DE102012219389A1 - Battery for use in motor car, has signal transmitter arranged in region of pressure-sensitive membrane, and electrical switching elements operatively connected with transmitter and formed to disconnect main electric current of battery - Google Patents

Abstract

The battery has one or multiple galvanic cells (Zx) i.e. lithium ion cells, arranged within a cell casing (107). A pressure-sensitive membrane (100) is formed as a part of the casing and deforms based on a difference in pressure (101) between an inner side (104) of the casing and an outer side (105) of the casing. A signal transmitter is arranged in a region of the membrane. One or multiple electrical switching elements e.g. relays or pyrotechnic switches, are operatively connected with the signal transmitter and formed to disconnect main electric current of the battery. The signal transmitter comprises a mechanical lever (103), an electrical contact element (106) and an electrical connection pole (Sx).

Description

The present invention relates to a battery and a motor vehicle, connected to the battery according to the invention, wherein the battery comprises at least one galvanic cell, which is arranged within a cell housing, and a pressure-sensitive membrane.

State of the art

A gas-tight lithium battery cell may, under certain circumstances, for example in the event of overcharging, overloading or even during a deep discharge, release gases which, if appropriate, generate high pressure inside the cell housing. In order to prevent further pressure increase and thus possible destruction of the battery cell to the so-called "thermal runaway", thermal death, a "overcharge protection" is integrated into the gas-tight lithium battery cell. This includes a metallic thin plate, which changes its shape at overpressure and creates a short circuit between the electrical poles of the cell. The short-circuit current activates an in-cell fuse to interrupt the current, thus avoiding the continuation of current flow. As a result, an intrinsically safe state of the cell is brought about in a first approximation.

DE 10 2011 053 701 A1 discloses an arrangement of lithium-ion polymer cells to avoid the risk of fire and / or explosion in the event of overcharge, over-discharge or mechanical damage, as well as an increase in temperature and pressure.

DE 10 2008 059 958 A1 discloses a protective device that protects a lithium-ion battery cell from malfunctioning of an elevated temperature and an increased internal pressure.

DE 30 39 809 A1 discloses an apparatus to improve the safety due to an inflation of the cell volume of a round cell due to gas evolution.

Disclosure of the invention

According to the invention, there is provided a battery comprising at least one galvanic cell disposed within a cell casing, the battery comprising a pressure sensitive membrane formed as part of the cell casing, and the membrane being configured to move in response to a pressure difference deforming the inside of the cell housing and the outside of the cell housing, and the battery comprises a signal transmitter which is arranged in the region of the membrane, wherein the battery has at least one electrical switching element which is operatively connected to the signal generator and forms a main electrical current of the battery to separate.

Preferably, each cell is arranged in each case a cell housing, each with at least one membrane and at least one signal generator, wherein in the context of the invention, the signal generator does not switch a main stream, so preferably can not be traversed by a main stream, but only generates a switching signal, which a switch, a relay, a pyro switch or a fuse, preferably located outside of the cell housing and preferably a multiple cell flowing through main current switching, is performed to activate the switch, the relay, the pyro switch or the fuse for separating the main current. Each module preferably has in each case one signal transmitter and at least one switching element for separating the main current. Preferably, a module has more than one switching element for separating the main current in order to be able to separate the electrical poles from a voltage and a current on both sides.

In a further preferred variant, each cell has a signal transmitter, which is routed through a line bus structure across modules to at least one switching element, more preferably to two switching elements for separating the main current of the module arrangement or the battery, on both sides of a voltage to the electrical poles of the battery and to be able to separate a current.

The invention has the advantage that in the event of damage, the battery cell is put into a harmless state and a short circuit to the overloaded cell, which would cause a flow of current for other cells, is avoided. Thus, further cells are protected against misuse. Also, to deactivate the overloaded cell, a high short-circuit current with a resulting interruption of an internal fuse is no longer necessary. This protects the overloaded cell from further stress and a so-called "thermal runaway". Likewise, the invention protects against a forcibly strong arc on a fuse, since no longer necessarily a short-circuit current is switched, which leads to the disconnection of the fuse. Thus, also the possibility of melting of the cell housing and the possibility of a fire of the electrolyte is avoided. It is also avoided by the invention that, as a result of a short circuit at the system level, which leads to the separation of the cell fuse, a high reverse voltage, "reverse polarity" caused by the other cells occurs. This also creates the possibility of dangerous levels avoided electrochemical reactions on the deactivated cell.

In a preferred embodiment, the electrical switching element is a relay.

One advantage is the possibility of protecting the entire module or the entire system in the event of damage in a cell, for example by interrupting the conductive connection to an external consumer or to a charger.

Preferably, the electrical switching element is a pyrotechnic switch.

A resulting advantage is that the entire battery pack is thus electrically separable and the possibility of further damage by external influences is avoided.

