on the negative electrode current collector, and a porous heat-resistant layer is partially provided between the separator and at least one of the positive electrode mixture layer and the negative electrode mixture layer. Since a porous heat-resistant layer is thus placed, a high performance lithium ion secondary battery capable of efficiently preventing internal short circuit due to overheating while preventing decrease in battery characteristics can be provided.
Description
Technical field
The present invention relates to the higher lithium rechargeable battery of fail safe, in more detail, relate to the lithium rechargeable battery that effectively to keep battery behavior.
Background technology
Lithium rechargeable battery is owing to be the higher storage battery of energy density, thereby can be as the main power source of various portable sets.The chemical cell of lithium rechargeable battery and so on has usually: anodal, negative pole and be configured in positive pole and negative pole between barrier film.The effect that this barrier film had is that anodal and negative pole are carried out electric insulation and keep electrolyte.
In present lithium rechargeable battery, main what adopt is the electrode group that the positive pole that will separate by barrier film and negative pole coiling form.In general, employed in such electrode group just have: positive electrode collector of aluminium foil and so on and the appendix anode mixture layer that is made of lithium composite xoide etc. thereon.Equally, negative pole has the negative electrode collector of Copper Foil and so on and the appendix anode mixture layer that is made of graphite etc. thereon.As barrier film, can use porous film sheet that constitutes by resins such as polyethylene etc.
, if the film like barrier film that is made of above-mentioned resin melts or shrinks because of overheated, internal short-circuit will take place.At this moment, the effect of the reaction heat that produces owing to instantaneous short circuit, barrier film further shrinks and short circuit is partly enlarged, and then produces huge reaction heat.So just there is the unusual overheated problem that is promoted.
In recent years, for avoiding such trouble, the someone has proposed to form on the surface of anode mixture floor and anode mixture layer the scheme (opening flat 7-220759 communique with reference to the spy) of porous matter refractory layer.Porous matter refractory layer is that the slip that will contain particulate and binding agent is coated in the surface of mixture layer and forms by drying.
And known that it is the fiercest that short-circuit reaction becomes under positive electrode collector and negative electrode collector and the contacted situation of anode mixture layer.Therefore, proposed only to be provided with the scheme of porous matter refractory layer in the incidental place of internal short-circuit.Specifically, following scheme is proposed: promptly, form the porous matter refractory layer (opening the 2004-63343 communique) that constitutes by powder and binding resin with reference to the spy at the exposed division of positive electrode collector that is provided with for the welding lead collector body and negative electrode collector.Above-mentioned powder has 500 ℃ or above thermal endurance.
Open the technology that flat 7-220759 communique is put down in writing according to the spy, can obtain the good lithium rechargeable battery of anti-short-circuit.But, also less even above-mentioned porous matter refractory layer has ionic conductivity because of this ionic conductance, cause the ionic conductivity of pole plate to reduce, thereby reaction impedance increase.Therefore, if such porous matter refractory layer is arranged on the whole zone of carrying out electrode reaction, then discharges and recharges reaction and will become and be difficult to take place.
In addition, as top institute descriptively, open in the 2004-63343 communique the spy, only putting down in writing easy and porous matter refractory layer be set because of the overheated place of internal short-circuit that causes.But know at present: open the place that the 2004-63343 communique is put down in writing the spy, the probability that internal short-circuit takes place is not too high.
Summary of the invention
So, the object of the present invention is to provide a kind of high performance lithium rechargeable battery, it to be can effectively prevent to keep because of the overheated internal short-circuit that causes, simultaneously the mode of battery behavior, what make cell reaction guarantees to become possibility.
The present invention relates to a kind of lithium rechargeable battery, it has the negative pole and the barrier film of strip-shaped positive electrode, band shape, have the positive pole that will separate by barrier film and negative pole reel the electrode group that forms with accommodate the electrode group end jar arranged, wherein just having positive electrode collector and appendix anode mixture layer thereon, negative pole has negative electrode collector and appendix anode mixture layer thereon, between at least one side and barrier film of anode mixture layer and anode mixture layer, partly disposing porous matter refractory layer.
In above-mentioned lithium rechargeable battery, preferably, at least one side of anode mixture layer and anode mixture layer, Yi Bian disposing porous matter refractory layer at least along above-mentioned mixture layer.
In above-mentioned lithium rechargeable battery, preferably, along the anodal at least one side's of band shape minor face, the exposed division of the positive electrode collector that does not have appendix anode mixture layer is being set, above-mentioned porous matter refractory layer is configured along the boundary portion of above-mentioned anode mixture layer and described exposed division.
In above-mentioned lithium rechargeable battery, institute preferably, minor face along the anodal at least one side of above-mentioned band shape, the exposed division of the above-mentioned positive electrode collector that does not have the above-mentioned anode mixture layer of appendix is being set, and above-mentioned porous matter refractory layer is configured across the opposed mode of above-mentioned barrier film with the boundary portion with the exposed division of above-mentioned anode mixture layer and above-mentioned positive electrode collector.
In above-mentioned lithium rechargeable battery, the exposed division of above-mentioned positive electrode collector preferably is provided with along the above-mentioned anodal minor face that stops side of reeling.
In above-mentioned lithium rechargeable battery, preferably, long limit along the anodal at least one side of above-mentioned band shape, the exposed division of the above-mentioned positive electrode collector that does not have the above-mentioned anode mixture layer of appendix is being set, and above-mentioned porous matter refractory layer is configured along at least 1 side of the boundary portion of the exposed division of above-mentioned anode mixture layer and above-mentioned positive electrode collector.
In above-mentioned lithium rechargeable battery, preferably, long limit along the anodal at least one side of above-mentioned band shape, the exposed division of the above-mentioned positive electrode collector that does not have the above-mentioned anode mixture layer of appendix is being set, and above-mentioned porous matter refractory layer is configured at least across the opposed mode of above-mentioned barrier film with 1 side with the boundary portion of the exposed division of above-mentioned anode mixture layer and above-mentioned positive electrode collector.
In above-mentioned lithium rechargeable battery, institute preferably, long limit along at least one side of above-mentioned banded negative pole, the exposed division of the above-mentioned negative electrode collector that does not have the above-mentioned anode mixture layer of appendix is being set, and above-mentioned porous matter refractory layer is configured along at least 1 side of the boundary portion of the exposed division of above-mentioned anode mixture layer and above-mentioned negative electrode collector.
In above-mentioned lithium rechargeable battery, preferably, long limit along at least one side of above-mentioned banded negative pole, the exposed division of the above-mentioned negative electrode collector that does not have the above-mentioned anode mixture layer of appendix is being set, and above-mentioned porous matter refractory layer is configured at least across the opposed mode of above-mentioned barrier film with 1 side with the boundary portion of the exposed division of above-mentioned anode mixture layer and above-mentioned negative electrode collector.
In above-mentioned lithium rechargeable battery, preferably, 2 end faces in the electrode group are disposing the exposed division of positive electrode collector and the exposed division of negative electrode collector respectively, anodal current-collecting terminals is welded on the exposed division of positive electrode collector, and the negative pole current-collecting terminals is welded on the exposed division of negative electrode collector.
In above-mentioned lithium rechargeable battery, porous matter refractory layer preferably be arranged on anode mixture layer and at least one side of anode mixture layer from the end of coiling origination side to the zone in precalculated position.At this, when the area that the area of porous matter refractory layer is set at A, mixture layer was set at B, the ratio A/B of area A and area B was preferably 0.02～0.3.Here, the area of so-called mixture layer refers to the area of the whole mixture layer that contacts with porous matter refractory layer.
In above-mentioned lithium rechargeable battery, porous matter refractory layer preferably be arranged on anode mixture layer above.
In above-mentioned lithium rechargeable battery, when the area that is set at A, anode mixture layer when the area with porous matter refractory layer was set at B1, the ratio A/B1 of area A and area B 1 was preferably 0.02～0.3.
In above-mentioned lithium rechargeable battery, the width of the anode mixture layer preferably width than anode mixture layer is big.
In above-mentioned lithium rechargeable battery, the thickness of porous matter refractory layer is preferably 1～10 μ m.
In above-mentioned lithium rechargeable battery, porous matter refractory layer preferably contains insulating properties filler and binding agent.
In above-mentioned lithium rechargeable battery, the insulating properties filler preferably contains at least a kind that is selected among alumina, magnesium oxide, titanium dioxide, zirconia and the silica.
In above-mentioned lithium rechargeable battery, binding agent preferably contains at least a kind among the modified rubber particle that comprises acrylonitrile unit and the polyvinylidene fluoride.
In above-mentioned lithium rechargeable battery, porous matter refractory layer preferably with respect to the insulating properties filler of per 100 weight portions, contains 1～5 parts by weight of adhesive.
Description of drawings
Fig. 1 is the cross-sectional view that schematically illustrates the employed electrode group of lithium rechargeable battery of an embodiment of the present invention.
Fig. 2 is the cross-sectional view that schematically illustrates the employed electrode group of lithium rechargeable battery of another embodiment of the present invention.
Fig. 3 a is the 1st end view that schematically illustrates the employed negative pole of lithium rechargeable battery of again of the present invention～embodiment.
Fig. 3 b is the 2nd end view of the negative pole of Fig. 3 a.
Fig. 4 is the longitudinal section that schematically illustrates the electrode group of using the negative pole shown in Fig. 3 a and Fig. 3 b and forming.
Fig. 5 a is the sectional view of the employed positive pole of electrode group, negative pole and barrier film that schematically illustrates the lithium rechargeable battery of another embodiment of the present invention.
Fig. 5 b is the end view of the negative pole shown in Fig. 5 a.
Embodiment
Below, describe with regard to the present invention with reference to accompanying drawing.
Lithium rechargeable battery of the present invention has strip-shaped positive electrode, banded negative pole and barrier film, and have the electrode group that the above-mentioned positive pole that will separate by barrier film and above-mentioned negative pole coiling form and accommodate above-mentioned electrode group end jar arranged.Just having positive electrode collector and the appendix anode mixture layer on positive electrode collector, negative pole has negative electrode collector and the anode mixture layer of appendix on negative electrode collector.Between at least one side and barrier film of anode mixture layer and anode mixture layer, partly disposing porous matter refractory layer.At this moment, Yi Bian porous matter refractory layer for example can being configured along the mixture layer at least.Constitute according to this, can not reduce battery behavior and suppress generation because of the overheated internal short-circuit that causes.
The following describes the preferred embodiment of the invention.As shown below, the present invention because of the overheated place that causes internal short-circuit, is being provided with porous matter refractory layer easily effectively.
Embodiment 1
Fig. 1 represents that the coiling of the employed electrode group of the lithium rechargeable battery of an embodiment of the present invention stops the part of side.
