CN204991777U - Long cycle life's energy storage device - Google Patents

Abstract

The utility model provides a long cycle life's energy storage device, including the ellipse columniform supporter of elasticity, the book core of oval cylindricality barrel and the energy storage structure of the external shell of the elliptical metal drum of inner chamber. Make pole piece and diaphragm keep hugging closely when the device circulates under supporter and metal casing combined action between them, the internal resistance remains unchanged. The fold of pole piece with the diaphragm, pole piece fracture have been avoided to the book core of oval cylindricality barrel. The utility model discloses constituting an organic whole with supporter, book core and the external shell of the elliptical metal drum of inner chamber, forming energy storage device, can make its internal resistance increment rate reduce, pole piece and diaphragm do not have the fold, and the pole piece does not split, realizes long cycle life.

Description

A kind of energy storage device of long circulation life

Technical field

The utility model relates to a kind of energy storage field, is specifically related to a kind of energy storage device of long circulation life.

Background technology

Energy storage device comprises battery and ultracapacitor etc., is widely used in the field such as number, electric automobile, needs long-life energy storage device.

Energy storage device can be divided into stacked and takeup type structure according to inner core pack arrangement.Laminated structure energy storage device is generally cuboid and square, its advantage is that device area of dissipation is large, rapid heat dissipation, internal heat generation gas out of control discharges easily via device outer case pressure relief device, thus fail safe is high, but may burr be produced owing to preparing pole piece, make energy storage device self discharge large.In addition, laminated structure energy storage device, as lithium ion battery, in charge and discharge use procedure, the material generation change in volume of positive and negative plate, positive and negative plate generation change in volume, makes pole piece and membrane separation, internal resistance increases fast, and cause circulating battery poor, useful life is short.The manufacture of takeup type structure energy storage device is simple, be generally cylindrical structure, but the internal heat produced in charge and discharge process is difficult to distribute outward.Cylindrical structure core pack arrangement is too closely knit, if core short circuit is inner, gas can not be discharged, and energy storage device easily occurs safety problem.

Comprehensively the advantage of stacked and takeup type structure energy storage device, is prepared into the energy storage device of takeup type cuboid and square core bag.But prepare the volume crook pole piece easily breaking core when this core wraps in pressing, cause energy storage device internal short-circuit or micro-short circuit, cyclicity declines; When core flattens, due to barrier film, the different fold causing pole piece and barrier film of positive and negative electrode pole piece extension, thus make device internal resistance increase fast, cycle life is short; Core when charge and discharge due to pole piece volume increase, recover change, make pole piece and membrane separation, device internal resistance increases fast, device cycle and useful life short.

Utility model content

For the energy storage device Problems existing of takeup type core bag, at the utility model, desirable to provide the long circulation life energy storage device structure of a kind of metal drum body case of inner chamber ellipse and the winding core bag of built-in elastic elliptical cylinder-shape supporter, the cyclicity solving the existence of above-mentioned takeup type structure energy storage device is poor, uses the problem that cycle life is short.

According to the embodiment of the utility model technology, comprise staving shell, core and be built in the support cylindrical shell of core.Described staving shell, for placing core, is the shell of energy storage device, it is characterized in that: metal material, and inner chamber is elliptical cylinder-shape.Described core, be wound into by pole piece, barrier film, pole piece, 4 layers, barrier film, it is characterized in that: in elliptical cylinder-shape cylindrical shape, cross section is oval ring.Described supporter, is characterized in that: make with mechanical swelling or the swelling elastomeric material of electrolyte, in elliptical cylinder-shape bucket body structure, its cross section is oval ring.Described energy storage device is that supporter is inserted core, then reenters into metal staving, and sealing, fluid injection forms, and it is characterized in that: resilient supporter in core bag in described device, has the metal drum body case of inner chamber ellipse outward.Described energy storage device comprises and carries out the device of energy storage by electrochemical principle and carried out the device of energy storage by physical principle.

Described supporter, in elliptical cylinder-shape cylindrical shell, its cross section outer wall contour ovalize, meets oval normal equation, that is: oval upper any point coordinate (x, y), outer wall major semiaxis a ₁₂with semi-minor axis b ₁₂meet equation (1).Cylindrical shell wall thickness is T1, and the ellipse that its cross section inwall contour is formed meets equation (2), wherein major semiaxis a ₁₁=a ₁₂-T1, semi-minor axis b ₁₁=b ₁₂-T1.Elastomer barrel lenght is L1.

