DE102013016668A1 - Device for reducing the internal pressure in a battery case - Google Patents

Abstract

The invention relates to a device (1) for reducing the internal pressure in a battery housing (2). According to the invention, the device (1) comprises at least one valve body (3) and at least one spring element (4), the valve body (3) being counterbalanced by a rise in the internal pressure in the battery housing (2) against a spring force of the spring element (4) from an opening (FIG. 5) in the battery housing (2) closing position in a the opening (5) releasing position is movable and at a decrease in the internal pressure in the battery case (2) by the spring element (4) in which the opening (5) closing position is movable, wherein the spring element (4) has at least one first region (B1) and at least one second region (B2), wherein the first region (B1) of the spring element (4) is connected to the valve body (3) and wherein the second region (B2) of the spring element (4) on an inner side (2.2) of the battery case (2) is applied such that it in a movement of the valve body (3) of the opening (5) in the battery case (2) closing position in di e the position (5) releasing position in the direction of the opening (5) is movable until it rests against a holding element (9) of the battery case (2).

Description

The invention relates to a device for reducing the internal pressure in a battery housing according to the features of the preamble of claim 1.

Batteries are generally known from the prior art which comprise a plurality of individual cells electrically connected in series and / or in parallel with one another, ie. H. electrochemical energy storage units, which are arranged in a battery housing. Such batteries are for example designed as traction batteries of at least partially electrically operated vehicles.

The invention is based on the object to provide an improved device for reducing the internal pressure in a battery case.

The object is achieved by a device for reducing the internal pressure in a battery housing with the features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

A device for reducing the internal pressure in a battery housing according to the invention comprises at least one valve body and at least one spring element, wherein the valve body is movable by an increase of the internal pressure in the battery housing against a spring force of the spring element from a opening in the battery housing closing position in a position releasing the opening and at a decrease in the internal pressure in the battery housing by the spring element in the position closing the opening is movable, wherein the spring element has at least a first region and at least a second region, wherein the first region of the spring element is connected to the valve body and wherein the second region the spring element abuts on an inner side of the battery housing in such a way that, in the event of a movement of the valve body, it can move from the position closing the opening in the battery housing into the opening-releasing position in direction g of the opening is movable until it rests against a holding element of the battery case.

The valve body, which forms a closure unit for closing the opening, can in particular close the opening in the battery housing from the outside and support itself on the battery housing via the spring element. It is clamped by the preset spring force with the battery case and keeps the opening fluid-tight closed so that, for example, neither air nor water or dust can penetrate into the battery case. At a pressure increase in the interior of the battery case, which acts on the valve body, the opening opens by lifting the valve body in response to the spring stiffness of the spring element. Ie. the opening is made solely by the pressure in the interior of the battery case, which acts on the valve body and counteracts the spring force of the spring element. In this way, in particular, a discharge of gases and / or liquids from the battery housing is made possible, which are caused by defective battery cells. As a result, damage or explosion of the battery case is avoided and allows controlled discharge of these fluids and / or gases from the battery case. When renewed pressure drop, the spring element pulls the valve body back and thus closes the opening again, so that the battery case is again closed fluid-tight.

Due to the inventive design of the device in which the spring element is designed as a so-called drag spring, so that the second region of the spring element is not firmly anchored to the battery housing, but in the movement of the valve body of the opening in the battery housing closing position in the Opening releasing position on the inside of the battery case in the direction of the opening slides until it rests against the holding member of the battery case and is held by this, a relatively narrow, flat design of the spring element allows, which requires a very small space in the interior of the battery case , An opening of the valve body is thus made possible by an elastic deformation of the spring element and in addition by the movement of the second region of the spring element, d. H. by sliding along the second area of the spring element along the inside of the battery housing to the holding element at the opening. In this way, a very wide opening travel of the valve body is made possible by means of this very flat spring element, so that the opening in the battery case is completely released and a large opening cross-section is reached. As a result, a very rapid pressure reduction is ensured inside the battery case, thus avoiding damage or explosion of the battery case due to excessive internal pressure. Since the spring element is designed such that the second region of the spring element rests in any position of the valve body on the inside of the battery case, a secure closing of the opening in the battery housing is ensured by the valve body.

