DE102015205319A1 - Electric battery cell - Google Patents

Abstract

The present invention relates to a stackable battery cell (100) for storing electrical energy, comprising a first electrically conductive outer contact layer (103-1), a planar anode (107-1) which is in full-surface electrical contact with the first outer contact layer (103-1) a second electrically conductive outer contact layer (103-2), a planar cathode (107-2) in electrical contact with the second outer contact layer (103-3) and a separator layer (105) arranged between the anode (107-1 ) and the cathode (107-2) is arranged.

Description

The present invention relates to a stackable battery cell for storing electrical energy, such as in an accumulator.

Current lithium-ion batteries provide sufficient energy density, discharge rate, and cycle life for electronic consumer goods only, such as laptops or smartphones. With these batteries, the currents at the retrieved services are comparatively low. However, electric vehicle applications require higher energy density and voltage than consumer products.

The primary task of the battery cell cells is to provide energy for an electric drive. The efficiency of the battery cells increases with increasing battery voltage, since heat loss is only defined by the amount of current flow. In today's technical solutions, the internal resistance on the battery contacts, i. The metallic connection between the individual cells is a crucial loss factor through heat development. This affects stronger with increasing current. The internal heating of the battery cell also causes chemical stress, which can be described by the Arrhenius equation. As the temperature rises, the chemical kinetics of the side reactions in the battery cell increase exponentially. The temperature development due to high currents leads to cell aging in the long term and is thus a lifetime-determining wear factor.

The publication US 2011/0117418 relates, for example, to a battery cell in which electrodes are alternately electrically connected via the bottleneck of lateral terminal lugs, each having an electrically conductive side.

The publication US 2012/10177977 relates to a battery cell in which electrodes are alternately electrically connected via the bottleneck of individual welding points, each with an electrically conductive side.

The current of these battery cells concentrates in the terminal lugs or welding points and locally causes a high heating of the battery cells, which leads to punctual aging.

It is the object of the present invention to provide an easily combinable battery cell which can provide high voltage in combination with other battery cells without overheating in local areas.

According to a first aspect, the object is achieved by a stackable battery cell for storing electrical energy, having a first electrically conductive outer contact layer; a flat anode, which is in full-surface electrical contact with the first outer contact layer; a second electrically conductive outer contact layer; a two-dimensional cathode, which is in full-surface electrical contact with the second outer contact layer; and a separator layer disposed between the anode and the cathode. Thereby, the technical advantage is achieved that any battery voltage can be generated by stacking multiple battery cells without changing the cell chemistry. Due to the large outer contact layers, a punctual heating of the battery cell is prevented.

In an advantageous embodiment of the battery cell, the first outer contact layer and / or the second outer contact layer is formed by a metal plate. As a result, for example, the technical advantage is achieved that heat during charging and discharging of the battery cell can be efficiently led over the metal plate.

In a further advantageous embodiment of the battery cell, the metal plate has a recess for receiving the anode or for receiving the cathode. As a result, for example, the technical advantage is achieved that the anode or the cathode are surrounded by the metal plate.

In a further advantageous embodiment of the battery cell, the recess is arranged centrally in the metal plate. As a result, for example, the technical advantage is achieved that the heat can be dissipated evenly to all sides.

In a further advantageous embodiment of the battery cell, the metal plate is formed of aluminum or copper. As a result, for example, the technical advantage is achieved that the battery cell has a low weight or high conductivity.

In a further advantageous embodiment of the battery cell, the first and / or the second outer contact layer is formed by a metal foil. As a result, for example, the technical advantage is achieved that the battery cell can be manufactured with a low material usage.

In a further advantageous embodiment of the battery cell, the metal foil is laminated together with the separator layer. As a result, for example, the technical advantage is achieved that the battery cell can be manufactured with a high energy storage density.

In a further advantageous embodiment of the battery cell, the first outer contact layer and / or the second outer contact layer is partially covered with an outer insulation layer. As a result, for example, the technical advantage is achieved that subregions of the outer contact layer can be excluded from a current flow. In these subareas, for example, a planar electrical circuit can be placed.

