DE102015224948A1 - Battery cell with coated enveloping foil - Google Patents

Abstract

It is a battery cell (10), in particular a lithium-ion battery cell, with at least two electrodes (6a, 6b) comprising a cladding film (1a, 1b) for forming a shell of the battery cell (10), said on the inside of the cladding film (1a , 1b) at least partially a coating (3a, 3b) of an electrically conductive material, in particular a metal, is applied and wherein on the coating (3a, 3b) an active material (5a, 5b) of an electrode (6a, 6b) is applied such that an electrode (6a, 6b) comprising the coating (3a, 3b) and the active material (5a, 5b) is formed, wherein the cladding film (1a, 1b) comprises an electrically non-conductive material and wherein an electrical contacting the battery cell (10) via a supernatant (3c, 3d) of the coating (3a, 3b) on the active material (5a, 5b) of the electrode (6a, 6b) also takes place and wherein the supernatant (3c, 3d) in particular from the battery cell (10), in particular by the wrapping film (1a, 1b) is led out.

Description

The present invention relates to a battery cell, in particular a lithium-ion battery cell, a battery and to the use thereof, according to the preamble of the independent claims.

State of the art

A battery cell is an electrochemical energy storage device that, when discharged, converts the stored chemical energy into electrical energy through an electrochemical reaction. It is becoming apparent that in the future both in stationary applications, such as wind turbines, in motor vehicles, which are designed as hybrid or electric motor vehicles, as well as electronic devices, new battery systems will be used, to the very high demands in terms of reliability, safety , Efficiency and lifetime are provided. Due to their high energy density, lithium-ion batteries are used in particular as energy stores for electrically powered motor vehicles.

Out DE 10 2008 011 523 A1 is a three-dimensional microbattery is known in which two adjacent chambers are formed in a substrate. The two chambers are separated by a porous, impregnated with an electrolyte partition. One chamber is filled with an active material for the anode, the other with an active material for the cathode. At the bottom of the chambers each electrical connections are arranged.

The DE 102012207999 A1 discloses a pouch cell with an enveloping foil made of an elastic and electrically insulating material, for example plastic, wherein a force sensor is arranged on the enveloping foil.

In the DE102013214112 A1 For example, there is disclosed a battery module having a plurality of soft prismatic battery cells having flexible polymer-walled bags wherein thermoelectric elements are embedded in the cell-bag walls.

Conventional battery cells comprise, for example, a housing or a jacket, which is present in particular in pouch cells as a foil, in which, for example, two electrodes, an anode and a cathode, and a separator separating the anode and the cathode from each other are arranged. In this case, the anode and the cathode respectively comprise a metallic carrier foil which is coated with an active material.

Disclosure of the invention

According to the invention, a battery cell, in particular a lithium-ion battery cell, having at least two electrodes comprising a cladding film for forming a shell of the battery cell, wherein on the inside of the cladding film at least partially a coating of an electrically conductive material, in particular a metal, is applied and wherein an active material of an electrode is applied to the coating so that an electrode comprising the coating and the active material is formed, provided with the characterizing features of the independent claims, and a battery and the use thereof.

Under the active material of a Eletkrode here a material is understood, in which lithium ions at loading or. Discharge processes of the battery cell can be stored or outsourced.