If the second area of the spring element were fastened to the battery housing such that it could not slide along the inside of the battery housing but was fixed in one position, this would be a Such a large opening travel of the valve body is not possible or it would be a spring element required, which rise much stronger in the opening of the battery housing position of the valve body on the inside of the battery case and thus would protrude much further into the interior of the battery case, ie a significant would require larger space inside the battery case to allow the necessary travel solely by the deformation of the spring element

Conveniently, the holding element is formed as a survey on the inside of the battery case, which surrounds the opening at least partially. This survey is for example designed as a covenant or indentation in the direction of the interior of the battery case, d. H. as a projection, on which the second region of the spring element hooks during the opening movement of the valve body and is thereby held. For example, this survey may have a corresponding undercut on which the second region of the spring element can hook safely.

Preferably, the second region of the spring element has at least one hook-shaped formation, which hooks into the position releasing the opening of the valve body in the holding element. This hook-shaped formation is expediently formed corresponding to the survey, so that a secure hooking is possible, for example in an undercut formed by the holding element.

In an advantageous embodiment, the valve body and the spring element are formed independently of each other and connected to each other. This structure with a separation of the partial functions valve body and spring element makes it possible to represent a mechanically very robust solution in which, for example, a correspondingly thick valve body is to be used. Nevertheless, the opening behavior is freely adjustable, because this valve body can be combined, for example, with a soft and thin spring element.

The comparatively free adjustability of the spring stiffness and the geometry of the spring element, together with the inherently very stable valve body, enables a structure which is very stable in itself and which can be set comparatively precisely to a specific opening pressure. The battery case is then safely and reliably sealed up to this pressure and opens at comparatively exact this predetermined pressure. In contrast to prior art constructions, which vary over a larger pressure range from a minimum opening at one end to the opening in the entire area, a much better and more specifically controllable construction can thus be achieved. This is in particular very good to put under a leak test under pressure to check the tightness of the battery case. As long as this pressure is below the triggering pressure, unlike in a construction known from the prior art, there are no leaks due to a valve flap that is already slightly lifted off in a surface area.

In an alternative embodiment, the valve body and the spring element may for example also be integrally formed, for example made of metal or, particularly simple and inexpensive to implement, made of plastic.

Expediently, the spring element has at least two spring arms which are substantially transverse to a central axis of the opening. Preferably, the spring arms are curved and / or wavy, with the curvature and / or curl rising in the opening in the battery housing closing position of the valve body on the inside of the battery case. By the said preferred embodiments of the spring arms and in particular by the formation of the spring element as a drag spring, as already described above, a small design of the valve body can be realized, since the curvature and / or curl of the spring arms substantially less beyond the inside of the battery case in the direction the interior of the battery case rises, as would be required for a spring element, the second region is firmly anchored to the battery case. This is due to a small free or installation space inside a battery case of a battery of particular advantage.

In order to allow a good stabilization of the spring element and arranged on this valve body, in particular during the opening movement of the valve body and thereby a uniform movement of the valve body relative to the battery housing, the spring element preferably has at least three spring arms, which each span an equal angle between them. As a result, the spring arms of the spring element are evenly distributed over the opening in the battery housing, so that the valve body is supported by the spring element uniformly on the battery case.

In an advantageous embodiment, the spring element is formed of metal. This allows a comparatively stable and in particular temperature-stable construction, so that even at elevated temperatures in the battery case or in the vicinity of the battery case, the safety-relevant functionality of the device for reducing the internal pressure in the battery case continue to work safely and reliably. In an alternative embodiment, however, the spring element may for example also be made of plastic. It is then in particular very inexpensive and easy to manufacture.

Preferably, the valve body has a disc-shaped or plate-shaped base body, which is provided with at least one mandrel, wherein the spring element is connected to the mandrel. This structure allows a very simple and efficient construction of the two-part device for closing an opening in the battery case and for reducing the internal pressure at a corresponding overpressure in the battery case. The disk-shaped or plate-shaped base body is correspondingly stable form and is then provided with a mandrel which, for example, centrally or in the case of several mandrels distributed over the surface perpendicularly protrudes from the disk-shaped or planar formation. This mandrel is then, for example, positively, non-positively and / or materially connected to the spring element.

