DE102012017184A1 - Electrochemical energy storage cell of electrochemical energy storage device e.g. battery mounted in motor vehicle, has envelope that consists of functional layer separated from electrode assembly in normal operating state - Google Patents

Abstract

The storage cell (10) has a sheet-like envelope (24) that partially encloses an electrode assembly (12) comprising a first electrode of a first polarity, and a second electrode of a second polarity. The envelope has a functional layer (243) that is electrically conductively connected to the first electrode of the electrode assembly by an electrically conductor, and an electrically insulating layer. The functional layer in a laminating direction is separated from the electrode assembly in the normal operating state. An independent claim is included for an electrochemical energy storage device.

Description

The present invention relates to an electrochemical energy storage cell, in particular in the form of a Pouch- or Coffeebag cell, and an electrochemical energy storage device or battery with at least one such electrochemical energy storage cell.

The invention will be described by way of example in connection with lithium-ion batteries for supplying vehicle drives. It should be noted that the invention can also be used regardless of the type of battery, the chemistry of the electrochemical energy storage cell and regardless of the type of powered drive.

Batteries with a plurality of electrochemical energy storage cells for supplying motor vehicle drives are known from the prior art. Usually, the electrochemical energy storage cells are electrically interconnected, in particular for increasing the battery voltage, the battery power and / or the range of the vehicle powered by the battery.

Conventional energy storage cells have an electrode assembly with at least two electrodes of different polarity and a separator. The separator separates or complains the electrodes of different polarity. Furthermore, conventional energy storage cells have a cell envelope which at least partially surrounds the electrode assembly. In the case of so-called Pouch- or Coffeebag cells, this cell envelope is formed like a foil and is generally multi-layered.

Particularly in the case of use in motor vehicles, but not only there, it is particularly important for such batteries or energy storage cells to be safe. The safety must be ensured even when mechanical loads from the outside, such as the impact of foreign bodies such as nails and the like. In addition to the approach to prevent ingress of foreign bodies, for example, by high-strength battery case, another approach is to at least partially controlled to discharge the (partial) penetration of a foreign body in a battery or energy storage cell, a threat to, for example, vehicle occupants and rescue workers to diminish. Such protective measures are becoming increasingly important with larger battery capacities and higher energy densities.

It is therefore an object of the invention to provide batteries or energy storage cells with increased security available.

This object is achieved by an electrochemical energy storage cell having the features of claim 1. Particularly preferred embodiments and further developments of the invention are the subject of the dependent claims.

The electrochemical energy storage cell according to the invention has an electrode assembly which has at least one first electrode of a first polarity and at least one second electrode of a second polarity, and a foil-like sheath which at least partially surrounds the electrode assembly. The enclosure has at least one first functional layer, which is at least partially electrically conductive and is electrically conductively connected to the at least one first electrode of the electrode assembly, and at least one electrical insulating layer, which the first functional layer in the normal operating state of the energy storage cell in a direction of the sheath of the Electrode assembly disconnects.

If a foreign body acts on or impinges on a battery according to the invention, in particular on an electrochemical energy storage cell according to the invention, for example in the case of an accident, in particular of a motor vehicle, then the energy storage cell can be damaged. It has been observed that a conventional battery releases energy to the environment in an uncontrolled manner, in particular after damage, in particular of one of its energy storage cells. The energy storage cell according to the invention has the advantage that the first functional layer of the enclosure of the energy storage cell can form a closed current path between the electrodes of different polarity of the energy storage cell in the case of a foreign body entering the enclosure or a pressure acting on the enclosure. The energy storage cell can then discharge in a controlled manner via this closed current path. The wrapping with the at least one first functional layer can therefore also be referred to as a "nail safety device".

While the first functional layer of the enclosure is separated from the components of the energy storage cell second polarity in the normal operating state of the energy storage cell, this insulation is bridged when entering a foreign body either by the foreign body itself, for example, if it is an electrically conductive foreign body such as a metal nail, or by a deformation of the envelope and a direct contact between the lifted first functional layer and the corresponding other components. The latter mechanism also takes place in the case of a locally localized, in particular substantially punctual pressure action from outside on the casing.

The first functional layer is part of the film-like enclosure, so that a particularly simple construction of the electrochemical energy storage cell according to the invention results with a small number of components. In this case, the first functional layer is preferably integrated into the envelope of the energy storage cell or inserted as part of a common multi-layer structure or as a separate structural unit. Through this installation of the protective mechanism in the enclosure of the energy storage cell, the desired increase in security can be achieved with the energy storage cells according to the invention, regardless of the structure of the battery with these energy storage cells.

An electrochemical energy storage cell in the sense of the invention means a device which serves, in particular, to convert at least temporarily chemical energy into electrical energy and at least temporarily to provide electrical energy, in particular to a consumer. From such an energy storage cell is to be distinguished in this context, an electrochemical energy storage device which receives one or preferably a plurality of such energy storage cells in a housing. Such an energy storage device is referred to in the context of the invention as a battery.

The electrochemical energy storage cell has an electrode assembly. An electrode assembly in the sense of the invention means a device which serves in particular for the provision of electrical energy. The electrode assembly is preferably configured to convert in particular stored chemical energy into electrical energy before the electrode assembly provides this electrical energy to a consumer. The electrode assembly is preferably also configured to convert supplied electrical energy into chemical energy and to store it as chemical energy. One speaks then of a rechargeable electrode assembly.

