CN205231171U - Lithium ion battery cathode pole piece and battery - Google Patents
Lithium ion battery cathode pole piece and battery Download PDFInfo
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- CN205231171U CN205231171U CN201520971880.7U CN201520971880U CN205231171U CN 205231171 U CN205231171 U CN 205231171U CN 201520971880 U CN201520971880 U CN 201520971880U CN 205231171 U CN205231171 U CN 205231171U
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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
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The utility model relates to the field of lithium ion cells, especially, relate to a lithium ion battery cathode pole piece and contain the lithium ion battery of this kind of negative pole pole piece. The utility model provides a lithium ion battery cathode pole piece, including negative current collector and attached to the last anode material layer of negative current collector, the anode material layer include negative pole central zone and link to each other with negative pole central zone be located negative pole central zone outlying negative pole fringe region, part at least the anode material layer thickness of negative pole fringe region is greater than negative pole central zone's anode material layer thickness, and the negative pole edge produced the lithium deposit when lithium ion battery that contains this negative pole pole piece can effectively avoid low temperature to charge, and then improves the low temperature blanking voltage that charges to improve battery capacity, energy and power.
Description
Technical field
The utility model relates to field of lithium ion battery, particularly relates to a kind of lithium ion battery negative electrode and the lithium ion battery containing this kind of cathode pole piece.
Background technology
Lithium ion battery due to have energy density high, have extended cycle life, the series of advantages such as open circuit voltage is high, safety non-pollution, be widely used in mobile phone, notebook computer, digital camera, video camera, numerous portable communications such as PDA, MP3, Bluetooth, PMP, entertainment electronics, and progressively expand to the field such as electric automobile, space station, its occupation rate of market reaches more than 90%.Therefore, lithium ion battery is that current most is competitive and realized the secondary energy sources of new generation of commercialized development.
Just because of the wide spread of its application, its applied environment also becomes variation, and its cryogenic property etc. also becomes outstanding, becomes the Focal point and difficult point of its research and development.The existing method improving lithium ion battery cryogenic property has: improve electrode formulation, electrolyte prescription, reduction pole piece thickness, improve pole piece porosity etc., current commercial Li-ion batteries comparative maturity, above-mentioned several schemes reach optimum state substantially, limited space is improved to the cryogenic property of lithium ion battery, constrains its development and application.
Utility model content
The application makes the discovery of the following fact and problem and understanding based on inventor:
Inventor finds in the research of lithium ion battery, and the electrode material layer thickness on existing electrode plates is generally consistent, when battery low temperature charges, if overtension, then produces lithium deposition.Also have in order to process requirements, improve pole piece yields and by technical scheme thinning for electrode material layer edge, but the pole piece edge both positive and negative polarity spacing of this kind of battery is elongated, research finds that its polarization also increases, when battery low temperature charging voltage is too high, still can produce lithium deposition.Lithium deposition, through recycling, finally can become dead lithium, makes the fail safe of battery can not get ensureing.
For the problems referred to above, inventor finds through further investigation: during the charging of lithium ion battery low temperature, and its lithium deposition generally produces in the position, both sides of the edge of negative electrode material layer, and its width produced, greatly within 40mm, has nothing to do with the width of positive plate and negative plate.Meanwhile, we have also investigated the charging of graphite, graphite is layered crystal, when there is embedding lithium reaction (charging) in graphite, and first every 3 layers of embedding 1 layer of lithium in graphite linings, this is the III embedding lithium in rank; After embedding expiring, become every 2 layers embed 1 layer of lithium, this is the II embedding lithium in rank; After embedding expiring, become every 1 layer embed 1 layer of lithium, this is the I embedding lithium in rank.Produce the mechanism of lithium deposition when further we have studied the charging of graphite cathode low temperature, find that graphite cathode does not produce lithium deposition when the III embedding lithium in rank, from the II embedding lithium in rank, just may produce lithium deposition.In view of this, the structure of present inventor's anticathode pole piece is improved.Specifically, designed by pole piece, increase the thickness at negative electrode material layer edge on cathode pole piece, when avoiding low temperature to charge, negative electrode material layer edge produces lithium deposition, and then improve low temperature charge cutoff voltage, thus improve battery capacity, energy and power, efficiently solve the problem in correlation technique.
The utility model is intended to solve one of technical problem in correlation technique at least to a certain extent.For this reason, the utility model proposes a kind of lithium ion battery negative electrode.
The utility model also proposed a kind of lithium ion battery with above-mentioned lithium ion battery negative electrode.
According to lithium ion battery negative electrode of the present utility model, comprise negative current collector and be attached to the negative electrode material layer on described negative current collector, the negative pole fringe region being positioned at periphery, negative pole central area that described negative electrode material layer comprises negative pole central area and is connected with negative pole central area, the negative material layer thickness of at least part of described negative pole fringe region is greater than the negative material layer thickness of negative pole central area.