The electrode group of Fig. 1 have strip-shaped positive electrode 11, banded negative pole 12 and be configured in positive pole and negative pole between barrier film 13.In the electrode group of Fig. 1, anodal 11 by positive electrode collector 11a and appendix the anode mixture layer 11b on its two sides constitutes.Anode mixture layer 12b on its two sides constitutes negative pole 12 by negative electrode collector 12a and appendix.In addition, positive pole 11 and negative pole 12 are wound on together by the separation of barrier film.Moreover, there is not the exposed division 15 of the positive electrode collector of anode mixture layer, the minor face that stops side along the coiling of positive pole is provided with.
In the electrode group of Fig. 1, with the opposed mode of boundary portion of the exposed division of anode mixture layer and positive electrode collector, the separation anode mixture layer by barrier film 13 is provided with porous matter refractory layer 14.In addition, in Fig. 2, represented to be provided with the situation of porous matter refractory layer 14 along the boundary portion of the exposed division of anode mixture layer and positive electrode collector.In addition, in Fig. 2, the inscape identical with Fig. 1 put on identical sequence number.
In civilian battery,, the exposed division of the collector body that does not have the anode mixture layer is set as described above usually along at least one side of anodal minor face.In this case, boundary portion and periphery thereof at the exposed division of anode mixture layer and positive electrode collector often are short-circuited because of overheated easily.This is based on following reason: that is to say, for example aluminium foil is used as positive electrode collector, because this aluminium foil is soft, cut very difficult often so do not produce the protrusion (the following cutting burr that also claims) of palpus shape.For this reason, do not producing the imbalance that will produce cutting between cutting burr anode mixture layer that just can cut and the collector body exposed division, in the boundary portion of positive electrode collector and anode mixture layer, the cutting burr of positive electrode collector just becomes and is easy to generate.
Moreover, anodal for example can obtain positive plate, cut this positive plate along its length again and make by on the two sides of collector body, forming the mixture layer.In this case, behind the long distance ground cutting anode mixture layer, in order to cut the exposed division of collector body, above-mentioned imbalance becomes more remarkable, thereby the cutting burr more is easy to generate.
Therefore, when positive electrode collector was made of the flexible material of aluminium foil and so on, the cutting burr was more prone to take place.This cutting burr contacts with in opposite directions anode mixture layer by puncturing barrier film, and internal short-circuit just becomes and taken place easily like this.
In this case, preferably the boundary portion along the exposed division of anode mixture layer and positive electrode collector is provided with porous matter refractory layer, perhaps as shown in Figure 1, with with the opposed mode of above-mentioned boundary portion, the separation by barrier film on the negative pole, configuration porous matter refractory layer on anode mixture layer especially.Like this, by the position configuration porous matter refractory layer that is easy to generate at the cutting burr,,, thereby can avoid the internal short-circuit that causes because of overheated because this cutting burr can not reach anode mixture layer yet even punctured under the situation of barrier film 13 at the cutting burr.Moreover, even for example barrier film produces fusing,, thereby can prevent contacting of positive electrode collector (cutting burr) and anode mixture layer also owing to there is porous matter refractory layer.
In addition, even porous matter refractory layer is set, perhaps, also can suppress the reduction of battery behavior across the opposed mode of barrier film porous matter refractory layer to be set with above-mentioned boundary portion along above-mentioned boundary portion.This be because: owing to be provided with current-collecting terminals at the exposed division of positive electrode collector, this peripheral electronic conductivity improves, even there is porous matter insulating barrier, giving and accepting of electronics also carried out actively, thereby can suppress the reduction of ionic conductivity.
As mentioned above, according to the present invention, can not reduce battery behavior and the internal short-circuit that prevents from effectively to cause because of overheated.For this reason, can greatly improve the reliability of lithium rechargeable battery.
In addition, porous matter refractory layer further preferably with the opposed mode of above-mentioned boundary portion, by diaphragm configuration on anode mixture layer.This be because, compare to the anode mixture layer, anode mixture layer has higher porosity usually, so even porous matter refractory layer is set, also can keep the balance of ionic conductivity well on anode mixture layer.
When porous matter refractory layer was set on anode mixture layer, when the area with porous matter refractory layer is set at A, when the area of anode mixture layer was set at B1, porous matter refractory layer area A was preferably 0.02～0.3 with respect to the ratio A/B1 of anode mixture layer area B 1.If ratio A/B1 is greater than 0.3, then because the mobile obstruction that is subjected to porous matter refractory layer of ion often causes that battery behavior reduces.If ratio A/B1, then often causes anti-internal short-circuit performance less than 0.02 and reduces.Therefore, by ratio A/B1 is set at 0.02～0.3, just can make battery behavior and the good balance of anti-internal short-circuit property retention.
In addition, in each anode mixture layer that is provided with porous matter refractory layer, ratio A/B1 is preferably in above-mentioned scope.
In addition, under porous matter refractory layer was arranged on situation on the anode mixture layer, the length of the Width of the anode mixture layer preferably length than the Width of anode mixture layer was bigger.This be because: in lithium rechargeable battery because positive pole is the volume controlled utmost point, so must be longer with the Design of length of the Width of anode mixture layer than the length of the Width of anode mixture layer, can avoid the loss of battery capacity thus.
In addition, porous matter refractory layer also can be arranged on the positive pole along the boundary portion of the exposed division of anode mixture layer and positive electrode collector.This situation is also same with above-mentioned situation, even produced the cutting burr, can prevent that also this cutting burr from reaching anode mixture layer.
The exposed division of above-mentioned positive electrode collector both can be provided with along the reel minor face of origination side of positive pole, also can be as shown in Figure 1, be provided with along the positive pole minor face that stops side of reeling.
The thickness of porous matter refractory layer is preferably 1～10 μ m.If the thickness of porous matter refractory layer is thinner than 1 μ m, the inhibition effect of internal short-circuit is reduced.If the thickness of porous matter refractory layer surpasses 10 μ m, then reaction impedance increases, and battery behavior often more or less reduces.Therefore, be 1～10 μ m by thickness adjusted with porous matter refractory layer, then can suppress the generation of internal short-circuit by means of porous matter refractory layer, also can between battery behavior and anti-internal short-circuit, keep good balance simultaneously.
As porous matter refractory layer 14, operablely be, with the high-fire resistance resin for example fusion temperature be the material that 250 ℃ or above aromatic polyamides or polyamide-imides are configured as the filter paper shape, and the material that constitutes by insulating properties filler and binding agent etc.
Porous matter refractory layer by the high-fire resistance resin of filter paper shape constitutes for example is configured between positive pole and the negative pole.By the porous matter refractory layer that insulating properties filler and binding agent constitute, for example be configured in anode mixture layer and/or anode mixture layer above.
In addition, even in above-mentioned porous matter refractory layer, the also preferred porous matter refractory layer that constitutes by insulating properties filler and binding agent.This be because: with the insulating properties filler is main material, with binding agent they is together with each other, thereby has improved structural strength.
As the employed insulating properties filler of porous matter refractory layer, the preferred use is selected from least a among alumina, magnesium oxide, titanium dioxide, zirconia and the silica.This be because: as the inorganic oxide of these alumina, magnesium oxide, titanium dioxide, zirconia and silica and so on, its heat conductivity is higher, and chemical property is stable.In addition, also can be with at 1000 ℃ or following temperature does not melt or the resin beads (beads) of incombustible high-fire resistance etc. is used as the insulating properties filler.
In general, because binding agent sucks electrolyte and swelling after constituting battery, so its addition is few more good more.Therefore, make the land used binding agent, even preferably also just demonstrate the material of bond effect on a small quantity as porous matter refractory layer.As such binding agent, preferably use polyvinylidene fluoride (following brief note is PVDF) and contain at least a among the modified rubber of acrylonitrile unit.
An example as the modified rubber that contains acrylonitrile unit, (for example can list emboliform material, BM-500B with Japanese ZEON (strain) making of core-shell (core-shell) structure), and when making porous matter refractory layer in the employed solvent soluble material (for example, by acrylonitrile unit and CH
2The BM-720H that the Japanese ZEON (strain) that the unit constitutes makes) etc.
For example, using under the situation of PVDF as binding agent, preferably making the viscosity that has appropriateness as the paste of presoma.By using such paste, can form uniform porous matter refractory layer.
In addition, the emboliform modified rubber (for example BM-500B) that contains acrylonitrile unit is preferably with the binding agent with tackifying, be used in combination with PVDF and carboxymethyl cellulose (following brief note is CMC), poly(ethylene oxide) (following brief note is PEO), other modified rubber (for example BM-720H) that contains acrylonitrile unit etc. specifically.
The amount of the binding agent that is contained in the porous matter refractory layer, preferably the insulating properties filler with respect to per 100 weight portions is 1～5 weight portion.As mentioned above, after constituting battery, swelling takes place owing to sucking electrolyte in binding agent, so when the amount of binding agent surpassed 5 weight portions, the hole in the porous matter refractory layer reduced, and often causes the reduction of ionic conductivity.When the amount of binding agent is less than 1 weight portion, often cause the reduction of the mechanical strength of porous matter refractory layer.Therefore, be adjusted to above-mentioned scope by amount with binding agent, the ionic conductivity that can make porous matter refractory layer have appropriateness, the while can also be improved the structural strength of porous matter refractory layer.
As the positive active material that is contained in the anode mixture layer, for example can use lithium composite xoide.As the example of lithium composite xoide, can list and use composition formula LiMO
2Or LiM
2O
4The material of expression.Here, element M is in the transition metal of Co, Mn, Ni, Fe and so at least a kind.In addition, also the part of above-mentioned transition metal can be used as positive active material with the displacement of typical elements such as Al, Mg.
As positive electrode collector, can not add the special ground that limits and use the material that constitutes by material stable under anodal current potential.As such positive electrode collector, for example can use the material that constitutes by aluminium foil.
As the negative electrode active material that is contained in the anode mixture layer, for example can use to embed or to insert lithium and take off embedding or take off the material of inserting lithium.As its example, can list graphite, silicide, titanium alloy material etc.They both can use separately, also can make up two or more uses.
As negative electrode collector, can not add the special ground that limits and use the material that constitutes by material stable under the negative pole current potential.As such negative electrode collector, for example can use the material that constitutes by Copper Foil.
As barrier film, can use the material that constitutes by porous film, this porous film has the confining force of higher electrolyte, and is all very stable under the current potential of arbitrary electrode of anodal and negative pole.As such barrier film, the material that for example can list the material that constitutes by polypropylene (following brief note is PP), constitute by polyethylene, the material that constitutes by polyimides, the material that constitutes by polyamide etc.
