Battery with heat conductor

Abstract

Battery with a casing (1) and a stack (2) arranged within the casing (1) comprising several first electrodes (3a) and several second electrodes (3b) arranged alternately in the stack (2) and each having a current conductor (7a, 7b), wherein the current conductors (7a) of the first electrodes (3a) are electrically connected to a first battery terminal (8a) and the current conductors (7b) of the second electrodes (3b) are electrically connected to a second battery terminal (8b), wherein the first electrodes (3a) are additionally connected to each other via at least one thermal conductor (9a), excluding the second electrodes (3b), and / or the second electrodes (3b) are additionally connected to each other via at least one thermal conductor (9b), characterized in thatthat the heat conductor (9a) connecting the first electrodes (3a) and / or the heat conductor (9b) connecting the second electrodes (3b) does not contact the casing (1).

Description

The invention relates to a battery, in particular a battery provided as a traction battery of a motor vehicle, by means of which electrical energy can be provided for operating an electric traction motor of the motor vehicle, according to the preamble of claim 1.A battery is an electrochemical-based electric energy storage device, in the discharge of which stored chemical energy is converted into electric energy by an electrochemical redox reaction. In the context of the invention, batteries are understood to be both so-called primary batteries which are provided only for a single discharge and not for a renewed charging, and also so-called secondary batteries or accumulators which are provided for a multiple charging and are designed accordingly. Charging a secondary battery represents the electrolytic reversal of the electrochemical redox reaction which takes place during the discharge and is realized by the application of an electrical voltage.A battery comprises one or, usually, a plurality of battery cells or galvanic cells. The battery cells each have two electrodes, a separator arranged between the electrodes for electrically separating the electrodes and an electrolyte serving as an ion conductor between the electrodes (cf. U.S. Pat. No. 6,027,831 A).Batteries and in particular the lithium-ion batteries which are mainly used at present as traction batteries in motor vehicles should be stored and in particular operated, i.e. charged and discharged, in a defined temperature range in order to avoid power deficits, damage and / or accelerated aging. Exceeding the temperature range does not have to be based exclusively on a temperature adaptation with a correspondingly high ambient temperature; rather, batteries generate waste heat to a considerable extent during charging or discharging of a battery, which leads to self-heating. It may therefore be useful to temperature control batteries in order to avoid the temperature range being exceeded or underrun. In the case of traction batteries of motor vehicles, such a temperature control is usually carried out by means of an integration of the traction batteries into a cooling system of the motor vehicle, by means of which thermal energy can be transferred to the traction batteries or discharged from the latter via a temperature control liquid. In this case, casings or housings of individual batteries or battery modules, which form the traction battery in a manner connected to form a so-called battery stack, are usually tempered. Within the casings, however, a multiplicity of individual battery cells are usually arranged in a stack. It follows from this that a tempering via the cladding is more effective for layers of the stack located relatively close to the cladding and the tempering effect decreases significantly towards the center within the cladding.In order to improve cooling of a battery cell as a result of self-heating of the electrodes, a foil-shaped heat conductor can be arranged between the electrodes of the battery cell according to U.S. Pat. No. 9,865,904 B2, wherein a section of the heat conductor projecting beyond the stack with the electrodes is connected to a metallic housing of the battery cell.US 2005 / 0 026 014 A1 discloses a battery stack having a plurality of batteries arranged in a stack, each of which consists of a plurality of stacked galvanic cells. Each of the batteries includes two battery poles. The battery poles of the batteries of the battery stack are thermally coupled to a housing of the battery stack via an elastic thermal material.US 2015 / 0 064 511 A1 describes a battery with anodes, cathodes and a Z-shaped separator. The anodes comprise a substrate acting as a current conductor and the cathodes comprise a substrate acting as a current conductor. The substrates of the anodes on the one hand and of the cathodes on the other hand each form a heat conductor, wherein the heat conductors of the anodes and the heat conductors of the cathodes are each joined together at a junction and integrated into a casing of the battery and optionally also led out of the latter in order to form contact with coolant channels.The invention is based on the object of realizing the most uniform possible temperature control of a battery in a simple manner.This object is achieved with a battery according to claim 1. Preferred embodiments of such a battery are the subject matter of the further patent claims and / or emerge from the following description of the invention.A battery according to the invention, preferably in an embodiment as a secondary battery, comprises a casing, for example in the form of a housing or a so-called pouch cell casing, and a stack arranged within the casing, having a plurality or at least two first electrodes and having a plurality or at least two second electrodes which are arranged alternately in the stack, preferably with an intermediate arrangement of a separator in each case, i.e. a second electrode is arranged between two first electrodes and a first electrode is arranged between two second electrodes. The electrodes each have a current collector, wherein the current collectors of the first electrodes are electrically conductively connected to a first battery pole and the current collectors of the second electrodes are electrically conductively connected to a second battery pole. According to the invention, it can be provided that the first electrodes are connected to one another via at least one additional heat conductor, excluding the second electrodes. Alternatively or, preferably, additionally, it can be provided that the second electrodes are connected to one another via at least one additional heat conductor with the exclusion of