Preferably, the width of negative pole fringe region is 1 ~ 50mm.
Further preferably, the width of negative pole fringe region is 3 ~ 30mm.
Further preferred, the width of negative pole fringe region is 5 ~ 15mm.
Preferably, cathode pole piece is square, and the negative material layer thickness that the Width of cathode pole piece is positioned at the negative pole fringe region of both sides, negative pole central area is greater than the negative material layer thickness of negative pole central area.
Preferably, large 0.25 times-0.6 times of the negative material layer thickness of the negative electrode material layer Thickness Ratio negative pole central area of negative pole fringe region.
Or preferably, the negative material layer thickness of negative pole fringe region changes in gradient.
Further preferably, described negative pole fringe region is from the outside away from negative pole central area to negative pole central area rounding off.The i.e. curved or falcate in negative pole fringe region cross section.
Produce the situation of lithium deposition when cathode pole piece of the present utility model can effectively avoid battery low temperature to charge, and then wider charging window can be adopted, and then improve battery capacity, energy and power.
According to a kind of lithium ion battery of the utility model, comprise battery container, pole piece and electrolyte, described pole piece and electrolyte sealing are contained in described battery container, described pole piece comprises anode pole piece, cathode pole piece and the barrier film between anode pole piece and cathode pole piece, wherein, described cathode pole piece is above-mentioned cathode pole piece.
Preferably, anode pole piece comprises plus plate current-collecting body and is attached to the positive electrode material layer on described plus plate current-collecting body, described positive electrode material layer comprises the positive pole central area relative with negative pole central area and the positive pole fringe region relative with negative pole fringe region, and the positive electrode layer thickness of at least part of described positive pole fringe region is less than the positive electrode layer thickness of positive pole central area.
Preferably, the positive electrode material layer of positive pole fringe region is consistent with the gross thickness of the positive electrode material layer of positive pole central area and the negative electrode material layer of negative pole central area with the gross thickness of the negative electrode material layer of negative pole fringe region.
Preferably, the positive electrode layer thickness of positive pole fringe region is successively decreasing away from gradient on direction, positive pole central area, and the negative material layer thickness of described negative pole fringe region is increasing progressively away from gradient on direction, negative pole central area.
Preferably, the gradient amount of decrease of successively decreasing is consistent with the amplification that gradient increases progressively.
Preferably, the Capacity Ratio of the capacity of the positive electrode material layer of positive pole fringe region and the negative electrode material layer of negative pole fringe region is 1:2-1:6.
Further preferably, the Capacity Ratio of the capacity of the positive electrode material layer of positive pole fringe region and the negative electrode material layer of negative pole fringe region is 1:3.2-1:4.
The utility model is specifically as follows positive electrode material layer edge thinning on anode pole piece, on cathode pole piece, negative electrode material layer edge is thickening, different relative to positive electrode material layer extra proportion with the negative electrode material layer of marginal position in the center of cathode pole piece, the negative electrode material layer extra proportion of marginal position is higher, when can effectively avoid low temperature to charge, negative pole edge produces lithium deposition, and then improve low temperature charge cutoff voltage, thus improve battery capacity, energy and power.
Accompanying drawing explanation
Fig. 1 is the structural representation of the cathode pole piece according to the utility model embodiment;
Fig. 2 is the structural representation of the cathode pole piece according to another embodiment of the utility model;
Fig. 3 is the structural representation of the anode pole piece according to the utility model embodiment;
Fig. 4 is the structural representation of the anode pole piece according to another embodiment of the utility model;
Fig. 5 is the structural representation of the pole piece according to the utility model embodiment;
Fig. 6 is the structural representation of the pole piece according to another embodiment of the utility model;
Fig. 7 is that the utility model embodiment 1 anode pole piece prepares slurry schematic diagram;
Fig. 8 is that the utility model embodiment 1 cathode pole piece prepares slurry schematic diagram;
Fig. 9 is that the utility model embodiment 5 anode pole piece prepares slurry schematic diagram;
Figure 10 is that the utility model embodiment 5 cathode pole piece prepares slurry schematic diagram.
Reference numeral:
Cathode pole piece-1, negative pole central area-11, negative pole fringe region-12, negative current collector-13;
Anode pole piece-2, positive pole central area-21, positive pole fringe region-22, plus plate current-collecting body-23;
Negative pole coating roller-3;
Positive pole coating roller-4.
Embodiment
Be described below in detail embodiment of the present utility model, the example of described embodiment is shown in the drawings.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the utility model, and can not be interpreted as restriction of the present utility model.