The at least two electrodes are formed by at least one anode and by at least one cathode. According to the invention, the enveloping foil of the battery cell comprises an electrically non-conductive material and the electrical contacting of the battery cell takes place via a projection of the coating beyond the active material of the electrode. In particular, the supernatant is led out of the battery cell, in particular through the cladding film. It is advantageous that the battery cell according to the invention has a significantly lower weight compared to conventional battery cells, since the metallic carrier foil conventional battery cells, for example by a coated with an electrically conductive material, in particular a metal, electrically non-conductive sheath film, in particular plastic, is replaced , As a result, less metal is used, resulting in a significant weight reduction of the battery cell. The thickness of the electrically conductive coating, in that it is applied to the cladding film, in the present invention can be significantly lower than the metallic carrier foils of conventional battery cells. As a result, the required amount of metals, such as aluminum or copper, which have a higher weight than, for example, non-conductive materials such as plastic, significantly reduced, which both reduces costs and causes a significant weight reduction. Especially the weight saving is an important aspect in the sale of battery cells and in particular of lithium ion battery cells. As a result of the lower weight of a battery cell installed in vehicles, for example, fuel consumption can thus also be reduced. Furthermore, the life cycle of the battery cell is improved, since less production energy is needed to produce the battery cell and the transport costs can be reduced due to the lighter weight. Furthermore, it is advantageous that the contacting of the battery cell via a supernatant of the coating on the active material of the electrode, and the supernatant is led out in particular from the battery cell, in particular through the cladding film, since the electrically conductive coating thus additionally acts as a current conductor. Thus, compared to conventional battery cells account for components for contacting the battery cell, such as current conductors, current collectors, external contacts or terminals or other from the electrode further components. The fact that these components are omitted, the battery cell offers more space for the electrically active components, ie for the electrode assembly comprising the electrodes and the separator. As a result, a higher energy density of the battery cell can be achieved. The electrically conductive coating is formed as an extension of the electrode. For this purpose, a part of the electrically conductive coating of the electrode, which is not coated in an outer region with active material, for example, from the battery cell, in particular through the cladding film, led out. Another advantage of the battery cell according to the invention is that it can be made very simple, thin and flexible by the structure described above. By thinly configured battery cells, for example, a high packing density can advantageously be achieved in the assembly of battery cells into modules or batteries. In such a module or in such a battery, a targeted charging or discharging and interconnecting individual battery cells is possible because the individual battery cells are directly accessible and contactable.

In a preferred embodiment, the cladding film encases an electrode assembly comprising only an anode, a separator and a cathode. As a result, the structure and thus the production of the battery cell is simple. With regard to the assembly of the battery cells and the local conditions, such a battery cell is also well adaptable in shape, for example, to the circumstances of the installation site.

It is also advantageous if the electrically conductive material of the coating comprises a metal, in particular aluminum, copper, nickel, gold, stainless steel or a metal alloy of the aforementioned metals.

Further advantageous embodiments of the present battery cell will become apparent from the dependent claims.

In a particularly preferred embodiment, it is advantageous if the wrapping film is formed in two parts with a first wrapping film and a second wrapping film. In this case, a first coating, which in particular comprises aluminum, is applied to the first wrapping film and a cathode active material is applied to the first coating, so that the first coating with applied cathode active material forms a cathode. The cathode active material includes, for example, a lithium metal oxide LiMeO. Alternatively, the cathode active material comprises a non-oxidic material. A second coating, which in particular comprises a copper, is applied to the second cladding film and an anode active material is applied to the second cladding, so that the second coating with applied anode active material forms an anode. The anode active material comprises, for example, a graphite, in particular a natural or a synthetic graphite, silicon and / or a titanate.

The cathode active material is separated from the anode active material by a separator. The separator comprises, for example, microporous plastics as well as nonwovens of glass fiber or polyethylene or composite films of, for example, polyethylene or propylene or ceramic materials. It is advantageous that the structure of the battery cell described is designed very simple, and thus also the production of the battery cell. An advantage of an electrically conductive coating of the first aluminum foil is that aluminum is a suitable cathode component and is also very easy and inexpensive and available in large quantities. An advantage of an electrically conductive coating of the second cladding made of copper is that copper is a suitable anode component and is also very resistant to corrosion, which, inter alia, brings a long service life. Furthermore, copper is easy to process and can be optimally deformed even at low temperatures.

