CN1688041A

CN1688041A - Safety valve for lithium ion cell

Info

Publication number: CN1688041A
Application number: CNA2005100391650A
Authority: CN
Inventors: 许锷铭; 吴德喜; 曹正平; 顾敏敏
Original assignee: 汤国江
Priority date: 2005-04-27
Filing date: 2005-04-27
Publication date: 2005-10-26

Abstract

This invention discloses a safety valve mounted on the orifice of the Li ionic battery shell including a battery top cover with a seat at the middle sealed-in with the cover. A central hole is set on the seat, and the diameter of the upper section is greater than that of the lower to form circle stage at the middle, a valve plug, a spring and a wafer are set in the central hole from the bottom to the top on the circle stage. A central hole is on the wafer, its edge is sealed-in with the central orifice of the valve seat, a rubber film is on the wafer, its surrounding is sealed-in with the wafer, a cover with an air gate at the center is set on the rubber film and downward center is set at the air gate, the peak of the center is in a gap with the film.

Description

Safety valve for lithium ion cell

(1) technical field

The present invention relates to a kind of air valve.Be mounted in the safety valve for lithium ion cell of lithium-ion battery shell oral area specifically.

(2) background technology

As everyone knows, lithium ion battery short circuit in use occurs, overcharges, cross when situation such as putting, and can cause electric current out of control, thereby battery temperature is raise.When temperature was elevated to certain altitude such as 75～95 ℃, the material of inside battery such as electrolyte etc. can decompose, produce gas.Along with the pressure rising of gas, can make battery container expand, be out of shape.When serious, also can make the battery container explosion.Therefore, no matter be the aluminum hull lithium ion battery or the lithium ion battery of stainless steel casing, its oral area all is equipped with safety valve, to be used to avoid the generation of the problems referred to above.At present, used safety valve mainly contains following two kinds of forms on the lithium ion battery.

A kind of is thin slice disengaged safety valve.The positive wire of this thin slice disengaged safety valve is welded on the positive plate of battery, and is in contact with one another with positive terminal on the metal top cover, constitutes electric channel.When inside battery air pressure increased, the cell cover bulging that makes progress broke away from positive wire and positive terminal, thereby cuts off electric channel, plays the safeguard protection effect.But, can only hour play a protective role in interior pressure because the gas of inside battery fails to get rid of.When the excessive or interior pressure of interior pressure increases suddenly, still can lead to the housing bursting accident.Therefore, the safety valve of this form can only be used on the low capacity lithium ion battery, and in can not being used in, on the jumbo lithium ion battery, the scope of application is restricted.

Another kind is the indentation that has certain depth in the metal shell Surface Machining of battery.After the interior pressure of battery container increased, and makes housing expand into to a certain degree, indentation can break automatically, prevents the generation of housing bursting accident with this.Though adopt the mode of processing indentation on metal shell, can prevent the battery container bursting accident.But higher to requirement on machining accuracy, because the degree of depth of indentation is difficult to accurate control,, all do not have the safeguard protection effect no matter be too shallow or too dark, be difficult to guarantee its action message.Therefore, the reliability of this mode is relatively poor.

(3) summary of the invention

The technical problem to be solved in the present invention provides a kind of safety valve for lithium ion cell.Adopt this safety valve for lithium ion cell, can avoid the housing explosion of lithium ion battery, reliability is better.

For addressing the above problem, the present invention takes following technical scheme:

Safety valve for lithium ion cell of the present invention comprises cell cover, is characterized in that there are valve seat, the two phase sealing-in in the cell cover middle part.Centre bore is arranged on the valve seat, and the epimere diameter of centre bore is greater than its hypomere, so that form ring-shaped step therebetween.Be disposed with valve plug, spring and compressing tablet in the centre bore on the ring-shaped step from bottom to top, the upper and lower side of spring withstands on respectively on compressing tablet and the valve plug.Centre bore is also arranged, the centre bore oral area sealing-in mutually of its edge and valve seat upper end on the compressing tablet. rubber film is arranged on the compressing tablet, around this rubber film with compressing tablet sealing-in mutually.Valve gap is arranged on the rubber film, and there is venthole at the valve gap center, the venthole place be provided with down stretch top.Said stretching between top tip and rubber film down left spacing.

