DE102015222171A1 - Spacer for a battery cell for forming a distance between the battery cell and another battery cell - Google Patents

Abstract

A spacer (1) for a battery cell (10), in particular for a lithium-ion battery cell, for forming a distance between the battery cell (10) and a further battery cell (10) is described, wherein the battery cell (10) has a housing with at least four side surfaces (6a-d), wherein the spacer (1) is adapted to receive a battery cell (10), so that the battery cell (10) at least partially on a first side surface (6a) and at least partially on one of these opposite second side surface (6c ) of the housing of the battery cell (10) and at least partially on at least one further housing surface of the housing of the battery cell (10) of the spacer (1) is surrounded, and wherein the spacer (1) at least on a third side surface (6c) of the housing of Battery cell (10) at least partially in a region, in particular in an edge region, in the form of a Umgriffs (19) is formed under recess a further region, in particular a central region, of the third side surface (6c) of the housing of the battery cell (10).

Description

The present invention relates to a spacer for a battery cell for forming a distance between the battery cell and another battery cell, to a battery and to a use of the spacer or the battery 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, Performance and life are made. Due to their high energy density and their low self-discharge, in particular lithium ion batteries are used as energy storage for electrically powered vehicles.

For high power energy systems, for example, for use in motor vehicles, a plurality of battery cells are mechanically assembled into modules, and for example connected in parallel or in series. From such battery modules, for example, battery packs are constructed. A battery includes, for example, one or more battery modules or battery packs. Often one of the electrodes is electrically conductively connected to the battery cell housing, so that a potential is applied to the battery cell housing. As a result, for example, corrosion of the battery cell housing can be prevented. The housings of the battery cells must then be provided, for example, with insulation to adjacent battery cells or to the vehicle ground in order to prevent the risk of a short circuit. Currently, battery cells are electrically isolated from each other, for example, by polymer-based materials. These include, for example, adhesive tapes, shrink tubing or insulation coatings.

In the DE 102009035500 A1 is disclosed a battery with several single cells. The individual cells are arranged inside enveloping sheets which partially surround the individual cells. The individual cells are held and arranged in such a force-locking manner that changes in distance due to thermal expansion are compensated.

The DE 102013015785 A1 discloses a cell block for a battery comprising a plurality of single cells. The individual cells are inserted into a frame which has a corresponding opening for each individual cell. The openings are separated from each other by partitions. The partitions are designed to be flexible and allow a length compensation, or tolerance compensation between the individual cells.

The DE 102012018062 A1 discloses a single battery cell. The single cell is surrounded by a half shell. Two half-shells each form housing side walls for the battery cell and completely surround the battery cell.

Disclosure of the invention

According to the invention a spacer for a battery cell for forming a distance between the battery cell and another battery cell, a battery and the use of the spacer or the battery with the characterizing features of the independent claims are provided.

The spacer is adapted to receive a battery cell with a housing having at least four side surfaces, so that it is at least partially surrounded on a first and on a second side surface of the housing, which are opposite, and at least partially on at least one further housing surface of the spacer. In addition, the spacer engages around a third side surface of the housing of the battery cell at least partially in a region, in particular in an edge region, in the form of a Umgriffs recess of another area, in particular a central region, the third side surface of the housing of the battery cell. An at least partially comprising a housing surface of the battery cell through the spacer means that the housing surface is completely surrounded by the spacer or alternatively, that the spacer comprises recesses, so that the spacer surrounds only areas of the housing surface.

