CN201741582U

CN201741582U - High magnification cylindrical super capacitor

Info

Publication number: CN201741582U
Application number: CN2010202464690U
Authority: CN
Inventors: 张海林
Original assignee: Shuangdeng Science & Technology Development Academy Co Ltd Nanjing City
Current assignee: Shuangdeng Science & Technology Development Academy Co Ltd Nanjing City
Priority date: 2010-06-30
Filing date: 2010-06-30
Publication date: 2011-02-09
Anticipated expiration: 2020-06-30

Abstract

The utility model discloses a high magnification cylindrical super capacitor; current collectors in the positive plate and the negative plate of a capacitor are respectively single-sheet stripe aluminum foils; one positive ear is arranged at one second of the long side of the current collector of the positive plate; two negative plates are respectively arranged at one fourth and three fourths of the current collector of the negative plate; or two positive ears are respectively arranged at one fourth and three fourths of the long side of the current collector of the negative plate; and one negative ear is arranged at one second of the long side of the current collector of the negative plate. The thicknesses of the aluminum foils are 10-50 Mum. The high magnification cylindrical super capacitor adopts single ear on the traditional positive and negative plates and improves the structure that the ear is arranged at one end of the plate, induces a three-ear structure, implements structure optimization through theoretical analysis, and optimizes the thicknesses of the aluminum foils, can obviously reduce the inner resistance of a capacitance, and improve the magnification performance of the capacitance, is suitable for the application fields of high power pulse and high requirement on instantaneous power, and has obvious practical values and economic benefits.

Description

High-magnification cylindrical type ultracapacitor

Technical field

The utility model relates to a kind of ultracapacitor, particularly powerful column type ultracapacitor.

Background technology

It is big that ultracapacitor has power density, advantages such as the speed that discharges and recharges is fast, long service life, operating temperature range are wide, non-maintaining, economic environmental protection are used having aspect industrial electrical equipment, consumer electronics, communications and transportation, green energy resource field high power pulse, the instantaneous power maintenance widely.

High power pulse and instantaneous power all require ultracapacitor to have lower equivalent series internal resistance.In general, the ultracapacitor internal resistance is: R _i=R _El+ R _{Act (N)}+ R _{Act (P)}+ R _{Con (N)}+ R _{Con (P)}+ R _{Col (N)}+ R _{Col (P)}+ R _{Tab (N)}+ R _{Tab (P)}, R wherein _ElRepresent bath resistance, R _ActRepresent electrode activity layer resistance, R _ConRepresent the contact resistance of electrode activity layer and collector, R _ColRepresent collector resistance, R _TabRepresent lug resistance, subscript N, P represent negative pole and positive pole respectively.At present, people more still improve from aspects such as electrodes conduct performances, seldom have from the capacitor design configuration aspects and optimize with improved, and in fact the structural design of pole piece and lug is vital in the capacitor.Collector in the positive/negative plate of column type ultracapacitor respectively is the strip aluminium foil, and lug is welded on the side of aluminium foil.Traditional positive/negative plate adopts monopole ear, and lug is in an end of pole piece, and this structure makes and electric capacity thermal effect variation strengthened the capacitor internal resistance.The thickness of selecting as the aluminium foil of collector is also reasonable inadequately in addition, also has influence on the electric capacity thermal effect.Above defective causes existing column type ultracapacitor high-rate discharge ability not good, and range of application is restricted.

The utility model content

The technical problems to be solved in the utility model is the defective that overcomes existing ultracapacitor pole piece configuration aspects, and a kind of improvement pole piece structure is provided, and reduces the capacitor internal resistance, improves the high-magnification cylindrical type ultracapacitor of high-rate discharge ability.

The technical solution of the utility model is: the collector in the high-magnification cylindrical type ultracapacitor in the positive and negative plate respectively is individual strip aluminium foil, positive and negative lug is welded on the side of strip aluminium foil, its improvements are that described anode ear is one, be positioned at 1/2 place of the length direction side of positive plate collector, negative electrode lug is two, lays respectively at 1/4 and 3/4 place of the length direction side of negative plate collector; Perhaps described anode ear is two, lays respectively at 1/4 and 3/4 place of the length direction side of positive plate collector, and negative electrode lug is one, is positioned at 1/2 place of the length direction side of negative plate collector.