Embodiment 2
Fig. 3 a and Fig. 3 b represent the 1st end view and the 2nd end view of employed negative pole in the lithium rechargeable battery of another embodiment of the present invention.In addition, Fig. 4 represents to use the longitudinal section of the electrode group of the negative pole made shown in Fig. 3 a and Fig. 3 b.In the present embodiment, porous matter refractory layer etc. also use the material same with above-mentioned embodiment 1.
In the present embodiment, strip-shaped positive electrode 21 by positive electrode collector 21a and on its two sides the anode mixture layer 21b of institute's appendix constitute.Banded negative pole 22 by negative electrode collector 22a and on its two sides the anode mixture layer 22b of institute's appendix constitute.Along an anodal side's long limit, the exposed division 25 of the positive electrode collector that does not design the anode mixture layer is being set here.Equally, shown in Fig. 3 a and Fig. 3 b,, the exposed division 26 of the negative electrode collector that does not design anode mixture layer is being set along negative pole one side's long limit.Anodal current-collecting terminals is welded on the exposed division 25 of positive electrode collector, and the negative pole current-collecting terminals is welded on the exposed division 26 of negative electrode collector.
The such positive pole 21 and the negative pole 22 that pass through the barrier film separation are wound up, just constitute electrode group shown in Figure 4.Here, the coiling negative pole makes the 1st side shown in Fig. 3 a towards interior all sides, and the 2nd side shown in Fig. 3 b is towards outer circumferential side, and the end of β side becomes the end of coiling origination side, and the end of α side becomes the termination side of reeling.In addition, the length of the Width of anode mixture layer is longer than the length of the Width of anode mixture layer.
In the battery of height output purposes etc., as top institute narrate, the exposed division of positive electrode collector that does not have appendix anode mixture layer is along at least one square band shape that becomes on the long limit of positive pole, do not have the exposed division of the negative electrode collector of appendix anode mixture layer to be arranged to band shape along at least one side on the long limit of negative pole.In this case, at least one side of the boundary portion of at least one side of the boundary portion of the exposed division of anode mixture layer and positive electrode collector and the exposed division of anode mixture layer and negative electrode collector produces short circuit because of overheated easily.It is generally acknowledged that this is based on following reason: promptly under the incomplete situation of welding condition of the exposed division of collector body and current-collecting terminals, the propagation of heat often takes place during welding, thereby barrier film is dissolved.Under the more situation of this heat propagation, the fusing of barrier film is sometimes crossed the exposed division of collector body and is reached the end of mixture layer.Under these circumstances, anode mixture layer and anode mixture layer often come in contact on a large scale, thereby cause large-scale internal short-circuit.
So, preferably, along the boundary portion of the exposed division of each anode mixture layer on the two sides that is arranged on negative electrode collector and negative electrode collector porous matter refractory layer 24 is set, perhaps across the opposed mode of barrier film porous matter refractory layer 24 to be set with this boundary portion.Equally, preferably, porous matter refractory layer 24 is set, perhaps across the opposed mode of barrier film porous matter refractory layer 24 to be set with this boundary portion along each the anode mixture layer on the two sides that is arranged on positive electrode collector and the boundary portion of positive electrode collector.In Fig. 3 a and Fig. 3 b, represented to be provided with the situation of porous matter refractory layer 24 along the boundary portion of the exposed division of each anode mixture layer on the two sides that is arranged on negative electrode collector and negative electrode collector.
Owing to be provided with porous matter insulating barrier in this wise, so, even making, the heat propagation when the exposed division of current-collecting terminals and collector body welds can prevent that also anode mixture layer and the direct of anode mixture layer from contacting under the situation of barrier film fusing or contraction.That is to say, can avoid the internal short-circuit that causes because of overheated.
In addition, in the present embodiment, even the preposition on the mixture layer is provided with porous matter refractory layer, battery behavior also can reduce hardly.This is based on the reason same with above-mentioned embodiment 1.
In the present embodiment, porous matter refractory layer both can be provided with a side of negative or positive electrode, also can be provided with the both sides of anodal and negative pole.
In positive pole and/or negative pole, under the situation of the exposed division that collector body is set along 2 long limits respectively, preferably each boundary portion along the exposed division of mixture layer and collector body is provided with porous matter refractory layer, perhaps across the opposed mode of barrier film porous matter refractory layer to be set with each boundary portion.
In addition, in each face of each face of positive pole and/or negative pole, when the exposed division that collector body only is set along long limit of the side and when the opposing party's long side is not provided with the exposed division of collector body, also can porous matter refractory layer be set along the long limit of a side's of the exposed division that collector body is not set mixture layer.For example, in the negative pole shown in Fig. 3 a and Fig. 3 b,, porous matter refractory layer 24 is set along the boundary portion of the exposed division of mixture layer and collector body and the long limit of mixture layer that a side of exposed division is not set.
In addition, for example when negative pole appears at the most peripheral of electrode group, at the 2nd side of negative pole, not across barrier film and not with the opposed part of positive pole, porous matter refractory layer 24 can be set, perhaps as Fig. 3 b and shown in Figure 4, also porous matter refractory layer 24 can be set.
In addition, under the situation that porous matter refractory layer is set on the anode mixture layer, same with above-mentioned embodiment 1, ratio A/B1 is preferably 0.02～0.3.
In addition, in the present embodiment, as shown in Figure 4, preferably dispose the exposed division of positive electrode collector, dispose the exposed division of negative electrode collector at the opposing party's end face at electrode group one side's end face.Anodal current-collecting terminals and negative pole current-collecting terminals like this, just can be set and they are contacted with each other.
In addition, in the present embodiment, electrode for example can be made by following method.At first, the mixture layer is set,, thereby obtains battery lead plate so that form the exposed division of collector body along parallel limit at the length direction of the collector body of band shape.Secondly, along the parallel lines cutting electrode plate of the Width of this band shape collector body, can make the electrode of pre-sizing thus.In this case, because the distance of cutting is shorter, promptly the stress distance of exerting one's influence is shorter, so different with the situation of above-mentioned embodiment 1, the influence that the cutting burr produces can be ignored.
Embodiment 3
Fig. 5 a represents the cross-sectional view of the employed positive pole of the lithium rechargeable battery of another embodiment of the present invention, barrier film and negative pole.In addition, in the present embodiment, porous matter refractory layer etc. are also same with above-mentioned embodiment 1.
Shown in Fig. 5 a, anodal 31 comprise positive electrode collector 31a and the appendix anode mixture layer 31b on its two sides.Negative pole 32 comprises negative electrode collector 32a and the appendix anode mixture layer 32b on its two sides.Moreover, anodal 31 and each of negative pole 32 above the mixture layer, to preposition, porous matter insulating barrier 34 is set from the end of coiling origination side.As an example, Fig. 5 b is the schematic diagram of a face of expression negative pole, and this face is positioned at the opposition side of face of the contact barrier film of negative pole.
No matter purposes and formation, the core periphery of the electrode group that the reel positive pole separated by barrier film and negative pole constitute causes short circuit because of overheated easily.This is based on following reason: promptly anodal and negative pole adopts the high material of conductivity to make.Moreover its manufacturing equipment also uses the high material of conductivity.The fragment of these materials (below be also referred to as foreign conducting matter) have time image attached on anodal, negative pole or the barrier film like that, remain in mistakenly in the electrode group as a rule.The diameter of foreign conducting matter is about several μ m, if the original depth (10～30 μ m) as barrier film can be guaranteed in the interval between positive pole and the negative pole, then is difficult to produce internal short-circuit.But the core periphery of electrode group is the origination side of reeling that begins of anodal and negative pole, the easiest being subjected to because of discharging and recharging the influence of the rapid expansion contraction that causes.Therefore, barrier film is often squeezed broken, thereby can not keep its original depth.Thus, even the diameter about only several μ m, if foreign conducting matter is present near the core of electrode group, then at this position periphery, foreign conducting matter also can puncture barrier film, so that anode mixture layer and anode mixture layer contact, thereby internal short-circuit takes place.So, generate heat because of short circuit, cause the barrier film fusing, thereby short circuit enlarges further.
As mentioned above, in the present embodiment, to preposition porous matter refractory layer is set from the end of the initial winding side of each mixture layer.Here, when the area with porous matter refractory layer be made as A, when the area of mixture layer is made as B, area A is preferably 0.02～0.3 with respect to the ratio A/B of area B.This is based on and above-mentioned same reason.
So, by to preposition porous matter refractory layer being set around the end of origination side,, also can prevent the positive pole that causes because of foreign conducting matter and the short circuit of negative pole even make in effect under the situation of thickness attenuation of barrier film because of various stress from electrode roll.Moreover the barrier film that porous matter refractory layer replaces the maintenance of thickness attenuation, electrolyte to become difficult keeps electrolyte, also can guarantee ionic conductivity.Therefore, even on the mixture layer, be provided with porous matter refractory layer, also can suppress the reduction of battery behavior.
In the present embodiment, porous matter refractory layer both can be provided with a side of negative or positive electrode, also can be provided with the both sides of anodal and negative pole.In addition, in the present embodiment, the length of the Width of the anode mixture layer preferably length than the Width of anode mixture layer is longer.
In above-mentioned embodiment 2 and embodiment 3, as porous matter refractory layer, can be same with embodiment 1.In addition, the amount of the binding agent that the thickness of porous matter refractory layer, porous matter refractory layer are contained etc., also same with the situation of embodiment 1.
Below the manufacture method of just anodal, negative pole and porous matter refractory layer describe.
Positive pole for example can be made by following method.
Above-mentioned positive active material and conductive agent, binding agent, dispersant etc. is mixing, be modulated into anodal paste.The mode that has exposed division then with the precalculated position of positive electrode collector is coated in the anodal paste that obtains on the positive electrode collector and carries out drying, has just obtained forming on positive electrode collector the positive plate of anode mixture layer.The positive plate that obtains is rolled into preset thickness, cuts into predetermined size, just can obtain positive pole.As above-mentioned conductive agent, can use acetylene black carbon blacks such as (following brief note are AB), graphite material here,, stable metal superfine powder under anodal current potential.As binding agent, can use material stable under anodal current potential, for example PVDF, the modified rubber that contains acrylonitrile unit, polytetrafluoroethylene etc.Moreover, realizing stabilisation for making anodal paste, also the cellulose derivative of carboxymethyl cellulose (following brief note is CMC) etc. can be added in the anodal paste as tackifier.
Negative pole for example can be made by following method.
Above-mentioned negative electrode active material and binding agent, dispersant etc. is mixing, be modulated into the negative pole paste.The mode that has exposed division then with the precalculated position of negative electrode collector is coated in the negative pole paste that obtains on the negative electrode collector and carries out drying, just obtains having formed on negative electrode collector the negative plate of anode mixture layer.The negative plate that obtains is rolled into preset thickness, cuts into predetermined size, just can obtain negative pole.,, can use material stable under the negative pole current potential here, for example PVDF, butadiene-styrene rubber copolymer (following brief note is SBR) etc. as binding agent.In addition, realize stabilisation, also cellulose derivatives such as CMC can be added in the negative pole paste as tackifier for making the negative pole paste.