$\frac{x^2}{a_{12}^2}+\frac{y^2}{b_{12}^2}=1---\left(1\right)$

$\frac{x^2}{a_{11}^2}+\frac{y^2}{b_{11}^2}=1---\left(2\right)$

Described core, in elliptical cylinder-shape cylindrical shell, the oval contour of its cross section inwall meets oval normal equation, that is: oval upper any point coordinate (x, y), major semiaxis a ₂₁with semi-minor axis b ₂₁meet following equation (3).Core wall thickness is T1.The oval contour of its cross section outer wall meets oval normal equation, that is: oval upper any point coordinate (x, y), major semiaxis a ₂₂with semi-minor axis b ₂₂meet equation (4), and major semiaxis a ₂₂=a ₂₁+ T2, semi-minor axis b ₂₂=b ₂₁+ T2.For fixing core, core length L2 < L1.Retention gap μ l between supporter and core.Semi-minor axis b ₂₁with major semiaxis a ₂₁ratio b ₂₁/ a ₂₁reflection core volume crook pole piece bending curvature.B ₂₁/ a ₂₁when the elliptical cylinder-shape body structure core bag being greater than certain value can avoid core to flatten, barrier film, positive and negative electrode pole piece extend the different fold causing pole piece and barrier film, and the fractureing of volume crook pole piece.

$\frac{x^2}{a_{21}^2}+\frac{y^2}{b_{21}^2}=1---\left(3\right)$

$\frac{x^2}{a_{22}^2}+\frac{y^2}{b_{22}^2}=1---\left(4\right)$

Described staving shell, its inner chamber is ellipse staving, and inwall oval contour in cross section meets oval normal equation, that is: oval upper any point coordinate (x, y), major semiaxis a ₃₁with semi-minor axis b ₃₁meet following equation (5).Gap μ 2 is left, therefore major semiaxis a between outer casing inner wall and core ₃₁=a ₂₂+ μ 2, semi-minor axis b ₃₁=b ₂₂+ μ 2.Staving length L3 > L2, wall thickness is T3.Staving profile is cuboid, square or Elliptic Cylinder.

$\frac{x^2}{a_{31}^2}+\frac{y^2}{b_{31}^2}=1---\left(5\right)$

For avoiding the pole piece radius of curvature of core curls inward volume crook too small, this place's pole piece is caused to fracture, the oval semi-minor axis b of core cross section inwall ₂₁with major semiaxis a ₂₁ratio b ₂₁/ a ₂₁should larger better, but b ₂₁/ a ₂₁larger, then the space of core inside retention is larger, and the volumetric specific energy of energy storage device is less, therefore b ₂₁/ a ₂₁must be rationally.Work as b ₂₁/ a ₂₁when>=0.03, bending part pole piece does not fracture.

For making supporter play a supportive role to core, the pole piece of core and barrier film being close to, stoping energy storage device circulation internal resistance to increase; Due to maximum about the 1.0mm of volumetric expansion recruitment of supporter itself, during core charge and discharge volumetric expansion, the oval long and short semiaxis increase of core inwall about 0.5mm, thus supporter and core gap μ 1 should be μ 1≤0.3mm; On the other hand, for easy to assembly, between supporter and core, need gap, i.e. μ 1 > 0.Therefore, μ 1 is 0 < μ 1≤0.3mm is good.

Reaction force is had to core expansive force for making shell, the pole piece of core and barrier film are close to, energy storage device circulation internal resistance is stoped to increase, between outer casing inner wall and core, gap μ 2 should not be excessive, because core during charge and discharge expands, the oval long and short semiaxis increase of core outer wall about 0.5mm, μ 2 should be μ 2≤0.4mm; On the other hand, be easy to assembly and core expansive force excessive extruding shell when preventing charge and discharge, cause shell excessive to core reaction force, squeeze off pole piece, between outer casing inner wall and core, gap μ 2 should not be too small, best μ 2 >=0.1mm.Therefore, outer casing inner wall and core gap μ 2 should be 0.1≤μ, 2≤0.4mm.

For making shell have reaction force to core expansive force, the pole piece of core and barrier film are close to, energy storage device circulation internal resistance does not increase, and shell must have intensity, has rigidity, and cell wall is better thicker, but shell wall thickness, containment weight conference make energy storage device specific energy decline.Wall thickness is lower than the metal shell of 0.1mm, and casing rigidity is low, and thus wall thickness should be T3 >=0.1mm.

The device that the utility model is applicable to energy storage comprises and carries out the device of energy storage by electrochemical principle and carried out the device of energy storage by physical principle.This energy storage device is: lithium ion battery, polymer Li-ion battery, Ni-MH battery, lead-acid battery, ultracapacitor battery, superbattery, mixed capacitor, electrochemical capacitor etc.

