Background technology
Along with the fast development of Portable consumption electronic products of all kinds,, all press for lighter, more high-performance and secondary cell more cheaply such as mobile phone, mobile computer (Note Book), individual mobile digital secretary (PDA) etc.In at present all secondary cells, lithium macromolecule battery meets above-mentioned requirement most, because it has high-energy-density, long cycle-index, high operation voltage, long storage life, and the fail safe can take into account battery and use the time.
In the investigative technique formerly, the U.S. the 5th, 540, disclose a kind of copolymer that uses Kynoar and hexafluoropropylene in No. 741 patents as binding agent and add dibutyl phthalate (dibutylphthalate, hereinafter referred is DBP) as the plasticizer of positive and negative electrode slurry film forming and barrier film film forming, make and to break away from substrate behind both positive and negative polarity battery lead plate and the barrier film coating film forming, and allow the back segment electrode material to the current collection net, with positive and negative electrode the hot binding process engineering of barrier film can simple and easyly be finished.Behind a synthetic monocell (bicell), utilize the methyl alcohol equal solvent to extract DBP again, make battery lead plate and barrier film have loose structure.
The advantage of the manufacture method that above-mentioned patent is taken off is that mainly the introducing of plasticiser allows electrode material have good plasticity after filming and can be in conjunction with collector body, electrode material and barrier film, has the pore-creating effect again concurrently after plasticiser takes out and forms electrolyte path.The positive and negative electrode plate is combined closely each other by barrier film in addition, and the composition surface is difficult for forming the emptying aperture that harms ion transport, so the demand of also removing the tight pressing electrode of external packing from, and it is lighter and thinner to make battery to make ground.Precisely because it is tediously long that middle DBP takes out process time, and consume a large amount of extractants, make it easily give birth to residual and influence battery behavior.Normal is that This is what people generally disapprove of.
Therefore, the inventor recognizes and is necessary to be improved on the manufacture method of positive and negative electrode bonding type lithium macromolecule battery.
Summary of the invention
The object of the present invention is to provide a kind of electrode bonding type lithium macromolecule battery manufacture method and technology of novelty, it can improve the shortcoming of above-mentioned existing electrode bonding type lithium macromolecule battery manufacture method, and under the advantage that keeps the electrode bonding, make to be easier to processing and fabricating, and can promote the characteristic of battery.Be primarily characterized in that the barrier film slurry that utilizes the present invention to develop, after solvent evaporates, the surface can form the gel that is easy to bind, and this prescription does not use plasticiser (plasticizer such as DBP), monocell is binded needn't carry out tediously long extraction step more afterwards.
The invention provides a kind of lithium macromolecule battery, comprising: positive plate is with fit after heating and pressurizing program heated-air drying and forming of cathode film material and positive electrode collector; Negative plate is negative electrode film material and negative electrode collector to be fitted after heated-air drying and forming after the heating and pressurizing program; And barrier film; Above-mentioned positive/negative plate and barrier film are cut into behind the certain size according to positive plate-barrier film-negative plate-barrier film-positive plate or negative plate-barrier film-positive plate-barrier film-negative plate storehouse mode heated-air drying and form a battery cell after heating and pressurizing; Wherein, in barrier film and cathode film, negative electrode film slurry, add the different solvent of two kinds of boiling points height of N-N-methyl-2-2-pyrrolidone N-and acetone to improve the feasibility of binding processing, make barrier film after the volatilization of low boiling point solvent acetone, still contain an amount of high boiling solvent N-N-methyl-2-2-pyrrolidone N-and gel; Positive and negative electrode film slurry is after the volatilization of low boiling point solvent acetone, and this an amount of high boiling solvent N-N-methyl-2-2-pyrrolidone N-can be kept the plasticity of battery lead plate; And this high boiling solvent N-N-methyl-2-2-pyrrolidone N-can volatilize in room temperature or remove fully via heating after bonding machines naturally.
Such manufacture method has more following characteristic:
(1) shortens the processing procedure time.
