CN202019011U - Safety valve for lithium ion power battery - Google Patents

Abstract

The utility model relates to a safety valve for a lithium ion power battery. Currently adopted safety valves are generally thin metal sheets arranged on end caps, and are scrapped once batteries are opened. The safety valve for a lithium ion power battery is characterized in that a mounting groove is arranged on an injection molded battery cover plate, an exhaust hole is arranged at the bottom of the mounting groove, a valve bonnet and a spring are arranged in the mounting groove, air outlet holes are arranged on the valve bonnet, the lateral wall of the valve bonnet is connected with the lateral wall of the upper portion of the mounting groove in a threaded manner, a valve spool comprises a spring positioning pin, a sealing sheet and an inverted cone frustum adjusting pin sequentially from top to bottom, the upper end of the spring is movably connected with the bottom surface of the valve bonnet, and the lower end of the spring is movably connected with part of the sealing sheet. The safety valve with restorability is capable of greatly improving safety of the lithium ion battery, preventing shell bulging of the battery and effectively prolonging the service life of the battery.

Description

The lithium-ion-power cell safety valve

Technical field

The utility model belongs to field of mechanical technique, relates to a kind of lithium-ion-power cell safety valve.

Background technology

In recent years; serious day by day along with energy crisis and global environment problem; the development and application of new forms of energy has become the upsurge in the whole world; adopting LiFePO4 is the lithium-ion-power cell of positive electrode; be regarded as the best energy of new-energy automobiles such as electric automobile, hybrid vehicle, growth momentum is swift and violent.

Along with the appearance of lithium ion battery development of technology and new material, lithium ion battery is more a lot of than lithium ion battery raising in the past in fail safe.Therefore, lithium ion battery is more and more toward large scale development.Especially the lithium ion battery of used for electric vehicle generally adopts large-scale rectangular cell.But the electrolyte of present all kinds of lithium ion batteries adopts carbonate group electrolyte basically.And the lithium ion battery of employing carbonate group electrolyte is in the initial charge process, simultaneously in the normal charge and discharge process of battery, owing to be accompanied by the continuous destruction and the production of SEI film, it is inevitable more than producing being reflected in the battery of gas, carrying out along with charge and discharge cycles, the amount of gas of accumulation is more and more in the battery, causes inner pressure of battery to rise, and brings hidden danger for the fail safe of battery.

At present, general lithium-ion-power cell can be provided with safety valve on end cap, adopts the punching press attenuate to form the foil of band indentation usually, or adopts the sheet metal of prefabricated indentation to be welded in end cap formation safety valve.After inner pressure of battery surpassed set point, sheet metal broke at prefabricated indentation place, and inside battery gas discharges by breach, and inner pressure of battery descends, thereby prevents battery explosion.And in a single day open when the safety valve of this type, battery is also scrapped thereupon, can't re-use.

Summary of the invention

The purpose of this utility model is at the deficiencies in the prior art, and a kind of safety valve for lithium ion cell is provided, and this safety valve can repeat open and close, accurately controls inner pressure of battery, improves the fail safe of battery, prevents the leakage of inside battery electrolyte simultaneously.

The utility model is to offer columniform mounting groove on the battery cover board of injection molding, and open-top, the bottom of mounting groove have steam vent, and mounting groove is communicated with by steam vent with lithium ion inside.

Valve gap and spring are arranged in the mounting groove, wherein have venthole on the valve gap, and the sidewall of valve gap is threaded with the upper portion side wall of mounting groove.

Spool comprises successively that from top to bottom the spring holder of cylinder, the diaphragm seal of platypelloid type, the adjusting of rounding stage body sell three parts, and the lower surface area of diaphragm seal part is greater than the upper surface area of regulating pin part.Described spool is one-body molded, and its material is acrylonitrile-butadiene rubber, butadiene-styrene rubber, fluorubber, ethylene-propylene rubber or butyl rubber.

The upper end of spring and the bottom surface of valve gap flexibly connect, and the lower end of spring is enclosed within outside the spring holder of spool, and flexibly connects with diaphragm seal.

The underrun taper seat transition of steam vent and mounting groove, the tapering of this taper seat is consistent with the tapering of the lateral surface of the adjusting pin part of spool.

The utility model adopts the method for injection mo(u)lding, directly outpours mounting groove on plastic cover plate, places spool and spring then in mounting groove, tightens valve gap, by the predeformation amount of setting spring, reaches the effect of control inner pressure of battery and sealing.When cell internal pressure during greater than setting, this safety valve is opened, discharge unnecessary gas after, safety valve cuts out the sealing that keeps battery again, can accurately control inner pressure of battery, keeps battery security; Safety valve can repeat to open and close simultaneously, prevents the leakage of inside battery electrolyte, guarantees that battery is reliable and practical.The utility model is applicable in the lithium-ion-power cell, especially is fit to be applied in the lithium-ion-power cell of big capacity and high-multiplying power discharge.