The electrode assembly has at least two electrodes of different polarity (first and second electrodes according to the invention). Preferably, the electrodes of the electrode assembly each have a particular metallic collector foil and one or two active compositions. The active composition is applied to the collector foil at least on one side. Two active materials of different polarity are arranged on different surfaces of the collector foil and spaced by the collector foil. When charging or discharging the electrode assembly, electrons are exchanged between the collector foil and the active mass (s). Preferably, the collector foil comprises the materials copper and / or aluminum. Preferably, one or more Ableitfahnen are in particular cohesively connected to the collector foil, preferably integrally formed. Preferably, the electrode assembly is in particular materially connected in particular via the Ableitfahnen of the electrodes with two Stromleiteinrichtungen different polarity, which serve for electrically connecting the electrode assembly with at least one electrode assembly of an adjacent energy storage cell and / or at least indirectly the electrical connection with battery terminals.

The electrodes of different polarity of the electrode assembly are preferably spaced apart by a separator, wherein the separator is conductive for ions, but not or only slightly for electrons. Preferably, the separator contains at least part of the electrolyte or of the conductive salt. Preferably, the electrolyte is formed in particular after closing the energy storage cell substantially without a liquid portion. Preferably, the conductive salt comprises lithium ions. With particular preference, lithium ions are stored or intercalated during charging into the negative electrode and are removed again during discharging.

Preferably, the electrode assembly is formed as a substantially cuboid electrode stack. The electrode stack has a predetermined sequence of stack sheets in its stacking direction, with two electrode sheets of different polarity being separated from a separator sheet. Electrode sheets of the same polarity are preferably electrically connected to one another, in particular via a common current-conducting device. This configuration of the electrode assembly offers the advantage that the charging capacity of the electrode assembly, for example in ampere hours [Ah] or watt-hours [Wh], more rarely in coulombs [C], can be increased in a simple manner by adding further electrode sheets. Particularly preferably, at least two separator sheets are connected to one another and surround a delimiting edge of an electrode sheet. Such an electrode assembly with a single, in particular meander-shaped separator offers the advantage that a parasitic current, starting from this limiting edge to an electrode sheet of a different polarity, is encountered.

The electrode assembly of the energy storage cell is at least partially enclosed by a film-like envelope. An enclosure in the sense of the invention is understood in particular to mean a device which at least partially surrounds the energy storage cell and delimits it to its surroundings. Due to the foil-like design of the sheath, this can provide an at least partially adaptive mechanical structure in which components of the energy storage cell are located. Preferably, the film-like envelope is multi-layered, ie formed from two, three, four, five or more layers. The several layers of the sheath are preferably firmly connected to one another and / or jointly produced in one production step as a uniform layer composite. The foil-like sheath preferably has an electrical insulating layer on its inner side facing the electrode assembly. The film-like covering preferably has a fluid-tight layer, preferably a metal layer, which preferably serves as a water vapor barrier. Energy storage cells with such film-like sheaths are also referred to as pouch or Coffeebag cells.

According to the invention, the film-like enclosure has at least one first functional layer and at least one electrical insulating layer. In the context of the invention, the covering can consist only of these functional and insulating layers, but preferably also has further layers or layers in addition to the layers mentioned.

In one embodiment of the invention, the at least one first functional layer and / or the at least one electrical insulating layer are an integral part of the envelope, i. H. they form with the enclosure a common component which is disposed around the electrode assembly. In another embodiment of the invention, the at least one first functional layer and the at least one electrical insulating layer are provided as a separate structural unit separate from the usual or remaining enclosure; they can then preferably be materially connected to this or mounted in a separate manufacturing step to the electrode assembly. In this embodiment, the functional and insulating layers may themselves be formed like a foil or substantially dimensionally stable. Also, these functional and insulating layers can be arranged in this embodiment, both within the rest of the envelope, both outside the rest of the envelope or partly inside and partly outside the rest of the envelope.

The sheath of the electrode assembly according to the invention comprises at least one, i. H. preferably one, two, three or more first functional layers and at least one, d. H. preferably one, two, three or more electrical insulating layers.

The at least one first functional layer preferably extends over the entire area of the enclosure, at least essentially over the entire main surfaces of the enclosure on both sides of the electrode assembly in the stacking direction thereof, or at least substantially over the entire main surface of the enclosure on one side of the electrode assembly in its stacking direction stacking direction. In the case of several, i. H. At least two first functional layers preferably extend substantially congruently or at least partially overlapping one another in the enclosure. The at least one electrical insulating layer preferably extends over the entire region of the sheath or at least substantially over the entire main surfaces of the sheath to both sides of the electrode assembly in its stacking direction.

The at least one first functional layer is at least partially, preferably substantially electrically conductive over its entire area. The at least one first functional layer is at least partially, preferably substantially electrically conductive over its entire layer thickness. The at least one first functional layer is preferably formed in one piece or joined together from several sections. The at least one first functional layer is constructed in a single-layered or multilayered manner.

The at least one first functional layer of the sheath is connected directly or indirectly with the first electrodes of the electrode assembly in an electrically conductive manner. Preferably, the at least one first functional layer of the sheath is electrically conductively connected to all first electrodes of the electrode assembly.

The at least one first functional layer of the sheath is separated from the electrode assembly by at least one electrical insulating layer in the laminar direction of the sheath. In this context, an electrical insulating layer is to be understood as meaning a layer having such a large electrical resistance, in particular in its layer thickness direction, which has an electrical current flow between the first and second electrodes of the electrode assembly via the at least one first functional layer even when the energy storage cell is completely charged and over the entire Use temperature range of the energy storage cell can substantially prevent. The required resistance depends in this context, in particular, on the contact resistance between the at least one first functional layer of the sheath and the first electrode of the electrode assembly from. The resistance of the electrical insulating layer can be influenced in particular by the choice of the material and the layer thickness of the insulating layer. The electrical insulating layer is single-layered or multi-layered.