the first electrodes. "With the exclusion" means in this case that the heat conductor is not connected to the corresponding electrodes or does not contact them. "In addition" means that the heat conductor is provided in addition to or separately from the current collectors, which connect the respective (first or second) electrodes at least via the respectively associated (first or second) battery pole and in this case can also have a heat-conducting effect in addition to the current-conducting function.The heat conductor or conductors can be used to achieve an additional, relatively good heat-conducting connection from electrodes located relatively centrally within the stack to electrodes located on the edge side in a structurally simple manner, so that an advantageous temperature control of the centrally located electrodes can also be achieved by a corresponding large heat flow via these electrodes on the edge side.According to the invention, it is furthermore provided that the heat conductor connecting the first electrodes and / or the heat conductor connecting the second electrodes does not contact the casing. As a result, in the case of an also electrically conductive configuration of the heat conductor, as can be produced in particular in the case of the preferred configuration of the heat conductor from metal, an electrical short circuit of the battery via a likewise electrically conductive configuration can be avoided. Such an electrically conductive configuration of the enclosure can result in particular from the fact that it is at least partially formed from metal, as a result of which a dimensionally stable configuration in the form of a housing can be realized. In addition, an embodiment of the casing made of metal can also enable advantageous temperature controllability of the battery cells accommodated within the casing as a result of a relatively high thermal conductivity of the casing realized as a result.A battery according to the invention which is particularly advantageous from a structural point of view can be realized in that the first electrodes and / or the second electrodes have at least partially, preferably all (in each case) an electrically conductive substrate which serves as a current conductor of the respective electrode and which can be formed for this purpose from or with an electrically conductive material. One or more regions of the substrate, which may in particular be situated outside the stack, may / may represent the current conductor belonging to the respective electrode and / or a portion of the heat conductor connecting the corresponding electrode. Such a section of the substrate can be connected directly or indirectly (i.e. via at least one further electrically conductive element, for example a current conductor of another electrode) to the corresponding battery pole for use as a current conductor. For use as a portion of the thermal conductor, such a region may be connected to a corresponding region of at least one other electrode of the same type to form the thermal conductor or a portion thereof. Such a connection can be realized, for example, by welding.It can furthermore preferably be provided that the substrate is provided with a coating of an active material at least on one side (i.e. on one of the sides situated in the stacking direction), optionally on both sides (i.e. with both sides situated in the stacking direction), so that the electrodes can act as anodes or cathodes within the scope of use of the battery. The region or regions of the substrate serving as a current collector or heat conductor can then preferably be free of the coating, as a result of which, inter alia, coating material can be saved. For an electrode which is intended to function as an anode of the battery, it can also be provided that the substrate does not have a coating with active material if an in situ deposition of anodically active material takes place during use of the battery, as can be implemented in a known manner at least in solid-state lithium-ion batteries.Furthermore, it can preferably be provided that the current collectors and / or the substrates and / or the heat conductor or conductors are at least partially (i.e. at least one / one of them and / or optionally not completely), preferably all / completely made of metal, whereby a good current conductivity and / or heat conductivity can be realized in a simple and cost-effective manner.Preferably, it can be provided that the heat conductor runs outside the stack. This enables in particular simple fabrication of the battery.According to a preferred embodiment of a battery according to the invention, it can be provided that the stack is of cuboidal configuration, wherein the heat conductor connecting the first electrodes is arranged on the same side as the first battery pole and / or the heat conductor connecting the second electrodes is arranged on the same side as the second battery pole. On the one hand, this allows a relatively compact configuration of the battery because usually on that side or on those sides on which the battery poles are arranged, a free space which is not filled by the stack is provided within the enclosure, within which the current collectors are guided. Portions of this free space that are not blocked by the current collectors can then be used for an arrangement of the heat conductor(s). If the battery poles are also arranged on different sides of the stack, an electrical short circuit as a result of an unintentional contact of the heat conductor connecting the first electrodes with the second battery pole or the current collectors connected thereto of the second electrodes and / or of the heat conductor connecting the second electrodes with the first battery pole or the current collectors connected thereto of the first electrodes can additionally be avoided in an electrically conductive configuration of the heat conductor(s).According to a further preferred embodiment of a battery according to the invention, it can be provided that the stack is of cuboidal configuration, wherein the heat conductor connecting the first electrodes is arranged on another side of the stack in comparison with the first battery pole and / or the heat conductor connecting the second electrodes is arranged on another side of the stack in comparison with the second battery pole. In this case, it can be provided on the one hand that the heat conductor connecting the first electrodes is arranged on the same side as the second battery pole and / or the heat conductor connecting the second electrodes is arranged on the same side as the first battery pole. This embodiment can also be advantageous with regard to a configuration