But the utlity model has restore funcitons, can be in the scope of setting with the interior pressure-controlled of battery, when inner pressure of battery increased, gas that can in time will be unnecessary was discharged outside the battery fail safe of assurance battery; When the interior pressure of battery returned to the value of regulation, it is closed that safety valve then again can be in time, prevents battery leakage, guarantees the operate as normal of battery, can not make that battery is disposable to be scrapped.Therefore, the safety valve that employing can repeat to open and close can improve the fail safe that becomes lithium ion battery greatly, prevent that drum shell phenomenon from appearring in battery, and the working life that can effectively prolong battery.For lithium-ion-power cell, especially as the LiFePO4 class electrokinetic cell of Vehicular dynamic battery, this safety valve can in use provide good safeguard protection effect.

Description of drawings

Fig. 1 is a structural representation of the present utility model;

Fig. 2 is the structural representation of spool among Fig. 1.

Embodiment

Below in conjunction with accompanying drawing the utility model is further described.

As shown in Figure 1, a kind of lithium-ion-power cell safety valve is to offer columniform mounting groove 2 on the battery cover board 1 of injection molding, and the open-top of mounting groove 2, bottom have steam vent 7, and mounting groove 2 is communicated with by steam vent 7 with lithium ion is inner.

Valve gap 3 and spring 5 are arranged in the mounting groove 2, wherein have venthole 4 on the valve gap 3, and the sidewall of valve gap 3 is threaded with the upper portion side wall of mounting groove 2.

Spool 6 structure that is formed in one, its material adopts acrylonitrile-butadiene rubber, butadiene-styrene rubber, fluorubber, ethylene-propylene rubber or butyl rubber.As Fig. 2, spool 6 comprises the diaphragm seal 6-2 of cylindrical spring holder 6-1, disc, adjusting pin 6-3 three parts of rounding stage body from top to bottom successively, and the lower surface area of diaphragm seal 6-2 is greater than the upper surface area of regulating pin 6-3.

The bottom surface of the upper end of spring 5 and valve gap 3 flexibly connects, and the lower end of spring 5 is enclosed within outside the spring holder 6-1 of spool 6, and flexibly connects with diaphragm seal 6-2, and the two ends of spring 5 prop up the bottom surface of valve gap 3 and the upper surface of diaphragm seal 6-2 respectively.

Spring 5 adopts stainless steel material, its predeformation amount XCalculate according to Hooke's law:

Wherein kBe the elastic deformation coefficient of spring, Press in the lithium ion battery for setting, r _o Least radius for steam vent.

The underrun taper seat transition of steam vent 7 and mounting groove 2, the tapering of this taper seat is consistent with the tapering of the lateral surface of the adjusting pin 6-3 of spool.

Behind the plastic cover plate of lithium-ion-power cell and the housing welding fabrication, steam vent 7 by safety valve injects electrolyte, put into spool 6 and spring 5 then, tighten valve gap 3, the adjusting pin 6-3 of spool 6 is arranged on the taper seat part of steam vent 7, by spool 6 closed exhaust holes 7, predeformation amount is determined according to the inner pressure of battery of setting.

The battery safety valve that assembles, the pressure that produces when inside battery surpasses setup pressure value, and spool 6 is by last top, and the gas that inside battery produces is by steam vent 7 and venthole 4 dischargings.And returning to setup pressure value when following when pressure, spool 6 is under the effect of spring 5, again with steam vent 7 sealings.This safety valve reduces inner pressure of battery by repeating open and close, guarantees battery security.When cell internal pressure was lower than setting pressure, because the elastic force that strained spring produces, spring locked close being pressed together in the steam vent with the adjusting of the rounding stage body of spool, prevents the leakage of inside battery electrolyte.

Claims (1)

1. the lithium-ion-power cell safety valve is characterized in that this safety valve is to offer columniform mounting groove on the battery cover board of injection molding, and open-top, the bottom of mounting groove have steam vent, and mounting groove is communicated with by steam vent with lithium ion inside;

Valve gap and spring are arranged in the mounting groove, wherein have venthole on the valve gap, and the sidewall of valve gap is threaded with the upper portion side wall of mounting groove;

Spool comprises successively that from top to bottom the spring holder of cylinder, the diaphragm seal of platypelloid type, the adjusting of rounding stage body sell three parts, and the lower surface area of diaphragm seal part is greater than the upper surface area of regulating pin part; The upper end of spring and the bottom surface of valve gap flexibly connect, and the lower end of spring is enclosed within outside the spring holder of spool, and flexibly connects with diaphragm seal;

The underrun taper seat transition of steam vent and mounting groove, the tapering of this taper seat is consistent with the tapering of the lateral surface of the adjusting pin part of spool.

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