By the porous matter refractory layer that insulating properties filler and binding agent constitute, for example can make by following method.
Use stirring insulating properties filler, binding agent, dispersants etc. such as two wrist formula mixing rolls, just obtain paste.With scraper plate (doctor blade) and the die head methods such as (die coat) that applies the paste that obtains is coated on the part shown in the above-mentioned embodiment 1～3, by adopting the dry paste that should apply such as far infrared and hot blast, just can form porous matter refractory layer.
Be that the basis describes with regard to the present invention below with embodiment.
Embodiment 1
(battery 1-1)
(anodal making)
Mix with cobalt acid lithium, the PVDF of 4 weight portions, the AB of 3 weight portions and an amount of N-N-methyl-2-2-pyrrolidone N-(the following NMP that also claims) of two wrist formula mixing rolls, just produce anodal paste 100 weight portions.The anodal paste that obtains is coated in the two sides of the positive electrode collector (thickness 15 μ m) that is made of aluminium foil, dry, rolling after, just obtain having the positive plate of collector body and the mixture layer of appendix on its two sides.At this moment, the coiling of the positive pole that obtains in cutting stops side, and the mode with the exposed division that forms positive electrode collector has applied anodal paste on positive electrode collector.Being rolled the gross thickness that makes positive plate is 160 μ m.
Secondly, the positive plate that obtains is cut by the size of width 53mm, length overall 580mm, just obtain positive pole.At this, the length of the mixture layer that forms on the two sides of collector body is 550mm separately on 2 surfaces, so just makes the exposed division of collector body appear at the end of the anodal termination side of reeling.In addition, when cutting is anodal, the interval of 2 cutting edges is set at 200 μ m, just producing at the cutting part of positive electrode collector exposed division highly is the cutting burr of 50～100 μ m.
(making of negative pole)
Mix with electrographite, the SBR of 1 weight portion, the CMC of 1 weight portion and an amount of water of two wrist formula mixing rolls, just produce the negative pole paste 100 weight portions.The negative pole paste that obtains is coated in the two sides of the collector body (thickness is 10 μ m) that is made of Copper Foil, dry, rolling after, just obtain having the negative plate of collector body and the mixture layer of appendix on its two sides.Being rolled the gross thickness that makes negative plate is 180 μ m.
Secondly, the negative plate that obtains is cut by the size of width 55mm, length overall 650mm, just obtain negative pole.At this, the length of the mixture layer that forms on the two sides of collector body is 620mm separately on 2 surfaces, so just makes the exposed division of collector body appear at the end that the negative pole coiling stops side.
(formation of porous matter refractory layer)
As shown in Figure 1, when constituting the electrode group, the boundary portion of exposed division that stops set anode mixture layer of side and positive electrode collector with the coiling with positive pole forms porous matter refractory layer across the opposed mode of barrier film on anode mixture layer.Porous matter refractory layer forms by following method.
Mean particle diameter with respect to per 100 weight portions is the alumina particle of 0.5 μ m, adds the PVDF of 3 weight portions, adds an amount of NMP again, just obtains mixture.After stirring this mixture with two wrist formula mixing rolls, use the zirconia ball of diameter, carry out bead and grind (bead mill) disperseing alumina particle and PVDF, thereby obtain paste as 0.2mm.When constituting the electrode group, with the opposed mode of above-mentioned boundary portion, by the separation of barrier film, the paste that the obtains length with 10mm is coated on the anode mixture layer, just obtain porous matter refractory layer after the drying.At this, the thickness of porous matter refractory layer is 5 μ m.In addition, the width setup of porous matter refractory layer is identical with the width of anode mixture layer.
(assembling of battery)
Positive pole and negative pole that the barrier film (thickness 23 μ m) obtain as described above, constitute by the porous film by the PP system of reeling is separated just obtain the electrode group.
Secondly, the electrode group that obtains is inserted diameter is 18mm, highly for the cylinder type of 65mm has in the substrate jar, and adding electrolyte.At this, as electrolyte, use in the ratio with 20: 40: 40 (weight ratio) is mixed with the mixed solvent of EC, DEC and DMC, with the concentration dissolving LiPF of 1 mol
6And the solution that obtains.
Secondly, seal, just produce lithium rechargeable battery with the peristome of hush panel to metal can.The nominal capacity of the battery that obtains is 2Ah.The battery of making like this is made as battery 1-1.
(battery 1-2～1-5)
With the thickness setting of porous matter refractory layer is 0.8 μ m, 1 μ m, 10 μ m or 12 μ m, in addition, similarly makes lithium rechargeable battery with the manufacture method of battery 1-1.The battery that obtains is made as battery 1-2～1-5 respectively.
(battery 1-6～1-10)
When making porous matter refractory layer, replace the alumina particle with the filler that constitutes by magnesium oxide, titanium dioxide, zirconia, silica or aromatic polyamides identical with the alumina particle diameter, in addition, similarly make lithium rechargeable battery with the manufacture method of battery 1-1.The battery that obtains is made as battery 1-6～1-10 respectively.
(battery 1-11)
When making porous matter refractory layer, use with PVDF and replace PVDF with modified rubber mixture weight, that contain acrylonitrile unit (BM-500B that Japanese ZEON (strain) makes and the mixture (mixing ratio (weight ratio) is 1: 1) of BM-720H) (the following modified rubber mixture that also claims), in addition, similarly make lithium rechargeable battery with the manufacture method of battery 1-1.The battery that obtains is made as battery 1-11.
(battery 1-12～1-15)
When making porous matter refractory layer, except the amount with the PVDF in the alumina particle of per 100 weight portions was set at 0.8 weight portion, 1 weight portion, 5 weight portions or 7 weight portions respectively, the manufacture method of all the other and battery 1-1 was similarly made lithium rechargeable battery.The battery that obtains is made as 1-12～1-15 respectively.
(embodiment 1-16～1-19)
Except the length setting of porous matter refractory layer was 12.4mm, 49.6mm, 186mm or 248mm, the manufacture method of all the other and battery 1-1 was similarly made lithium rechargeable battery.The battery that obtains is made as battery 1-16～1-19 respectively.
(reference battery 1-1)
Except the whole surface at anode mixture layer formed porous matter refractory layer, the manufacture method of all the other and battery 1-1 was similarly made lithium rechargeable battery.The battery that obtains is made as reference battery 1-1.
(relatively battery 1-1)
Except porous matter refractory layer was not set, the manufacture method of all the other and battery 1-1 was similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 1-1.
(relatively battery 1-2)
Except only the exposed division of positive electrode collector is provided with porous matter refractory layer, the manufacture method of all the other and battery 1-1 is similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 1-2.
(relatively battery 1-3)
Except only the exposed division of negative electrode collector is provided with porous matter refractory layer, the manufacture method of all the other and battery 1-1 is similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 1-3.
(relatively battery 1-4)
Use PP system resin tape (thickness is 25 μ m) to replace porous matter refractory layer, boundary portion along the exposed division of anode mixture layer and positive electrode collector is provided with PP system resin tape, in addition, similarly make lithium rechargeable battery with the manufacture method of battery 1-1.The battery that obtains is made as comparison battery 1-4.
Each battery that obtains is carried out following evaluation.
(test for short-circuit)
Each battery (each 20) is charged to after cell voltage reaches 4.1V with the current value of 400mA, under 45 ℃ environment, preserved 7 days.To be made as short circuit battery because of preservation makes open circuit voltage reduction 300mV or above battery.The ratio of the short circuit battery of representing with percentage is shown in table 1～5.
(capacity affirmation)
To not observe 1 unusual battery through above-mentioned test for short-circuit in each battery, be discharged to cell voltage with the current value of 400mA and reach 3.0V.
Secondly, the battery after the discharge is charged to cell voltage with the constant current value of 2A reaches 4.2V, then, reduce to 50mA with the constant-potential charge of 4.2V to current value till.Battery after then will charging is discharged to cell voltage with the constant current value of 400mA and reaches 3.0V.Such charge and discharge cycles is repeated 2 times.The discharge capacity (discharge capacity) of the 2nd circulation has been represented in table 1～5.
(high-rate characteristics evaluation)
Battery to after the above-mentioned capacity affirmation carries out following discharging and recharging.
Each battery is charged to cell voltage with the constant current value of 2A reach 4.2V, then, charge to till current value reduces to 50mA with the constant voltage values of 4.2V.Battery after then will charging is discharged to cell voltage with the constant current value of 4A and reaches 3.0V, obtains the high rate discharge capacity.The high rate discharge capacity of representing with percentage with respect to the ratio (high rate discharge Capacity Ratio) of the discharge capacity of in above-mentioned capacity is confirmed, obtaining shown in table 1～5.
(unusual elevated temperature test)
Above-mentioned each battery that carries out the excessive rate evaluating characteristics is charged to cell voltage with the current value of 400mA reach 4.25V, under 120 ℃ environment, placed 6 hours then.At this moment, the temperature of outside batteries surpass 130 ℃ situation be judged as taken place overheated.What each battery was overheated has but shown in table 1～3 and 5.
(cycle life characteristics)
Battery 1-16～1-19 has been carried out the measurement of capacity sustainment rate.
Under 45 ℃ environment, each battery is charged to cell voltage with the constant current value of 2A reaches 4.2V, then, with the constant voltage values charging of 4.2V till current value reduces to 50mA.Battery after then will charging is discharged to cell voltage with the constant current value of 2A and reaches 3.0V.Such charge and discharge cycles is repeated 500 times.The ratio (capacity sustainment rate) of the discharge capacity the when discharge capacity of the 500th circulation of representing with percentage is confirmed with respect to above-mentioned capacity is as shown in table 4.
In addition, the data of also having represented battery 1-1 in table 2～3.In addition, in table 4, represented ratio A/B1 simultaneously.