of the battery that is as compact as possible. Alternatively, it can be provided that the heat conductor connecting the first electrodes and / or the heat conductor connecting the second electrodes is / are arranged on one side of the stack without a battery pole.Furthermore, it can preferably be provided that the heat conductor connecting the first electrodes and the first battery pole are arranged on opposite sides of the stack and / or the heat conductor connecting the second electrodes and the second battery pole are arranged on opposite sides of the stack. This can also have an advantageous effect with regard to the mullability and / or the dimensions of the battery.Preferred embodiments of a battery according to the invention, which relate to a heat conductor or specifically to the heat conductor connecting the first electrodes or the heat conductor connecting the second electrodes, are to be understood such that, provided the battery comprises a plurality of corresponding heat conductors, they apply at least to one, preferably to a plurality, particularly preferably to all of these heat conductors.The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings. The drawings show, in each case in a simplified illustration: FIG. 1 : a battery according to the invention according to a first embodiment in a sectional illustration; FIG. 2 : a longitudinal section through the battery according to FIG. 1 along the sectional plane II-II in FIG. 1 ; FIG. 3 : an electrode of the battery according to FIGS. 1 and 2 in a plan view; FIG. 4 : shows a battery according to the invention according to a second embodiment in a sectional illustration; FIG. 5 shows an electrode of the battery according to FIG. 4 in a plan view; FIG. 6 : shows a battery according to the invention according to a third embodiment in a sectional illustration; and FIG. 7 : an electrode of the battery according to FIG. 6 in a plan view.The drawings show various embodiments of batteries according to the invention. These each comprise a casing 1 in the form of a cuboidal housing, for example made of a metal, and a cuboidal stack 2 with electrodes 3 arranged within the housing. Specifically, the stack 2 is in the form of a so-called electrode-separator composite (ESV) and for this purpose comprises, in an alternating arrangement, a plurality of first electrodes 3 awhich function as anodes when the battery discharges, and a plurality of second electrodes 3 bwhich function as cathodes when the battery discharges. As a result of the alternating arrangement of the electrodes 3, a first electrode 3 ais arranged between two second electrodes 3 band a second electrode 3 bis arranged between two first electrodes 3 a, respectively. Adjacent electrodes 3 are each separated by a layer of a separator 4 and are thereby also electrically insulated from one another.Each of the electrodes 3 comprises a planar, foil-like substrate 5, which can be made of copper, for example, in the case of the first electrodes 3 aprovided as anodes and of aluminum in the case of the second electrodes 3 bprovided as cathodes. In a square portion thereof, the two large areas of each of the electrodes 3 located in the stacking direction of the stack 2 are provided with a coating of an active material 6 in order to enable the various electrodes 3 a, 3 bto act as anodes or cathodes during use of the battery. In the region of these square sections of the substrates 5 and thus of the electrodes 3, these and the correspondingly square-shaped layers of the separator 4 are stacked, resulting in the cuboid shape of the stack 2.On a transverse side of the rectangular section of each electrode 3, in the illustrated embodiment, three regions of the substrate 5 separated from one another and spaced apart are provided in total, in which the substrate 5 is not provided with the coating of the respective active material 6. These regions of the electrodes 3 serve either as a current collector 7, via which the individual electrodes 3 are electrically conductively connected to a respectively assigned battery pole 8 of the battery, or as a section of a heat conductor 9, which connects all of the electrodes 3 a, 3 bof one type (first electrodes 3 aor second electrodes 3 b) in a heat-conducting manner. To form such a heat conductor 9, the corresponding regions of the electrodes to be connected in a heat-conducting manner or of the substrates 5 thereof are connected to one another, for example welded.The current collectors 7 aof all first electrodes 3 aare connected to a first ( 8 a) of the battery poles 8, and the current collectors 7 bof all second electrodes 3 bare connected to a second ( 8 b) of the battery poles 8.In the battery shown in FIGS. 1, 2 to 3, the arrangement of the heat conductors 9 of the individual electrodes 3 is such that they are arranged on the same side as the associated current collector 7, wherein the current collector 7 is arranged between the associated heat conductors 9 with respect to the transverse direction of the electrodes 3. This results in the fact that the heat conductors 9 aconnecting the first electrodes 3 aare arranged on the same side of the stack 2 as the first battery pole 8 a, and the heat conductors 9 bconnecting the second electrodes 3 bare arranged on the same side of the stack 2 as the second battery pole 8 b.In the embodiment example shown in FIGS. 4 and 5, the heat conductors 9 of the individual electrodes 3, on the other hand, are arranged on the side opposite the associated current conductor 7. The heat conductors 9 aconnecting the first electrodes 3 aare arranged on the same side of the stack 2 as the second battery pole 8 band as the current collectors 7 bconnecting the latter to the second electrodes 3 b. And the heat conductors 9 bconnecting the second electrodes 3 bare arranged on the same side of the stack 2 as the first battery pole 8 aand as the current collectors 7 aconnecting it to the first electrodes 3 a. In this embodiment example as well, the current collectors 7 of the individual electrodes 3 are arranged between the associated heat conductors 9.In the embodiment example shown in FIGS. 6 and 7, the heat conductors 9, on the other hand, are arranged on the longitudinal sides of the stack 2 and thus on sides of the stack 2 without a battery pole 8.LIST OF REFERENCE CHARACTERS1 Casing 2 Stack 3 Electrode 3 aFirst electrode 3 bSecond electrode 4 Separator 5 Substrate 6 Active material 7 Current collector 7 aCurrent collector of the first electrode 7 bCurrent collector of the second electrode 8 Battery pole 8 aFirst battery pole 8 bSecond battery pole 9 Heat conductor 9 aConductor of the first electrode 9 bConductor of the second electrode