Supporter material described in the utility model is selected from one or more of stainless steel, Ethylene Propylene Terpolymer, nitrile rubber and silica gel.

Metal shell material described in the utility model is selected from stainless steel, aluminum or aluminum alloy, nickel-clad iron.

Flexible elliptical cylinder-shape supporter is comprised, the energy storage device of the core of elliptical cylinder-shape cylindrical shell and the metal drum body case of inner chamber ellipse according to scheme of the present utility model.Built-in elastic supporter fills the expansion of core inner chamber in charge and discharge process caused by the change in volume of positive and negative electrode, support core, and the expansive force that the metal drum body case of inner chamber ellipse makes core volume become large generation turns to core inner, keep being close to when making pole piece and barrier film at device cycle under the acting in conjunction of supporter and metal shell, internal resistance remains unchanged.Elliptical cylinder-shape body structure core bag avoids the buckling phenomena that core flattens rear pole piece and barrier film, thus makes device internal resistance constant, and cyclicity increases.According to the semi-minor axis b of the utility model scheme ₂₁the core that dimensional requirement makes, the pole piece of the involute crook of core can not fracture, thus improves the cyclicity of energy storage device further.

Therefore, flexible elliptical cylinder-shape supporter is comprised according to the utility model embodiment, the energy storage device of the core of elliptical cylinder-shape cylindrical shell and the metal drum body case of inner chamber ellipse, can make that energy storage device internal resistance increase rate reduces, the pole piece of core and barrier film corrugationless, core is part not, realizes its long circulating useful life.

Other features and advantages of the utility model more fully present in following description.

Accompanying drawing explanation

Fig. 1 long circulation life energy storage device schematic diagram

Fig. 2 states flexible elliptical cylinder-shape supporting body structure

Fig. 3 states the metal drum shell mechanism of inner chamber ellipse

Fig. 4 states the core structure of elliptical cylinder-shape cylindrical shell

Fig. 5 states conventional cuboid core structure, is used as the core comparative illustration with the utility model scheme

Fig. 6 energy storage device sectional view, states the flexible elliptical cylinder-shape supporter of the utility model scheme, the core of elliptical cylinder-shape cylindrical shell and the metal drum body case structural relation of inner chamber ellipse

Embodiment

Below by example with reference, the utility model is described in detail, simultaneously by comparative illustration effect of the present utility model.The following examples just meet the example of the utility model technology contents, and do not illustrate that the utility model is only limitted to the content described in following example, the product manufactured according to this claim all belongs to the utility model content.

Fig. 1 is energy storage device energy storage device schematic diagram, the visible positive terminal 101 of profile, negative terminal 105, cover plate 102, liquid injection hole 103 and battery case 104.Fig. 2 describes flexible elliptical cylinder-shape supporter 201 structure.Fig. 3 states metal drum shell 104 structure of inner chamber ellipse.Fig. 4 describes core 401 structure of elliptical cylinder-shape cylindrical shell.Core 401 is reeled by barrier film 411, negative plate 412, barrier film 411 and positive plate 413 and forms.Fig. 5 is conventional cuboid core 501 structure.Conventional core 501 is also reeled by barrier film 411, negative plate 412, barrier film 411 and positive plate 413, flatten and form.Fig. 6 is energy storage device sectional view, presents energy storage device internal structure.Nexine is flexible elliptical cylinder-shape supporter 201, and intermediate layer is the core 401 of elliptical cylinder-shape cylindrical shell, and skin is the metal drum shell 104 of inner chamber ellipse.

Embodiment 1

In order to the utility model is described, the present embodiment makes 80Ah cuboid lithium ion battery, as shown in Figure 1.Anode material for lithium-ion batteries adopts LiFePO usually ₄, LiNiCoMnO ₂, LiNiCoAlO ₂, LiMn ₂o ₄, LiCoO2 or wherein two kinds of mixtures, negative material adopts C, Li ₄t _i5o ₁₂, Si or its compound, Sn or its compound, electrolyte adopts 1.2MLiPF ₆+ EC+EMC, barrier film adopts PE film, PP film, PP/PE film, scribbles SiO ₂or Ai ₂o ₃pE composite membrane.

Make the supporter 201 of flexible elliptical cylinder-shape in advance, the plate-like elastic body of the stainless steel Elliptic Cylinder that elastomeric material can select electrolyte resistance to dissolve also can be can by the swelling elastomeric material of electrolyte, as Ethylene Propylene Terpolymer, nitrile rubber and silica gel.This example adopts swelling Ethylene Propylene Terpolymer material, according to inwall major semiaxis a ₁₁for 49.55mm, semi-minor axis b ₁₁for 1.55mm, cylindrical shell wall thickness T1 is 0.25mm, outer wall major semiaxis a ₁₂for 49.8mm, semi-minor axis b ₁₂for 1.8mm, barrel lenght L1 is 190mm.Die sinking, makes elastic elliptic pillar support body 201, as Fig. 2 with injection moulding process.