As shown in accompanying drawing 1,2, lithium ion battery negative electrode 1 of the present utility model, the negative electrode material layer comprising negative current collector 13 and be attached on described negative current collector 13.Improvements of the present utility model are, the structure of anticathode pole piece 1 is improved, and negative current collector 13 and negative electrode material layer, the utility model does not limit.Such as, negative current collector 13 can be Copper Foil.Negative electrode material layer can be single layer structure, and can be also Material cladding layer multi-layer structure etc., usually, negative electrode material layer can comprise negative electrode active material, negative electrode binder and cathode conductive agent.Described negative electrode active material can adopt all negative electrode active materials that can be purchased, as graphite.Described cathode conductive agent can be at least one in acetylene black, conductive carbon black, electrically conductive graphite, Graphene, carbon nano-tube etc.Described negative electrode binder can be the various binding agents for lithium ion secondary battery negative pole in prior art, as being one or more in polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), sodium carboxymethylcellulose (CMC) and butadiene-styrene rubber (SBR).
The negative pole fringe region 12 being positioned at periphery, negative pole central area 11 that negative electrode material layer comprises negative pole central area 11 and is connected with negative pole central area 11, main improvements of the present utility model are, the negative material layer thickness of at least part of described negative pole fringe region 12 is greater than the negative material layer thickness of negative pole central area 11.
In the utility model, negative pole central area 11 refers to the region away from cathode pole piece 1 edge, and negative pole fringe region 12 refers to the edge of negative electrode material layer, namely depends on the region at nearly cathode pole piece 1 edge.At least part of described negative pole fringe region 12 refers to and also all can adopt the technical solution of the utility model by negative pole fringe region 12 by part negative pole fringe region 12.
The utility model is preferred, and the width of negative pole fringe region 12 is 1 ~ 50mm, and further preferably, the width of negative pole fringe region 12 is 3 ~ 30mm, and further preferably, the width of negative pole fringe region 12 is 5 ~ 15mm.Further optimization the technical solution of the utility model, avoids battery capacity to lose while avoiding producing lithium deposition as far as possible.
As shown in Figure 1, 2, in specific embodiment of the utility model, cathode pole piece 1 can be square, and the negative material layer thickness that the Width of cathode pole piece 1 is positioned at the negative pole fringe region 12 of both sides, negative pole central area 11 is greater than the negative material layer thickness of negative pole central area 11.On the Width of cathode pole piece 1, negative electrode material layer on negative current collector 13 is from while be divided into successively to another side: negative pole fringe region 12, negative pole central area 11 and negative pole fringe region 12, the thickness of the utility model and negative electrode material layer is divided into successively to another side: thick, Bao Hehou.Namely the utility model can adopt and only thicken in the both sides of cathode pole piece 1 Width.
Wherein, the negative material layer thickness of negative pole fringe region 12 can adopt homogeneous thickness, also can graded.
As shown in Figure 1, in some embodiments, the negative material layer thickness of negative pole fringe region 12 adopts homogeneous thickness, the now profile of cathode pole piece similar " recessed " font, preferably, large 0.25 times-0.6 times of the negative material layer thickness of the negative electrode material layer Thickness Ratio negative pole central area 11 of negative pole fringe region 12.
As shown in Figure 2, in some embodiments, the negative material layer thickness of negative pole fringe region 12 changes in gradient, preferably, and negative pole central area 11 and negative pole fringe region 12 smooth connection.Concrete, negative pole fringe region 12 is from the outside away from negative pole central area 11 to negative pole central area 11 rounding off, the i.e. curved or falcate in negative pole fringe region 12 cross section, the concrete shape in variable gradient and cross section is relevant with design capacity with the width of negative pole fringe region 12.
The concrete preparation method of above-mentioned cathode pole piece 1 can be, configuration cathode size, according to the width of required negative pole fringe region 12, negative pole central area 11, selected relevant position on negative current collector 13, negative current collector 13 applies cathode size, during coating, negative pole fringe region 12 cathode size is thick, negative pole central area 11 negative material is thin, be specifically as follows negative current collector 13 to move along its length, the mode in its width direction by controlling coating slurry flow applies.Wherein, on the width corresponding to the negative pole fringe region 12 of negative pole central area 11 and both sides, the flow of slurry is different, concrete flow is relevant with negative current collector 13 movement velocity, and the thickness of negative pole fringe region 12 cathode size that only coating need be made to be formed is greater than the thickness of negative pole central area 11 cathode size.Then drying, roll-in obtain cathode pole piece 1.Wherein, the method for oven dry is the method that this area is commonly used, as dried at 100 DEG C.The method of described roll-in is the method that this area is commonly used, and carries out roll-in as adopted the pressure of 2.0MPa.After roller process, on negative current collector 13, the negative material thickness of regional and/or width there will be certain change, but change is very little, and the numerical value after change is still in above-mentioned scope.