In a preferred embodiment, the electrically nonconductive material of the enveloping film is a plastic, in particular a thermoplastic, for example a polyamide, a polyethylene, a polypropylene or a polyethylene terephthalate, or alternatively, in particular, a thermoset, for example an epoxy resin, an acrylate or a polyurethane. In a further preferred embodiment, the enveloping film comprises a composite material comprising, for example, at least two different plastics. An advantage of a plastic film is that plastics form a watertight barrier and, in addition, the total weight of the film and thus the total weight of the battery cell is reduced. Since plastics are often available inexpensively, thus also the manufacturing cost of the battery cell can be reduced, which in turn improves the life cycle of the battery cell, as for their production less production energy must be applied and the lower cost of the battery cell transport costs are reduced. Polyamide is characterized by a high Strength, a high chemical and weather-related resistance, as well as by a low tendency to form stress cracks. Polyethylene and polypropylene are both robust and flexible, have high mechanical and chemical stability and are also weldable. Furthermore, polyethylene has a high toughness, low water absorption and water vapor permeability, as well as a high resistance to chemicals and is also easy to process and inexpensive. Polypropylene has a low water absorption, is chemically resistant, electrically insulating and easy to process and inexpensive. Polyethylene terephthalates have a high breaking strength and temperature stability. Thermosets, such as epoxy resins, acrylates or polyurethanes have a high chemical and thermal resistance. It is advantageous in the case of an enveloping film made of a composite material comprising, for example, at least two different plastics, that different desired properties of the various plastics can be combined with one another in this way.

In a further embodiment, the cladding film has a thickness of between 10 μm and 200 μm, preferably between 20 μm and 100 μm. The advantage here is that the cladding film is stable in this thickness range, so that it is not easily damaged and yet flexible.

In a further advantageous embodiment, the battery cell is sealed for sealing, welded or glued. In this case, the first wrapping film and the second wrapping film are connected to one another, for example by means of a circumferential seal, for example a peripheral seal, for example by means of a heat-sealing method. An advantage of a seal by a seal is that a tight, good connection is formed. The material of the seal or of the seal is selected, for example, from polyetheretherketone (PEEK) or another polymer from the substance group of polyetherketones (PEK).

Alternatively, the first and the second wrapping film are connected to each other, for example by means of a circumferential weld. The advantage here is that a weld results in a dense long-lasting connection of the components to be welded and also a welded joint is easy and quick to produce. Furthermore, alternatively, the first and the second wrapping film are glued together, for example. An adhesive bond has the advantage that no weakening of the joining parts occurs. If necessary, adhesive bonds can be elastic, damp vibrations and are also cost-effective.

In one embodiment, the seal extends circumferentially from the first coating of the first wrapping film to the second wrapping film and from the second coating of the second wrapping film to the first wrapping film. The advantage here is that the interior of the battery cell comprising the anode, the cathode and the separator, in this way reliably sealed and protected and the battery cell can also be electrically contacted via the first coating and / or the second coating. In an alternative preferred embodiment, the first and second cladding sheets of the battery cell are sealed by a seal such that the sealing extends from the first cladding foil to the second cladding of the second cladding foil and / or the sealing from the second cladding foil to the first Coating of the first wrapping film is sufficient. In addition to the advantages already mentioned for this embodiment, there is also the fact that here too the end of the metallic coating, via which no contacting takes place, is located within the battery cell and therefore does not have to be insulated to the outside. Thus, the safety of the battery cell is increased.

