DE102021128831A1 - Electrical energy store and arrangement for generating a cell-internal short circuit of an electrical energy store - Google Patents

Abstract

An electrical energy store (10) and an arrangement (1) for generating a cell-internal short circuit of an electrical energy store (10) are proposed. The arrangement (1) comprises: an energy supply (3) and a penetrator (4) coupled to the energy supply (3), the energy supply (3) being set up to produce the cell-internal short-circuit in response to a trigger signal, the penetrator (4). to move.

Description

The present invention relates to an electrical energy storage device and an arrangement for generating a cell-internal short circuit of an electrical or electrochemical energy storage device. In particular, the present invention relates to a test setup for realistically simulating the effect of a cell-internal short circuit in an electrical energy store or a storage cell.

The electrification of individual passenger transport is currently progressing rapidly. One approach to keeping electrical energy available in the means of transport is to store it electrochemically, for example in lithium-ion cells or lithium-polymer cells. When protecting the high-voltage battery (HVS), there is often the problem of how a fault pattern occurring in the means of transport can be represented particularly realistically. The most likely fault pattern in a lithium-ion cell in an HVS is a particle between the electrode layers which, over a certain period of time or during charging, punctures the separator (separating layer between the electrodes) and thus causes an internal cell electrical short circuit (ISC). In validation, it is therefore necessary to simulate this cell-internal electrical short circuit in a robust and realistic manner, without provoking further fault patterns mixed with the fault under investigation, so that the influence of the test setup-specific modification is as small as possible. Different mechanisms are used in the prior art to simulate the cell-internal short circuit. A first approach is also referred to as "nail triggering". Here, a nail is inserted or driven from the outside into the accumulator, the electrical conductivity of which short-circuits the penetrated electrodes of the cells with one another. The disadvantage here is the violation of the mechanical integrity of the memory and the cell housing as well as the long way of the nail until the actual penetration of the cells. A second approach is called "rapid heating". Here, the runaway of the cell is thermally triggered. When a critical temperature is exceeded and the ISC is inducted as a result of thermal shrinkage of the separator, adjacent electrodes of different polarity come into contact, which causes the short circuit. For triggering, energy is introduced into the system that is not present in the real error pattern. This externally introduced energy can influence the time behavior of the test and weaken structures of the storage structure, which would (initially) have remained intact in the real error pattern.

In nail triggering, the nail injures several components of the electrical energy storage device by penetrating the HVS: HVS cover, cooler and cell housing. This leads to a reaction that does not correspond 100% to the real error pattern (ISC due to particles) and can therefore cause expenses in the safeguarding and the HVS design that would not be necessary at all to safeguard real error cases.

It is therefore an object of the present invention to provide a realistic test setup for investigating the effects of a cell-internal electrical short (ISC).

This problem is solved by the features of an arrangement according to claim 1 and by an electrical energy store with the features according to claim 5. The subclaims show preferred developments of the invention.

Accordingly, an arrangement for generating a cell-internal short circuit of an electrical or electrochemical energy store is proposed. The arrangement can be understood primarily as a component of a test setup that is not required or not to be used in series production. This does not preclude the arrangement from using components that are in any case located in the electrical energy store. The arrangement includes an energy supply, which can be designed, for example, as a hose line, cylinder, piston, rod, coil, spindle or the like. The energy supply is used to apply energy to a penetrator that is energetically coupled or operatively connected to the energy supply. The energy supply is set up in this way, in response to a trigger signal, to move the penetrator to produce the cell-internal short circuit. In other words, the energy supply is set up to exert a force on the penetrator, which forces it through at least one storage cell within the electrochemical energy store. Here, the penetrator can be accelerated by gas pressure, by a solid-mechanical power transmission or in some other way. Since the energy guide and the penetrator can be arranged within a storage housing of the electrical energy storage device, it is possible to move the penetrator to penetrate the storage cell without piercing the storage housing of the electrical energy storage device. The storage housing can therefore remain intact, as a result of which the subsequent events within the electrical energy storage device are very close to an actual (real) fault. The protection is thus better and the measures to protect real electrical energy storage can be designed more needs-based.

The penetrator can preferably have an electrically conductive spike and/or bolt and/or mandrel (eg made of metal). The penetrator can be coupled to the energy supply by being configured as a piston at least in sections or provided with a thread. At least the penetrator is partially made of metal or an electrically conductive material and is in particular provided with a metallic jacket.