Make the metal drum body case 104 of inner chamber ellipse in advance, material adopts the aluminium, stainless steel, nickel, nickel plating iron-clad etc. of electrolyte resistance corrosion.Housing profile can be cuboid, square and Elliptic Cylinder.This example adopts aluminium, cuboid profile.According to size inner chamber major semiaxis a ₃₁for 64.25mm, semi-minor axis b ₃₁for 16.25mm, bucket wall thickness T 3 is 0.5mm, the wide 129.0mm of outer wall, thick 33.0mm, and the long L3 of staving is 210mm, and the Aluminum Drum 104 of the inner chamber ellipse of making, as Fig. 3.Between shell 104 inwall and core 401, gap μ 2 is 0.25mm.

Adopt LiFePO ₄be positive and negative electrode material with graphite C.Respectively LiFePO ₄with graphite C according to certain ratio batching, homogenate, is coated on aluminium foil and Copper Foil, rolls, cut, and makes positive plate 413 and cathode pole piece 412.Negative plate 412, scribble Ai ₂o ₃pE composite diaphragm 411, positive plate 413, scribble Ai ₂o ₃pE composite diaphragm 411 totally 4 layers be overlappingly rolled into core 401.Core has cylindrical, square through angle, hot pressing Ping Dai garden or cuboid core usually.Cuboid core 501 as shown in Figure 5.This example adopts the scheme of utility model to adopt the cylindroid body volume pin of setting size, rolls out the core 401 of cylindrical tube.Its cross section inwall major semiaxis a ₂₁for 50.0mm, semi-minor axis b ₂₁for 2.0mm, b ₂₁/ a ₂₁be 0.04, the thick T2 of core is 14mm, outer wall major semiaxis a ₂₂for 64.0mm, semi-minor axis b ₂₂for 16.0mm, core length L2 is 185mm, as shown in Figure 4.Between core 401 and supporter 201, gap μ 1 is 0.2mm.

Supporter 201 is inserted core 401, the core of built-in supporter is put into the metal staving 104 of inner chamber ellipse, positive and negative electrode lug, by metal joining strips, adopts ultra-sonic welded or clinching method to be connected on the positive and negative pole of cover plate again, then dry, inject 1.2MLiPF ₆+ EC+EMC electrolyte, envelope liquid injection hole, changes into.With CC+CV (80A, 3.65V) charging, 80A constant current, to the program of 2.5V, circulates after 1000 times and measures battery capacity, reflect circulating battery.Measurement result: battery remaining power is 98% of initial capacity.Find after disassembling battery, battery cathode sheet 412, barrier film 411 and positive plate 413 corrugationless and break; Battery cathode sheet 412 and positive plate 413 are close to barrier film 411 respectively.

Embodiment 2

Make 8000F ultracapacitor, electrode material adopts the active carbon of 1500m2/g, and electrolyte adopts 1.2MTEABF4+PC, and other are identical with making 80A cuboid lithium ion battery.Circulation is measured and is charged to 2.7V according to 30A, and 30A is discharged to 1.35V scheme and measures, and circulates 50000 times, measures condenser capacity and characterizes its cyclicity.Measurement result: capacitor residual capacity is 99% of initial capacity.Find after disassembling battery, capacitor anode sheet 412, barrier film 411 and positive plate 413 corrugationless and break; Negative plate 412 and positive plate 413 are close to barrier film 411 respectively.

Comparative example 1

Core 401 inside does not adopt elastic elliptic pillar support body 201, but select inelastic strutting piece, all the other are identical with embodiment 1, make 80Ah battery lithium ions battery, with the loop test mode that embodiment 1 is identical, its cyclicity result: battery remaining power is 93% of initial capacity.Find after disassembling battery, battery cathode sheet 412, barrier film 411 and positive plate 413 have segregation phenomenon.

Comparative example 2

Battery case does not adopt the metal staving 104 of inner chamber ellipse, but select the aluminum plastic membrane shell without rigidity, the 80Ah battery of all the other making identical with embodiment 1, with the loop test mode that embodiment 1 is identical, its cyclicity result: battery remaining power is 93% of initial capacity.Find after disassembling battery, core 401 becomes loose, and battery cathode sheet 412, barrier film 411 and positive plate 413 have segregation phenomenon; Housing distortion.