Table 1
| The thickness of porous matter refractory layer (μ m) | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Overheated has or not | |
| Battery 1-1 | 5 | 5 | 1989 | 89 | Do not have |
| Battery 1-2 | 0.8 | 60 | 1991 | 90 | Have |
| Battery 1-3 | 1 | 5 | 1990 | 89 | Do not have |
| Battery 1-4 | 10 | 5 | 1990 | 88 | Do not have |
| Battery 1-5 | 12 | 0 | 1988 | 84 | Do not have |
Table 2
| The kind of filler | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Overheated has or not | |
| Battery 1-1 | Alumina | 5 | 1989 | 89 | Do not have |
| Battery 1-6 | Magnesium oxide | 5 | 1992 | 88 | Do not have |
| Battery 1-7 | Titanium dioxide | 5 | 1980 | 86 | Do not have |
| Battery 1-8 | Zirconia | 5 | 1988 | 89 | Do not have |
| Battery 1-9 | Silica | 5 | 1985 | 90 | Do not have |
| Battery 1-10 | Aromatic polyamides | 5 | 1991 | 88 | Do not have |
Table 3
| The kind of binding agent | The amount of binding agent (weight portion) | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Overheated has or not | |
| Battery 1-1 | PVDF | 3 | 5 | 1989 | 89 | Do not have |
| Battery 1-11 | The modified rubber mixture | 3 | 0 | 1992 | 91 | Do not have |
| Battery 1-12 | PVDF | 0.8 | 40 | 1992 | 93 | Have |
| Battery 1-13 | PVDF | 1 | 5 | 1990 | 92 | Do not have |
| Battery 1-14 | PVDF | 5 | 5 | 1987 | 88 | Do not have |
| Battery 1-15 | PVDF | 7 | 0 | 1990 | 82 | Do not have |
Table 4
| The length (mm) of porous matter refractory layer | Ratio A/B1 | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Capacity sustainment rate (%) | |
| Battery 1-16 | 12.4 | 0.02 | 5 | 1984 | 89 | 83 |
| Battery 1-17 | 49.6 | 0.08 | 5 | 1990 | 88 | 84 |
| Battery 1-18 | 186 | 0.30 | 0 | 1988 | 89 | 84 |
| Battery 1-19 | 248 | 0.40 | 0 | 1992 | 85 | 85 |
Table 5
| The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Overheated has or not | |
| Reference battery 1-1 | 5 | 1981 | 83 | Do not have |
| Compare battery 1-1 | 95 | 1995 | 90 | Have |
| Compare battery 1-2 | 80 | 1997 | 91 | Have |
| Compare battery 1-3 | 85 | 1992 | 89 | Have |
| Compare battery 1-4 | 5 | 1958 | 87 | Have |
The result that the comparison battery 1-1 of porous matter refractory layer is not set is, is subjected to having a mind to the influence of the cutting burr that is provided with, and the result almost all has been short-circuited.In addition, be provided with the comparison battery 1-2 of porous matter refractory layer and be provided with the comparison battery 1-3 of porous matter refractory layer at the exposed division of negative electrode collector at the exposed division of positive electrode collector, 1-1 compares with the comparison battery, although short circuit has minimizing slightly, does not almost see the effect that prevents short circuit.As its reason, can list at battery 1-2 relatively with relatively among the battery 1-3, with the opposed suitable position, position that is easy to generate the cutting burr, porous matter refractory layer is not set.
With with the opposed mode of boundary portion of the exposed division of anode mixture layer and positive electrode collector, anode mixture layer is provided with the battery 1-1～1-19 of porous matter refractory layer, the ratio of its short circuit battery is lower.This be because: by the effect of porous matter refractory layer, can reduce the degree that the cutting burr arrives anode mixture layer.
Replace alumina with the battery 1-6～1-9 as the insulating properties filler with magnesium oxide, titanium dioxide, zirconia or silica, though capacity is variant slightly, the ratio of short circuit battery is lower, has sufficient thermal endurance.In addition, use the battery 1-10 of aromatic polyamides as the insulating properties filler, the ratio of its short circuit battery is also lower.
Replace battery capacity and other the battery of the comparison battery 1-4 of porous matter refractory layer to compare with resin tape, be significantly less than nominal capacity (2Ah).It is generally acknowledged this be because: the part of the anode mixture layer that covers with resin tape can not be carried out ionic conduction, and corresponding with this area portions, battery capacity has correspondingly reduced.
Reference battery 1-1 and battery 1-1～1-19 of being provided with porous matter refractory layer on the whole surface of anode mixture layer compare, and high-rate characteristics has reduced.It is generally acknowledged this be because: owing on the whole surface of anode mixture layer, be provided with porous matter refractory layer, thereby cause reaction impedance obviously to rise.
The thickness of porous matter refractory layer is the battery 1-2 of 0.8 μ m, and the ratio of its short circuit battery more or less increases, but the superheating phenomenon also can see unusual heat up the time.It is generally acknowledged this be because: porous matter refractory layer is thinner, and then observes many fine pin holes on this porous matter refractory layer, thus short position increase, thereby can not fully suppress the generation of internal short-circuit.Therefore, if the very thin thickness of porous matter refractory layer then often can not obtain sufficient thermal endurance.
On the other hand, the thickness of porous matter refractory layer is the battery 1-5 of 12 μ m, and its high rate discharge characteristic has reduction slightly.It is generally acknowledged this be because: the thickness of the porous matter refractory layer of formation is thicker, causes reaction impedance to increase.Therefore, the thickness of porous matter refractory layer is preferably 1～10 μ m.
Replace PVDF with battery 1-11 with the modified rubber mixture, have sufficient thermal endurance as binding agent.In addition, also can see the deterioration of the battery behavior that produces because of the swelling of above-mentioned modified rubber.Moreover in battery 1-11, the ratio of short circuit battery is minimum.It is generally acknowledged this be because: by using the modified rubber mixture, the flexibility of porous matter refractory layer more or less improves.
In addition, the amount of the binding agent in per 100 weight portion insulating properties fillers is the battery 1-12 of 0.8 weight portion, and the ratio of its short circuit battery more or less improves, the superheating phenomenon in the time of also can seeing unusual elevated temperature test in addition.Therefore, if the amount of binding agent seldom, often can not obtain sufficient thermal endurance.In addition, in unusual elevated temperature test, disassemble and produce the result that unusual overheated battery (battery 1-2 and battery 1-12) is observed, confirm that porous matter refractory layer begins to produce to peel off from anode mixture layer on a large scale, and produced short circuit in these parts.
On the other hand, the amount of binding agent is the battery 1-15 of 7 weight portions, though sufficient thermal endurance is arranged, the high rate discharge characteristic more or less reduces.It is generally acknowledged this be because: the amount of the binding agent that is contained in the porous matter refractory layer is more, causes reaction impedance to increase.Therefore, the amount of binding agent is preferably 1～5 weight portion with respect to the insulating properties filler of per 100 weight portions.
Battery 1-16～battery 1-19 is owing to the outermost perimembranous in the electrode group is provided with porous matter refractory layer, so even change the length of porous matter refractory layer, also do not observe the improvement of capacity sustainment rate too much.But irrelevant with the length of porous matter refractory layer, the ratio of short circuit battery is minimized.In addition, the high rate discharge characteristic dimensions is held on the higher level.
Embodiment 2
(battery 2-1)
(anodal making)
Cobalt acid lithium, the PVDF of 4 weight portions, the AB of 3 weight portions and an amount of NMP with 100 weight portions mixes with two wrist formula mixing rolls, just produces anodal paste.The anodal paste that obtains is coated on the positive electrode collector (thickness 15 μ m) that is made of aluminium foil, dry, rolling after, just obtain having the positive plate of collector body and the mixture layer of appendix on its two sides.At this moment,, form the mode of the collector body exposed division of width 5mm continuously, on positive electrode collector, applied anodal paste with two sides at collector body along a side's of positive plate long limit.Being rolled the gross thickness that makes positive plate is 80 μ m.
Secondly, this positive plate is cut by the size of width 53mm, length 960mm, just obtain positive pole.In addition, in the positive pole that obtains, the width of collector body exposed division is 5mm, and the length of anode mixture layer Width is 48mm.
(making of negative pole)
Mix with electrographite, the SBR of 1 weight portion, the CMC of 1 weight portion and an amount of water of two wrist formula mixing rolls, just produce the negative pole paste 100 weight portions.The negative pole paste that obtains is coated on the collector body (thickness is 10 μ m) that is made of Copper Foil, dry, rolling after, just obtain having the negative plate of collector body and the mixture layer of appendix on its two sides.At this moment, the long limit along a side of negative plate to form the mode of the exposed division of width 5mm continuously on the two sides of collector body, has applied the negative pole paste on negative electrode collector.In addition, being rolled the gross thickness that makes negative plate is 100 μ m.
Secondly, be that 55mm, length are that the size of 1020mm is cut with the negative plate that obtains by width, just obtain negative pole.In addition, in the negative pole that obtains, the width of collector body exposed division is 5mm, and the length of anode mixture layer Width is 50mm.
(formation of porous matter refractory layer)
When constituting the electrode group, with with the opposing party's of the boundary portion of the exposed division of anode mixture layer and positive electrode collector and anode mixture layer the opposed mode in long limit, respectively along 2 long limits of each anode mixture layer, shown in Fig. 3 a and 3b like that, the separation by barrier film forms porous matter refractory layer continuously.The formation of porous matter refractory layer is carried out as follows.
Mean particle diameter with respect to per 100 weight portions is the alumina particle of 0.5 μ m, adds the PVDF of 3 weight portions, adds an amount of NMP again, just obtains mixture.After stirring this mixture with two wrist formula mixing rolls, use the zirconia ball of diameter, carry out bead and grind disperseing alumina particle and PVDF, thereby obtain paste as 0.2mm.The paste that obtains along separately 2 long limits of each anode mixture layer, apply with the width of 5mm, is just obtained porous matter refractory layer after the drying.At this, the thickness setting of porous matter refractory layer is 5 μ m.
Positive pole and negative pole that the barrier film (thickness 23 μ m) obtain as described above, constitute by the porous film by the PP system of reeling is separated just obtain the electrode group.At this moment, as shown in Figure 3, reel anodal and negative pole makes the exposed division of positive electrode collector be configured in the end face of electrode group upside, it is such that the exposed division of negative electrode collector is configured in the end face of electrode group downside.
Secondly, adopt electric resistance welding that anodal current-collecting terminals is welded on the exposed division of positive electrode collector separately, the negative pole current-collecting terminals is welded on the exposed division of negative electrode collector.At this moment, on electrode for resistance welding, adhere to cupric oxide powder, be easy to generate the condition of electric spark during as welding.
Use the electrode group of the such current-collecting terminals of welding, similarly make lithium rechargeable battery with the manufacture method of above-mentioned battery 1-1.The battery that obtains is made as battery 2-1.The nominal capacity of the battery that obtains in addition, is 1.3Ah.
(battery 2-2～2-5)
With the thickness setting of porous matter refractory layer is 0.8 μ m, 1 μ m, 10 μ m or 12 μ m, in addition, similarly makes lithium rechargeable battery with the manufacture method of battery 2-1.The battery that obtains is made as battery 2-2～2-5 respectively.