Other structure the utility model on cathode pole piece 1 do not limit, such as, can also containing the lug district not containing negative material on cathode pole piece 1, namely exposed collector is as negative lug or connect negative lug, the side that the negative pole fringe region 12 that lug district is generally positioned at negative electrode material layer is not connected with negative pole central area 11, namely be positioned at cathode pole piece 1 edge, general lug sector width is 2-100mm, is preferably 10-40mm.
Produce the situation of lithium deposition when cathode pole piece 1 of the present utility model can effectively avoid battery low temperature to charge, and then wider charging window can be adopted, and then improve battery capacity, energy and power.
According to a kind of lithium ion battery of the present utility model, comprise battery container, pole piece and electrolyte, described pole piece and electrolyte sealing are contained in described battery container, described pole piece comprises anode pole piece 2, cathode pole piece 1 and the barrier film (not shown) between anode pole piece and cathode pole piece, wherein, described cathode pole piece is above-mentioned cathode pole piece.Pole piece generally by anode pole piece 2, the barrier film of intermediate insulation and cathode pole piece 1 by winding or stacked obtained, anode pole piece 2, cathode pole piece 1 are oppositely arranged, generally, on the face that positive pole, negative pole are relative, correspondence is respectively equipped with positive electrode material layer and negative electrode material layer, namely corresponding with negative electrode material layer on cathode pole piece 1 on anode pole piece 2 position is provided with positive electrode material layer, and general anode pole piece 1 covers on anode pole piece 2 containing positive electrode part completely containing negative material part.
The positive electrode material layer that anode pole piece 2 comprises plus plate current-collecting body 23 and is attached on described plus plate current-collecting body 23, described positive electrode material layer comprises the positive pole central area 21 relative with negative pole central area 11 and the positive pole fringe region 22 relative with negative pole fringe region 12, and the positive electrode layer thickness of at least part of described positive pole fringe region 22 is less than the positive electrode layer thickness of positive pole central area 21.As shown in accompanying drawing 5,6, the utility model is preferred, on anode pole piece 2, the thickness of positive electrode material layer is also with the varied in thickness of negative electrode material layer on cathode pole piece 1, but variation tendency is just contrary, namely preferred, the positive pole fringe region 22 positive electrode layer thickness of negative pole fringe region 12 correspondence that negative material layer thickness is thick is thin.Further preferably, the positive electrode material layer of positive pole fringe region 22 is consistent with the gross thickness of the positive electrode material layer of positive pole central area 21 and the negative electrode material layer of negative pole central area 11 with the gross thickness of the negative electrode material layer of negative pole fringe region 12.Namely the pole piece be made up of anode pole piece 2, cathode pole piece 1 has the local thickness of material layer basically identical.
Wherein, plus plate current-collecting body 23 material of the present utility model, positive electrode are known in this field, and as in lithium rechargeable battery, plus plate current-collecting body 23 can be aluminium foil, and positive electrode comprises positive electrode binder, positive active material and positive conductive agent.The content of described positive electrode binder, positive active material and positive conductive agent is customary amount.The utility model has no particular limits positive active material, like the prior art.Described positive active material can adopt all positive active materials that can be purchased, as LiFePO
4, Li
3v
2(PO
4)
3, LiMn
2o
4, LiMnO
2, LiNiO
2, LiCoO
2, LiVPO
4f, LiFeO
2; Or ternary system Li
1+al
1- b-cm
bn
co
2, wherein-0.1≤a≤0.2,0≤b≤1,0≤c≤1,0≤b+c≤1, L, M, N are one or more in Co, Mn, Ni, Al, Mg, Ga and 3d transiting group metal elements.Described positive conductive agent can adopt any positive conductive agent known in the field, such as, can adopt one or more in graphite, carbon fiber, carbon black, metal dust and fiber.Positive electrode and solvent are obtained anode sizing agent, solvent used can be various solvent of the prior art, as being selected from one or more in 1-METHYLPYRROLIDONE (NMP), dimethyl formamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO) (DMSO), oxolane (THF) and water and alcohols.The consumption of solvent enables described anode sizing agent be coated on described plus plate current-collecting body 23.
Other structure the utility model on anode pole piece 2 do not limit, such as, also can also containing the lug district not containing positive electrode on anode pole piece 2, namely exposed collector is as positive pole ear or connect positive pole ear.
In some embodiments, as shown in Figure 3, the positive electrode layer thickness of positive pole fringe region 22 can the homogeneous thickness of employing as similar in cathode pole piece 1, and now, the profile of anode pole piece corresponds to " recessed " font of cathode pole piece, is similar to " convex " font.Preferably, the positive electrode layer thickness of the positive electrode material layer Thickness Ratio positive pole central area 21 of positive pole fringe region 22 is little 0.3 times-0.7 times.
