A kind of battery core packing film and batteryTechnical field
The present invention relates to field of batteries, particularly relate to a kind of battery core packing film and battery.
Background technology
In use easily discharge gas for metal current box packaging lithium battery, pressure increase causes explosion issues, starts on the market to release a kind of novel flexible packing material, i.e. aluminum plastic film.This packaging material can expand release pressure, thus prevent blast.
As shown in Figure 1, in prior art, flexible packing material generally includes separator 1, aluminium foil layer 2 and adhesive layer 3.Battery packs battery core with packaging film in process of production, and by the both positive and negative polarity of heat-sealing extraction two metal pole piece as battery.But, such flexible packing material, has following shortcoming: 1. the corrosive liquids of lithium battery can be infiltrated by adhesive layer 3 and directly etching aluminium foil layer is surperficial usually, thus the adhesive layer being attached to aluminium foil layer surface is come off, packaging film lost efficacy, thus battery failure.2. adhesive layer is generally polypropylene, and adopt film mode polypropylene to be salivated aluminium foil surface and form film, its bonding strength is very little, is difficult to meet battery needs; Need to introduce adhesive, the electrolyte of lithium battery is organic solvent, easily contacts with adhesive phase through hot sealing layer, makes electrolyte contamination cause battery performance to decline.3. time for the high power discharge that may repeatedly occur in actual use procedure, due to the heating of electric current ambassador battery electrode, battery electrode is connected with hot sealing layer again, thermal deformation and heat trnasfer make to produce micropore and micro-delamination between the hot sealing layer of ate electrode and aluminium foil layer, reduce the performance even destroying battery.
Summary of the invention
The technical problem that the present invention mainly solves is to provide a kind of battery core packing film and battery, effectively can prevent the corrosive liquids corrosive aluminum foil layer of battery, guarantee that the adhesive layer on aluminium foil layer surface does not come off, battery no leakage, improves the useful life of packaging film; Aluminium foil and battery and electrolyte contacts one side be not containing adhesive, and the battery performance avoiding the pollution of electrolyte to cause declines; Stop packaging film micropore and micro-delamination near high-rate battery discharge situation bottom electrode, ensure the performance of battery.
For solving the problems of the technologies described above; the technical scheme that the present invention adopts is: provide a kind of battery core packing film; described battery core packing film comprises the separator, aluminium foil layer and the adhesive layer that set gradually; protective layer is provided with between described aluminium foil layer and described adhesive layer; wherein, described protective layer is plastic layer.
Wherein, described plastic layer is polyvinylidene chloride layer.
Wherein, the thickness of described protective layer is between 0.1 ~ 10 micron.
Wherein, the thickness of described protective layer is between 0.5 ~ 6 micron.
Wherein, described battery core packing film is by cold-punching molding or the coated battery of straight forming.
For solving the problems of the technologies described above, another technical solution used in the present invention is: provide a kind of battery, the battery core packing film that described battery is above-mentioned and battery, by the coated described battery of described battery core packing film, the adhesive layer of described battery core packing film is closest to described battery and and electrolyte contacts.
Wherein, described battery is lithium ion flexible package battery, from sealing out extraction two panels bonding jumper after battery encapsulation, as the both positive and negative polarity electrode of battery.
The invention has the beneficial effects as follows: the situation being different from prior art, the present invention by arranging protective layer between the aluminium foil layer and adhesive layer of battery core packing film, and protective layer is polyvinylidene chloride layer.Thus can avoid that the corrosive liquids of battery is infiltrated by adhesive layer and corrosive aluminum foil layer is surperficial, guarantee that the adhesive layer on aluminium foil layer surface does not come off, battery no leakage, improve the useful life of packaging film; Aluminium foil and battery and electrolyte contacts one side be not containing adhesive, and the battery performance avoiding the pollution of electrolyte to cause declines; Stop micropore and micro-delamination near packaging film electrode slice in high-rate battery discharge situation, ensure the performance of battery.
Adopt traditional film technique, as film or extrude complex technique or multi-layer co-extruded complex technique etc., between the aluminium lamination and hot sealing layer polypropylene of packaging film, introduce polyvinylidene chloride layer, avoid introducing adhesive, but the polyvinylidene chloride thickness introduced like this is thicker, disturbs the heat sealability of hot sealing layer, is not suitable for the requirement of lithium ion battery to packaging film.
Accompanying drawing explanation
Fig. 1 is the structural representation of battery core packing film in prior art;
Fig. 2 is the structural representation of a kind of battery core packing film that embodiment of the present invention provides.