Under the normal operating state of the energy storage cell, in which the at least one first functional layer of the sheath is separated from the electrode assembly by the at least one electrical insulating layer in the layer direction of the sheath, all operating states are to be understood in which loading or unloading of the energy storage cell and a stable energy storage safely possible. The at least one electrical insulating layer separates the first functional layer (s) of the enclosure from the electrode assembly at least in such a safe normal operating condition. In certain hazardous situations, in particular when exposed to pressure or foreign bodies on the energy storage cell or its enclosure, however, the electrical insulation caused by the least one electrical insulation layer can be repealed.

In a preferred embodiment of the invention, the sheath further comprises at least one second functional layer, which is at least partially electrically conductive and is electrically conductively connected to the at least one second electrode of the electrode assembly, and at least one further electrical insulating layer, which the first and second functional layers of Encapsulation in the normal operating state of the energy storage cell in the layer direction of the enclosure separates from each other, on.

In this embodiment, the first and second functional layers of the sheath are electrically conductively connected or short-circuited in a danger state described above, so that a closed current path can form between the electrodes of different polarity of the energy storage cell, via which the energy storage cell can discharge in a controlled manner.

The above statements in connection with the at least one first functional layer of the envelope apply correspondingly to this at least one second functional layer of the envelope. The above statements in connection with the at least one insulating layer apply correspondingly to this at least one further insulating layer.

In another preferred embodiment of the invention, the envelope in a stacking direction of the electrode assembly on one side of the electrode assembly at least a first functional layer, which is at least partially electrically conductive and is electrically connected to the at least one first electrode of the electrode assembly, and on the On the other side of the electrode assembly at least a second functional layer, which is at least partially electrically conductive and is electrically conductively connected to the at least one second electrode of the electrode assembly, on.

The first functional layer on one side of the electrode assembly and the second functional layer on the other side of the electrode assembly are preferably electrically insulated from one another, at least in the normal operating state of the energy storage cell. In the layer direction of the cladding, at least one electrical insulating layer is preferably arranged between the at least one first functional layer and the electrode subassembly, and at least one electrical insulating layer is preferably arranged between the at least one second functional layer and the electrode subassembly. The electrical insulating layers on both sides of the electrode assembly are preferably interconnected or separate from one another. The at least one first functional layer on one side of the electrode assembly is electrically connected to at least one first electrode of the electrode assembly and the at least one second functional layer on the other side of the electrode assembly is electrically connected to at least one second electrode of the electrode assembly, so in this preferred Embodiment the first and second functional layers of the envelope on the different sides of the electrode assembly operate independently. Preferably, the first and second functional layers on the different sides of the electrode assembly are each electrically connected to an electrode type of the electrode assembly which is not exposed in the stacking direction of the electrode assembly.

The above statements in connection with the at least one first functional layer of the envelope apply correspondingly to these first and second functional layers of the envelope.

In a modification of the last-described embodiment, the energy storage cell according to the invention can also be equipped on one side only with a "nail safety device". In this case, the sheath in a stacking direction of the electrode assembly on the one side of the electrode assembly has at least one first functional layer which is at least partially electrically conductive is formed and electrically conductively connected to the at least one first electrode of the electrode assembly, while on the other side of the electrode assembly no functional layer which is at least partially electrically conductive and is electrically connected to any electrode of the electrode assembly, is provided. In the layer direction of the cladding, at least one electrical insulating layer is preferably arranged between the at least one first functional layer and the electrode subassembly.

In yet another preferred embodiment of the invention, the electrode assembly in a stacking direction of the electrode assembly as the outermost electrode in each case a second electrode and has the enclosure in a stacking direction of the electrode assembly on both sides of the electrode assembly at least a first functional layer, which at least partially formed electrically conductive is and is electrically connected to the at least one first electrode of the electrode assembly.

The first functional layer on one side of the electrode assembly and the first functional layer on the other side of the electrode assembly are preferably formed integrally with each other, electrically interconnected as separate components or electrically isolated from each other as separate components. In the layer direction of the cladding, at least one electrical insulating layer is preferably arranged in each case between the at least one first functional layer and the electrode subassembly. The electrical insulating layers on both sides of the electrode assembly are preferably interconnected or separate from one another.

In a preferred embodiment of the invention, the first functional layer and / or the second functional layer of the sheath are formed substantially fluid-tight. In this embodiment, it is preferably possible to dispense with an additional fluid-tight layer in the enclosure. The first or second functional layer, which is designed to be fluid-tight, can thus simultaneously serve as a water vapor barrier. In embodiments in which a functional layer is provided on only one side of the electrode assembly, an additional fluid-tight layer is preferably provided on the other side of the electrode assembly.

In a preferred embodiment of the invention, the envelope has on its side facing the electrode assembly side of the first and / or second functional layers at least one stab-resistant protective layer. This puncture-resistant protective layer preferably comprises a woven or knitted fabric of reinforcing fibers, in particular aramid fibers, and / or one or more metallic inserts, which are preferably joined together, and / or one or more oxide-ceramic inserts, which are preferably plate-shaped. This embodiment has the advantage that the envelope opposes a foreign body increased mechanical resistance to its penetration into the interior of the energy storage cell.

In a further embodiment of the invention, the electrode assembly facing the electrical insulating layer of the envelope is also formed as a stab resistant protective layer.