Take such scheme, have the following advantages:

Because safety valve for lithium ion cell of the present invention, there are valve seat, the two phase sealing-in in its cell cover middle part.Centre bore is arranged on the valve seat, and the epimere diameter of centre bore is greater than its hypomere, so that form ring-shaped step therebetween.Be disposed with valve plug, spring and compressing tablet in the centre bore on the ring-shaped step from bottom to top, the upper and lower side of spring withstands on respectively on compressing tablet and the valve plug.Centre bore is also arranged, the centre bore oral area sealing-in mutually of its edge and valve seat upper end on the compressing tablet.Rubber film is arranged on the compressing tablet, this rubber film around with compressing tablet sealing-in mutually.Valve gap is arranged on the rubber film, and there is venthole at the valve gap center, and the venthole place is provided with down stretches toply, and this time stretched between top tip and rubber film and left spacing.

When the gas pressure in the battery container was low, valve plug returned automatically and opens, and the air pressure in the battery container is alleviated, and had both played the safeguard protection effect, can not make battery failure again.When the gas pressure in the battery container further raises, can force rubber film upwards heave and withstand on down stretch top on.Stretch toply when poking rubber film when pressure is elevated to be enough to make down, the high pressure gas in the battery container is known from experience from the venthole at valve gap center and is discharged.Thereby avoided the generation of battery container bursting accident, both safety was reliable again.

(4) description of drawings

Fig. 1 is a safety valve for lithium ion cell structural representation of the present invention;

Fig. 2 is the safety valve for lithium ion cell structural representation of the present invention of another kind of form.

(5) embodiment

As shown in Figure 1 and Figure 2, safety valve for lithium ion cell of the present invention comprises cell cover 14, and the sealing shape is connected between the oral area of cell cover 14 and battery cell body 15, and its middle part is provided with

valve seat

18, and 14 of this valve seat and cell covers are and seal shape and link together.Said valve seat 18 is cylindric, is processed with centre bore 10 on it.Centre bore 10 epimere diameters on the valve seat 18 are greater than its hypomere, so that form ring-shaped step 19 on the sidewall within it.That section centre bore 10 length under the ring-shaped step 19 are shorter, and that section centre bore 10 length on the ring-shaped step 19 are longer.On ring-shaped step 19, be disposed with valve plug 3, spring 5 and compressing tablet 13 according to from bottom to top order.Valve plug 3 wherein, both spherical valve plug can be conical valve plug also, depends on the needs.The upper and lower end of said spring 5 withstands on respectively on the lower surface and valve plug 3 of compressing tablet 13.Sealing-in mutually between centre bore 10 oral areas of compressing tablet 13 edges and valve seat 18 upper ends, its sealing-in mode is a processing shallow annular groove 16 on valve seat 18 upper surfaces around centre bore 10 oral areas, and in this shallow annular groove, sealing ring 4 is set, realize sealing-in mutually between centre bore 10 oral areas of compressing tablet 13 edges and valve seat 18 upper ends with this.

For improving

valve plug

3 and 10 times intersegmental sealing effectivenesss of valve seat 18 centre bores, on the ring-shaped step 19 on valve seat 18 centre bores 10 madial walls, a valve pad 2 is set.Said valve pad 2 is a rubber mount, also is processed with centre bore on it, and the upper end of this centre bore is a back taper, matches with spherical valve plug or conical valve plug with convenient.

Said compressing tablet 13 is a sheet metal, also is processed with centre bore on it.The periphery of centre bore is processed into down convex edge 7, and spring 5 upper ends are trapped among the outside of this time convex edge.

Be provided with rubber film 11 on the compressing tablet 13, valve gap 12 is arranged on the rubber film 11.Valve gap 12 caping lower surface centers wherein be equipped with down stretch top 8, this time stretch top tip over against rubber film 11 and and 11 of rubber films leave the gap.Stretch down on valve gap 12 caping around top 8 and be processed with two ventholes 6.

Be processed with pit 9 in the middle of the lower surface of valve gap 12, stretch top 8 down and be fixed on center at the bottom of the hole of pit 9.Said venthole 6 is opened at the bottom of the hole of stretching down around top 8.

See Fig. 1, be processed with the dark groove 17 of annular on the upper surface of valve seat 18, pit 9 holes of valve gap 12 are processed with annular lower convex platform 1 along the outside.The height of the dark groove 17 of said annular is greater than the height of annular lower convex platform 1.Be processed with internal thread on the lateral wall of the dark groove 17 of annular, be processed with external screw thread on the annular lower convex platform 1, the two is screwed together by this internal and external screw thread, and makes between dark groove 17 madial walls of annular and annular lower convex platform 1 madial wall and leave the gap.