(battery 2-6～2-10)
When making porous matter refractory layer, the filler that uses magnesium oxide, titanium dioxide, zirconia, silica or aromatic polyamides by same diameter to constitute replaces the alumina particle, in addition, similarly makes lithium rechargeable battery with the manufacture method of battery 2-1.The battery that obtains is made as 2-6～2-10 respectively.
(battery 2-11)
When making porous matter refractory layer, use with PVDF and replace PVDF with modified rubber mixture weight, that contain acrylonitrile unit (BM-500B that Japanese ZEON (strain) makes and the mixture (mixing ratio (weight ratio) is 1: 1) of BM-720H), in addition, similarly make lithium rechargeable battery with the manufacture method of battery 2-1.The battery that obtains is made as battery 2-11.
(battery 2-12～2-15)
When making porous matter refractory layer, except the amount with the PVDF in the alumina particle of per 100 weight portions was set at 0.8 weight portion, 1 weight portion, 5 weight portions or 7 weight portions, the manufacture method of all the other and battery 2-1 was similarly made lithium rechargeable battery.The battery that obtains is made as battery 2-12～2-15 respectively.
(battery 2-16～2-20)
Except that the width of porous matter refractory layer was 0.5mm, 1mm, 10mm, 15mm or 20mm, the manufacture method of all the other and battery 2-1 was similarly made lithium rechargeable battery.The battery that obtains is made as battery 2-16～2-20 respectively.
(reference battery 2-1)
Except the whole surface at anode mixture layer formed porous matter refractory layer, the manufacture method of all the other and battery 2-1 was similarly made lithium rechargeable battery.The battery that obtains is made as reference battery 2-1.
(relatively battery 2-1)
Except porous matter refractory layer was not set, the manufacture method of all the other and battery 2-1 was similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 2-1.
(relatively battery 2-2)
Except only the exposed division of positive electrode collector is provided with porous matter refractory layer, the manufacture method of all the other and battery 2-1 is similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 2-2.
(relatively battery 2-3)
Except the exposed division at negative electrode collector was provided with porous matter refractory layer, the manufacture method of all the other and battery 2-1 was similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 2-3.
(relatively battery 2-4)
Use polyimides system resin tape (5mm is wide, thickness is 25 μ m) to replace porous matter refractory layer, boundary portion along the exposed division of anode mixture layer and positive electrode collector is provided with this PP system resin tape, in addition, similarly make lithium rechargeable battery with the manufacture method of battery 2-1.The battery that obtains is made as comparison battery 2-4.
Each battery that obtains is carried out following evaluation.
(test for short-circuit)
Each battery (each 20) is charged to after cell voltage reaches 4.1V with the current value of 260mA, under 45 ℃ environment, preserved 7 days.To be made as short circuit battery because of preservation makes open circuit voltage reduction 300mV or above battery.The ratio of the short circuit battery of representing with percentage is shown in table 6～10.
(capacity affirmation)
To not observe 1 unusual battery through above-mentioned test for short-circuit in each battery, be discharged to cell voltage with the current value of 260mA and reach 3.0V.
Secondly, the battery after the discharge is charged to cell voltage with the constant current value of 1.3A reaches 4.2V, then, reduce to 50mA with constant-potential charge to the current value of 4.2V till.Battery after then will charging is discharged to cell voltage with the constant current value of 260mA and reaches 3.0V.Such charge and discharge cycles is repeated 2 times.The discharge capacity (discharge capacity) of the 2nd circulation has been represented in table 6～10.
(high-rate characteristics evaluation)
Battery to after the above-mentioned capacity affirmation carries out following discharging and recharging.
Each battery is charged to cell voltage with the constant current value of 1.3A reach 4.2V, then, charge to till current value reduces to 50mA with the constant voltage values of 4.2V.Battery after then will charging is discharged to cell voltage with the constant current value of 5.2A and reaches 3.0V, obtains the high rate discharge capacity.The high rate discharge capacity of representing with percentage with respect to the ratio (high rate discharge Capacity Ratio) of the discharge capacity of in above-mentioned capacity is confirmed, obtaining shown in table 6～10.
In addition, the data of also having represented battery 2-1 in table 7～9.In addition, the numerical value of also having represented ratio A/B1 at table 9 simultaneously.
Table 6
| The thickness of porous matter refractory layer (μ m) | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | |
| Battery 2-1 | 5 | 5 | 1293 | 86 |
| Battery 2-2 | 0.8 | 40 | 1290 | 90 |
| Battery 2-3 | 1 | 5 | 1288 | 88 |
| Battery 2-4 | 10 | 5 | 1289 | 86 |
| Battery 2-5 | 12 | 0 | 1290 | 80 |
Table 7
| The kind of filler | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | |
| Battery 2-1 | Alumina | 5 | 1293 | 86 |
| Battery 2-6 | Magnesium oxide | 0 | 1292 | 91 |
| Battery 2-7 | Titanium dioxide | 5 | 1282 | 85 |
| Battery 2-8 | Zirconia | 5 | 1288 | 88 |
| Battery 2-9 | Silica | 5 | 1289 | 86 |
| Battery 2-10 | Aromatic polyamides | 5 | 1290 | 86 |
Table 8
| The kind of binding agent | The amount of binding agent (weight portion) | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | |
| Battery 2-1 | PVDF | 3 | 5 | 1293 | 86 |
| Battery 2-11 | The modified rubber mixture | 3 | 0 | 1292 | 86 |
| Battery 2-12 | PVDF | 0.8 | 30 | 1290 | 85 |
| Battery 2-13 | PVDF | 1 | 5 | 1288 | 84 |
| Battery 2-14 | PVDF | 5 | 5 | 1288 | 86 |
| Battery 2-15 | PVDF | 7 | 0 | 1289 | 79 |
Table 9
| The width (mm) of porous matter refractory layer | Ratio A/B1 | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | |
| Battery 2-1 | 5 | 0.10 | 5 | 1293 | 86 |
| Battery 2-16 | 0.5 | 0.01 | 15 | 1292 | 89 |
| Battery 2-17 | 1 | 0.02 | 5 | 1296 | 87 |
| Battery 2-18 | 10 | 0.20 | 0 | 1288 | 87 |
| Battery 2-19 | 15 | 0.30 | 0 | 1290 | 84 |
| Battery 2-20 | 20 | 0.40 | 0 | 1290 | 80 |
Table 10
| The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | |
| Reference battery 2-1 | 0 | 1290 | 77 |
| Compare battery 2-1 | 95 | 1297 | 90 |
| Compare battery 2-2 | 50 | 1296 | 89 |
| Compare battery 2-3 | 45 | 1297 | 90 |
| Compare battery 2-4 | 0 | 1052 | 58 |
The comparison battery 2-1 of porous matter refractory layer is not set, and short circuit has all taken place in most battery.This is because the influence that the electricity of having a mind to take place when being subjected to current-collecting terminals welded toward the collector body exposed division on is cremated causes barrier film to melt.In addition, the comparison battery 2-2 of porous matter refractory layer is set and the comparison battery 2-3 of porous matter refractory layer is set at the exposed division of negative electrode collector at the exposed division of positive electrode collector, 2-1 compares with the comparison battery, though the ratio of short circuit battery has reduction slightly, do not observe the obvious effects that prevents short circuit.It is generally acknowledged this be because: at battery 2-2 relatively with relatively among the battery 2-3, because the formation position of porous matter refractory layer is improper, so the fusing of the barrier film that produces because of electric spark arrives the end of anode mixture layer and the end of anode mixture layer, can not keep the insulation of anodal and negative pole.
On the other hand, the position shown in Fig. 3 a, the 3b and 4 is provided with the battery 2-1～2-20 of porous matter refractory layer, can reduce the possibility of battery short circuit.It is generally acknowledged this be because: even arrive in the fusing of the barrier film that produces because of electric spark under the situation of end of the end of anode mixture layer and/or anode mixture layer, also because the thermal endurance of the alumina that porous matter refractory layer is contained is higher, porous matter refractory layer is remained on the anode mixture layer, thereby can keep the insulation of anodal and negative pole.
Use resin tape to replace the battery capacity of the comparison battery 2-4 of porous matter refractory layer, compare, be significantly less than nominal capacity (1.3Ah) with other battery.It is generally acknowledged this be because: the part of the anode mixture layer that covers with resin tape can not be carried out ionic conduction, and corresponding with this area portions, battery capacity has correspondingly reduced.
The width of porous matter refractory layer is the battery 2-16 of 0.5mm, although surpass relatively battery 2-1～3, the ratio of short circuit battery has raising slightly.It is generally acknowledged this be because: because the width of porous matter refractory layer is too narrow and small, can not bring into play its effect (guaranteeing insulation) fully because of thermal endurance improves.On the other hand, the width of porous matter refractory layer is the battery 2-19 of 20mm, although surpass reference battery 2-1, the high rate discharge characteristic has reduction slightly.It is generally acknowledged this be because: because the width of porous matter refractory layer is very wide, the reaction impedance composition correspondingly is increased.Therefore, ratio A/B1 is preferably 0.02～0.3.
Replace alumina with the battery 2-6～2-9 as the insulating properties filler with magnesium oxide, titanium dioxide, zirconia or silica, although capacity difference more or less, the ratio of short circuit battery reduces, and has sufficient thermal endurance.In addition, in using the battery 2-10 of aromatic polyamides as the insulating properties filler, the ratio of short circuit battery has also descended.
The thickness of porous matter refractory layer is the battery 2-2 of 0.8 μ m, and the ratio of short circuit battery more or less improves, and observes superheating phenomenon during unusual elevated temperature test.It is generally acknowledged this be because: porous matter refractory layer is thinner, and then observes many fine pin holes on this porous matter refractory layer, so in battery 2-2, short position increases, thereby can not fully suppress the generation of internal short-circuit.Therefore, if the very thin thickness of porous matter refractory layer then often can not obtain sufficient thermal endurance.
On the other hand, the thickness of porous matter refractory layer is the battery 2-5 of 12 μ m, and its high rate discharge characteristic more or less reduces.It is generally acknowledged this be because: because the thickness of porous matter refractory layer is very thick, causing reaction impedance increases.Therefore, the thickness of porous matter refractory layer is preferably 1～10 μ m.
Replace PVDF with battery 2-11 with the modified rubber mixture, have sufficient thermal endurance as binding agent.In addition, also can see the deterioration of the battery behavior that produces because of the swelling of above-mentioned modified rubber.Moreover in battery 2-11, the ratio of short circuit battery is minimum.It is generally acknowledged this be because: by using the modified rubber mixture, the flexibility of porous matter refractory layer more or less improves.
In addition, the amount of the binding agent in per 100 weight portion insulating properties fillers is the battery 2-12 of 0.8 weight portion, and the ratio of its short circuit battery more or less improves, and does not also have sufficient thermal endurance in addition.In addition, disassemble the result that the battery that produces short circuit is observed, confirm that porous matter refractory layer begins to produce to peel off from anode mixture layer on a large scale, and produced short circuit in these parts.