In a preferred embodiment of the invention, at least one discharge resistor is connected between the first functional layer and the at least one first electrode of the electrode assembly and / or between the second functional layer and the at least one second electrode of the electrode assembly. This at least one discharge resistor is preferably arranged at least partially outside the sheath and / or connected to a component outside the sheath in a heat-conducting manner. The discharge resistor is in particular provided to convert electrical energy from the electrode assembly into heat energy during controlled discharging. In this embodiment, a discharge current which flows out of the electrode assembly with short-circuited first and second functional layers can also be limited by the discharge resistor. In this way, the electric heating power can be limited. Preferably, one, two, three, four or more discharge resistors are provided for an energy storage cell.

Preferably, the at least one discharge resistor has a predetermined electrical resistance value. Preferably, the total electrical resistance is at least 0.5 Ω, more preferably at least 2 Ω, more preferably at least 5 Ω, more preferably at least 10 Ω, further preferably at least 20 Ω, more preferably at least 50 Ω, further preferably at least 100 Ω, more preferably at least 200 Ω, more preferably at least 500 Ω, more preferably at most 1000 Ω. Particularly preferably, the discharge resistance is adapted to the electrical voltage of the energy storage cell such that the heating power in the discharge resistor during controlled discharging of the energy storage cell is limited to at most 500 W, more preferably to at most 200 W, more preferably to at most 100 W, further preferably to at most 50th W, more preferably not more than 20 W, more preferably not more than 10 W, more preferably not more than 2 W.

As a result of the preferred arrangement and / or heat-conducting connection of the at least one discharge resistor outside the enclosure, it can preferably be achieved that the heat generated by the energy storage cell during controlled discharging is dissipated to the outside and the interior of the cell with the electrode arrangement is not overheated.

In yet another preferred embodiment of the invention, the at least one first functional layer and / or the at least one second functional layer of the sheath are at least partially formed as metal foils.

The invention also provides an electrochemical energy storage device comprising at least one above-described electrochemical energy storage cell of the invention. Such an electrochemical energy storage device may also be referred to as a battery. The energy storage device also has a preferably dimensionally stable housing for receiving the at least one energy storage cell and at least two battery terminals of different priority, which are electrically conductively connected to the / the electrode assembly (s) of the at least one energy storage cell on. In the case of a plurality of energy storage cells in the battery, these are preferably connected in series and / or parallel to one another via their current conducting devices between the battery terminals.

The energy storage device according to the invention contains at least one energy storage cell according to the invention described above. In one embodiment of the invention, the energy storage device contains exclusively energy storage cells, which are designed according to the invention. In another embodiment of the invention, the energy storage device includes one or more energy storage cells, which are configured according to the invention, and one or more differently configured energy storage cells. In the latter case, the energy storage cells, which according to the invention have an enclosure with first and possibly second functional layers, preferably arranged in an arrangement direction of the energy storage cells outside and thus close to a housing wall of the battery. This has the advantage that only the outer energy storage cells, which are exposed to a greater risk of foreign body impact, must be formed according to the invention with a special enclosure.

In the embodiment of the energy storage cell with at least one discharge resistor, it is preferably connected in a thermally conductive manner to the housing of the battery.

In a preferred embodiment of the invention, at least one measuring device is provided, which is configured to detect a state and / or a state change of the electrical connection between the at least one first functional layer and the at least one second functional layer of the enclosure of at least one of the at least one energy storage cell. In another preferred embodiment of the invention, at least one measuring device is provided, which is configured, a state and / or a change in state of the electrical connection between the at least one first functional layer of the envelope and the at least one first electrode and / or between the at least one second functional layer the enclosure and the at least one second electrode to detect at least one of the at least one energy storage cell. Depending on the configuration of the energy storage cells or their sheaths, a hazardous state of the battery, in particular due to a pressure or foreign body action on one or more energy storage cells, can thus also be detected with such a measuring device. The measuring device is preferably configured to detect an electrical current and / or an electrical voltage, in particular of the electrode assembly of an energy storage cell.

In a further preferred embodiment of the invention, at least one current interrupt device is provided, which is configured to interrupt the electrically conductive connection between at least one of the battery terminals and the / the electrode assembly (s) of the at least one energy storage cell. The current interrupt device is preferably coupled to the above-mentioned measuring device.

The current interruption device serves, in particular, to electrically isolate the energy storage cell from its environment. With the aid of the current interruption device, in particular the electrical connection between one of the current conducting devices of the energy storage cell and a battery connection, in particular of the same polarity, can be interrupted at least temporarily. The current interruption device is in particular provided to be activated and, in the activated state, to interrupt the electrical connection between the current conducting device and the battery connection, in particular of the same polarity. The current interruption device preferably has a controlled switch, preferably a semiconductor switch or a relay. Preferably, the power interruption device is controlled by a battery control device or a battery management system. The controlled switch of the current interrupt device may preferably according to a particular be closed again for a predetermined period of time. This preferred embodiment has the advantage that after closing the switch, the electrical voltage of the energy storage cells can be measured via the battery terminals. In another preferred embodiment, the current interruption device has a separating device, which is activated in particular by the battery control device, and an electrical conductor. The electrical conductor is connected between the Stromleiteinrichtung the energy storage cell and the battery terminal. The separating device is provided to act on the electrical conductor such that its electrical conductivity largely, in particular substantially completely lost. Preferably, the separator is configured to divide the electrical conductor so that the current path between the current conducting device and the battery connection is interrupted. This preferred embodiment offers the advantage of increased safety of the battery, especially after harmful action of a foreign body.