In particular, the arrangement can be set up to be arranged in a storage housing of the electrochemical energy store. In this case, a cavity located in all energy storage devices in a head area between a storage housing and a cell housing can be used and the arrangement can be designed particularly flat for this purpose. In particular, the arrangement can have a height in the range from 10 mm to 50 mm, preferably in the range between 15 mm and 35 mm, in order to be able to be accommodated in commercially available traction energy stores.

Of course, the arrangement can be further developed by providing an energy store for charging the energy guide with energy for driving the penetrator. In other words, this energy store is also arranged within the storage housing. The same applies to a triggering mechanism for causing the energy supply of the arrangement to be charged with energy. These features are discussed in detail in connection with the following explanations.

For example, the arrangement can have a pressure accumulator (gas pressure accumulator) which is designed, for example, as a CO ₂ cartridge, such as is used in airsoft guns or in cream frothers. These pressure accumulators usually have a predetermined breaking point, which is provided, for example, by a metallic membrane. If the membrane is penetrated in a predefined manner, for example by pressing the pressure accumulator onto a (second) penetrator, the stored gas escapes and applies energy to the energy supply in order to move or accelerate the penetrator coupled to the energy supply in order to produce the cell-internal short circuit . Alternatively or additionally, a gas generator (eg in the manner of a pyrotechnic gas generator, as is used in airbags) can be provided, which has an explosive powder and, in particular, also an ignition mechanism. The ignition mechanism can be actuated inductively from outside the electrical energy store, for example. For example, an electromagnetic field can heat up the firing mechanism or the firing mechanism can be deformed in the manner of a primer cap of a firearm cartridge to generate a spark. An electromechanical compressor can also compress gas located in the electrical energy store and/or gas sucked in from outside the electrical energy store and, if necessary, apply the compressed gas to the energy guide. Alternatively or additionally, an electric motor, for example a linear drive, a spindle drive or the like can be provided in order to drive the penetrator. The aforementioned mechanisms can be used independently or in any combination of the aforementioned mechanisms as an actuator. An electrical line, a Bowden cable, a fluid guide, a gas guide, alternating electromagnetic fields or a combination of the above can be used to trigger the actuator. In this way it can be avoided that the storage housing of the electrical energy storage device is damaged before the test-provoked error reaction has even started.

According to a second aspect of the present invention, an electrical energy store is proposed, which could also be referred to as a “test setup” or “test subject”. In particular, it can be a near-series electrical energy storage device, which has a storage housing and one or more electrochemical cells for storing electrical energy. The cell or cells has or have a cell housing arranged in each case in the storage housing. The electrical energy store itself therefore has a storage housing and one or more cell housings within the storage housing. In addition, an arrangement according to the invention is provided between the storage housing and the cell housing, as has been described in detail above. In other words, the above-mentioned arrangement is located inside the storage housing, but outside the cell housing or cell housings. In this way, a test sequence can be provoked for the electrical energy store, as has already been described in detail above.

The penetrator is preferably arranged in front of or at a predetermined breaking point of the cell housing of the electric cell. Such a predetermined breaking point is also referred to as a "cell vent". During operation, the cell vent must ensure that excessive gas pressure can escape at this point, thus preventing worse things from happening. Since the cell vent would be destroyed comparatively early in any case in the course of an attempt addressed according to the invention, the cell vent can be used to remove the penetrator by the electrochemical To drive the cell without weakening the stability of the cell housing at other points, which may be relevant for the course of the reaction in the further course. Thus, the resilience of the test result achieved according to the invention is further improved compared to the prior art. For this purpose, the penetrator can also have a positioning device or be fixed by a positioning device of the arrangement at or in front of the predetermined breaking point of the cell housing such that the energy supply has little choice but to drive the penetrator through the predetermined breaking point. The positioning device can, for example, be latched, glued or fixed in some other way at the predetermined breaking point. in particular, a friction fit and/or a form fit can be entered into with the predetermined breaking point. It is irrelevant here whether the positioning device is an (integral) part of the penetrator or an additional part (component).

The electrical energy storage device can have an actuator which is arranged in the storage device housing. The actuator is therefore also arranged between the wall of the cell housing and the wall of the storage housing. This has the advantage that the energy required to drive the penetrator is already carried within the storage housing and a weakening of the storage housing is required at best to implement the trigger mechanism/release mechanism.