As shown in Figure 2, valve seat 18 is connected with 12 of valve gaps, can also be in the following ways promptly at the annular lower convex platform 1 inboard machining internal thread of valve gap 12 bottoms, threading on valve seat 18 cylindricals, the two is screwed together by this internal and external screw thread.Annular lower convex platform 1 outside threading in valve gap 12 bottoms, configuration fastening screw nut 21 on annular lower convex platform 1.And around the top of valve gap 12, process radially outer lug boss 20.During assembling, cell cover 14 can be clamped in radially between the outer lug boss 20 and fastening screw nut 21 by fastening screw nut 21.And on outer lug boss 20 lower surfaces radially processing one annular seal groove, the embedded sealing ring 4 of annular seal groove is realized sealing between valve gap 12 and the cell cover 14 with this.

Claims

1. safety valve for lithium ion cell comprises cell cover (14), it is characterized in that there is valve seat (18) at cell cover (14) middle part, and the two is the sealing shape and links together; Centre bore (10) is arranged on the valve seat (18), and the epimere diameter of centre bore (10) is greater than its hypomere, so that form ring-shaped step (19) therebetween; Be disposed with valve plug (3), spring (5) and compressing tablet (13) in the centre bore (10) on the ring-shaped step (19) from bottom to top, the upper and lower end of spring (5) withstands on respectively on compressing tablet (13) and the valve plug (3); Compressing tablet also has centre bore on (13), and centre bore (10) oral area of its edge and valve seat (18) upper end is sealed; Rubber film (11) is arranged on the compressing tablet (13), this rubber film around with compressing tablet (13) sealing-in mutually; Valve gap (12) is arranged on the rubber film (11), and there is venthole (6) at valve gap (12) center, and venthole (6) is located to be provided with down and stretched top (8); Leave spacing between said tip of stretching down top (8) and rubber film (11).

2. safety valve for lithium ion cell according to claim 1 is characterized in that ring-shaped step (19) located valve pad (2), and valve pad has centre bore on (2); The back taper of the epimere of this centre bore for ease of cooperating with valve plug (3).

3. safety valve for lithium ion cell according to claim 1 is characterized in that the centre bore oral area of valve seat (18) upper surface has shallow annular groove (16) all around, and shallow annular groove (16) is embedded with sealing ring (4).

4. safety valve for lithium ion cell according to claim 1 is characterized in that said valve plug (3) is spherical valve plug.

5. safety valve for lithium ion cell according to claim 1 is characterized in that said valve plug (3) is conical valve plug.

6. safety valve for lithium ion cell according to claim 1 is characterized in that in the middle of the lower surface of valve gap (12) pit (9) being arranged, and stretches top (8) down and is fixed on center at the bottom of the hole of pit (9); On said venthole (6) is opened at the bottom of stretching top (8) hole on every side down.

7. safety valve for lithium ion cell according to claim 6, pit (9) hole that it is characterized in that valve gap (12) lower surface along on the shallow annular groove is arranged, there is annular convex platform at the upper surface edge of said rubber film (11), and this annular convex platform embeds the hole along in the last shallow annular groove.

8. according to the described safety valve for lithium ion cell of arbitrary claim in the claim 1～7, it is characterized in that stretching top (8) for conical under said.

9. safety valve for lithium ion cell according to claim 7 is characterized in that there is the dark groove (17) of annular in shallow annular groove (16) outside on valve seat (18) upper surface, annular lower convex platform (1) is arranged below the valve gap (12); The width of the dark groove (17) of annular is greater than the height of annular lower convex platform (1), on the lateral wall of the dark groove (17) of annular internal thread is arranged, on the annular lower convex platform (1) external screw thread is arranged, the two is screwed together by this internal and external screw thread, and makes between the madial wall of the madial wall of the dark groove (17) of annular and annular lower convex platform (1) and leave the gap.

10. safety valve for lithium ion cell according to claim 7, annular lower convex platform (1) is arranged at the bottom that it is characterized in that valve gap (12), there is internal thread annular lower convex platform (1) inboard, on valve seat (18) cylindrical external screw thread is arranged, and the two is screwed together by this internal and external screw thread; There is external screw thread in annular lower convex platform (1) outside of valve gap (12) bottom, is furnished with fastening screw nut (21) on the annular lower convex platform (1); Radially outer lug boss (20) is arranged around the top of valve gap (12), during assembling, cell cover (14) can be clamped in radially between the outer lug boss (20) and fastening screw nut (21) by fastening screw nut (21); On said radially outer lug boss (20) lower surface annular seal groove is arranged, annular seal groove is embedded with sealing ring (4).