In a further advantageous embodiment of the battery cell, the first outer contact layer and / or the second outer contact layer is rectangular. As a result, the technical advantage is achieved, for example, that a cuboid structure of the battery can be realized.

According to a second aspect, the object is achieved by a battery having a stack of a plurality of battery cells according to the first aspect. As a result, for example, the same technical advantages, as solved by the battery cell according to the first aspect.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below.

Show it:

1 a cross-sectional view through a battery cell;

2 a plan view of the battery cell; and

3 a schematic view of a battery with multiple battery cells.

1 shows a cross-sectional view through a battery cell 100 , The battery cell 100 converts chemical energy of an exothermic reaction into electrical power. In the battery cell 100 the reaction partners are spatially separated from each other.

The battery cell 100 comprises a first electrically conductive outer contact layer 103-1 and a second electrically conductive outer contact layer 103-2 as electrodes. About the outer contact layers 103-1 and 103-2 there is a surface contact of the battery cell 100 with other identical battery cells 100 , The battery cells 100 can be easily stacked and stacked for this purpose.

Inside the battery cell 100 is a flat anode 107-1 arranged on one side in full-surface electrical contact with the first outer contact layer 103-1 stands. In the same way is inside the battery cell 100 a flat cathode 107-2 arranged on one side in full-surface electrical contact with the second outer contact layer 103-2 stands. Due to the full-surface contact is the emergence of local heating of the battery cell 100 prevented, which could otherwise arise at individual contact points. In addition, the outer contact layers generate 103-1 and 103-2 a current-carrying encapsulation of the battery cell.

Between the anode 107-1 and the cathode 107-2 is an ion-conducting separator layer 105 arranged, which allows an ion flux. In addition, between the anode 107-1 and the cathode 107-2 an optional layered diffusion barrier 111 be arranged, for example in a lithium sulfur cell. Between the anode 107-1 and the separator layer 105 as well as between the cathode 107-2 and the separator layer 105 is the electrolyte 117 ,

The first outer contact layer 103-1 and the second outer contact layer 103-2 are electrically separated from each other by a circumferential insulating layer 109 separated in an edge region of the first outer contact layer 103-1 and the second outer contact layer 103-2 is arranged. Complete ionic isolation in the edge area in addition to electrical cell isolation between the two outer contact layers 103-1 and 103-2 is advantageous in the case of a lithium sulfur cell because diffusion of soluble lithium sulfur compounds is prevented. The insulation layer 109 can be formed by a sealant, which is a leakage of the electrolyte 117 prevented. By the electrical separation of the two outer contact layers 103-1 and 103-2 arises between these the battery voltage.

The reaction takes place when lithium as the ion to the cathode 107-2 is transported. Since lithium in the stored original state at the anode 107-1 is present neutral, takes place at the anode 107-1 a cleavage of the electron. At the cathode 107-2 the lithium ion is again provided with an electron for charge equalization. The lithium ion transport is controlled by the electric current in the external circuit and is converted there as power.

The anode 107-1 and the cathode 107-2 may comprise an intercalating material as an active material which causes a small volume change during charging and discharging operations. The intercalation material has a high cycle stability. The active material can be on the cathode 107-2 with a polymer binder, such as polyvinylidene fluoride (PVDF), to be fixed on a conductive arrester foil. In addition, the cathode can 107-2 Conducting carbon black and graphite may be added to provide sufficient conductivity for electrons from the active material to ensure the arrester foil. This can be done in a similar way for the anode 107-1 be provided.

Through the battery cell 100 For example, the charge or power draw of a battery can be increased because the current at constant voltage due to the large outer contact layers 103-1 and 103-2 Contact areas increased and no local heating of the battery cell 100 takes place.