The trigger mechanism can, for example, work inductively, magnetically, mechanically, gas-controlled, fluidically, in particular by means of a Bowden cable or via electrical lines/optical fibers. Bluetooth, Bluetooth Low Energy, WLAN or the like can be used in particular for the use of wireless signals in order to provide the triggering signal, which originates from outside the electrical energy store, for controlling the triggering mechanism or the actuator. In principle, however, it is also possible to install a timer in the electrical energy store as a triggering mechanism, which starts the actuator at a predefined point in time once the electrical energy store has been completed.

The penetrator can preferably be set up to be accelerated in the direction of the cell housing in order to produce the cell-internal short circuit. In this case, the penetrator can move away from the wall of the accumulator housing or even be supported on it or receive an impulse from it. In particular, if the storage housing is designed to be elastic, an impact from outside the storage housing at the point where the penetrator is located could directly accelerate the penetrator or activate the actuator so that it uses the energy supply to force the penetrator to produce the cell-internal short-circuit moves. In principle and preferably, openings or feedthroughs through the storage housing of the electrical energy storage device can also be used to activate the actuator or apply energy to the energy supply, so that an additional weakening of the storage device housing can be dispensed with for this purpose. Such openings are provided, for example, for venting the accumulator housing, for cooling/supplying heat to the electrical energy accumulator, or for electrical energy and information lines, so that the joint use of the aforementioned lines/ducts or the additional arrangement of a line for triggering the actuator does not go against the grain weight falls.

As a result, a particularly realistic simulation of a probable error can take place.

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen elektrischen Energiespeichers mit einem Ausführungsbeispiel einer erfindungsgemäßen Anordnung vor einer Auslösung des Aktuators;
• 2 eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen elektrischen Energiespeichers mit einem Ausführungsbeispiel einer erfindungsgemäßen Anordnung nach einer Auslösung des Aktuators;
• 3 ein zweites Ausführungsbeispiel eines erfindungsgemäßen elektrischen Energiespeichers mit einem Ausführungsbeispiel einer erfindungsgemäßen Anordnung vor einem Auslösen des Aktuators; und
• 4 ein zweites Ausführungsbeispiel eines erfindungsgemäßen elektrischen Energiespeichers mit einem Ausführungsbeispiel einer erfindungsgemäßen Anordnung nach einem Auslösen des Aktuators.

Further details, features and advantages of the invention result from the following description and the figures. Show it:

• 1 a schematic representation of an exemplary embodiment of an electrical energy store according to the invention with an exemplary embodiment of an arrangement according to the invention before the actuator is triggered;
• 2 a schematic representation of an embodiment of an electrical energy store according to the invention with an embodiment of an arrangement according to the invention after a triggering of the actuator;
• 3 a second exemplary embodiment of an electrical energy store according to the invention with an exemplary embodiment of an arrangement according to the invention before the actuator is triggered; and
• 4 a second exemplary embodiment of an electrical energy store according to the invention with an exemplary embodiment of an arrangement according to the invention after the actuator has been triggered.

1 shows an embodiment of an electrical energy store 10, which is designed as an electrical energy store / traction battery of a car. The electrical energy storage has a storage housing 5, within which an embodiment of an inventive arrangement 1 and an example shown electrochemical cell 2 are located. The electrochemical cell 2 has a cell housing 7, in the upper side of which there is a predetermined breaking point 9 in the form of a cell vent. This is preferably used according to the invention in order to introduce a penetrator 4 into the electrochemical cell 2 for the purpose of producing an electrical cell-internal short circuit. A cylinder is provided as an energy supply 3 to direct the gas pressure generated by a gas generator 6 comprising a primer 6a and explosive 6b to the penetrator 4 . To activate the percussion cap 6a, electrical lines 13 are led out of the accumulator housing 5 by means of a passage, where an electrical voltage U can be applied to them. An alternative ignition mechanism is shown above the electrical energy store 10 . This has an AC voltage source U and an antenna 12 . An alternating field can be generated in the gas generator 6 by means of the antenna 12, so that the percussion cap 6a thermally ignites the explosive 6b. Since the memory housing 5 remains intact in this case, a realistic error situation is brought about.

2 shows the in 1 shown arrangement after ignition of the gas generator (reference number 6 in 1 ). The generated gas 6c pushes the penetrator 4 through the predetermined breaking point 9 and thus into the electrochemical cell 2. Here the metallic penetrator 4 leads to a cell-internal short circuit. The further courses within the electrical energy store 10 correspond to a real error case and are not the subject of the invention.