In one embodiment, it is advantageous if the first cladding film has a protrusion beyond the cathode active material that corresponds to the length of the supernatant of the first coating beyond the cathode active material and / or if the second cladding film forms a protrusion beyond the anode active material, which length of the supernatant of the second coating beyond the anode active material. The advantage here is that the mechanical stability of the supernatant of the first and the second coating is increased by the supernatant of the enveloping film and the first or the second coating is at least partially protected from external influences. Furthermore, the ensprechende active material is thus already on one side electrically insulated by the supernatant of the cladding film, whereby the security of the battery cell is increased. In one embodiment, it is advantageous if further electrodes are accommodated in the battery cell, which are in particular stacked on one another. The advantage here is that the energy density of the battery cell is thus increased and at the same time the material of the cladding foil is saved, since then a separate cladding film is not required for each unit of anode, separator and cathode. The carrier foils of the further electrodes are made, for example, analogously to the cladding foil of a further electrically non-conductive material such as plastic, on which one or both sides a further electrically conductive coating is applied. The further electrically conductive coating comprises in the case of a cathode, for example aluminum and in the case of an anode, for example copper. On the further electrically conductive coating, for example, a applied further anode or cathode active material, so that the respective further electrically conductive coating together with the respective further active material forms a further anode or a further cathode. Advantageous in carrier films, which are formed from a further non-conductive material that thus further weight of the battery cell can be saved, since a non-conductive material such as plastic is lighter than, for example, an electrically conductive material such as a metal. The further electrically conductive coating of the carrier film of a further electrically non-conductive material can then be made thinner, for example, than if the carrier film were made directly from an electrically conductive material and is nevertheless stable and functional. Furthermore advantageous here is that not every single electrode must be contacted separately electrically, but the electrodes of the same polarity collected on the supernatants, which are led out of the battery cell, in particular through the cladding foil, are contactable.

In one embodiment, it is advantageous if the battery cell has a liquid electrolyte. The electrolyte serves as a lithium-ion conductor. The liquid electrolyte comprises, for example, the lithium conducting salt lithium hexa-fluorophosphate (LiPF ₆ ) dissolved in an organic solvent. The solvents used are, for example, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate or dimethyl carbonate.

Furthermore, a battery comprising at least one battery cell according to the invention for the reasons already mentioned is advantageous and also the use of the battery in an electric vehicle, in a hybrid vehicle or in a plug-in hybrid vehicle. Alternatively, the battery is used for example in ships, two-wheelers, aircraft, stationary energy storage, power tools, entertainment electronics and / or household appliances.

Short description of the drawing

Embodiments of the present invention are illustrated in the drawing and explained in more detail in the following description of the figures. It shows:

1 FIG. 2: a schematic representation of a first variant of a battery cell according to the invention with a projection of an electrically conductive coating in a cross section, FIG.

2 FIG. 2: a schematic representation of a second variant of the battery cell according to the invention with a projection of an electrically conductive coating and a projection of a covering film in a cross section, FIG.

3 a schematic representation of a third variant of the battery cell according to the invention, and

4 : a schematic representation of the battery cell according to the invention according to 2 with several electrodes.