On the other hand, the amount of binding agent is the battery 2-15 of 7 weight portions, though sufficient thermal endurance is arranged, the high rate discharge characteristic more or less reduces.It is generally acknowledged this be because: the amount of the binding agent that is contained in the porous matter refractory layer is more, causes reaction impedance to increase.Therefore, the amount of binding agent is preferably 1～5 weight portion with respect to the insulating properties filler of per 100 weight portions.
Embodiment 3
(battery 3-1)
(anodal making)
Cobalt acid lithium, the PVDF of 4 weight portions, the AB of 3 weight portions and an amount of NMP with 100 weight portions mixes with two wrist formula mixing rolls, just produces anodal paste.The anodal paste that obtains is coated on the positive electrode collector (thickness 15 μ m) that is made of aluminium foil, dry, rolling after, just obtain having the positive plate of collector body and the mixture layer of appendix on its two sides.At this moment, being rolled the gross thickness that makes positive plate is 160 μ m.
Secondly, the positive plate that obtains is cut by the size of width 53mm, length overall 630mm, just obtain positive pole.At this moment, the length of the mixture layer that forms on the two sides of collector body is set at 600mm respectively on 2 surfaces.
(making of negative pole)
With two wrist formula mixing rolls the Delanium of 100 weight portions, the butadiene-styrene rubber copolymer binder of 1 weight portion (BM-400B (solid constituent is 40 weight %) that Japanese ZEON (strain) makes), the CMC of 1 weight portion and an amount of water are mixed, just produce the negative pole paste.The negative pole paste that obtains is coated on the collector body (thickness is 10 μ m) that is made of Copper Foil, dry, rolling after, just obtain having the negative plate of collector body and the mixture layer of appendix on its two sides.At this, being rolled the gross thickness that makes negative plate is 180 μ m.
Secondly, the negative plate that obtains is cut by the size of width 55mm, length overall 650mm, just obtain negative pole.At this moment, the length of the mixture layer that forms on the two sides of collector body is respectively 620mm on 2 surfaces.
(formation of porous matter refractory layer)
In the present embodiment, only on negative pole two sides' mixture layer, form porous matter refractory layer.The formation of porous matter refractory layer is carried out as follows.
At per 100 weight portion mean particle diameters is in the alumina particle of 0.5 μ m, adds the PVDF of 3 weight portions, adds NMP again, uses dispersion machine to mix, and is modulated into mixture.At this moment, making solid constituent is 50 weight %.Then, use the dispersion machine that does not use solvent to disperse alumina particle and the PVDF that is contained in this mixture, just obtain paste.
With the paste that obtains anode mixture layer two sides, begin to carry out the coating that length is 124mm from the end of coiling origination side, just obtain porous matter refractory layer after the drying.At this, make the width of the width of porous matter refractory layer and anode mixture layer identical.In addition, the thickness setting of porous matter refractory layer is 5 μ m.
Appear at the such mode of core of electrode group with porous matter refractory layer, positive pole and negative pole that the barrier film (thickness 23 μ m) that constitutes by the porous film by the PP system of reeling is separated just obtain the electrode group.At this moment, in the place of the end 5mm of distance negative pole coiling origination side, under the state of Ni powder that disposes diameter 8 μ m, reel as foreign conducting matter.
Use the electrode group that obtains like this, similarly make lithium rechargeable battery with the manufacture method of battery 1-1.The battery that obtains is made as battery 3-1.At this, the nominal capacity of the battery that obtains is 2Ah.
(battery 3-2～3-5)
Except that the thickness setting of porous matter refractory layer was 0.8 μ m, 1 μ m, 10 μ m or 12 μ m, the manufacture method of all the other and embodiment 3-1 was similarly made lithium rechargeable battery.The battery that obtains is made as battery 3-2～3-5 respectively.
(battery 3-6～3-10)
When making porous matter refractory layer, the filler of using magnesium oxide, titanium dioxide, zirconia, silica or aromatic polyamides by same diameter to constitute replaces the alumina particle, in addition, similarly makes lithium rechargeable battery with the manufacture method of battery 3-1.The battery that obtains is made as battery 3-6～3-10 respectively.
(battery 3-11)
When making porous matter refractory layer, with replacing PVDF with modified rubber mixture weight, that contain acrylonitrile unit (BM-500B of Japanese ZEON (strain) system and the mixture (mixing ratio (weight ratio) is 1: 1) of BM-720H) with PVDF, in addition, similarly make lithium rechargeable battery with the manufacture method of battery 3-1.The battery that obtains is made as battery 3-11.
(battery 3-12～3-15)
When making porous matter refractory layer, except the amount with the PVDF in the alumina particle of per 100 weight portions was set at 0.8 weight portion, 1 weight portion, 5 weight portions or 7 weight portions, the manufacture method of all the other and battery 3-1 was similarly made lithium rechargeable battery.The battery that obtains is made as battery 3-12～3-15 respectively.
(embodiment 3-16～3-20)
From the end of the coiling origination side of anode mixture layer, be 10mm, 12.4mm, 49.6mm, 186mm or 248mm with the length setting of porous matter refractory layer, in addition, similarly make lithium rechargeable battery with the manufacture method of battery 3-1.The battery that obtains is made as battery 3-16～3-20 respectively.
(reference battery 3-1)
Except that the whole surface at anode mixture layer formed porous matter refractory layer, the manufacture method of all the other and battery 3-1 was similarly made lithium rechargeable battery.The battery that obtains is made as reference battery 3-1.
(relatively battery 3-1)
Except porous matter refractory layer was not set, the manufacture method of all the other and battery 3-1 was similarly made lithium rechargeable battery.The battery that obtains is made as comparison battery 3-1.
Each battery that obtains is carried out following evaluation.
(test for short-circuit)
Each battery (each 20) is charged to after cell voltage reaches 4.1V with the current value of 260mA, under 45 ℃ environment, preserved 7 days.To be made as short circuit battery because of preservation makes open circuit voltage reduction 300mV or above battery.The ratio of the short circuit battery of representing with percentage is shown in table 11～15.
(capacity affirmation)
To not observe 1 unusual battery through above-mentioned test for short-circuit in each battery, be discharged to cell voltage with the current value of 400mA and reach 3.0V.
Secondly, the battery after the discharge is charged to cell voltage with the constant current value of 2A reaches 4.2V, then, reduce to 50mA with constant-potential charge to the current value of 4.2V till.Battery after then will charging is discharged to cell voltage with the constant current value of 400mA and reaches 3.0V.Such charge and discharge cycles is repeated 2 times.The discharge capacity (discharge capacity) of the 2nd circulation has been represented in table 11～15.
(high-rate characteristics evaluation)
Battery to after the above-mentioned capacity affirmation carries out following discharging and recharging.
Each battery is charged to cell voltage with the constant current value of 2A reach 4.2V, then, charge to till current value reduces to 50mA with the constant voltage values of 4.2V.Battery after then will charging is discharged to cell voltage with the constant current value of 4A and reaches 3.0V, obtains the high rate discharge capacity.The high rate discharge capacity of representing with percentage with respect to the ratio (high rate discharge Capacity Ratio) of the discharge capacity of in above-mentioned capacity is confirmed, obtaining shown in table 11～15.
(cycle life characteristics)
Under 45 ℃ environment, each battery is charged to cell voltage with the constant current value of 2A reaches 4.2V, then, with the constant voltage values charging of 4.2V till current value reduces to 50mA.Battery after then will charging is discharged to cell voltage with the constant current value of 2A and reaches 3.0V.Such charge and discharge cycles is repeated 500 times.The ratio (capacity sustainment rate) of the discharge capacity the when discharge capacity of the 500th circulation of representing with percentage is confirmed with respect to above-mentioned capacity is shown in table 11～15.
At this, also represent the result of battery 3-1 simultaneously in table 12～14.In addition, in table 14, represented ratio A/B1 simultaneously.
Table 11
| The thickness of porous matter refractory layer (μ m) | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Capacity sustainment rate (%) | |
| Battery 3-1 | 5 | 5 | 1992 | 86 | 91 |
| Battery 3-2 | 0.8 | 15 | 1990 | 90 | 82 |
| Battery 3-3 | 1 | 5 | 1988 | 88 | 86 |
| Battery 3-4 | 10 | 5 | 1986 | 89 | 90 |
| Battery 3-5 | 12 | 0 | 1990 | 75 | 90 |
Table 12
| The kind of filler | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Capacity sustainment rate (%) | |
| Battery 3-1 | Alumina | 5 | 1992 | 86 | 91 |
| Battery 3-6 | Magnesium oxide | 0 | 1992 | 88 | 90 |
| Battery 3-7 | Titanium dioxide | 5 | 1983 | 86 | 86 |
| Battery 3-8 | Zirconia | 5 | 1988 | 90 | 88 |
| Battery 3-9 | Silica | 5 | 1986 | 87 | 88 |
| Battery 3-10 | Aromatic polyamides | 5 | 1990 | 87 | 86 |
Table 13
| The kind of binding agent | The amount of binding agent (weight portion) | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Capacity sustainment rate (%) | |
| Battery 3-1 | PVDF | 3 | 5 | 1992 | 86 | 91 |
| Battery 3-11 | The modified rubber mixture | 3 | 0 | 1994 | 89 | 91 |
| Battery 3-12 | PVDF | 0.8 | 20 | 1986 | 90 | 92 |
| Battery 3-13 | PVDF | 1 | 5 | 1988 | 88 | 90 |
| Battery 3-14 | PVDF | 5 | 5 | 1990 | 87 | 90 |
| Battery 3-15 | PVDF | 7 | 0 | 1986 | 85 | 86 |
Table 14
| The length (mm) of porous matter refractory layer | Ratio A/B1 | The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Capacity sustainment rate (%) | |
| Battery 3-1 | 124 | 0.20 | 5 | 1992 | 86 | 91 |
| Battery 3-16 | 10 | 0.016 | 5 | 1988 | 90 | 83 |
| Battery 3-17 | 12.4 | 0.02 | 5 | 1986 | 88 | 85 |
| Battery 3-18 | 49.6 | 0.08 | 5 | 1992 | 89 | 87 |
| Battery 3-19 | 186 | 0.30 | 0 | 1986 | 90 | 89 |
| Battery 3-20 | 248 | 0.40 | 0 | 1990 | 83 | 90 |
Table 15
| The ratio of short circuit battery (%) | Discharge capacity (mAh) | High rate discharge Capacity Ratio (%) | Capacity sustainment rate (%) | |
| Reference battery 3-1 | 5 | 1981 | 80 | 90 |
| Compare battery 3-1 | 95 | 1995 | 90 | 80 |
The reference battery 3-1 of porous matter refractory layer is set on the whole surface of anode mixture layer and the comparison battery 3-1 of porous matter refractory layer is not set, its battery capacity does not have too big difference.In addition, reference battery 3-1 compares with comparing battery 3-1, and its high rate discharge characteristic is low.It is generally acknowledged that its reason is that porous matter refractory layer has inhibition for the diffusion of lithium ion.