The flat outer contact layers 103-1 and 103-2 can through metal plates 113-1 and 113-2 may be formed, for example, made of copper or aluminum and form an electrical arrester. In the middle of the metal plates 113-1 and 113-2 recesses may be formed, in each of which the anode 107-1 or cathode 107-2 is included.

Heat generated by the flow of current causes increased cell temperature and accelerates unwanted chemical side reactions. This heat can pass through the metal plates 113-1 and 113-2 be discharged evenly. In addition, the manufacturing quality of the flat surface of the manufactured in one piece outer contact layers 103-1 and 103-2 increase.

Due to the high surface area of the anode 107-1 and the cathode 107-2 and the parallel arrangement to the electrode layers, a charge content increase is achieved. As a result, the allowable current can be increased. The battery voltage of the battery cell 100 is retained and is at the outer contact layers 103-1 and 103-2 measurable.

An electrical contact of the mutually insulated battery cells 100 However, it can also be done centrally or in peripheral areas, so that high currents over the entire cross section are avoided. Individual areas of the outer contact layers 103-1 and 103-2 can do this by means of an outer insulation layer 115 be covered, for example, a partially applied insulation film. In these areas, a flat electronic circuit can then be arranged. The illustrated advantages of the battery cell 100 stay here.

In an advantageous embodiment, the battery cell 100 realized with a large area, such as with a width of 210 mm and a length of 297 mm or area with a width of 0.5 m and a length of 1 m. As a result, the current and the area of the electrical contact are increased, ie the dimension of Zellekaspelung.

2 shows a plan view of the battery cell 100 , The battery cell 100 has a rectangular outer contact layer 103-1 on that through the metal plate 113-1 is formed. In the middle of the metal plate 113-1 can have a recess for the anode 107-1 be formed. The battery cell 100 has a sandwich structure.

3 shows a schematic view of a battery 200 with several battery cells 100 , To the voltage of the battery 200 To increase, will be multiple battery cells 100 connected in series by stacking. The electrolyte 117 the battery cells 100 is encapsulated against each other. The battery 200 may be a high voltage cell with compressed electrodes in three-dimensional gradient design.

This results in a further technically advantageous structure to the battery cells 100 to connect in series and the electrolyte 117 to encapsulate against each other. The encapsulation is achieved by a combination of the separator layer 105 with a metal foil as outer contact layer 103-1 achieved in a molding process. The prerequisite for this structure is the stability of the molding compound to cell chemistry. The metal foil can with the separator layer 105 be laminated together.

In the bag-shaped structure is the anode 107-1 or the cathode 107-2 between the separator layer 105 and the metal foil used, so that this contacted the metal foil over its entire surface on one side. The metal foil of the bag is energized. The flat metal foils, such as aluminum or copper foils, cause an ionic insulation to the outside and serve as external contact layers 103-1 and 103-2 the battery cell 100 ,

The electrolyte 117 will be in the anode 107-1 , Cathode 107-2 and the separator layer 105 co-compressed or filled by additional feed channels. Within the bag thus formed is only one cell. The filling of the electrolyte 117 However, it can also be done only in an example outer bag or a Can, which includes several series-connected battery cells. In the edge region of the metal foils also becomes an insulating layer 109 for mutual electrical separation of the outer contact layers 103-1 and 103-2 used.

The battery cells 100 can be stacked on top of each other, so the voltage of the battery 200 is increased. In addition, this structure allows monitoring and bridging individual battery cells 100 through a suitable electrical sensor, which is directly on the stack of battery cells 100 can be arranged.

The battery cells 100 can be based on lithium-sulfur (LiS). By a larger number of these battery cells 100 can lower the voltage of LiS battery cells 100 be easily compensated compared to Li-ion battery cells.

The dimension of the metal foils, for example, also have a width of 0.5 m and a length of 1 m. The battery 200 has a high power density and a low overall volume with the same use of active chemical materials. Parallel connections of the battery 200 To increase the current can be done at higher voltage levels, so that in a single cell composite of battery cells, a lower current flows. This leads to an improved heat situation within the battery cells 100 , At a higher voltage occur in the battery 200 lower currents at the level of the battery cells 100 on, without the performance drops. Spot warming can be easily deduced from the chemistry of the battery cell 100 be shielded.