Preferably, a plurality of pressure-sensitive membranes are arranged in and / or on the cell housing and associated with each cell a plurality of signal generators in order to detect a plurality of pressure differences can.

The advantage is that a multi-level warning system with early detection and a multi-level system response can be installed.

In a particularly preferred variant, the signal transmitter has an element for measuring an electrical voltage of the galvanic cell.

The advantage of this is that an intrinsically safe state of the overall system can be brought about quickly and in a timely manner.

It is preferred that the galvanic cell is a lithium-ion cell.

The advantage is that lithium is well and cheap available as a resource.

Preferably, the signal generator can be arranged on a cover of the galvanic cell.

An advantage achieved thereby is a reduced susceptibility to errors due to the shortest possible route.

As an additional variant, two switching elements are connected to two terminal terminals of the battery and configured to disconnect a voltage of the battery from both terminal terminals.

An advantage here is also an electrical isolation, as in particular a two-sided electrical isolation takes place and thus both contacts / terminals are switched off current and voltage.

Furthermore, it is preferred that the connection of a first signal output of the first signal generator to a second signal output of the second signal generator has a line bus structure.

An advantage achieved thereby shortening of the cable routes and thus an improved reliability.

With regard to a further aspect of the invention, a motor vehicle with a battery according to one of the aforementioned features is disclosed, wherein the motor vehicle is electrically and mechanically connected to the battery.

Advantage is a use of the battery according to the invention in a motor vehicle, in particular, the improved safety is of importance.

According to a preferred variant of the invention, a battery is provided which comprises at least one galvanic cell enclosed in a respective cell housing and a pressure-sensitive membrane in the cell housing, which is formed to at least a discrete amount of a pressure difference of at least a discrete extent reacting a deformation, and comprises a signal generator in the effective range of deformation of the membrane, wherein the battery has at least one electrical switching element, which is operatively connected to the signal generator and adapted to separate a main electrical current of the battery.

It is also possible that the membrane is connected to a strain gauge or other element suitable for detecting a different degree of deformation of the membrane, whereby a continuous or finely quantized value range of the membrane bending can be detected. In this case, the strain gauge is a signal generator. The electronics for the strain gauge is another signal generator.

Preferably, the housing of the cells are formed gas-tight, so that a fluid from the interior of the housing can take place only from an exceeding of a certain housing internal overpressure by means of preferably in the housing wall integrated pressure relief valves or Burstöffnungen. Preferably, each cell has a membrane and a signal generator, which each detects the different deflections of the membrane and is able to distinguish with respect to the signal variety.

drawings

Embodiments of the invention will be explained in more detail with reference to the drawings and the description below. Show it:

1 a two-dimensional schematic representation of a galvanic lithium-ion element with an inventive overpressure membrane according to a preferred embodiment, and

2 a two-dimensional schematic representation of a preferred embodiment of the battery according to the invention with a pyrotechnic switch.

1 shows a two-dimensional schematic representation of a preferred embodiment of a galvanic lithium-ion element Zx, which is also referred to as "cell Zx". Where "x" is a contiguous index indicating that in the preferred embodiment, a plurality of cells Zx are stacked.

On one in a cell cover 102 integrated metallic, electrically conductive overpressure membrane 100 works from an inside 104 of the cell case 107 an internal pressure and from an outside 105 of the cell case 107 an external pressure. A pressure difference between internal pressure and external pressure provides as overpressure 101 on the membrane 100 a deformation work, so that the membrane 100 at overpressure 101 bulges. The orientation of the curvature depends on whether the housing interior 104 an overpressure, with the membrane 100 bulges outward, or a vacuum, leaving the diaphragm 100 bulges inward, has.

According to the invention is in the effective range of the curvature of the membrane 100 a movable element, preferably a mechanical lever 103 , which is activated as a result of a change in the membrane curvature, and subsequently on the outside of the cell lid 102 arranged electrical switching element Sx activated. The effective range of the curvature is an area which is between a maximum inner curvature and a maximum outer curvature of the membrane 100 located. Preferably, the curvature of the membrane 100 Within two specific limits with respect to an inner and an outer curvature elastic and thus reversible deformation.

In the case of an arrangement of several membranes 100 In the case of a cell Zx, by varying the membrane thicknesses, different deflection intensities can be achieved, each with a specific overpressure.

In this case, "x" is a continuous index, which indicates that in the preferred variant, a plurality of switching elements Sx in the region of an overpressure membrane 100 are arranged such that the vaulting-dependent switching thresholds of the switching elements Sx differ from each other.

The inventive illustration of several bulges of the overpressure membrane 100 On various electrical switching states can be a variety of strengths of the overpressure 101 be logically coupled with a variety of events. An event for a preferably strongest overpressure to register 101 For example, could be the electrical separation of the poles of the galvanic element Zx or activation of a cell fuse, preferably a pyrotechnic fuse.