Surrounded by the term is meant that the spacer on the respective housing surface or the respective region of the housing surface of the battery cell, in particular directly rests, so that the respective housing surface or the respective region of the housing surface is bordered by the spacer. An advantage of the inventive spacer is that it forms a distance between the battery cell, which surrounds this and another battery cell, so that the battery cells are held by the spacer at a distance from each other. Inside a battery cell at least two electrodes are arranged, which separated by a separator. Battery cells are often clamped together. The often very large clamping forces thus generated can lead to a very high load and thus, for example, to a decreasing porosity of the separator. In addition, for example, it comes to local overloading of the electrodes and it form, for example, porous dendritic lithium deposits, which can lead to an internal short circuit. The spacer counteracts this and ensures that certain bracing values or surface pressure values are not exceeded. As a result, the clamping force, which is introduced in the mechanical tension of the battery cells in this mechanically fixed to be limited, whereby the battery cells are less heavily loaded. Because of this, the components inside the battery cells, such as the separator or the electrodes, are longer functional and thus more durable. In addition, the safety of the battery cells is increased because short circuits due to excessive loads and a concomitant degradation of the components of the battery cells are prevented. Furthermore, it is advantageous that the battery cell undergoes mechanical protection through the spacer, so that it can not be easily damaged, for example, by impact-like forces acting on the battery cell from the outside. Corresponding shock-like forces, for example, undergoes a battery cell installed in a battery system of a vehicle, for example in the event of an impact, caused, for example, by an accident or when traveling on uneven road surfaces. By means of the spacer, the inner life of the battery cell is thus protected and the risk of battery cell damage significantly reduced, which provides additional security for occupants of a vehicle. In this case, it is advantageous in one embodiment if the spacer surrounds a large number of housing surfaces and if it surrounds the respective housing surfaces over the entire surface, since in this way the battery cell experiences the greatest possible mechanical protection. In an alternative embodiment, it is advantageous if the spacer only partially surrounds the opposing first and second side surfaces, as well as a further housing surface, since in this way material costs and weight are saved.

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

In one embodiment, the at least one further housing surface of the housing of the battery cell is a bottom surface and / or a lid surface. The advantage here is that the material of the spacer is saved, since these housing surfaces are smaller in area than, for example, the larger side surfaces of the housing of a prismatic battery cell. In a particularly preferred embodiment, the at least one further housing surface of the housing of the battery cell is a fourth side surface. The advantage here is that the spacer at least partially surrounds the battery cell on the first, the second and the fourth side surface of the housing of the battery cell, and partially on the third side surface of the housing in the form of a wrap. Thus, multiple battery cells can be strung together with spacers, for example when building a battery module, without that two battery cells can touch, or there is no separating element between them. In this case, the spacers are all arranged one behind the other in the same orientation, so that the embracing of the spacer, which is arranged on the third side surface of the housing of the battery cell located in this battery cell adjacent to the surface of a further spacer, which surrounds a fourth side surface of another battery cell , In this way, the juxtaposed spacers each form a separating element between the individual battery cells. Thus, a load can be particularly well mitigated by excessive clamping forces and also ensure that the battery cells due to the given mechanical frame by the spacer still not by a swelling, for example by loading and unloading or by signs of aging, deform.

In a particularly advantageous and preferred embodiment, the spacer is made electrically insulating. The material of the spacer in this case comprises, for example, a plastic, preferably a polyolefin, in particular a polyethylene, a polypropylene, a polyethylene terephthalate or a polycarbonate.

This offers the great advantage that the isolation of the individual battery cells can be omitted. The spacer thus assumes the function of electrical insulation and compliance with the necessary distance between adjacent battery cells, for example in a battery module. The fact that the battery cells thus no longer need to be electrically insulated, for example, with shrink tubing or paints, and the instead electrically insulating spacers on the third side surface is designed as Umgriff and not the entire surface, almost eliminates a whole area to be isolated.

This saves space and costs for the insulation material. By the function of the spacer as insulation a component and process reduction is achieved, through which further costs are saved. The steps for applying the insulation to the battery cell omitted, thereby saving time and labor costs and whereby the mounting of the insulation in the form of the spacer is simplified. Furthermore, it is advantageous that an insulation of the cooling plate, which is usually applied directly to the battery cells and this cools, for example, during operation, is eliminated. In this case, the insulation material of the spacer is made thickened at the location adjacent to the cooling plate, for example.

In a further embodiment, the spacer is made in one piece, in particular by an injection molding process, by thermoforming or a deep-drawing process. By means of an injection molding process, for example, plastic components with complex geometry and high accuracy can be produced in short cycle times. Injection molding processes are very economical processes, especially in the production of large quantities.