Further improving is that described aluminum foil thickness is 10～50 μ m.

The beneficial effects of the utility model are: adopt monopole ear with traditional positive/negative plate, lug is in the structure of pole piece one end and compares, the utility model is introduced three extreme ear structures, carry out structure optimization by theory analysis, simultaneously aluminum foil thickness has been done preferably, can obviously reduce the electric capacity internal resistance, improve the high rate performance of electric capacity.The utility model is simple in structure, do not increase manufacturing cost, have wide range of applications, and has significant practical value and economic benefit.

Can be described further by following theory analysis the beneficial effects of the utility model:

At present, the positive and negative electrode of ultracapacitor adopts aluminium foil as collector, according to R _Col=ρ * L/ (W * T), wherein R _ColBe collector resistance, the resistivity of ρ current collector material, L collector length, W is the collector width, T is a collector thickness, and to determining the ultracapacitor of model size, the length L of its used collector and width have just been determined thereupon usually, therefore, can reduce collector resistance by increasing collector thickness.Concrete computational process is as follows: suppose that the unit interval amount one of unit are reaction is decided to be n mol electronics, and then overall reaction electric current I=n * F * L * W, the electric current that unit are produces is n * F, and wherein F is a Faraday constant, and L, W are as previously shown.Calculating chart 1a negative pole heat production Q-at first, an end place that does not have lug with negative pole is a rectangular coordinate initial point 0, then the electric current I at x point place arbitrarily _x=n * F * W * X, the resistance of Δ x is R again _x=ρ * Δ x/ (W * T), then the heat production dQ-=of negative current collector (n * F * W * X) ²(integration is carried out to equation (1) in W * T) (1) to * ρ * dx/ in 0～L scope, obtain Q-=I at last ²* R-/3.The anodal heat production Q of Fig. 1 a ₊The same negative pole of rational analysis, Q ₊=I ²* (R ₊/ 3), because the electric current of all generations all flows through both positive and negative polarity ear, then Q _{Tab ±}=I ²* (R _Tab++ R _Tab-).Therefore, Q=I ²* R _-/ 3+I ²* R ₊/ 3+I ²* (R _Tab++ R _Tab-) (2).(W * T), with the relevant parameter substitution equation (2) of anodal, negative pole and lug, in the time of just can be in the hope of heavy-current discharge, the characteristic of current collector material be to the influence of electric capacity thermal effect Q according to resistance general formula R=ρ * L/.Calculating shows: it is limited during by increase collector aluminum foil thickness the electric capacity thermal effect being improved, and in addition, in the confined space, certainly will reduce capacitance if aluminum foil thickness is excessive.Therefore, comprehensive multiple factor, the thickness of aluminium foil should be 10～50um, and optimum range is 10～30um.

As everyone knows, lug plays a part UNICOM's collector and external circuit in electric capacity, and therefore, lug material, number and position all can influence the electric capacity internal resistance, and from the angle of structure optimization, the utility model emphasis is considered the latter's influence.In theory, the number of lug is many more, and the electric capacity internal resistance is few more, but the increase of lug number, and the more space that certainly will account for causes capacitance to reduce.In addition, the lug number is too much, the manufacturability variation of electric capacity, and the manufacturing cost of electric capacity also can increase.Therefore, the comprehensive influence of various factors of the lug number that is adopted in the positive/negative plate.The utility model improves the structure of positive and negative each lug of traditional capacitance pole piece, introduces three extreme ear structures.As the analytic set fluid electric capacity thermal effect is influenced, we have carried out Theoretical Calculation and analysis respectively at the diverse location of lug in three extreme ear structures, final selected the technical solution of the utility model, promptly anodal lug is placed in the middle, two lugs of negative pole place 1/4 place and 3/4 place of negative plate respectively, or lug of negative pole is placed in the middle, and anodal two lugs place 1/4 place and 3/4 place of positive plate respectively.