It is also possible that the plurality of stacked cells Zx each have at least one switching element Sx, wherein the switching elements Sx are electrically connected to one another.

An event for, for example, the weakest overprint to register 101 For example, it could be the triggering of a warning message or the activation of a system reaction.

In a preferred embodiment of the invention, the element Sx is not used as a switch, but as an electrical connection and as a mechanical support for an electrically conductive and mechanically elastic flexible designed lever 103 , which is electrically and mechanically connected to the holder Sx. At a remote from the bracket end of the lever 103 there is an electrical contact element 106 , In case of an internal overpressure 101 bulges the electrically conductive membrane 100 in the direction of the contact element 106 and stops at a certain overpressure 101 an electrical contact between the membrane 100 and the contact element 106 ago.

2 shows a two-dimensional schematic representation of a preferred embodiment of the battery according to the invention, which has a plurality of stacked galvanic cells Zx, where "x" is a continuous index and also includes the respective numerical index of the cells Z1, Z2 and Z3.

For each cell Zx, there is preferably at least one respectively corresponding switching element Sx, which is provided by a respective predefined strength of an internal overpressure 101 is activated.

In a preferred embodiment of the invention, the element Sx is not used as a switch, but as an electrical connection and as a mechanical Holder for an electrically conductive and mechanically elastic flexible designed lever 103 , which is electrically and mechanically connected to the holder Sx. An advantage achieved thereby is a simplified routing, since in this case the electrical connection poles S1, S2, S3 and Sx can be electrically connected in parallel and thus can be guided by the shortest route from one cell Z1 to the next cell Z2.

In case of overpressure 101 becomes due to a curvature of the membrane 100 an electrical switching operation in the area of the cell cover 102 activated, which performs a separation of the entire battery pack, the stacked cells Zx, from a consumer or a charger. The separation from the load or the charger is carried out for example by means of a first interrupt relay R1 and preferably by means of a second interrupt relay R2 in order to carry out an electrical separation of both poles.

A preferred embodiment, as an alternative to the interrupting relays R1 and R2, comprises pyrotechnic switches or pyrotechnic fuses, also called pyro-fuses. These have the advantage of being able to separate high currents reliably and quickly by means of an electrochemical reaction, without requiring logical electronic components (active components).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011053701 A1 [0003]
• DE 102008059958 A1 [0004]
• DE 3039809 A1 [0005]

Claims (10)

Battery ( 200 ) comprising: (i) at least one galvanic cell (Zx) disposed within a cell casing (Z); 107 ) is arranged; (ii) a pressure-sensitive membrane ( 100 ), which as part of the cell housing ( 107 ), wherein the membrane ( 100 ) is formed, depending on a pressure difference ( 101 ) between the inside ( 104 ) of the cell housing ( 107 ) and the outside ( 105 ) of the cell housing ( 107 ) to deform; and (iii) a signaling device ( 103 . 106 , S1, S2, S3, Sx), which in the region of the membrane ( 100 ), characterized in that (iv) the battery ( 200 ) has at least one electrical switching element (R1, R2), which is connected to the signal transmitter ( 103 . 106 , S1, S2, S3, Sx) and is designed to generate a main electrical current of the battery ( 200 ) to separate. Battery ( 200 ) according to claim 1, wherein the electrical switching element (R1, R2) is a relay. Battery ( 200 ) according to one of the preceding claims, wherein the electrical switching element (R1, R2) is a pyrotechnic switch. Battery ( 200 ) according to any one of the preceding claims, wherein a plurality of pressure-sensitive membranes ( 100 ) in and / or on the cell housing ( 107 ) and a plurality of signalers ( 103 . 106 , S1, S2, S3, Sx) of each cell (Zx) is assigned to a plurality of pressure differences ( 101 ) to detect. Battery ( 200 ) according to one of the preceding claims, wherein the signal generator ( 103 . 106 , S1, S2, S3, Sx) has an element for measuring an electrical voltage of the galvanic cell (Zx). Battery ( 200 ) according to one of the preceding claims, wherein the galvanic cell (Zx) is a lithium-ion cell. Battery ( 200 ) according to one of the preceding claims, wherein the signal generator ( 103 . 106 , S1, S2, S3, Sx) is arranged on a cover of the galvanic cell (Zx). Battery ( 200 ) according to one of the preceding claims, wherein two switching elements (R1, R2) with two terminal terminals of the battery ( 200 ) are connected and formed, an electrical voltage of the battery ( 200 ) from both connection terminals. Battery ( 200 ) according to one of the preceding claims, wherein the connection of a first signal output of the first signal generator ( 103 . 106 , S1, S2, S3, Sx) with a second signal output of the second signal generator ( 103 . 106 , S1, S2, S3, Sx) has a line bus structure. Motor vehicle with the battery ( 200 ) according to one of the preceding claims, wherein the motor vehicle with the battery ( 200 ) is electrically and mechanically connected.

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