Conveniently, the spring element has at least one bore for the at least one mandrel. This construction, in which either one central or a plurality of holes distributed over the spring element are provided, is particularly simple and efficient. Advantageously, the mandrel is held in the bore via cutting claws integrated into the spring element. Ie. the bore or each of the holes is formed, for example, as a stamped opening so that it has in one direction beyond the main plane of the opening bent out cutting claws. Now, if the mandrel or now the thorns are inserted into the individual holes, then they can be inserted very easily and efficiently in one direction, so that a simple and efficient installation is possible. The cutting claws of the spring element then dig into the mandrel and thus keep the valve body at a load by the internal pressure safely and reliably on the spring element. The structure is particularly simple and efficient. When mounting the spring element is then easy to position inside the battery case to position the valve body from the outside and thereby press the mandrel into the hole. He is to be fixed by the cutting claws there, so that a very simple, efficient and quick installation of the device in the battery case is possible. As an alternative to the cutting claws, other form-fitting, cohesive and / or non-positive attachments of the spring element on the valve body are possible, for example screwing, welding or gluing the spring element to the valve body, advantageously with the mandrel.

Advantageously, the valve body is in the position closing the opening on a valve seat, wherein between the valve seat and the valve body at least one sealing element is arranged. Such a sealing element allows a very good seal against environmental influences such as moisture, water and dust, so that in addition to the pure safety functionality also a very good seal of the battery case at regular internal pressures through the device is possible.

The device allows a simple, safe and reliable internal pressure monitoring of a battery case and can also seal this well against environmental influences such as water and dust. It is therefore particularly suitable for realizing the internal pressure monitoring in a battery housing, which has a plurality of individual battery cells, which form a traction battery of an at least partially electrically driven vehicle. Such a traction battery of a hybrid or electric vehicle must function safely and reliably even under adverse conditions such as vibration, dust, water and other environmental influences. As frequently used battery technology is to call lithium-ion technology, which has correspondingly high safety requirements and thus makes a device for monitoring the internal pressure required, which works safely and reliably and in case of damage after breaking down the internal pressure, the battery case again safe and reliably closes to prevent manipulation and / or accidental contact of persons, accident workers or the like with parts within the battery case. The device is particularly well suited for this purpose.

Embodiments of the invention are explained in more detail below with reference to drawings.

Showing:

1 schematically a sectional view of a device for reducing the internal pressure in a battery case in the closed state,

2 schematically a sectional view of a device for reducing the internal pressure in a battery case in the open state,

3 schematically a spring element in plan view, and

4 schematically a detailed view of a spring element in a perspective view.

Corresponding parts are provided in all figures with the same reference numerals.

The 1 and 2 show schematically a sectional view of a device 1 to reduce the internal pressure in a battery case 2 , wherein the device 1 in 1 in the closed state and in 2 is shown in the open state. From the battery case 2 is in the 1 and 2 for reasons of clarity, only one area is shown, in which the device 1 on the battery case 2 is arranged.

In the battery case 2 For example, a plurality of individual battery cells (not shown in detail here) arranged in series and / or in parallel with one another are arranged, that is to say electrochemical energy storage and / or energy converter units. These in the battery case 2 arranged single battery cells form a battery, such as a traction battery of an at least partially electrically powered vehicle, for example, a hybrid vehicle, electric vehicle or fuel cell vehicle. The individual battery cells of the battery are designed, for example, as lithium-ion single cells or lithium-polymer single cells.

The battery case 2 has, as already mentioned, at least one such device 1 for reducing the internal pressure in the battery case 2 in the event of an unwanted increase in pressure. The device 1 includes, as in the 1 and 2 illustrated, at least one valve body 3 and at least one spring element 4 , The spring element 4 is in the 3 and 4 shown in more detail, wherein 3 the spring element 4 in plan view and shows 4 a detailed view of an embodiment of the spring element 4 in a perspective view shows.