In a further preferred embodiment, a force acts on the battery cell via the spacer, so that the battery cell is mechanically braced. Over the life of a battery cell increases their internal pressure and it comes, for example, to a swelling of the battery cell, which is due among other things to the swelling of the active material of the electrodes, for example during charging and / or gas formation inside the battery cell. This can lead to a considerable loss of power of the battery cell. In order to counteract this, the battery cells, which are assembled, for example, into modules, are advantageously clamped together mechanically and fixed in this way. By clamping the battery cells together, a certain length tolerance and mechanical stability of the battery cells in the module are furthermore achieved. In addition, the battery cell can not slip during handling during assembly of the battery modules, whereby the assembly is simplified and can be done more precisely. Thus, the spacer takes over the function of maintaining a distance between the battery cells and the tension of the battery cells, with certain bracing values or surface pressures due to the construction of the spacer still not be exceeded, so that the components of the battery cells are not overloaded.

Furthermore, a battery is described with at least two battery cells, which are held by at least one spacer according to the invention at a distance from each other.

In an advantageous embodiment, at least two spacers are mechanically connected to each other, for example via the wrap. The advantage here is that instead of individual spacers, a cell module box or a cell stack box is obtained. A spacer is connected via the wraparound, which rests only in edge regions on the third side surface of the battery cell, with a spacer side surface of a further spacer, said spacer side surface abuts the fourth side surface of another battery cell connected. As a result, the battery cell on the third side surface of the housing is given some space, for example, for expansion, wherein the space of the material thickness of the spacer 1 equivalent. In this way, the force acting on the battery cell pressure, for example, in the clamped state, limited so that no damage to the components of the battery cell occur. In addition, a cell module box or cell stack box is easier to handle, for example, when assembling individual battery cells or individual battery modules to a battery in the module and pack assembly. Furthermore, manufacturing and logistics costs in battery module production can be saved by using the cell module box or the cell stack box as a transport container.

In an advantageous embodiment, the mechanical connection is produced via a welding method, in particular via an ultrasonic welding method. An advantage of a welding process is that a dense and stable and durable connection between the components to be welded is achieved. An advantage of an ultrasonic welding process is that high efficiency is achieved by fast process times, as well as a homogeneous solidification in the joining zone of the corresponding components, whereby exact welds are obtained with very good quality.

Furthermore, it is advantageous if the mechanical connection is a peripheral connection, so that the spacers are connected to one another at a connecting line throughout. The advantage here is that the cell module box or cell stack box formed in this way forms dense and electrically isolated chambers. As a result, on the one hand, the safety through the tightness and thus ensured electrical insulation of the individual chambers is very high, since a short circuit can be almost excluded by coming into contact with battery cells. In addition, liquid can not pass from one chamber to another, for example due to a leak in the cell module box or cell stack box, but is prevented from spreading, as a result of which safety is also increased. In addition, the shape of the cell module box or the cell stack box, for example, better preserved in shock or other external or internal influences on the battery, as it is more stable due to the peripheral compound. Alternatively, the spacers are only partially connected to each other at a connecting line, so that no circumferential continuous connection is formed, but the connection only partially formed along the connecting line.

In a further embodiment, it is provided that the battery cells are held apart from the spacer by an additional component, in particular an intermediate piece. The advantage here is that the material thickness of the spacer can be made very thin due to the additional component, whereby space and material costs of the spacer can be saved.

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 : the schematic representation of a first variant of the spacer according to the invention for a battery cell,

2 : the schematic representation of a prismatic battery cell,

3 : the schematic representation of the spacer according to the invention according to 1 with a battery cell according to 2 which is surrounded by the spacer,

4 : the schematic representation of a second variant of the spacer according to the invention with a battery cell according to 2 which is surrounded by the spacer,

5a : the schematic representation of an unfinished cell module box or cell stack box according to the invention with spacers 1 with partially inserted battery cells,

5b : The schematic representation of an enlarged section of the cell module box or cell stack box with spacers according to the invention 5a , and

6 the schematic representation of a finished cell module box or cell stack box with juxtaposed spacer according to the invention according to the 1 . 3 . 5a and 5b , by which a distance between battery cells, which are surrounded by the spacers, is formed.