Claims

A battery comprising a casing (1) and a stack (2) arranged within the casing (1), having a plurality of first electrodes (3a) and a plurality of second electrodes (3b) which are arranged alternately in the stack (2) and which each have a current collector (7a, 7b), wherein the current collectors (7a) of the first electrodes (3a) are electrically conductively connected to a first battery pole (8a) and the current collectors (7b) of the second electrodes (3b) are electrically conductively connected to a second battery pole (8b), wherein the first electrodes (3a) are additionally connected to one another via at least one heat conductor (9a) with the exclusion of the second electrodes (3b) and / or the second electrodes (3b) are additionally connected to one another via at least one heat conductor (9b) with the exclusion of the first electrodes (3a), characterized in that the heat conductor (9a) connecting the first electrodes (3a) and / or the heat conductor (9b) connecting the second electrodes (3b) do not contact the casing (1).Battery according to Claim 1, characterized in that the first electrodes (3a) and / or the second electrodes (3b) have at least partially an electrically conductive substrate (5), wherein a region of the substrate (5) represents the current conductor (7a, 7b) belonging to the respective electrode (3a, 3b) and / or a region of the substrate (5) represents a section of the respective heat conductor (9a, 9b).Battery according to Claim 2, characterized in that the substrate (5) is provided at least on one side with a coating of an active material (6), wherein the region of the substrate (5) which represents the current collector (7a, 7b) belonging to the respective electrode (3a, 3b) and / or the region of the substrate (5) which represents the section of the respective heat conductor (9a, 9b) is free of the coating.Battery according to either of Claims 2 and 3, characterized in that the current collectors (7a, 7b) and / or the substrates (5) and / or the heat conductors (9a, 9b) are at least partially formed from metal.Battery according to one of the preceding claims, characterized in that the heat conductor (9a, 9b) runs outside the stack (2).Battery according to one of the preceding claims, characterized in that the stack (2) is of cuboidal configuration, wherein the heat conductor (9a) connecting the first electrodes (3a) is arranged on the same side as the first battery pole (8a) and / or the heat conductor (9b) connecting the second electrodes (3b) is arranged on the same side as the second battery pole (8b).Battery according to one of Claims 1 to 5, characterized in that the stack (2) is of cuboidal configuration, wherein the heat conductor (9a) connecting the first electrodes (3a) is arranged on another side of the stack (2) in comparison with the first battery pole (8a), and / or the heat conductor (9b) connecting the second electrodes (3b) is arranged on another side of the stack (2) in comparison with the second battery pole (8b).Battery according to Claim 7, characterized in that the heat conductor (9a) connecting the first electrodes (3a) is arranged on the same side as the second battery pole (8b) and / or the heat conductor (9b) connecting the second electrodes (3b) is arranged on the same side as the first battery pole (8a).Battery according to Claim 7, characterized in that the heat conductor (9a) connecting the first electrodes (3a) and / or the heat conductor (9b) connecting the second electrodes (3b) is / are arranged on one side of the stack (2) without a battery pole (8a, 8b).Battery according to one of Claims 7 to 9, characterized in that the heat conductor (9a) connecting the first electrodes (3a) and the first battery pole (8a) are arranged on mutually opposite sides of the stack (2), and / or the heat conductor (9b) connecting the second electrodes (3b) and the second battery pole (8b) are arranged on mutually opposite sides of the stack (2).

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