3 shows a schematic representation of a second exemplary embodiment of an electrical energy store 10 according to the invention with an exemplary embodiment of an arrangement 1 according to the invention. For the sake of simplicity, the differences from that in FIGS 1 and 2 explained arrangement shown. In the present case, the gas generator 6 is designed as a CO ₂ cartridge, which is located inside a housing 8 . A second penetrator 18 is set up to pierce a predetermined breaking point within the gas generator 6 and to allow compressed gas stored in it to escape, which subsequently drives the penetrator 4 through the predetermined breaking point 9 . Outside the electrical energy store 10, a control unit 14 receives a signal S, in response to which an antenna 12 transmits a wireless signal, for example according to the Bluetooth standard, to an antenna 12 located within the storage housing 5. The signals received by the antenna 12 are forwarded to an electronic control unit 11, which controls an electric motor 15 as part of the triggering mechanism. A spindle 16 is rotated in a threaded sleeve 17 by means of the electric motor 15 so that the gas generator 6 is pressed onto the second penetrator 18 . The structure shown has the advantage that, due to the wireless transmission between the antennas 12, the storage housing 5 has no weak points and therefore has no serial status.

4 shows the result of the triggered trigger mechanism in 3 . The gas generator 6 pressed onto the second penetrator 18 has been opened at the predetermined breaking point, so that compressed gas 6d has driven the penetrator 4 through the predetermined breaking point 9 and caused a cell-internal short circuit. The deflection of the compressed gases 6d by 90° enables a particularly low overall height of the actuator 1 according to the invention. This can therefore be accommodated in a particularly elegant manner in an electrical energy store designed close to series production.

The penetrator 4 has to break through the predetermined breaking point 9, but not through the storage housing 5, so that less force or energy is required to finally drive the penetrator 4 into the electrochemical cell 2 to produce the cell-internal short circuit.

An alternative way of triggering the aforementioned process would be to use a compressed air line which is fed with compressed air from outside the storage housing 5 . Arrived in the storage housing 5 or at the gas generator 6, the compressed air could press the gas generator 6 onto the second penetrator 18, where the compressed gas 6d moves the penetrator 4.

Reference List

1

arrangement

2

electrochemical cell

3

energy management

4

penetrator

5

storage enclosure

6

gas generator

6a

primers

6b

explosive

6c

compressed gas

6d

compressed gas

7

cell case

8th

Housing

9

predetermined breaking point

10

electrical energy storage

11

control unit

12

antenna

13

Management

14

control unit

15

electric motor

16

spindle

17

threaded sleeve

Claims (10)

Arrangement (1) for generating a cell-internal short circuit of an electrical energy store (10) comprising • an energy supply (3) and • a penetrator (4) coupled to the energy supply (3), the energy supply (3) being set up to move the penetrator (4) in response to a triggering signal in order to produce the cell-internal short circuit. Arrangement (1) according to claim 1 , wherein the penetrator (4) has an electrically conductive spike and/or bolt and/or mandrel. Arrangement (1) according to claim 1 or 2 , wherein the arrangement (1) is set up to be arranged in a storage housing (5) of the electrical energy storage device (2). Arrangement (1) according to any one of the preceding claims, further comprising an actuator (6) which is coupled to the energy supply (3), wherein the actuator (6) - an accumulator and/or - a gas generator and/or - a compressor and/or - Includes electric motor (15). Electrical energy storage device (10) comprising - a storage housing (5), - an electrochemical cell (2) which has a cell housing (7) arranged in the storage housing (5), further comprising an arrangement according to claim 1 is arranged between the storage housing (5) and the cell housing (7). Electrical energy store (10) after claim 5 , wherein the penetrator (4) is arranged in front of or at a predetermined breaking point (9) of the cell housing (7). Electrical energy store (10) after claim 5 or 6 , wherein an actuator (6) is arranged in the storage housing (5). Electrical energy store (10) after claim 7 , further comprising a triggering mechanism which is set up to cause the actuator (6) to act on the energy guide (3) with energy. Electrical energy store (10) after claim 8 , wherein the triggering mechanism is set up to use - electromagnetic induction and/or - wireless transmission and/or - wired signaling and/or - a fluid line and/or - an electrical line (13). Electrical energy store (10) according to one of Claims 5 until 9 , wherein the penetrator (4) is set up to be accelerated in the direction of the cell housing (7) in order to produce the cell-internal short circuit and in this way to be removed in particular from a wall of the storage housing (5).

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