Embodiments of the invention

In 1 is a battery cell 10 represented with a first wrapping film 1a and a second wrapping film 1b , The first wrapping film 1a and the second wrapping film 1b comprise an electrically non-conductive material, for example a plastic, in particular a thermoplastic such as a polyamide, a polyethylene, a polypropylene or a polyethylene terephthalate. The wrapping film 1a . 1b has, for example, a thickness between 10 .mu.m and 200 .mu.m, preferably between 20 .mu.m and 100 .mu.m. On the first wrapping film 1a is a first coating 3a applied from an electrically conductive material. The first coating 3a includes, for example, an aluminum. On the first coating 3a is still a cathode active material 5a applied. The electrically conductive, first coating 3a and the cathode active material applied thereto 5a together form a cathode 6a , The cathode active material 5a For example, it includes a lithium metal oxide LiMeO. Alternatively, the cathode active material comprises 5a a non-oxidic material. On the second wrapping film 1b is a second coating 3b applied from an electrically conductive material. The second coating 3b includes, for example, a copper. On the second coating 3b is an anode active material 5b applied. The electrically conductive, second coating 3b and the anode active material applied thereto 5b together form an anode 6b , The anode active material 5b includes, for example, a graphite, in particular a natural or a synthetic graphite, silicon and / or a titanate. The cathode 6a and the anode 6b are through a separator 7 separated from each other. The separator 7 includes, for example, microporous plastics, nonwovens of glass fiber or polyethylene or composite films of, for example, polyethylene and propylene or ceramic materials. The battery cell 10 is in 1 through a seal 9 sealed. The seal 9 is for example a seal. Here are the first wrapping film 1a and the second wrapping film 1b For example, connected by a peripheral seal with each other. Alternatively, the seal 9 formed by a, in particular circumferential, welding or bonding. The seal 9 in 1 seals the edge area of the battery cell 10 between the first wrapping film 1a and the second wrapping film 1b from, so only one first supernatant 3c the first coating 3a at one point and a second supernatant 3d the second coating 3b at another location, for example at one of the first supernatant 3c opposite point, from the seal 9 protrudes. In the cross-sectional view in 1 the sealing is enough 9 thus at the point where the second supernatant 3d the second coating 3b from the seal 9 stands out from the first wrapping film 1a to the second coating 3b the second wrapping film 1b and at the point where the first supernatant 3c from the first coating 3a from the seal 9 protrudes from the second wrapping film 1b to the first coating 3a the first wrapping film 1a , The battery cell 10 has, for example, a liquid electrolyte in its interior. The liquid electrolyte comprises, for example, the lithium conducting salt lithium hexa-fluorophosphate (LiPF ₆ ) dissolved in an organic solvent. The solvents used are, for example, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate or dimethyl carbonate. In 1 points the battery cell 10 only a cathode 6a and an anode 6b on which through the separator 7 are separated from each other.

In 2 is a second variant of the invention 10 shown. In contrast to 1 has the first wrapping film 1a the battery cell 10 a first supernatant 1c over the cathode active material 5a which is the length of the first supernatant 3c the first coating 3a over the cathode active material 5a also corresponds. Furthermore, the second wrapping film has 1b the battery cell 10 a second supernatant 1d via the anode active material 5b on which the length of the supernatant 3d the second coating 3b via the anode active material 5b also corresponds.

3 shows a third variant of the battery cell according to the invention 10 , In contrast to 2 is sufficient for the seal 9 circulating from the first coating 3a the first wrapping film 1a to the second coating 3b the second wrapping film 1b ,

In 4 is the battery cell according to the invention 10 out 2 with several electrodes 6a . 6b . 60a . 60b shown. Between the cathode 6a and another anode 60b is a separator 7 arranged and between the anode 6b and another cathode 60a is also a separator 7 arranged.

One the further anode 60b and the other cathode 60a separating electrically non-conductive foil 100 is on one side with another first coating 30a , in particular of aluminum, and on the other side with a further second coating 30b , in particular of copper. On the further first coating 30a is another cathode active material 50a applied and on the further second coating 30b is another anode active material 50b applied. The separating electrically non-conductive foil 100 is for example analogous to the first wrapping film 1a and the second wrapping film 1b designed, in particular of a plastic. To the further cathode 60a electrically with the first coating 3a to connect is a first current conductor 300 arranged so that this from the further first coating 30a to the first coating 3a runs. To the other anode 60b electrically with the second coating 3b to connect is a second current collector 400 arranged so that this from the further second coating 30b to the second coating 3b runs. To the counter electrode in each case in front of the respective current conductor 300 . 400 electrically isolate, each is an electrically insulating element 12 between the first current conductor 300 and the other anode 60b and between the second current collector 400 and the other cathode 60a appropriate. In an alternative embodiment with several in the battery cell 10 located electrodes and at least two electrically non-conductive films 100 can be on both sides of any electrically non-conductive foil 100 the same coating be applied with respective active material, so that on both sides of the electrically non-conductive film 100 the same electrode is arranged.

Furthermore, combinations of the in the 1 - 4 described embodiments with each other also subject of the present invention.