The valve body 3 the device 1 closes, as in 1 shown, an opening 5 in the battery case 2 by placing a on the valve body 3 arranged sealing element 6 in a circumferential area of the opening 5 on an outside 2.1 of the battery case 2 rests. This circumferential area of the opening 5 is also used as a valve seat 7 designated. Ie. in the opening 5 closing position is the valve body 3 which has a closure unit for closing the opening 5 forms, with its sealing element 6 on the valve seat 7 on, wherein the sealing element 6 between the valve seat 7 and the valve body 3 is arranged. Through the sealing element 6 it is ensured that the valve body 3 the opening 5 Closes fluid-tight, so that gases, dust and moisture are not in the interior of the battery case 2 can penetrate.

The valve body 3 consists of a disc-shaped basic body 3.1 as well as a thorn 3.2 , The thorn 3.2 is in the embodiment shown here, in which the main body 3.1 is round and disc-shaped, ideally arranged centrally. He is trained to drill 4.1 of the spring element 4 , what a 3 is shown in more detail to correspond. The hole 4.1 is formed as a punched recess, which is surrounded for example by cutting claws, not shown. The thorn 3.2 has a circumferential groove 8th on, in which the spring element 4 can anchor, for example, by the cutting claws in this groove 8th intervene and get caught up in it. For arranging the valve body 3 is, for example, the thorn 3.2 from the outside through the opening 5 in the battery case 2 pass through and the spring element 4 inside the battery case 2 with its bore 4.1 on the thorn 3.2 defer until it is in the groove 8th of the thorn 3.2 engages, ie until, for example, the cutting claws of the spring element 4 in the groove 8th of the thorn 3.2 snag. This provides a safe and reliable connection between the valve body 3 and the spring element 4 reached.

In the in 1 illustrated closed position hold spring arms 4.2 of the spring element 4 the valve body 3 prestressed on the valve seat 7 pressed to the battery case 2 close tightly. Due to an internal pressure in the battery case 2 , which is so high that it puts a force on the valve body 3 exerts which of the spring element 4 applied forces exceeds, the valve body 3 in the in 2 shown opened position, so that the pressure in the interior of the battery case 2 can degrade.

Ie. the valve body 3 is due to an increase in the internal pressure in the battery case 2 against a spring force of the spring element 4 from one the opening 5 in the battery case 2 closing position in one the opening 5 releasable position movable and a decrease in the internal pressure in the battery case 2 by the spring element 4 back into the opening 5 closing position movable.

The spring element 4 is designed as a so-called drag spring. In the example shown here, it has a first area B1 and three second areas B2. The first area B1 of the spring element 4 includes the hole 4.1 , ie over the first area B1 is the spring element 4 with the valve body 3 connected. The second areas B2 of the spring element 4 are end portions of the three spring arms 4.2 , With these second areas B2 is the spring element 4 so on an inside 2.2 of the battery case 2 that the second areas B2 upon movement of the valve body 3 from the opening 5 in the battery case 2 closing position in the opening 5 releasing position towards the opening 5 move until the second areas B2 on a holding element 9 of the battery case 2 issue.

Ie. the second areas B2 of the spring element 4 are not fixed to the battery case 2 anchored, but slide during the movement of the valve body 3 from the opening 5 in the battery case 2 closing position in the opening 5 releasing position on the inside 2.2 of the battery case 2 in the direction of the opening 5 along until it stops at the retaining element 9 of the battery case 2 and be held by this. As a result, a relatively flat design of the spring element 4 allows, which a very small space inside the battery case 2 requires.

An opening path of the valve body 3 is that way, as in 2 represented by an elastic deformation of the spring element 4 and additionally by the movement of the second regions B2 of the spring element 4 allows, ie by the sliding along the second portions B2 of the spring element 4 along the inside 2.2 of the battery case 2 to the holding element 9 at the opening 5 , In this way is also by means of this very flat spring element 4 a very wide opening path of the valve body 3 allows, so that the opening 5 in the battery case 2 is completely released and a large opening cross section is reached. This is a very rapid pressure reduction inside the battery case 2 ensured and thus damage or explosion of the battery case 2 avoided by excessive internal pressure. Because the spring element 4 is formed such that the second regions B2 of the spring element 4 in any position of the valve body 3 on the inside 2.2 of the battery case 2 abutment, is a safe closing of the opening 5 in the battery case 2 through the valve body 3 ensured.