Embodiments of the invention

1 shows a first variant of a spacer 1 for a battery cell, in particular for a lithium-ion battery cell. The spacer 1 has two opposing smaller spacer side surfaces 16a . 16b , as well as a larger spacer side surface 16d and a spacer floor surface 17 on. At the smaller spacer side surfaces 16a . 16b is a whipping 19 formed, which starting from the smaller spacer side surfaces 16a . 16b at a 90 ° angle in the direction of the other smaller spacer side surface 16a . 16b projects. Furthermore, starting from the spacer base surface 17 an embrace 19 formed, which projects at a 90 ° angle from this and in the Umgriff 19 starting from the smaller spacer side surfaces 16a . 16b passes. Alternatively, the spacer has 1 only the smaller spacer side surfaces 16a . 16b with wrap 19 and the spacer floor area 17 without wraith 19 as well as the larger spacer side surface 16d on. Furthermore, alternatively, the spacer 1 only the smaller spacer side surfaces 16a . 16b with wrap 19 and the larger spacer side surface 16d on. Furthermore, alternatively, the spacer 1 For example, in all the above embodiments, a spacer cover surface, not shown, which, for example, also a wrap 19 forms, which points from this at a 90 ° angle in the direction of the Umgriffs the bottom surface and, for example, in the Umgriff 19 starting from the smaller spacer side surfaces 16a . 16b passes. The spacer 1 is designed, for example, electrically insulating. The material of the spacer 1 In this case, for example, comprises a plastic, in particular a polyethylene terephthalate, a polycarbonate or a polyolefin, preferably a polyethylene and / or a polypropylene.

The spacer 1 is for example made in one piece, in particular by means of an injection molding process.

In 2 is a prismatic battery cell 10 shown with a housing having a first side surface 6a , a second side surface 6b , a third side surface 6c and a fourth side surface 6d , a floor area 7 and a lid surface 8th , The housing includes, for example, a plastic or a metal such as aluminum or metal alloys, especially steel. Furthermore, the battery cell includes 10 an electrode assembly, not shown, with a cathode, a separator and an anode, which, for example, wound into each other or stacked on top of each other. The cathode comprises, for example, a cathode foil, which is coated with an active material and the anode comprises, for example, an anode foil, which is coated with an active material. The cathode foil comprises, for example, aluminum and the anode foil comprises, for example, copper. The battery cell 10 also includes two terminals 3 which directly or for example via current conductors to the cathode or the anode of the battery cell 10 are electrically connected. At the terminals 3 can the electricity the battery cell 10 be tapped. Furthermore, the battery cell includes 10 For example, a safety valve 4 which allows gas to escape in the event of excessive internal battery pressure.

In 3 is the spacer 1 according to 1 with a battery cell 10 according to 2 , which of the spacer 1 is surrounded. The spacer 1 is formed the battery cell 10 so absorb that first side surface 6a and the second side surface 6b the housing of the battery cell 10 from the smaller spacer side surfaces 16a . 16b are surrounded, so in 3 only the smaller spacer side surfaces 16a . 16b are visible. Furthermore, the fourth side surface 6d the housing of the battery cell 10 from the larger spacer side surface 16d surround. In 3 is just a small overhang of the larger spacer side surface 16d over the battery cell 10 visible, noticeable. The floor area 7 the housing of the battery cell 10 is from the spacer base 17 surrounded, what in 3 because of the perspective is not visible. In addition, a lateral edge region and a lower edge region of the third side surface 6c the housing of the battery cell 10 from a wrap 19 of the spacer 1 , starting from the smaller spacer side surfaces 16a . 16b and the spacer base 17 surrounded by a recess of a central area of the third side surface 6c the housing of the battery cell 10 , The spacer 1 For example, it is located directly on the battery cell 10 so that it is firmly enclosed and can not slip. Preferably acts on the spacer 1 a force on the battery cell 10 so that the battery cell 10 is mechanically clamped.