In a preferred embodiment of the invention, the battery has a display device. The display device is provided, in particular to indicate the hazardous state of the energy storage cell with respect to the functional layers of its envelope and / or to transmit corresponding information in particular to a battery controller or an independent controller. This embodiment offers the advantage that information about the state of the battery or the energy storage cell (s) can be made available to a person. Particularly preferably, the display device is configured as a beeper, light emitting diode, infrared interface, GPS device, GSM module, first near-field radio or transponder.

Further advantages, features and applications of the present invention will become apparent from the following description taken in conjunction with the figures. Show:

1 a schematic representation of the structure of an electrochemical energy storage cell according to a preferred embodiment of the present invention;

2 a schematic representation of the layer structure of a sheath of the energy storage cell of 1 according to a first embodiment;

3 a schematic representation of the layer structure of a sheath of the energy storage cell of 1 according to a second embodiment;

4 a schematic representation of the structure of an electrochemical energy storage device or battery with a plurality of energy storage cells according to a preferred embodiment of the present invention;

5 a schematic representation of the layer structure of an enclosure of an energy storage cell according to another embodiment;

6 a schematic representation of the layer structure of a sheath of an energy storage cell according to yet another embodiment; and

7 a schematic representation of the layer structure of a sheath of an energy storage cell according to yet another embodiment.

1 schematically shows the structure of a rechargeable electrochemical energy storage cell 10 in the form of a pouch cell according to the invention. The energy storage cell 10 contains an electrode assembly 12 , which of a foil-like cladding 24 is substantially completely enclosed.

As in 2 and 3 illustrates the electrode assembly 12 a substantially cuboid electrode stack of first electrodes 14 and second electrodes 16 different polarity. The first and second electrodes 14 . 16 are through a separator 18 separated from each other.

The arrester lugs (not shown) of the first electrodes 14 are with a first current conducting device (current conductor) 20 electrically connected. The arrester lugs (not shown) of the second electrodes 16 are with a second current conducting device (current conductor) 22 electrically connected. The two current conducting devices 20 . 22 are by the serving 24 passed through to the outside. The serving 24 is sealed fluid-tight in the area of these arrester passages.

Back to 1 are in the serving 24 the electrode assembly 12 a first functional layer 243 and a second functional layer 244 indicated. The second functional layer 244 is about a discharge resistor 26 electrically conductive with the second current conducting device 22 connected, the first functional layer 243 is, however, directly electrically conductive with the first Stromleiteinrichtung 20 connected. The first and the second functional layer 243 . 244 are each formed as electrically conductive metal foils. Besides, the first and the second are functional layer 243 . 244 in the layer direction 25 the serving 24 electrically isolated from each other.

Although not shown, alternatively or additionally, the first functional layer 243 the serving 24 via a discharge resistor 26 with the first current conducting device 20 be connected. There is also the possibility of multiple discharge resistors 26 provided. Furthermore, the at least one discharge resistor 26 the energy storage cell 10 also thermally conductively connected to an external component, for example, a battery housing to the case of the controlled discharge of the electrode assembly 12 dissipate the resulting heat to the outside.

Now hits a foreign body, such as a nail made of metal, on this energy storage cell 10 so this nail can be in the cladding 24 penetration. Once the electrically conductive nail the inner of the two functional layers of the sheath 24 touched or pierced, are the two functional layers 243 . 244 electrically connected by the nail and thus the first electrodes 14 and the second electrodes 16 the electrode assembly 12 shorted. The electrode assembly 12 can therefore be on the functional layers 243 . 244 the serving 24 and the discharge resistance 26 discharged in a controlled manner.

Also with the effect of a pressure from the outside on the energy storage cell 10 can the controlled discharge of the electrode assembly 12 respectively. If the pressure exceeds a certain level, then the envelope may 24 deform such that the first functional layer 243 and the second functional layer 244 contact each other. This can be particularly uneven, especially at substantially point on the energy storage cell 10 acting compressive forces happen. The same applies to the penetration of a foreign body from an electrically non-conductive or hardly conductive material.

Due to the intended discharge resistance 26 in the current path of the electrodes 14 . 16 and functional layers 243 . 244 The electrical energy is converted into heat output. The discharge resistance 26 is preferably at least partially outside the enclosure 24 arranged so that this heat from the energy storage cell 10 can be discharged to the outside and not the interior of the energy storage cell 10 is heated. About the resistance of the discharge resistor 26 can adjust the heat generated during discharge and the duration of the discharge process.

A first embodiment of the layer structure of an enclosure 24 the energy storage cell according to the invention 10 from 1 is in 2 shown.

In this embodiment, the enclosure contains 24 an outer, substantially fluid-tight layer 241 and an electrical insulating layer 242 on the electrode assembly 12 facing side of the fluid-tight layer 241 , This layer structure 241 . 242 corresponds essentially to the structure of conventional foil-like pouch cell wrappings.

In addition to these two layers 241 . 242 are the first functional layer 243 and the second functional layer 244 on the electrode assembly 12 facing side of the layers 241 . 242 intended. Between the two functional layers 243 . 244 is an electrical insulating layer 245 arranged.

On the electrode assembly 12 facing inside of the first functional layer 243 is also an electrical insulating layer 246 intended. This insulating layer 246 should - at least in the normal operating state of the energy storage cell 10 - Electrical insulation between the electrode assembly 12 and the serving 24 guarantee.

In a special variant of this embodiment, this inner insulating layer 246 at the same time formed as a stichfest protective layer. This is done for example by integrated fabric, knitted fabric, metal plates or the like. A foreign body should be so on a complete penetration of the envelope 24 and penetration into the electrode assembly 12 the energy storage cell 10 be prevented.