In some embodiments, as shown in Figure 4, the positive electrode layer thickness of positive pole fringe region 22 corresponds to cathode pole piece 1 and is successively decreasing away from gradient on direction, positive pole central area 21, positive pole central area 21 and positive pole fringe region 22 smooth connection, the negative material layer thickness of corresponding negative pole fringe region 12 is increasing progressively away from gradient on direction, negative pole central area 11.Concrete, be similar to the cathode pole piece corresponding with it, positive pole fringe region 22 is from the outside away from positive pole central area 21 to positive pole central area 21 rounding off, the i.e. curved or falcate in positive pole fringe region 22 cross section, the concrete shape in variable gradient and cross section is relevant with design capacity with the width of positive pole fringe region 22.Wherein, preferably, the positive electrode material layer gradient amount of decrease of successively decreasing is consistent with the amplification that negative electrode material layer gradient increases progressively.
The concrete preparation method of above-mentioned anode pole piece 2 can be, configuration anode sizing agent, according to the width of required positive pole fringe region 22, positive pole central area 21, selected relevant position on plus plate current-collecting body 23, plus plate current-collecting body 23 applies anode sizing agent, during coating, positive pole fringe region 22 anode sizing agent is thin, positive pole central area 21 anode sizing agent is thick, be specifically as follows plus plate current-collecting body 23 to move along its length, the mode in its width direction by controlling coating slurry flow applies.Wherein, on the width corresponding to the positive pole fringe region 22 of positive pole central area 21 and both sides, the flow of slurry is different, concrete flow is relevant with plus plate current-collecting body 23 movement velocity, and the thickness of positive pole fringe region 22 anode sizing agent that only coating need be made to be formed is less than the thickness of positive pole central area 21 anode sizing agent.Also can to adopt after homogeneous coating reduction processing again, reduction processing can be shaving, and then drying, roll-in obtain anode pole piece 2.Wherein, the method for oven dry is the method that this area is commonly used, as dried at 100 DEG C.The method of described roll-in is the method that this area is commonly used, and carries out roll-in as adopted the pressure of 2.0MPa.After roller process, anode collection, on 23, the positive electrode thickness of regional and/or width there will be certain change, but change is very little, and the numerical value after change is still in above-mentioned scope.
Preferably, the Capacity Ratio of the capacity of the positive electrode material layer of positive pole fringe region 22 and the negative electrode material layer of negative pole fringe region 12 is 1:2-1:6.Further preferably, the Capacity Ratio of the capacity of the positive electrode material layer of positive pole fringe region 22 and the negative electrode material layer of negative pole fringe region 12 is 1:3.2-1:4.Namely different relative to positive electrode material layer extra proportion with the negative electrode material layer of marginal position in the center of cathode pole piece 1, when can effectively avoid low temperature to charge, negative pole edge produces lithium deposition.
When making pole piece, can by anode pole piece 2 and cathode pole piece 1 on described length direction to place for benchmark alignment, placement of staggering in the direction of the width, exposes the lug district described anode pole piece 2 and cathode pole piece 1 not containing electrode material.And containing barrier film in the middle of anode pole piece 2 and cathode pole piece 1, cathode pole piece 1 covers on anode pole piece 2 completely containing negative material part and obtains pole piece containing carrying out winding when positive electrode part.Described barrier film is the barrier film that this area is commonly used, as polyethylene.Other structures of battery and manufacture method can be conventionally known to one of skill in the art, do not repeat them here.
The utility model is specifically as follows positive electrode material layer edge thinning on anode pole piece 2, on cathode pole piece 1, negative electrode material layer edge is thickening, different relative to positive electrode material layer extra proportion with the negative electrode material layer of marginal position in the center of cathode pole piece 1, the negative electrode material layer extra proportion of marginal position is higher, when can effectively avoid low temperature to charge, negative pole edge produces lithium deposition, and then improve low temperature charge cutoff voltage, thus improve battery capacity, energy and power.
Below by embodiment, the utility model is further described.
Embodiment 1
(1) preparation of anode pole piece
By LiFePO
4, acetylene black, PVDF (Kynoar), PVP (polyvinylpyrrolidone) prepare burden according to the weight ratio of 100:5:6:0.5, obtains anode sizing agent.Adopt positive pole coating roller 4 as shown in Figure 7 in the one side elder generation slurry of square aluminium foil, after synchronous 120 DEG C of oven dry, draw other one side again, synchronous 120 degree of oven dry, then compressing tablet.The dressing area of positive pole is 500*150mm, and the thickness of aluminium foil is 12 microns.Positive pole central area one side dressing thickness is 50 microns, and adopt at the positive pole fringe region one side dressing thickness of both sides, positive pole central area the graded progressively increased to positive pole central area from positive pole fringe region, the width of positive pole fringe region is 3mm.