Comparative example 3

Battery does not have supporter 201, do not adopt the core 401 of cylindrical tube and metal staving 104 structure of inner chamber ellipse, but adopt the cuboid core 501 at angle, band garden and conventional cuboid bucket body structure, the 80Ah battery of all the other making identical with embodiment 1, with the loop test mode that embodiment 1 is identical, its cyclicity result: battery remaining power is 90% of initial capacity.Find after disassembling battery, core 401 becomes loose, battery cathode sheet 412, has segregation phenomenon between barrier film 411 and positive plate 413; Battery cathode sheet 412, barrier film 411 and positive plate 413 have fold, and particularly negative plate 412 and barrier film 411 exist a large amount of fold; Positive plate 413 is had to fracture at bending part.

Comparative example 4

The oval semi-minor axis b of core 401 inwall of battery cylindrical shape cylindrical shell ₂₁for 1.0mm, i.e. b ₂₁/ a ₂₁be 0.02.Except battery minor axis and thickness direction reduce, all the other are identical with embodiment 1, make 80Ah battery lithium ions battery.With the loop test mode that embodiment 1 is identical, its cyclicity result: battery remaining power is 91% of initial capacity.Find after disassembling battery, core 401 becomes loose, battery cathode sheet 412, has segregation phenomenon between barrier film 411 and positive plate 413; Battery cathode sheet 412, barrier film 411 and positive plate 413 have fold; Positive plate 413 is had to fracture at bending part.

Comparative example 5

Between the core 401 of metal cylinder 104 and built-in elastic body 201, gap μ 2 is 0.8mm, the 80Ah battery of all the other making identical with embodiment 1, with the loop test mode that embodiment 1 is identical, and its cyclicity result: battery remaining power is 93% of initial capacity.Find after disassembling battery, core 401 becomes loose, battery cathode sheet 412, has segregation phenomenon between barrier film 411 and positive plate 413.

Comparative example 6

Metal cylinder bucket 104 fine aluminium, wall thickness T 3 is 0.08mm, the 80Ah battery of all the other making identical with embodiment 1, with the loop test mode that embodiment 1 is identical, its cyclicity result: battery remaining power is 96% of initial capacity.Find after disassembling battery, core 401 becomes loose, battery cathode sheet 412, has segregation phenomenon between barrier film 411 and positive plate 413, and battery case is out of shape.

Claims (10)

1. an energy storage device for long circulation life, described energy storage device carries out the device of energy storage by electrochemical principle or carried out the device of energy storage by physical principle, and this energy storage device comprises: staving shell, core and the supporter be built in core; Described energy storage device by supporter is inserted core, then loads staving shell the core being built-in with supporter, and then sealing, fluid injection is made; Core is formed by positive plate, barrier film, the stacked rear winding of negative plate; It is characterized in that: supporter cross section is oval ring, core cross section is oval ring, and the inner chamber of staving shell is elliptical cylinder-shape; Described supporter elastomeric material is made, and staving shell is metal material.

2. the energy storage device of long circulation life according to claim 1, is characterized in that: the semi-minor axis b of the cross section inwall ellipse of described core ₂₁with major semiaxis a ₂₁ratio be b ₂₁/ a ₂₁>=0.03.

3. the energy storage device of long circulation life according to claim 1, is characterized in that: the gap μ 1 between core and supporter is 0 < μ 1≤0.3mm.

4. the energy storage device of long circulation life according to claim 3, is characterized in that: the gap μ 2 between metal staving and core is 0.1≤μ, 2≤0.4mm.

5. the energy storage device of long circulation life according to claim 4, is characterized in that: described metal drum body case wall thickness T 3 >=0.1mm.

6. the energy storage device of long circulation life according to claim 1, is characterized in that: described energy storage device is lithium ion battery, polymer Li-ion battery, Ni-MH battery, lead-acid battery, ultracapacitor battery, mixed capacitor, electrochemical capacitor.

7. the energy storage device of long circulation life according to claim 1, is characterized in that: described elastomer material is selected from stainless steel making sheet shape elastomer, ethylene propylene diene rubber, nitrile rubber, one or more of silica gel.

8. the energy storage device of long circulation life according to claim 1, is characterized in that: described metal drum body case material is selected from stainless steel, aluminum or aluminum alloy, nickel-clad iron.

9. the energy storage device of long circulation life according to claim 8, is characterized in that: described metal drum body case material is aluminum or aluminum alloy.

10. the energy storage device of long circulation life according to claim 5, is characterized in that: described metal drum body case profile is cuboid, square or elliptical cylinder-shape.