(2) battery tool greater security.
(3) battery tool high-energy-density.
(4) battery tool superior cycle life.
(5) internal resistance of cell is low and stable.
(6) battery large current density electrical characteristics are better.
(7) more environmental protection of manufacturing process.
Embodiment
As shown in Figure 1, the manufacture method of lithium macromolecule battery of the present invention comprises:
Step 1 prepares a kind of tool stickiness and plastic cathode film, and it mainly is to utilize mixed slurry program that active material, assistant director of a film or play's agent, sticker and solvent are evenly formed cathode film after be coated with dry run;
Step 2 prepares a kind of tool stickiness and plastic negative electrode film, and it mainly is to utilize mixed slurry program that active material, assistant director of a film or play's agent, sticker and solvent are evenly formed negative electrode film after be coated with dry run;
Step 3 prepares a kind of tool stickiness and plastic barrier film, and it mainly is to utilize mixed slurry program that filler, sticker and solvent are evenly formed barrier film after be coated with dry run;
Step 4, the negative electrode collector for preparing good adhesion of a kind of tool and conductivity, it mainly is to coat the uniform material of assistant director of a film or play's agent, sticker and solvent again with treatment step before the pure water cleaning again after utilizing copper mesh or Copper Foil to soak through dilute sulfuric acid to form the negative electrode collector of coating adhesion coating after heated-air drying;
Step 5, the positive electrode collector for preparing good adhesion of a kind of tool and conductivity, it mainly is to coat the uniform material of assistant director of a film or play's agent, sticker and solvent again with treatment step before the pure water cleaning again after utilizing aluminium net or aluminium foil to soak through sodium hydroxide solution to form the positive electrode collector of coating adhesion coating after heated-air drying;
Step 6 prepares a kind of positive plate, and it mainly is to utilize the cathode film that before made and positive electrode collector to fit after heated-air drying and forming after the heating and pressurizing program;
Step 7 prepares a kind of negative plate, and it mainly is to utilize the negative electrode film that before made and negative electrode collector to fit after heated-air drying and forming after the heating and pressurizing program;
Step 8, prepare a kind of single-cell structure, it mainly is to utilize the positive/negative plate that before made and barrier film to cut into behind the certain size according to positive plate-barrier film-negative plate-barrier film-positive plate or negative plate-barrier film-positive plate-barrier film-negative plate storehouse mode heated-air drying and forming after heating and pressurizing;
Step 9 according to the needs of battery design capacity, is got an amount of preceding paragraph single-cell structure, and welding inserts in the aluminium foil bag after going up both positive and negative polarity conduction handle, after dewatering through vacuumize, injects electrolyte and carries out cell activation.
In above-mentioned processing procedure, should
(a) barrier film
Be to be 20~80wt%, filler (SiO with adhesive agent such as Kynoar
2, TiO
2, Al
2O
3..) be that 20~80wt% adds that an amount of solvent (acetone, NMP) fully mixes with ball mill and is made into required barrier film slurry after 5 hours.Thin film-forming method can be to be coated on on the film base material, and the mode of taking off after the equal solvent volatilization is made or with another porous polymeric membranes for example: polypropylene or polyethylene are that skeleton is coated the surface and formed compound barrier film.
(b) positive pole
Be that adhesive agent, assistant director of a film or play's agent, active material are added appropriate solvent acetone and NMP, N-Methyl-2-pyrrolidone (N-N-methyl-2-2-pyrrolidone N-) mixes slurry, fully mix with ball mill and to be made into required anode sizing agent after about 5 hours, wherein adhesive agent such as Kynoar are 2~15wt%, assistant director of a film or play's agent such as conductive carbon black are 2~10wt%, the lithium compound LiCoO of active material
2, LiNiO
2, LiMn
2O
4, LiNixCo
1-xO
2Be 75~96wt%.And electrode collector can be aluminium foil or aluminium net herein, directly in aluminium foil or online coating sizing-agent, cuts into required size with coating machine after drying, promptly finishes anodal making.With the aluminium net is that collector body fashion can be coated anode sizing agent one coated substrate, takes off with bonding current collection net of the mode of hot pressing and electrode material film after to be dried, cuts into required size after drying.