About the capacity sustainment rate is cycle life characteristics, compares with comparing battery 3-1, and reference battery 3-1 is much better.Disassemble the battery after the cyclic test, the distribution of electrolyte on the investigation pole plate, the result shows the comparison battery 3-1 that porous matter refractory layer is not set, and does not almost keep electrolyte in interior all sides of electrode group.On the other hand, the reference battery 3-1 of porous matter refractory layer is set on the whole surface of mixture layer as can be known, although compare with the outer circumferential side of electrode group, the maintenance dose of its electrolyte is less, maintains many electrolyte in interior all sides of electrode group.
In addition, lowly contrast with the anti-short-circuit that compares battery 3-1, the anti-short-circuit of reference battery 3-1 and battery 3-1～3-20 is improved.As mentioned above, owing near the core of electrode group, reduce because of various stress make the thickness of barrier film, so when foreign conducting matter being sneaked in this core, its influence shows easily.But, in reference battery 3-1 and battery 3-1～3-20, owing to have porous matter refractory layer at the core of electrode group, so can avoid the influence of foreign conducting matter.
Battery 3-1～3-20 compares with reference battery 3-1, and the high rate discharge characteristic is improved.It is generally acknowledged this be because: battery 3-1～3-20 compares with the reference battery 3-1 that whole surface is provided with porous matter refractory layer, and the area of porous matter refractory layer is less, thereby has reduced the diffusion impedance of lithium ion.In addition, cycle characteristics is also same with high-rate characteristics, and preferably porous matter refractory layer has less area.And be under 0.02～0.3 the situation at ratio A/B1, the battery that cycle characteristics is minimum, the area ratio of coating porous matter refractory layer is 85%, even like this, compare with the reference battery that porous matter refractory layer is set on the whole surface of mixture layer, also can obtain good result.It is generally acknowledged this be because: in the core side that barrier film keeps outer circumferential side that material plays a role and porous matter refractory layer to keep material to play a role as electrolyte as electrolyte fully, electrolyte remain in good poised state.No matter the area that promptly is arranged near the porous matter refractory layer the core is inadequately or too much, can destroy though the balance of the maintenance dose of above-mentioned electrolyte can temporarily be maintained eventually.But, by ratio A/B1 is set at 0.02～0.3, can prevent the reduction of battery behavior.
With the battery 3-6～3-9 of magnesium oxide, titanium dioxide, zirconia or silica replacement alumina, although capacity is variant slightly, the ratio of short circuit battery is lower, has sufficient thermal endurance.In using the battery 3-10 of aromatic polyamides as the insulating properties filler, the ratio of short circuit battery also is minimized.
The thickness of porous matter refractory layer is the battery 3-2 of 0.8 μ m, and the ratio of its short circuit battery is 15%, and some is higher, can not obtain sufficient thermal endurance.In addition, the capacity sustainment rate of battery 3-2 is compared not too big variation with the capacity sustainment rate that compares battery 3-1.It is generally acknowledged this be because: under the situation of the very thin thickness of porous matter refractory layer, suppress internal short-circuit or improve that to protect the liquid effect all be very difficult.
On the other hand, the thickness of porous matter refractory layer is the battery 3-5 of 12 μ m, and the capacity sustainment rate is expressed 90% high value, but the high rate discharge characteristic has reduction slightly.It is generally acknowledged this be because: the thickness of porous matter refractory layer is very thick, has caused the increase of reaction impedance.Therefore, the thickness of porous matter refractory layer is preferably 1～10 μ m.
In addition, use the modified rubber mixture to have sufficient thermal endurance with the battery 3-11 that replaces PVDF as binding agent.In addition, do not observe the deterioration of the battery behavior that causes because of above-mentioned modified rubber swelling, and the short circuit of battery seldom takes place.It is generally acknowledged this be because: by using the modified rubber mixture, the flexibility of porous matter refractory layer more or less improves.
In addition, the amount of the binding agent in per 100 weight portion insulating properties fillers is the battery 3-12 of 0.8 weight portion, and the ratio of its short circuit battery more or less improves.Therefore, the amount situation seldom for binding agent often can not obtain sufficient thermal endurance.In addition, disassemble the result that the battery of short circuit is observed, confirm that porous matter refractory layer begins to produce to peel off from anode mixture layer on a large scale, and produced short circuit in these parts.
On the other hand, the amount of binding agent is the battery 3-15 of 7 weight portions, though sufficient thermal endurance is arranged, the high rate discharge characteristic more or less reduces.It is generally acknowledged this be because: the amount of the binding agent that porous matter refractory layer is contained is a lot, has caused the increase of reaction impedance.Therefore, the amount of binding agent is preferably 1～5 weight portion with respect to the insulating properties filler of per 100 weight portions.
In addition, as discussed above, lithium rechargeable battery of the present invention owing to improved anti-short-circuit, and can be kept battery behavior, so can be as the power supply of the electronic equipment that requires to have extra high reliability etc.
Claims (19)
1, a kind of lithium rechargeable battery, it has the negative pole and the barrier film of strip-shaped positive electrode, band shape, have the described positive pole that will separate by described barrier film and described negative pole reel the electrode group that form with accommodate described electrode group end jar arranged, wherein, described just having positive electrode collector and the anode mixture layer of appendix on described positive electrode collector; Described negative pole has negative electrode collector and the anode mixture layer of appendix on described negative electrode collector; Between at least one side and described barrier film of described anode mixture layer and described anode mixture layer, partly disposing porous matter refractory layer.
2, lithium rechargeable battery according to claim 1 is wherein at least one side of described anode mixture layer and described anode mixture layer, Yi Bian along the described porous matter refractory layer of disposing at least of described mixture layer.
3, lithium rechargeable battery according to claim 2 wherein along the anodal at least one side's of described band shape minor face, is being provided with the exposed division of the described positive electrode collector that does not have the described anode mixture layer of appendix; Described porous matter refractory layer is configured along the boundary portion of described anode mixture layer and described exposed division.
4, lithium rechargeable battery according to claim 2 wherein along the anodal at least one side's of described band shape minor face, is being provided with the exposed division of the described positive electrode collector that does not have the described anode mixture layer of appendix; Described porous matter refractory layer is configured across the opposed mode of described barrier film with the boundary portion with the exposed division of described anode mixture layer and described positive electrode collector.
5, lithium rechargeable battery according to claim 3, the exposed division of wherein said positive electrode collector is provided with along the described anodal minor face that stops side of reeling.
6, lithium rechargeable battery according to claim 2, wherein along described banded anodal at least one side's long limit, the exposed division of the described positive electrode collector that does not have the described anode mixture layer of appendix is being set, and described porous matter refractory layer is configured along at least 1 side of the boundary portion of the exposed division of described anode mixture layer and described positive electrode collector.
7, lithium rechargeable battery according to claim 2, wherein along described banded anodal at least one side's long limit, the exposed division of the described positive electrode collector that does not have the described anode mixture layer of appendix is being set, and described porous matter refractory layer is configured at least across the opposed mode of described barrier film with 1 side with the boundary portion of the exposed division of described anode mixture layer and described positive electrode collector.
8, lithium rechargeable battery according to claim 2, wherein along at least one side's of described banded negative pole long limit, the exposed division of the described negative electrode collector that does not have the described anode mixture layer of appendix is being set, and described porous matter refractory layer is configured along at least 1 side of the boundary portion of the exposed division of described anode mixture layer and described negative electrode collector.
9, lithium rechargeable battery according to claim 2, wherein along at least one side's of described banded negative pole long limit, the exposed division of the described negative electrode collector that does not have the described anode mixture layer of appendix is being set, and described porous matter refractory layer is configured at least across the opposed mode of described barrier film with 1 side with the boundary portion of the exposed division of described anode mixture layer and described negative electrode collector.
10, lithium rechargeable battery according to claim 1, wherein at 2 end faces of described electrode group, disposing the exposed division of described positive electrode collector and the exposed division of described negative electrode collector respectively, anodal current-collecting terminals is welded on the exposed division of described positive electrode collector, and the negative pole current-collecting terminals is welded on the exposed division of described negative electrode collector.
11, lithium rechargeable battery according to claim 2, wherein said porous matter refractory layer be arranged on described anode mixture layer and at least one side of described anode mixture layer from the end of coiling origination side to the zone in precalculated position; When the area that is designated as A, described mixture layer when the area with described porous matter refractory layer was designated as B, the ratio A/B of area A and area B was 0.02～0.3.
12, lithium rechargeable battery according to claim 1, wherein said porous matter refractory layer be arranged on described anode mixture layer above.
13, lithium rechargeable battery according to claim 12, wherein, when the area that is designated as A, described anode mixture layer when the area with described porous matter refractory layer was designated as B1, the ratio A/B1 of area A and area B 1 was 0.02～0.3.
14, lithium rechargeable battery according to claim 12, the width of wherein said anode mixture layer is bigger than the width of described anode mixture layer.
15, lithium rechargeable battery according to claim 1, the thickness of wherein said porous matter refractory layer are 1～10 μ m.
16, lithium rechargeable battery according to claim 1, wherein said porous matter refractory layer contains insulating properties filler and binding agent.
17, lithium rechargeable battery according to claim 16, wherein said insulating properties filler contain at least a kind that is selected among alumina, magnesium oxide, titanium dioxide, zirconia and the silica.
18, lithium rechargeable battery according to claim 16, wherein said binding agent contain at least a kind among the modified rubber particle that comprises acrylonitrile unit and the polyvinylidene fluoride.
19, lithium rechargeable battery according to claim 16, wherein said porous matter refractory layer contain the described binding agent of 1～5 weight portion with respect to the described insulating properties filler of per 100 weight portions.
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| US6391488B1 (en) * | 1999-07-09 | 2002-05-21 | Matsushita Electric Industrial Co., Ltd. | Non-aqueous electrolyte cell |
| JP3937422B2 (en) * | 2000-03-23 | 2007-06-27 | ソニー株式会社 | Lithium ion battery and manufacturing method thereof |
| JP4177612B2 (en) * | 2002-07-30 | 2008-11-05 | 株式会社東芝 | Lithium ion secondary battery |
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2005
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| CN109694646A (en) * | 2017-10-24 | 2019-04-30 | 住友化学株式会社 | The composition of material as nonaqueous electrolytic solution secondary battery porous layer |
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