The "normal" layers 241 - 242 the serving 24 and the "Nail Safety Device" layers 243 - 246 the serving 24 are for example formed as a common layer composite.

In another embodiment, the "normal" layers 241 - 242 the serving 24 and the "Nail Safety Device" layers 243 - 246 the serving 24 formed as separate components which successively around the electrode assembly 12 be placed or after a preferably cohesive connection with each other together around the electrode assembly 12 be placed. In this case, the "nail safety device" layers 243 - 246 the serving 24 even be formed like a film or substantially dimensionally stable. In addition, the "Nail Safety Device" layers 243 - 246 the serving 24 optionally on both main sides of the electrode assembly 12 or only on one main side of the electrode assembly 12 be provided.

A second embodiment of the layer structure of a sheath 24 the invention Energy storage cell 10 from 1 is in 3 shown.

In this exemplary embodiment, the "nail safety device" layers provided according to the invention are integrated into the "normal" sheath layers. In particular, the second functional layer forms 244 at the same time the fluid-tight layer. The electrical insulation layer 242 forms the electrical insulation between the first and the second functional layer 243 . 244 ,

At the electrode assembly 12 facing inside of the first functional layer 243 is also an electrical insulating layer in this embodiment 246 provided, which optionally may be formed at the same time as puncture resistant protective layer.

The embodiment of 3 provides a particularly compact, multifunctional layer structure of the enclosure 24 to disposal.

In 2 and 3 is the electrically conductive connection between the first functional layer 243 the sheath and the first electrodes 14 the electrode assembly 12 through a first connection 21 indicated and is the electrically conductive connection between the second functional layer 244 the serving 24 and the second electrodes 16 the electrode assembly 12 through a second connection 23 indicated. On the representation of the at least one discharge resistor 26 was in 2 and 3 waived.

Even if the layers of the wrapping 24 and the electrode assembly 12 in 2 and 3 are each shown with intervals in between, is the energy storage cell 10 preferably constructed without these distances. In particular, the cladding is 24 preferably from a uniform layer composite 241 - 246 formed and is the electrode assembly 12 preferably formed without cavities and encloses the envelope 24 the electrode assembly 12 preferably without inclusion of voids. Furthermore, the layers can 241 - 246 the serving 24 each be single-layered or multi-layered.

Even if in 2 and 3 the serving 24 each in the stacking direction 19 the electrode assembly 12 on both main sides is shown substantially identical, so the cladding must 24 not necessarily on both major sides of the electrode assembly 12 be similar. For example, the first and second functional layers 243 . 244 also only on one main side of the electrode assembly 12 in the serving 24 to be available.

4 schematically shows the structure of an electrochemical energy storage device or battery 30 according to the present invention.

The battery 30 has a preferably dimensionally stable housing 32 , In this case 32 is a variety of energy storage cells 10 Recorded to set the desired performance of the battery. As in 4 indicated are the electrode assemblies 12 the energy storage cells 10 about her out of the serving 24 protruding Stromleiteinrichtungen 20 . 22 between two battery connections 34 and 36 connected in series. Alternatively, the energy storage cells 10 also be connected in parallel to each other or in a combination of parallel and series connection.

The discharge resistors 26 the energy storage cells 10 For example, with the case 32 the battery be thermally conductively connected. In this way, when controlled unloading an energy storage cell 10 resulting heat through the battery case 32 be discharged to the outside.

As in 4 illustrates the housing contains 32 several electrochemical energy storage cells 10 , which are arranged side by side. In one embodiment, the battery includes 30 exclusively energy storage cells 10 , which according to the embodiments of the 2 or 3 a serving 24 with first and second functional layers 243 . 244 exhibit.

In another embodiment, the battery includes 30 in addition to one or more energy storage cells according to the invention 10 also one or more differently configured energy storage cells, for example conventional energy storage cells without a "nail safety device". In this embodiment, the energy storage cells according to the invention 10 preferably in the arrangement direction of the energy storage cells (right / left direction in 4 ) outside and thus close to the housing 32 the battery 30 arranged. The risk of foreign body exposure exists in particular at these outer energy storage cells, which is why it may be sufficient to provide them only with a corresponding protective mechanism according to the invention.

As in 4 is a battery connection 34 a power interruption device 38 assigned. In addition, in the battery case 32 a measuring device 40 intended.

The measuring device 40 may include one or more measuring devices, which include a state and / or a state change of the electrical connection between the at least one first functional layer 243 and the at least one second functional layer 244 the serving 24 at least one of the energy storage cells 10 can capture. The measuring devices of the measuring device 40 are configured, for example, an electric current and / or an electrical voltage in particular of the electrode assembly 12 an energy storage cell 10 in order to detect the electrical resistance between the first and second functional layers 243 . 244 the serving 24 close.

With this measuring device 40 can thus be a hazardous state of the battery 30 in particular due to a pressure or foreign body action on one or more energy storage cells 10 be recorded.

The measuring device 40 is preferably connected to a battery control device or a battery management system. In addition, the measuring device 40 preferably with the current interrupt device 38 coupled.

The power interruption device 38 is configured, at a through the measuring device 40 detected dangerous condition the electrically conductive connection between the battery connection 34 and the energy storage cells 10 to interrupt, ie the battery connection 34 inside the case 32 disconnected. In this way, it is safe to prevent the battery 30 in a hazardous condition can continue to deliver electrical energy to a connected consumer.