(c) negative pole
Be that adhesive agent, assistant director of a film or play's agent, active material adding appropriate solvent acetone and NMP are mixed slurry, fully mix with ball mill and to be made into required cathode size after 5 hours, wherein adhesive agent such as Kynoar are 2~15wt%, assistant director of a film or play's agent such as conductive carbon black are 2~10wt%, and the upgrading product of the mutually little carbon ball in active material such as centre or native graphite or native graphite or other carbon material or tin compound or silicon compound are 75~96wt%.And electrode collector can be Copper Foil or copper mesh herein, directly in Copper Foil or online coating sizing-agent, cuts into required size with coating machine after drying, promptly finishes the making of negative pole.Anode sizing agent can be coated a coated substrate with the copper mesh for collector body fashion, take off in the mode of hot pressing after to be dried and bind current collection net and electrode material film, after drying, cut into required size.
Implement according to above-mentioned manufacture method, for instance:
(1)
Make barrier film-get Kynoar 70wt%, SiO
230wt% adds an amount of acetone, NMP.Fully mix with ball mill and to be made into required barrier film slurry in 5 hours.With the polypropylene porous film is that skeleton forms compound barrier film in an amount of slurry of surface coated.
Make anodal-to get conductive carbon black be 6wt%, Kynoar is 9wt%, LiCoO
285wt%.Proper amount of acetone and NMP.Fully mix with ball mill and to be made into required anode sizing agent after 5 hours.Slurry is coated a base material, treat to take off after the acetone volatilization,, cut into required size afterwards with bonding current collection net of the mode of hot pressing and electrode material film.
Making negative pole-get conductive carbon black 4wt%, Kynoar 11wt%, centre mutually little carbon ball 85wt%.Proper amount of acetone and NMP.Fully mix with ball mill and to be made into required cathode size after 5 hours.Slurry is coated a base material, treat to take off after the acetone volatilization, bind current collection net and electrode material film, cut into required size afterwards in the mode of hot pressing.
With hot binding positive pole, negative pole and barrier film, hot-air seasoning carries out follow-up fluid injection encapsulation after after 30 minutes.
(2)
Positive and negative electrode is with the first routine described making, and barrier film then is to get Kynoar 70wt%, SiO
230wt% adds an amount of solvent acetone, NMP.Fully mix to be made into required barrier film slurry in 5 hours with ball mill, be coated on then on the substrate for film deposition, take off after the equal solvent volatilization, colloid shape film.With hot binding positive pole, negative pole and barrier film, after putting after 12 hours, room temperature carries out follow-up fluid injection encapsulation.
The 600mAh lithium macromolecule battery that the foregoing description one is made is tested, and obtains every battery behavior of following table one.
Table one
Project |
The battery that this method is made |
0.5C efficiency for charge-discharge (%) |
98~99 |
Internal resistance (m Ω) |
45~55 |
Battery life (%) (0.5C discharges and recharges 100 times) |
95.2 |
Self-discharge rate (28 days) (%) |
92.4 |
(suppose to have a battery rated capacity be 600mAH then 0.5C discharge and recharge the representative be to discharge and recharge with the 300mA electric current)
As shown in Table 1, on the characteristic that battery is used always, as: 0.5C efficiency for charge-discharge, internal resistance, 0.5C discharge and recharge 100 times battery life, reach 28 days self-discharge rates as can be known, and the present invention can obtain good battery behavior and processability is good, the low lithium macromolecule battery that has environmental protection again concurrently of cost.
The above only is preferred embodiment of the present invention, be not to be used for limiting the working of an invention scope, be that all equivalences of doing according to the content of the present patent application claim change and modification, all should be technology category of the present invention, and limited by the request of following claim.