Embodiment
Refer to Fig. 2; Fig. 2 is the structural representation of a kind of battery core packing film that embodiment of the present invention provides; the battery core packing film that embodiment of the present invention provides comprises the separator 1, aluminium foil layer 2 and the adhesive layer 3 that set gradually; wherein; protective layer 4 is provided with between aluminium foil layer 2 and adhesive layer 3; wherein, protective layer 4 is plastic layer.
Wherein, the THICKNESS CONTROL of protective layer 4 is between 0.01 ~ 10 micron, is namely more than or equal to 0.01 micron to being less than or equal to 10 microns, such as 0.01 micron, 0.1 micron, 3 microns, 8 microns etc.Preferably, the THICKNESS CONTROL of protective layer 4 is between 0.1 ~ 6 micron, is namely more than or equal to 0.1 micron and is less than or equal to 6 microns, such as 0.2 micron, 0.5 micron, 6 microns etc.
Wherein, plastic layer is polyvinylidene chloride layer.
Polyvinylidene chloride film is the best plastic film of known barrier, but makes the polyvinylidene chloride layer thickness considerable influence battery heat-sealing performance at battery package film and inapplicable due to traditional film technique.For realizing the thin and object of densification of polyvinylidene chloride layer thickness, the present invention adopts polyvinylidene chloride latex film forming technology.
The embodiment of the present invention chooses polyvinylidene chloride latex; adopt roller coat or painting way; polyvinylidene chloride latex is coated in aluminium foil layer surface; adopt high temperature speed solidification mode; by it solidification, thus form polyvinylidene chloride densified thin layer on aluminium foil layer surface, it is 2 ~ 8g/m2 that coated weight controls; and closely careful at aluminium foil layer surface cure, thus play the effect of protective layer.
Relative to particulate form polyvinylidene chloride blown film or the film technology of routine; its polyvinylidene chloride layer formed is all thicker and sparse; be combined not tight with aluminium foil layer; thickness greatly also affects the mouldability requirement of packaging film; even become adhesive layer but not protective layer; and its heat sealability cannot meet the encapsulation requirement of lithium battery, in order to improve the glue that polyvinylidene chloride bonding strength is introduced, can react with electrolyte the performance affecting lithium battery again.These all make to adopt conventional method to use the defect place of polyvinylidene chloride in the packaging film of lithium battery, cannot meet the special technical requirement of lithium cell core packaging film.
The battery core packing film that present embodiment provides, it can pass through cold-punching molding or the coated battery of straight forming.Wherein, cold-punching molding refers to after prepared by packaging film, by the mode of punching press, packaging film is struck out given shape for carrying battery.Such as pit shape.And straight forming refers to and battery is directly placed on packaging film, by packaging film by cell core.
The battery core packing film that embodiment of the present invention provides, is provided with protective layer between the adhesive layer and aluminium foil layer of battery core packing film, and protective layer is polyvinylidene chloride plastic layer.In the prior art, the manufacture craft due to packaging film requires and performance limits, and is selected to the large difficult point of one in battery R&D process to protective layer material.Present invention applicant determines through studying for a long period of time to adopt polyvinylidene chloride plastic layer as protective layer material, it effectively can avoid that the corrosive liquids of battery is infiltrated by adhesive layer and corrosive aluminum foil layer is surperficial, guarantee that the adhesive layer on aluminium foil layer surface does not come off, battery no leakage, improves the useful life of packaging film; Aluminium foil and battery and electrolyte contacts one side, not containing adhesive, avoid the pollution of electrolyte to cause battery performance to decline; Stop packaging film micropore and micro-delamination near high-rate battery discharge situation bottom electrode, ensure the performance of battery.
Preferred as one, control the thickness of separator 1 in present embodiment between 20 ~ 30 microns, the thickness of aluminium foil layer 2 is between 30 ~ 90 microns, and the thickness of protective layer is between 0.5 ~ 6 micron, and the thickness of adhesive layer 3 is between 30 ~ 50 microns.
The battery core packing film that embodiment of the present invention provides, may be used for packing compact power, as battery of mobile phone, also may be used for packing electrical source of power, as lithium batteries such as electric automobile, electric motor car, electric tools.
On the basis of the battery core packing film provided in embodiment of the present invention, embodiment of the present invention provides a kind of battery further, battery core packing film in the above-mentioned execution mode of this battery and battery, by the coated battery of battery core packing film, wherein, the adhesive layer of battery core packing film closest to battery with contact electrolyte, wherein have two sheet metals to guide to outside batteries from battery packages inside.
Wherein, the battery that embodiment of the present invention provides can be lithium ion battery, solid state lithium battery etc.
The foregoing is only embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize specification of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.