The holding element 9 is as a survey on the inside 2.2 of the battery case 2 formed, which the opening 5 at least partially bordered. This survey is, for example, as in the 1 and 2 shown as a collar or indentation towards the interior of the battery case 2 formed, ie as a projection, on which the second areas B2 of the spring element 4 during the opening movement of the valve body 3 hook in and are held by it. This survey may for example also have a corresponding, not shown here undercut, on which the second areas B2 of the spring element 4 can safely hook up.

The second areas B2 of the spring element 4 wise, as in 3 and in a detailed view of another embodiment in FIG 4 shown, two hook-shaped formations 10 on which in the the opening 5 releasing position of the valve body 3 in the holding element 9 hook in, so that the spring element 4 safe on the retaining element 9 anchored and against slipping out of the opening 5 is secured. The hook-shaped formations 10 are expediently oriented downwards, ie in the direction of the inside 2.2 of the battery case 2 ,

The valve body 3 and the spring element 4 are, as already described, formed independently of each other and interconnected. This structure with a separation of the partial functions valve body 3 and spring element 4 allows to represent a mechanically very robust solution in which, for example, a correspondingly thick valve body 3 is to use. Nevertheless, the opening behavior is freely adjustable because of this valve body 3 for example, with a soft and thin spring element 4 can be combined.

The comparatively free adjustability of the spring stiffness and the geometry of the spring element 4 allows together with the very stable valve body 3 a very stable in itself structure, which is relatively precisely adjustable to a certain opening pressure. The battery case 2 is then safely and reliably sealed up to this pressure and opens at comparatively exact this predetermined pressure. In contrast to constructions of the prior art, a much better and more specifically controllable structure can thus be achieved. This is particularly good to put under pressure in a leak test to the tightness of the battery case 2 to consider. As long as this pressure is below the triggering pressure, unlike in a construction known from the prior art, there are no leaks due to a valve flap which is already slightly lifted off in a surface area.

The spring element 4 can be formed in particular from a metallic material. Due to the geometric design and spring stiffness of the material is the characteristic of the spring arms 4.2 influenced over long distances. This allows a comparatively exact response of the device 1 realize so that it safely and reliably triggers at a corresponding internal pressure, but at pressures below this internal pressure safely and reliably the opening 5 closes. By the construction with valve body 3 and separately formed spring element 4 , which in particular integrally the spring arms 4.2 has a high security and variability is achieved because a comparatively soft spring element 4 with a comparatively stable valve body 3 can be combined.

As in 3 shown, the spring element 4 three from the central axis of the opening 5 of the battery case 2 outgoing spring arms 4.2 on, with their end portions, which are the second areas B2 of the spring element 4 form, on the inside 2.2 of the battery case 2 abutment and in the open position of the valve body 3 on the holding element 9 issue. The spring arms 4 are designed and positioned so that they each span an equal angle, with three spring arms 4.2 each an angle of 120 °. Ie. they are over a perimeter of opening 5 evenly distributed, leaving the valve body 3 by the spring element 4 evenly on the battery case 2 is supported. This is a tilting and tilting of the valve body 3 avoided, leaving the valve body 3 always in a parallel orientation to the outside 2.1 of the battery case 2 is held and guided, and in particular during a closing movement safely completely sealed on the battery case 2 is created. In further, not shown embodiments, the spring element 4 alternatively also more than three spring arms 4.2 or for example as a bell-shaped spring element 4 be formed, the second area 2 closed ring is formed.