(2) preparation of cathode pole piece
Graphite, CMC (carboxymethyl cellulose), SBR (butadiene-styrene rubber) are prepared burden according to the weight ratio of 100:2:2, obtains cathode size.Adopt negative pole coating roller 3 as shown in Figure 8 in the one side elder generation slurry of square Copper Foil, after synchronous 120 degree of oven dry, draw other one side again, synchronous 120 degree of oven dry, then compressing tablet.The dressing area of negative pole is 504*154mm, and the thickness of Copper Foil is 16 microns.Negative pole central area one side dressing thickness 50 microns.The graded that negative pole fringe region one side dressing thickness in both sides, negative pole central area adopts negative pole fringe region progressively to reduce to negative pole central area, the width of negative pole fringe region is 3mm.
(3) preparation of pole piece
According to the sequential volume of anode pole piece, barrier film, cathode pole piece, barrier film around together, make both positive and negative polarity lug district relative, and on cathode pole piece containing negative material part cover completely on anode pole piece containing positive electrode part, then carry out the pole piece obtained as shown in Figure 6 that reels.The Capacity Ratio of the positive electrode of positive pole central area and the negative material of negative pole central area is 1:1.2.The Capacity Ratio of the positive electrode of positive pole fringe region and the negative material of negative pole fringe region is 1:4.
(4) preparation of battery
Pole piece is inserted in battery case, welding electrode ear, cover plate, fluid injection, forming and capacity dividing, be prepared into battery sample C1.
The capacity of battery is about 3Ah.Voltage is 3.2V.
Embodiment 2
The method step identical with embodiment 1 is adopted to prepare battery sample C2.Width unlike positive pole fringe region, negative pole fringe region is 10mm.
Embodiment 3
The method step identical with embodiment 1 is adopted to prepare battery sample C3.Width unlike positive pole fringe region, negative pole fringe region is 20mm.
Embodiment 4
The method step identical with embodiment 1 is adopted to prepare battery sample C4.Width unlike positive pole fringe region, negative pole fringe region is 50mm.
Embodiment 5
(1) preparation of anode pole piece
LiFePO4, acetylene black, PVDF (Kynoar), PVP (polyvinylpyrrolidone) are prepared burden according to the weight ratio of 100:5:6:0.5, obtains anode sizing agent.Positive pole coating roller 4 is as of fig. 9 shown adopted in the first slurry of the one side of square aluminium foil, after synchronous 120 DEG C of oven dry, to draw other one side again, synchronous 120 degree of oven dry, then compressing tablet.The dressing area of positive pole is 500*150mm, and the thickness of aluminium foil is 12 microns.Positive pole central area one side dressing thickness is 50 microns, and be 20 microns at the positive pole fringe region one side dressing thickness of both sides, positive pole central area, the width of positive pole fringe region is 10mm.
(2) preparation of cathode pole piece
Graphite, CMC (carboxymethyl cellulose), SBR (butadiene-styrene rubber) are prepared burden according to the weight ratio of 100:2:2, obtains cathode size.Adopt negative pole coating roller 3 as shown in Figure 10 in the one side elder generation slurry of square Copper Foil, after synchronous 120 degree of oven dry, draw other one side again, synchronous 120 degree of oven dry, then compressing tablet.The dressing area of negative pole is 504*154mm, and the thickness of Copper Foil is 16 microns.Negative pole central area one side dressing thickness 50 microns, be 80 microns at the negative pole fringe region one side dressing thickness of both sides, negative pole central area, the width of negative pole fringe region is 10mm.
(3) preparation of pole piece
According to the sequential volume of anode pole piece, barrier film, cathode pole piece, barrier film around together, make both positive and negative polarity lug district relative, and on cathode pole piece containing negative material part cover completely on anode pole piece containing positive electrode part, then carry out the pole piece obtained as shown in Figure 5 that reels.The Capacity Ratio of the positive electrode of positive pole central area and the negative material of negative pole central area is 1:1.2.The Capacity Ratio of the positive electrode of positive pole fringe region and the negative material of negative pole fringe region is 1:4.
(4) preparation of battery
Pole piece is inserted in battery case, welding electrode ear, cover plate, fluid injection, forming and capacity dividing, be prepared into battery sample C5.
The capacity of battery is about 3Ah.Voltage is 3.2V.
Embodiment 6
The method step identical with embodiment 5 is adopted to prepare battery sample C6.Thickness unlike the positive pole fringe region being positioned at both sides, positive pole central area is 25 microns, and the thickness being positioned at the negative pole fringe region of both sides, negative pole central area is 75 microns.The Capacity Ratio of the positive electrode of positive pole fringe region and the negative material of negative pole fringe region is 1:3.
Embodiment 7
The method step identical with embodiment 5 is adopted to prepare battery sample C7.Thickness unlike the positive pole fringe region being positioned at both sides, positive pole central area is 22 microns, and the thickness being positioned at the negative pole fringe region of both sides, negative pole central area is 78 microns.The Capacity Ratio of the positive electrode of positive pole fringe region and the negative material of negative pole fringe region is 1:3.6.