Description of drawings

Fig. 1 is a pole piece structural representation in the utility model, and A is a positive plate, and B is a negative plate;

Fig. 2 is the another kind of structural representation of pole piece in the utility model, and C is a positive plate, and D is a negative plate;

Fig. 3 is pole piece structural representation in the existing capacitor, and E is a positive plate, and F is a negative plate.

Embodiment

Embodiment 1:

As positive electrode active materials, acetylene black is conductive agent with active carbon, and Kynoar (PVDF) is a binding agent.The three is mixed and add 300 parts of N-methyl pyrrolidones (NMP) in 85: 7: 8 ratios and transfer and all become pasty state, be evenly coated on the thick aluminium foil of 20um and oven dry, be rolled into 136um at last, be cut into the strip of 57.5 * 1120mm, obtain positive plate.Anode ear is one, is welded on 1/2 place on the long limit of collector, and pastes protective tapes.

With the negative electrode active material activated carbon; conductive agent acetylene black; binding agent Kynoar (PVDF) by 85: 7: 8 mixed evenly and add 300 parts of N-methyl pyrrolidones (NMP) and transfer and all become pasty state; be evenly coated on the thick aluminium foil of 20um and oven dry; be rolled into 136um at last, be cut into the strip of 56 * 1080mm, obtain negative plate; two negative electrode lugs are welded on 1/4 and 3/4 place on the long limit of collector respectively, and paste protective tapes.As shown in Figure 1.

Adopt the thick TF barrier film of 25um then, press the sequential volume coiled 18650 electric cores of barrier film, positive pole, barrier film, negative pole.

At the bottom of above-mentioned electric core put into metal-back, slot rolling, weldering, inject nonaqueous electrolytic solution, 18650 column type ultracapacitors are covered, seal, finally are assembled in weldering.

Embodiment 2:

Similar to Example 1, difference is that anode ear is two, lays respectively at 1/4 and 3/4 place on the long limit of collector, and negative electrode lug is one, is positioned at 1/2 place on the long limit of collector.As shown in Figure 2.

Comparative example:

Technology and structure are made ultracapacitor routinely, wherein the pole piece structure as shown in Figure 3, each one of positive and negative lug lays respectively at the end on the long limit of collector.

The electrochemical capacitance Performance Detection

At first the various capacitors that said method is made change into and reprocessing, and adopt the internal resistance of the ac impedance measurement instrument mensuration electrochemical capacitance of 1000Hz, carry out big multiplying power discharging subsequently.

Method of testing is as follows:

The 1C charging, 1C electric current CC to 2.7V, cut-off current 5mA, 1C is used in dormancy 10 minutes then, 10C, 50C, 100C, 200C discharge into 1.35V.Performance comparison such as following table:

Experiment type	Internal resistance (m ohm)	1C discharge capacity (m Ah)	10C discharge capacity percentage (with respect to the IC discharge capacity)	50C discharge capacity percentage (with respect to the IC discharge capacity)	50C discharge capacity percentage (with respect to the IC discharge capacity)
						Embodiment 1.2	5.8	172	98.6％	97.8％	95.4％
Comparative example	12.6	176	95.8％	92.3％	80.6％

Last table is that the utility model embodiment and comparative example capacitive property compare, and the electric capacity internal resistance of clearly adopting the utility model making is less than about 50% of traditional design electric capacity internal resistance, and the multiplying power discharging property of electric capacity is fine.For ultracapacitor, the 100C discharge can reach 95.4% of initial capacity (1C discharge capacity).

Claims

1. high-magnification cylindrical type ultracapacitor, collector in this capacitor in the positive and negative plate respectively is individual strip aluminium foil, positive and negative lug is welded on the side of strip aluminium foil, it is characterized in that described anode ear is one, be positioned at 1/2 place of the length direction side of positive plate collector, negative electrode lug is two, lays respectively at 1/4 and 3/4 place of the length direction side of negative plate collector; Perhaps described anode ear is two, lays respectively at 1/4 and 3/4 place of the length direction side of positive plate collector, and negative electrode lug is one, is positioned at 1/2 place of the length direction side of negative plate collector.

2. by the described high-magnification cylindrical type of claim 1 ultracapacitor, it is characterized in that described aluminum foil thickness is 10～50 μ m.