In 4 is a second variant of the spacer 1 shown. Unlike the first, in the 1 and 3 illustrated variant of the spacer 1 is in 4 in addition to starting from the smaller spacer side surfaces 16a . 16b and the spacer base 17 trained wraith 19 also a whipping 19 which at an upper edge region of the third side surface 6c the housing of the battery cell 10 is present and which of the Umgriff 19 the smaller spacer side surface 16a up to the Umgriff 19 the smaller spacer side surface 16b ranges .. Alternatively, the upper edge of the third side surface 6c the housing of the battery cell 10 covering wraparound 19 be formed starting from a spacer cover surface, not shown in the figures. The spacer cover surface has, for example, recesses in the area of the terminals 3 the battery cell 10 and the safety valve 4 on. The Umgriff 19 can be a continuous whipping 19 starting from the smaller spacer side surfaces 16a . 6b , the spacer base 17 and / or the spacer cover surface may be formed. Alternatively, the Umgriff 19 only partially, starting from the mentioned spacer surfaces. Another difference of in 4 shown second variant of the spacer 1 to the in the 1 and 3 shown first variant of the spacer 1 is that the spacer side surfaces 16a . 16b . 16d no protrusion, which over the lid surface 8th the battery cell 10 stands out form.

Furthermore, also variants of the spacer 1 possible, which are not shown in the figures, but from a combination of in the 1 - 4 shown spacers 1 and their corresponding explanations.

In 5a is an unfinished cell module box 100 or a cell stacking box of spaced spacers 1a - 1m according to 1 shown. The lined spacers 1a - 1m form chambers in the cell module box 100 out. In these chambers are battery cells 10 introduced, so through the spacers 1a - 1m a distance between the battery cells 10 is trained. In 5 There are already four battery cells 10 into the cell module box 100 brought in. The battery cells 10 are then according to 3 from a spacer 1a - 1m surrounded, as well as on the third side surface 6c the housing of the battery cell 10 from another spacer 1a - 1m , For example, a battery cell 10 according to 3 from the twelfth spacer 1l surrounded, as well as on the third side surface 6c the housing of the battery cell 10 from the larger spacer side surface 16d of the eleventh spacer 1k , A spacer 1a - 1m is about the Umgriff 19 on the larger spacer side surface 16d another spacer 1a - 1m mechanically fastened. This is the larger side surface 16d a spacer 1a - 1m which the battery cell 10 then on the third side surface 6c of the housing does not directly surround this, so that an air gap is formed between them. In 5a is a connecting line 13 indicating the area in which the spacers 1 are connected to each other. The spacers 1a - 1m can completely along the connecting line 13 be connected to each other or only partially along the connecting line 13 , In addition, the spacers 1a - 1m in the case of a wraparound, which on the upper edge surface of the third side surface of the housing of the battery cell 10 rests on this encirclement 19 be connected to each other. The distance between the battery cells 10 is about the material thickness of the spacer 1a - 1m set or over the multiple of the material thickness, for example, when folding the material of the spacer 1a - 1m , so that it is formed of several layers of material. Alternatively, the distance between the battery cells 10 next to the spacer 1a - 1m by an additional, not shown in the figures component, in particular an intermediate piece set or be enlarged. In addition, unwanted air and creepage distances between the battery cells 10 in electrically insulating spacers 1a - 1m about the size of the area of the Umgriffs 19 be set. Limits the spacer 1a - 1m For example, to an electrically conductive component, for example, to a metallic cooling plate, which is connected to a vehicle mass, the length of the creepage distance corresponds to the shortest path of the example of electrically conductive housing of the battery cell 10 over the outer surface of the spacer 1a - 1m to the component which is grounded. If now the Umgriff 19 is increased, so at the same time the length of the creepage distance is increased. The same applies to the air route.

In this way, sufficient insulation of the battery cells 10 achieved without each other, that the juxtaposed spacers 1a - 1m must be seamlessly connected.