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 102008011523 A1 [0003]
• DE 102012207999 A1 [0004]
• DE 102013214112 A1 [0005]

Claims (12)

Battery cell ( 10 ), in particular lithium-ion battery cell, with at least two electrodes ( 6a . 6b ) comprising a wrapping film ( 1a . 1b ) for forming a shell of the battery cell ( 10 ), wherein on the inside of the enveloping film ( 1a . 1b ) at least partially a coating ( 3a . 3b ) is applied from an electrically conductive material, in particular a metal, and wherein on the coating ( 3a . 3b ) an active material ( 5a . 5b ) of an electrode ( 6a . 6b ) is applied so that an electrode ( 6a . 6b ) comprising the coating ( 3a . 3b ) and the active material is formed, characterized in that the enveloping film ( 1a . 1b ) comprises an electrically non-conductive material and that an electrical contact of the battery cell ( 10 ) over a supernatant ( 3c . 3d ) of the coating ( 3a . 3b ) about the active material ( 5a . 5b ) of the electrode ( 6a . 6b ), the supernatant ( 3c . 3d ) in particular from the battery cell ( 10 ), in particular by the wrapping film ( 1a . 1b ), is led out. Battery cell ( 10 ) according to claim 1, characterized in that the wrapping film ( 1a . 1b ) is formed in two parts with a first wrapping film ( 1a ) and a second wrapping film ( 1b ) and wherein a first coating ( 3a ) of the first wrapping film ( 1a ) comprises in particular an aluminum, and wherein on the first coating ( 3a ) a cathode active material ( 5a ) and wherein a second coating ( 3b ) the second wrapping film ( 1b ) comprises in particular a copper, and wherein the second coating ( 3b ) an anode active material ( 5b ) and wherein the cathode active material ( 5a ) through a separator ( 7 ) of an anode active material ( 5b ) is spatially separated. Battery cell ( 10 ) according to one of the preceding claims, characterized in that the electrically non-conductive material of the enveloping film ( 1a . 1b ) comprises a plastic, in particular a thermoplastic, for example a polyamide, a polyethylene, a polypropylene or a polyethylene terephthalate or in particular a thermoset, for example an epoxy resin, an acrylate or a polyurethane. Battery cell ( 10 ) according to one of the preceding claims, characterized in that the electrically non-conductive material of the enveloping film ( 1a . 1b ) is a composite material comprising at least two different plastics. Battery cell ( 10 ) according to one of the preceding claims, characterized in that the wrapping film ( 1a . 1b ) has a thickness of between 10 μm and 200 μm, in particular between 20 μm and 100 μm. Battery cell ( 10 ) according to one of the preceding claims, characterized in that the battery cell ( 10 ) is sealed for sealing, welded or glued. Battery cell ( 10 ) according to claim 6, characterized in that a seal ( 9 ) of the first wrapping film ( 1a ) to the second coating ( 3b ) of the second wrapping film ( 1b ) and / or that the seal ( 9 ) of the second wrapping film ( 1b ) to the first coating ( 3a ) of the first wrapping film ( 1a ) enough. Battery cell ( 10 ) according to any one of claims 2-7, characterized in that the first wrapping film ( 1a ) a supernatant ( 1c ) over the cathode active material ( 5a ), which corresponds to the length of the supernatant ( 3c ) of the first coating ( 3a ) over the cathode active material ( 5a ) and / or that the second wrapping film ( 1b ) a supernatant ( 1d ) via the anode active material ( 5b ), which of the length of the supernatant ( 3d ) of the second coating ( 3b ) via the anode active material ( 5b ). Battery cell ( 10 ) according to one of the preceding claims, characterized in that in the battery cell ( 10 ) further electrodes ( 60a . 60b ), which are in particular stacked on each other. Battery cell ( 10 ) according to one of the preceding claims, characterized in that the battery cell ( 10 ) has a liquid electrolyte. Battery comprising at least one battery cell ( 10 ) according to any one of claims 1-10. Use of a battery according to claim 11 in an electric vehicle, in a hybrid vehicle or in a plug-in hybrid vehicle.

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