Embodiment 8
The method step identical with embodiment 5 is adopted to prepare battery sample C8.Thickness unlike the positive pole fringe region being positioned at both sides, positive pole central area is 17 microns, and the thickness being positioned at the negative pole fringe region of both sides, negative pole central area is 83 microns.The Capacity Ratio of the positive electrode of positive pole fringe region and the negative material of negative pole fringe region is 1:5.
Comparative example 1
The method step identical with embodiment 5 is adopted to prepare battery sample D1.Unlike the consistency of thickness that tensile pulp machine is the dressing consistency of thickness that conventional tensile pulp machine makes anode pole piece surface, positive pole central area positive electrode layer thickness and positive pole fringe region positive electrode material layer, be 50 microns.The dressing consistency of thickness on cathode pole piece surface, the consistency of thickness of negative pole central area negative material layer thickness and negative pole fringe region negative electrode material layer, is also 50 microns.The Capacity Ratio of the positive electrode material layer on anode pole piece and the negative electrode material layer on cathode pole piece is 1:1.2.
Performance test:
1, battery capacity test
At 25 DEG C, battery sample C1-C8, D1 of embodiment 1-8, comparative example 1 being prepared are with the current charges 4 hours of design capacity 0.05C, again with the current charges 6 of design capacity 0.1C little up to voltage be 3.6 volts, and then with constant voltage 3.6 volts charging, to by electric current be 0.01C milliampere; Being discharged to cell voltage with the constant current of 0.2C is again 2.0 volts.The discharge capacity first of record battery.Then with the current cycle 3 times of design capacity 0.5C, recording most high discharge capacity is C0, and test result is as table 1.
2, battery low-temperature circulating
At-20 DEG C, electric discharge state battery C1-C8, D1 of embodiment 1-8, comparative example 1 being prepared place 8h, then with 0.2C current charges to 3.55V, shelve 30min, with 0.2C current discharge to 2.5V, shelve 30min, circulate 800 times, 0.5C capacity at battery testing one time 25 DEG C after every 200 circulations, be designated as C200, C400, C600, C800 respectively, test result is as table 1.
At-20 DEG C, electric discharge state battery C1-C8, D1 of embodiment 1-8, comparative example 1 being prepared place 8h, then with 0.2C current charges to 3.6V, shelve 30min, with 0.2C current discharge to 2.5V, shelve 30min, circulate 800 times, 0.5C capacity at battery testing one time 25 DEG C after every 200 circulations, be designated as C200, C400, C600, C800 respectively, test result is as table 2.
At-20 DEG C, electric discharge state battery C1-C8, D1 of embodiment 1-8, comparative example 1 being prepared place 8h, then with 0.2C current charges to 3.65V, shelve 30min, with 0.2C current discharge to 2.5V, shelve 30min, circulate 800 times, 0.5C capacity at battery testing one time 25 DEG C after every 200 circulations, be designated as C200, C400, C600, C800 respectively, test result is as table 3.
At-20 DEG C, electric discharge state battery C1-C8, D1 of embodiment 1-8, comparative example 1 being prepared place 8h, then with 0.2C current charges to 3.7V, shelve 30min, with 0.2C current discharge to 2.5V, shelve 30min, circulate 800 times, 0.5C capacity at battery testing one time 25 DEG C after every 200 circulations, be designated as C200, C400, C600, C800 respectively, test result is as table 4.
Table 1
Table 2
Table 3
Table 4
The utility model adopt normal temperature recover capacity judge battery low temperature charging whether there occurs lithium deposition, criterion is 98%, namely recover capacity be greater than 98% do not occur lithium deposition, recovery capacity be less than 98% there occurs lithium deposition.
Test result can be found out, the battery sample C1-C8 that the utility model is made, 0.2C electric current 3.6 at-20 DEG C, 3.65,3.7V circulates after 800 times, what its normal temperature capacity restoration rate was the poorest is respectively 98.9%, 93.1%, 82.6%, and the battery sample D1 of comparative example 1 is only 70.3%, 40.2%, 15.6% respectively, low temperature charging performance of the present utility model is excellent.
Claims (15)
1. a lithium ion battery negative electrode, it is characterized in that, comprise negative current collector and be attached to the negative electrode material layer on described negative current collector, the negative pole fringe region being positioned at periphery, negative pole central area that described negative electrode material layer comprises negative pole central area and is connected with negative pole central area, the negative material layer thickness of at least part of described negative pole fringe region is greater than the negative material layer thickness of negative pole central area.
2. cathode pole piece according to claim 1, is characterized in that, the width of described negative pole fringe region is 1 ~ 50mm.