The power interruption device 38 has, for example, a driven switch, for example a semiconductor switch or a relay. This controlled switch of the current interrupt device 38 can preferably be closed again after a predetermined period of time, so that after closing the switch, the electrical voltage of the energy storage cells 10 over the battery connections 34 . 36 can be measured. The said period of time is dimensioned so that the electrode assemblies 12 the endangered by a foreign body or pressure energy storage cells 10 at least largely on the functional layers 243 . 244 the serving 24 and the associated discharge resistors 26 can discharge.

Although not shown, the battery can 30 also have a display device. This indicator is provided to pass through the measuring device 40 detected hazard state of the energy storage cells 10 to display and / or transmit appropriate information in particular to a battery controller or an independent controller. With the help of the display device can a person information about the state of the battery 30 or the energy storage cell (s) 10 to provide.

5 shows schematically the layer structure of an enclosure 24 the energy storage cell 10 according to a third embodiment.

This embodiment differs from that in FIG 2 shown embodiment mainly in that in the stacking direction 19 the electrode assembly 12 (Right / left direction in 5 ) on both sides of the electrode assembly 12 only one functional layer in the envelope 24 is provided.

On one side of the electrode assembly 12 (left in 5 ) shows the envelope 24 next to the fluid-tight layer 241 and the electrical insulation layer 242 only (at least) a second functional layer 244 on which with the second electrodes 16 the electrode assembly 12 electrically connected 21 is. Between this second functional layer 244 and the electrode assembly 12 is in the layer direction 25 the serving 24 (Right / left direction in 5 ) an electrical insulating layer 246 intended. On the other side of the electrode assembly 12 (right in 5 ) shows the envelope 24 next to the fluid-tight layer 241 and the electrical insulation layer 242 only (at least) a first functional layer 243 on which with the first electrodes 14 the electrode assembly 12 electrically connected 21 is. Between this first functional layer 243 and the electrode assembly 12 is in the layer direction 25 the serving 24 (Right / left direction in 5 ) an electrical insulating layer 246 intended. The electrical insulation layers 246 on both sides of the electrode assembly 12 are preferably formed as a continuous, uniform insulating layer.

As in 5 shown, is the one functional layer 243 or 244 the serving 24 on their side of the electrode assembly 12 each with the electrode 14 respectively. 16 the electrode assembly 12 electrically connected, which in the stacking direction 25 the electrode assembly 12 not outside. This causes the following operation of the "Nail Safety Device" envelope.

Meets a foreign body, such as a metal nail, on this energy storage cell 10 So this nail can be the wrapper 24 punctured. Once the electrically conductive nail the electrode assembly 12 , ie the outer electrode touches, is the respective functional layer 243 . 244 the serving 24 through the nail with this outer electrode 16 . 14 electrically connected and are thus the first electrodes 14 and the second electrodes 16 the electrode assembly 12 shorted. The electrode assembly 12 can therefore be on the functional layer 243 . 244 the serving 24 and the discharge resistance 26 discharged in a controlled manner.

A corresponding mode of operation also applies to the effect of external pressure on the energy storage cell 10 and for the penetration of a foreign body of an electrically non-conductive or hardly conductive material.

Incidentally, the structure of the energy storage cell of 5 the first embodiment of 2 , Also, the energy storage cell of 5 in a corresponding manner in a battery according to 4 be used.

6 shows schematically the layer structure of an enclosure 24 the energy storage cell 10 according to a fourth embodiment.

This embodiment is based on a combination of the third embodiment of FIG 5 with the second embodiment of 3 , In particular, the wrapper contains 24 in the stacking direction 25 the electrode assembly 12 on both sides of the electrode assembly 12 only one functional layer at a time 243 or 244 and is this (at least) a functional layer 243 . 244 in a compact way in the enclosure 24 integrated.

In a variant of the invention 5 and 6 can the servings 24 the energy storage cells 10 also on only one main side of the electrode assembly 12 (ie only right or left in the figures) with an electrically conductive functional layer 243 . 244 be provided.

Incidentally, the structure of the energy storage cell of 6 the second embodiment of 3 , Also, the energy storage cell of 6 in a corresponding manner in a battery according to 4 be used.

7 schematically shows the structure of an energy storage cell 10 according to a fifth embodiment.

This embodiment differs from that in FIG 6 shown embodiment mainly in that in the stacking direction 19 the electrode assembly 12 (Right / left direction in 7 ) each have a second electrode (ie electrode of the second polarity) 16 as the outermost electrode of the electrode assembly 12 is arranged and the wrapping 24 on both sides of the electrode assembly 12 at least a first functional layer 243 contains. This first functional layer 243 and the electrical insulating layer 246 in this case, can be consistent throughout the entire wrapping 24 extend. The construction of the serving 24 can be further simplified in this way.

Around the first and second electrodes 14 . 16 the electrode assembly 12 short circuit in a hazardous state (penetration of a foreign body, pressure effect) is the first functional layer 243 the serving 24 each with the first electrodes (ie electrodes of the first polarity) 14 electrically connected while in the stacking direction 19 the electrode assembly 12 each second electrodes 16 lie outside.

Incidentally, the structure of the energy storage cell of 7 the embodiments of 3 and 6 , Also, the energy storage cell of 7 in a corresponding manner in a battery according to 4 be used.

Moreover, the embodiments described above may be combined with one another in any desired manner in order to arrive at further embodiments according to the present invention.