5b shows an enlarged section of the cell module box 100 or cell stack box 5a with the spacers 1a - 1d , The individual spacers 1a - 1d are along the connecting line 13 mechanically interconnected. The mechanical connection is produced, for example, via a welding method, in particular via an ultrasonic welding method. The mechanical connection is, for example, a circumferential connection, in particular a circumferential weld, so that the spacers 1a - 1d at the connecting line 13 continuous and seamlessly interconnected whereby a closed insulation of the battery cells 10 from each other. Alternatively, the spacers 1a - 1d along the connecting lines 13 only partially connected with each other.

In 6 is a finished cell module box 100 or cell stacking box with juxtaposed spacers according to the invention 1a - 1m represented by which a distance between the battery cells 10 , which of the spacers 1a - 1m are surrounded, is formed. The spacers 1a - 1m the cell module box 100 are preferably designed to be electrically insulating. In this case, the insulation of the first and the last battery cell takes place 10 the cell module box 100 for example, by a corresponding design of end plates of the module or alternatively by a correspondingly separately produced, not shown in the figures insulation element. This is according to the connection of the spacers 1a - 1m with each other with the Umgriff 19 the battery cell 10 mechanically connected, for example, welded, in particular continuous or alternatively regionally.

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 102009035500 A1 [0004]
• DE 102013015785 A1 [0005]
• DE 102012018062 A1 [0006]

Claims (11)

Spacer ( 1 ) for a battery cell ( 10 ), in particular for a lithium ion battery cell, for forming a distance between the battery cell ( 10 ) and another battery cell ( 10 ), the battery cell ( 10 ) a housing with at least four side surfaces ( 6a -D), characterized in that the spacer ( 1 ) is formed a battery cell ( 10 ), so that the battery cell ( 10 ) at least partially on a first side surface ( 6a ) and at least partially on one of these opposite second side surface ( 6c ) of the housing of the battery cell ( 10 ) and at least partially on at least one further housing surface of the housing of the battery cell ( 10 ) of the spacer ( 1 ), and that the spacer ( 1 ) at least on a third side surface ( 6c ) of the housing of the battery cell ( 10 ) at least partially in a region, in particular in an edge region, in the form of a wrap ( 19 ) is formed with the exception of a further region, in particular a central region, the third side surface ( 6c ) of the housing of the battery cell ( 10 ). Spacer ( 1 ) according to claim 1, characterized in that the at least one further housing surface of the housing of the battery cell ( 10 ) a floor surface ( 7 ) and / or a lid surface ( 8th ) and / or a fourth side surface ( 6d ). Spacer ( 1 ) according to one of the preceding claims, characterized in that the spacer ( 1 ) is designed electrically insulating. Spacer ( 1 ) according to one of the preceding claims, characterized in that the spacer ( 1 ) is made in one piece, in particular by means of an injection molding process, by means of thermoforming or by means of a deep-drawing process. Spacer ( 1 ) according to one of the preceding claims, characterized in that via the spacer ( 1 ) a force on the battery cell ( 10 ), so that the battery cell ( 10 ) is mechanically clamped. Battery with at least two battery cells ( 10 ), characterized in that the battery cells ( 10 ) via at least one spacer ( 1 ) according to any one of claims 1-5 are kept at a distance from each other. Battery according to claim 6, characterized in that at least two spacers ( 1 ) are mechanically interconnected. Battery according to claim 7, characterized in that the mechanical connection is made via a welding process, in particular an ultrasonic welding method. Battery according to one of claims 7 or 8, characterized in that the mechanical connection is a peripheral connection, so that the spacers ( 1 ) at a connecting line ( 13 ) are interconnected. Battery according to one of claims 6-9, characterized in that the battery cells ( 10 ) next to the spacer ( 1 ) are held at a distance from each other by an additional component, in particular an intermediate piece. Use of a spacer ( 1 ) according to any one of claims 1-5 or a battery according to any one of claims 6-10 in an electric vehicle, in a hybrid vehicle or in a plug-in hybrid vehicle.

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