The electrolyte 117 is subjected to a lower voltage so that decomposition reactions are reduced. This makes it possible to increase the battery voltage and to dispense with a classic arrester arrangement. This allows the construction and interconnection of the battery cells 100 be simplified so that the thermal stress is reduced and the life and performance are increased. The heat development of the battery cell 100 is lower so that current limits for a maximum allowable current can be increased. In addition, it is possible to increase the battery voltage and reduce the current while maintaining the same performance.

The production of the electrodes can be carried out by compression, in which a mechanical entanglement of expanded graphite takes place under high pressure in calenders, for example at a line load of 6000 N / mm. This produces a porous graphite foil into which the active materials of anode and cathode, including binders and conductive additives, are incorporated. As a result, solvent-free electrode films can be produced. The graphite foil in this case has the advantage of being itself electrically conductive and thus supporting the electrical contact through many conductive percolation paths. By degrees of freedom in the process of film pressing, other electrode and cell structures can be realized.

In general, the materials are for the anode 107-1 , the cathode 107-2 , the separator layer 105 , the electrolyte 117 , the diffusion barrier 111 and the outer contact layers 103-1 and 103-2 selectable from the known material classes.

By the cell structure of the battery 200 becomes a series connection of several battery cells 100 made possible by simply juxtaposing. This results in a current reduction with increasing voltage, so that ohmic losses are reduced within the battery. The result is a lower heat generation, which allows for optimized heat management.

All features explained and shown in connection with individual embodiments of the invention may be provided in different combinations in the article according to the invention, in order to simultaneously realize their advantageous effects.

The scope of the present invention is given by the claims and is not limited by the features illustrated in the specification or shown in the figures.

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

• US 2011/0117418 [0004]
• US 2012/10177977 [0005]

Claims (10)

Stackable battery cell ( 100 ) for storing electrical energy, comprising: a first electrically conductive outer contact layer ( 103-1 ); a flat anode ( 107-1 ), which are in full-surface electrical contact with the first outer contact layer ( 103-1 ) stands; a second electrically conductive outer contact layer ( 103-2 ); a flat cathode ( 107-2 ), which in full-surface electrical contact with the second outer contact layer ( 103-2 ) stands; and a separator layer ( 105 ), which between the anode ( 107-1 ) and the cathode ( 107-2 ) is arranged. Battery cell ( 100 ) according to claim 1, wherein the first outer contact layer ( 103-1 ) and / or the second outer contact layer ( 103-2 ) through a metal plate ( 113-1 . 113-2 ) is formed. Battery cell ( 100 ) according to claim 2, wherein the metal plate ( 113-1 . 113-2 ) a recess for receiving the anode ( 107-1 ) or to receive the cathode ( 107-2 ) having. Battery cell ( 100 ) according to claim 3, wherein the recess in the middle in the metal plate ( 113-1 . 113-2 ) is arranged. Battery cell ( 100 ) according to one of claims 2 to 4, wherein the metal plate ( 113-1 . 113-2 ) is formed of aluminum or copper. Battery cell ( 100 ) according to claim 1, wherein the first and / or the second outer contact layer ( 103-1 . 103-2 ) is formed by a metal foil. Battery cell ( 100 ) according to claim 6, wherein the metal foil with the separator layer ( 105 ) is laminated together. Battery cell ( 100 ) according to one of the preceding claims, wherein the first outer contact layer ( 103-1 ) and / or the second outer contact layer ( 103-2 ) partially with an outer insulation layer ( 115 ) is covered. Battery cell ( 100 ) according to one of the preceding claims, wherein the first outer contact layer ( 103-1 ) and / or the second outer contact layer ( 103-2 ) is rectangular. Battery ( 200 ) with a stack of several battery cells ( 100 ) according to one of claims 1 to 9.

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