LIST OF REFERENCE NUMBERS

10

Energy storage cell

12

electrode assembly

14

first electrodes

16

second electrodes

18

separator

19

Stacking direction of 12

20

first current conducting device

21

first connection

22

second Stromleiteinrichtung

23

second connection

24

wrapping

241

fluid-tight layer

242

electrical insulating layer

243

first functional layer

244

second functional layer

245

further electrical insulation layer

246

electrical insulating layer and / or puncture-resistant protective layer

25

Layer direction of 24

26

discharge

30

Energy storage device or battery

32

casing

34

first battery connection

36

second battery connection

38

Current interrupt device

40

measuring device

Claims (14)

Electrochemical energy storage cell ( 10 ), with an electrode assembly ( 12 ), which at least one first electrode ( 14 ) of a first polarity and at least one second electrode ( 16 ) has a second polarity; and a foil-like envelope ( 24 ), which the electrode assembly ( 12 ) at least partially enclosing, characterized in that the envelope ( 24 ) at least one first functional layer ( 243 ), which is at least partially electrically conductive and electrically conductive ( 21 ) with the at least one first electrode ( 14 ) of the electrode assembly ( 12 ), and at least one electrical insulating layer ( 246 ), which the first functional layer ( 243 ) in the normal operating state of the energy storage cell ( 10 ) in a layer direction ( 25 ) of the sheath from the electrode assembly ( 12 ) separates. Energy storage cell according to claim 1, characterized in that the envelope ( 24 ) at least one second functional layer ( 244 ), which is at least partially electrically conductive and electrically conductive ( 23 ) with the at least one second electrode ( 16 ) of the electrode assembly ( 12 ), and at least one further electrical insulating layer ( 245 ), which the first and second functional layers ( 243 . 244 ) of the envelope ( 24 ) in the normal operating state of the energy storage cell ( 10 ) in the layer direction ( 25 ) of the enclosure separates from each other. Energy storage cell according to claim 1, characterized in that the envelope ( 24 ) in a stacking direction ( 19 ) of the electrode assembly ( 12 ) on the one side of the electrode assembly at least a first functional layer ( 243 ), which is at least partially electrically conductive and electrically conductive ( 21 ) with the at least one first electrode ( 14 ) of the electrode assembly ( 12 ) and on the other side of the electrode assembly at least one second functional layer ( 244 ), which is at least partially electrically conductive and electrically conductive ( 23 ) with the at least one second electrode ( 16 ) of the electrode assembly ( 12 ) is connected. Energy storage cell according to claim 1, characterized in that the electrode assembly ( 12 ) in a stacking direction of the electrode assembly as the outermost electrode in each case a second electrode ( 16 ) having; and the wrapping ( 24 ) in a stacking direction ( 19 ) of the electrode assembly ( 12 ) on both sides of the electrode assembly at least a first functional layer ( 243 ), which is at least partially electrically conductive and electrically conductive ( 21 ) with the at least one first electrode ( 14 ) of the electrode assembly ( 12 ) connected is. Energy storage cell according to one of the preceding claims, characterized in that the first functional layer ( 243 ) and / or the second functional layer ( 244 ) of the envelope ( 24 ) are formed substantially fluid-tight. Energy storage cell according to one of the preceding claims, characterized in that the envelope ( 24 ) in the layer direction ( 25 ) of the sheath on its the electrode assembly ( 12 ) facing side of the first and / or second functional layers ( 243 . 244 ) at least one resistant protective layer ( 246 ) having. Energy storage cell according to one of the preceding claims, characterized in that between the first functional layer ( 243 ) and the at least one first electrode ( 14 ) of the electrode assembly ( 12 ) and / or between the second functional layer ( 244 ) and the at least one second electrode ( 16 ) of the electrode assembly ( 12 ) at least one discharge resistor ( 26 ) is switched. Energy storage cell according to claim 7, characterized in that the at least one discharge resistor ( 26 ) at least partially outside the envelope ( 24 ) and / or with a component outside the envelope ( 24 ) is thermally conductively connected. Energy storage cell according to one of the preceding claims, characterized in that the at least one first functional layer ( 243 ) and / or the at least one second functional layer ( 244 ) of the envelope ( 24 ) are at least partially formed as metal foils. Electrochemical energy storage device ( 30 ), with at least one electrochemical energy storage cell ( 10 ), wherein at least one of the energy storage cells ( 10 ) is configured according to one of claims 1 to 9; a housing ( 32 ) for receiving the at least one energy storage cell ( 10 ); and at least two battery terminals ( 34 . 36 ) of different priority, which are electrically conductive with the electrode assembly ( 12 ) or the electrode assemblies ( 12 ) of the at least one energy storage cell ( 10 ) are connected. Energy storage device according to claim 10, characterized in that at least one measuring device ( 40 ), which is configured, a state and / or a state change of the electrical connection between the at least one first functional layer ( 243 ) and the at least one second functional layer ( 244 ) of the envelope ( 24 ) at least one of the at least one energy storage cell ( 10 ) capture. Energy storage device according to claim 10, characterized in that at least one measuring device ( 40 ), which is configured, a state and / or a state change of the electrical connection between the at least one first functional layer ( 243 ) of the envelope ( 24 ) and the at least one first electrode ( 14 ) and / or between the at least one second functional layer ( 244 ) of the envelope ( 24 ) and the at least one second electrode ( 16 ) at least one of the at least one energy storage cell ( 10 ) capture. Energy storage device according to one of claims 10 to 12, characterized in that at least one current interrupt device ( 38 ), which is designed, the electrically conductive connection between at least one of the battery terminals ( 34 . 36 ) and the electrode assembly (s) ( 12 ) of the at least one energy storage cell ( 10 ) optionally to interrupt. Energy storage device according to one of claims 10 to 13, characterized in that it comprises a display device, which is configured, a hazardous state of at least one of the at least one energy storage cell ( 10 ) with regard to the functional layers of their envelope ( 24 ) and / or to transmit corresponding information to a control device.

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