3. cathode pole piece according to claim 2, is characterized in that, the width of described negative pole fringe region is 3 ~ 30mm.
4. cathode pole piece according to claim 3, is characterized in that, the width of described negative pole fringe region is 5 ~ 15mm.
5. cathode pole piece according to claim 1, it is characterized in that, described cathode pole piece is square, and the negative material layer thickness that the Width of cathode pole piece is positioned at the negative pole fringe region of both sides, negative pole central area is greater than the negative material layer thickness of negative pole central area.
6. cathode pole piece according to claim 1, is characterized in that, large 0.25 times-0.6 times of the negative material layer thickness of the negative electrode material layer Thickness Ratio negative pole central area of described negative pole fringe region.
7. cathode pole piece according to claim 1, is characterized in that, the negative material layer thickness of described negative pole fringe region changes in gradient.
8. cathode pole piece according to claim 7, is characterized in that, described negative pole fringe region is from the outside away from negative pole central area to negative pole central area rounding off.
9. a lithium ion battery, comprise battery container, pole piece and electrolyte, described pole piece and electrolyte sealing are contained in described battery container, described pole piece comprises anode pole piece, cathode pole piece and the barrier film between anode pole piece and cathode pole piece, it is characterized in that, described cathode pole piece is the cathode pole piece described in claim 1-8 any one.
10. lithium ion battery according to claim 9, it is characterized in that: described anode pole piece comprises plus plate current-collecting body and is attached to the positive electrode material layer on described plus plate current-collecting body, described positive electrode material layer comprises the positive pole central area relative with negative pole central area and the positive pole fringe region relative with negative pole fringe region, and the positive electrode layer thickness of at least part of described positive pole fringe region is less than the positive electrode layer thickness of positive pole central area.
11. lithium ion batteries according to claim 10, is characterized in that: the positive electrode material layer of described positive pole fringe region is consistent with the gross thickness of the positive electrode material layer of positive pole central area and the negative electrode material layer of negative pole central area with the gross thickness of the negative electrode material layer of negative pole fringe region.
12. lithium ion batteries according to claim 10, it is characterized in that: the positive electrode layer thickness of described positive pole fringe region is successively decreasing away from gradient on direction, positive pole central area, the negative material layer thickness of described negative pole fringe region is increasing progressively away from gradient on direction, negative pole central area.
13. lithium ion batteries according to claim 12, is characterized in that: the amount of decrease that described gradient is successively decreased is consistent with the amplification that gradient increases progressively.
14. lithium ion batteries according to claim 10, is characterized in that: the Capacity Ratio of the capacity of the positive electrode material layer of described positive pole fringe region and the negative electrode material layer of negative pole fringe region is 1:2-1:6.
15. lithium ion batteries according to claim 14, is characterized in that: the Capacity Ratio of the capacity of the positive electrode material layer of described positive pole fringe region and the negative electrode material layer of negative pole fringe region is 1:3.2-1:4.
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| CN111816838A (en) * | 2020-07-22 | 2020-10-23 | 珠海冠宇电池股份有限公司 | Lithium ion battery positive plate and preparation method thereof and lithium ion battery |
| WO2021020212A1 (en) * | 2019-07-31 | 2021-02-04 | 株式会社村田製作所 | Secondary battery and method for manufacturing same |
| CN112701246A (en) * | 2020-12-29 | 2021-04-23 | 珠海冠宇电池股份有限公司 | Electrode sheet and battery |
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| CN114628630A (en) * | 2022-03-21 | 2022-06-14 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| WO2024040472A1 (en) * | 2022-08-24 | 2024-02-29 | 宁德时代新能源科技股份有限公司 | Secondary battery, battery module, battery pack and electric apparatus |
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- 2015-11-30 CN CN201520971880.7U patent/CN205231171U/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021020212A1 (en) * | 2019-07-31 | 2021-02-04 | 株式会社村田製作所 | Secondary battery and method for manufacturing same |
| CN111816838A (en) * | 2020-07-22 | 2020-10-23 | 珠海冠宇电池股份有限公司 | Lithium ion battery positive plate and preparation method thereof and lithium ion battery |
| CN111816838B (en) * | 2020-07-22 | 2021-08-31 | 珠海冠宇电池股份有限公司 | Lithium ion battery positive plate and preparation method thereof and lithium ion battery |
| CN112701246A (en) * | 2020-12-29 | 2021-04-23 | 珠海冠宇电池股份有限公司 | Electrode sheet and battery |
| CN114122315A (en) * | 2021-11-22 | 2022-03-01 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| CN114628630A (en) * | 2022-03-21 | 2022-06-14 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| WO2024040472A1 (en) * | 2022-08-24 | 2024-02-29 | 宁德时代新能源科技股份有限公司 | Secondary battery, battery module, battery pack and electric apparatus |
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