The spring arms 4.2 are upwards, ie towards the inside of the battery case 2 arched or wavy formed and rise above the inner wall surface, d. h over the inside 2.2 of the battery case 2 so that the spring arms 4.2 of the spring element 4 have a sufficient spring travel, by their elastic deformation, in addition to the movement of the second regions B2 in the direction of the opening 5 , a sufficient opening travel of the valve body 3 to enable. Due to this design of the spring element 4 as a drag spring, allowing a combination of movement of the spring arms 4.2 with its second areas B2 in the direction of the opening 5 and elastic deformation of the spring arms 4.2 the opening stroke of the valve body 3 forms is at the largest possible axial opening width of the valve body 3 the smallest possible axial design of the spring element 4 and the valve body 3 and thus the entire device 1 realized. This is particularly advantageous because of the aim of minimizing the space required for a battery.

LIST OF REFERENCE NUMBERS

1

contraption

2

battery case

2.1

outside

2.2

inside

3

valve body

3.1

body

3.2

mandrel

4

spring element

4.1

drilling

4.2

spring arm

5

opening

6

sealing element

7

valve seat

8th

groove

9

retaining element

10

hook-shaped shape

B1

first area

B2

second area

Claims (10)

Contraption ( 1 ) for reducing the internal pressure in a battery case ( 2 ), characterized by at least one valve body ( 3 ) and at least one spring element ( 4 ), wherein the valve body ( 3 ) by an increase in the internal pressure in the battery case ( 2 ) against a spring force of the spring element ( 4 ) from an opening ( 5 ) in the battery case ( 2 ) closing position in an opening ( 5 ) releasable position is movable and a decrease in the internal pressure in the battery housing ( 2 ) by the spring element ( 4 ) into which the opening ( 5 ) closing position is movable, wherein the spring element ( 4 ) has at least one first region (B1) and at least one second region (B2), wherein the first region (B1) of the spring element (B1) 4 ) with the valve body ( 3 ) and wherein the second region (B2) of the spring element ( 4 ) on an inside ( 2.2 ) of the battery case ( 2 ) is applied in such a way that upon movement of the valve body ( 3 ) from the opening ( 5 ) in the battery case ( 2 ) closing position in which the opening ( 5 ) releasing position in the direction of the opening ( 5 ) is movable until it is attached to a holding element ( 9 ) of the battery case ( 2 ) is present. Contraption ( 1 ) according to claim 1, characterized in that the retaining element ( 9 ) as a survey on the inside ( 22 ) of the battery case ( 2 ) is formed, which the opening ( 5 ) bordered at least partially. Contraption ( 1 ) according to claim 1 or 2, characterized in that the second region (B2) of the spring element ( 4 ) at least one hook-shaped formation ( 10 ), in which the opening ( 5 ) releasing position of the valve body ( 3 ) in the holding element ( 9 ). Contraption ( 1 ) according to one of claims 1 to 3, characterized in that the valve body ( 3 ) and the spring element ( 4 ) are formed independently of each other and interconnected. Contraption ( 1 ) according to one of the preceding claims, characterized in that the spring element ( 4 ) at least two substantially transverse to a central axis of the opening ( 5 ) standing spring arms ( 4.2 ) having. Contraption ( 1 ) according to claim 5, characterized in that the spring arms ( 4.2 ) are curved and / or wavy, wherein the curvature and / or curl in the opening ( 5 ) in the battery case ( 2 ) closing position of the valve body ( 3 ) over the inside ( 2.2 ) of the battery case ( 2 ) raises. Contraption ( 1 ) according to one of the preceding claims, characterized in that the valve body ( 3 ) a disk-shaped or plate-shaped basic body ( 3.1 ), which with at least one mandrel ( 3.2 ), wherein the spring element ( 4 ) with the thorn ( 3.2 ) connected is. Contraption ( 1 ) according to claim 7, characterized in that the spring element ( 4 ) at least one bore ( 4.1 ) for the at least one mandrel ( 3.2 ) having. Contraption ( 1 ) according to one of the preceding claims, characterized in that the valve body ( 3 ) in which the opening ( 5 ) closing position on a valve seat ( 7 ), wherein between the valve seat ( 7 ) and the valve body ( 3 ) at least one sealing element ( 6 ) is arranged. Use of a device ( 1 ) according to one of claims 1 to 9 for internal pressure monitoring of a battery case ( 2 ) comprising a plurality of battery cells forming a traction battery of an at least partially electrically powered vehicle.

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