High-voltage battery with at least one battery module

Abstract

The invention relates to a high-voltage battery (1) with at least one battery module (3, 4) comprising a plurality of individual battery cells (5) which have at least one of the battery poles (8, 9) and a burst opening (10) on a first side, wherein all first sides of the individual battery cells (5) of the battery module (3, 4) are covered by a contact plate (11) which has electrical discharge clips (14) for electrically conductively connecting the battery poles (8, 9), wherein the contact plate (11) has a plurality of openings and / or sections (16, 16a, 16b) which, in the event of a thermal event in the battery module (3, 4), release openings (16c). The high-voltage battery according to the invention is characterized in that the openings and / or sections (16, 16a, 16b) are formed offset from the burst openings (10).

Description

[0001] The invention relates to a high-voltage battery with at least one battery module according to the type defined in more detail in the preamble of claim 1. The invention also relates to a vehicle with such a high-voltage battery.

[0002] A protective unit for a battery module of a high-voltage battery of a vehicle is known from the generic document DE 10 2018 125 618 A1. It essentially consists of a contact plate, which is referred to therein as a cell contacting system. This contact plate, typically made of plastic, has arrester clips for electrically contacting the battery terminals of the individual battery cells of the battery module. For safety reasons, in the design described in the generic document, an intermediate layer is inserted between the contact plate and the battery modules. This intermediate layer has openings for the battery terminals and openings aligned with the burst openings of the individual battery cells. In the event of a thermal incident in one of the individual battery cells, this is intended to create electrical and thermal insulation in order to protect the unaffected individual battery cells.The openings in the intermediate layer, which are aligned with the burst openings of the individual battery cells, are also aligned with openings in the contact plate to allow the hot gases to flow out of the area of the battery module in the event of a thermal event in an individual battery cell.

[0003] The inventors have now shown that this only works to a limited extent and, in the worst case, can even lead to thermal runaway of the entire battery module.

[0004] For further prior art, reference can also be made to US 2015 / 0221914 A1, which shows a battery housing made of an intumescent material. Venting chambers and channels are arranged within the housing.

[0005] Furthermore, reference can be made to JP 6 715 927 B2.

[0006] The object of the present invention is to further improve a high-voltage battery compared to the structure of the generic prior art.

[0007] According to the invention, this object is achieved by a high-voltage battery having the features of claim 1, and in particular in the characterizing part of claim 1. Advantageous embodiments and further developments emerge from the dependent claims. Claim 10 also specifies a vehicle with such a high-voltage battery, which also achieves the object.

[0008] In the high-voltage battery according to the invention, a contact plate with several openings and / or sections that release openings in the event of a thermal event in the battery module is used, as in the prior art. The key difference is that the openings and / or sections are offset from the burst openings of the individual battery cells. The high-voltage battery according to the invention therefore deliberately deviates from the usual design with aligned burst openings and openings in the contact plate and creates a structure in which, in the event of a thermal event in one of the individual battery cells, the gases escape from the burst opening, hit the contact plate, and are deflected by it, before flowing through the offset openings or openings that form in the event of a thermal event into the area above the contact plate.

[0009] The inventors have demonstrated in numerous tests that this design is particularly efficient because the hot gases, which often carry glowing particles or molten material, such as droplets of liquid aluminum or liquid copper, release a comparatively large amount of energy when the gas is guided between the individual battery cells and the contact plate from the burst opening of the individual battery cell to the opening in the contact plate. This energy decomposes the material of the contact plate, which typically consists largely of plastic. This removes a large amount of energy from the so-called venting gases, so that the design overall reduces the risk of thermal runaway of neighboring individual battery cells and modules by knowingly accepting the destruction of the contact plate.

[0010] The high-voltage battery according to the invention is designed such that both battery poles of the respective individual battery cell are arranged on the first side, with the burst opening being arranged between the battery poles. This is also the design shown in the generic prior art mentioned above, particularly when the individual battery cell is designed as a prismatic individual battery cell according to a further very advantageous embodiment. This design offers the particular advantage that both battery poles can be electrically contacted via the contact plate using their own arrester clips, so that the design only needs to be electrically connected from one side.

[0011] According to a further very advantageous variant of the high-voltage battery according to the invention, the contact plate has measuring lines aligned with the burst openings of the individual battery cells, i.e., extending above the burst openings, which measuring lines are designed in particular in the form of a flexible printed circuit board. Such measuring lines can, for example, run as a series of parallel measuring lines within the contact plate, preferably by inserting a flexible printed circuit board centrally between the battery terminals into the structure of the contact plate. This installation space is typically available here and is therefore particularly efficient for the use of the measuring line, in particular since these can be very easily connected from the central area to the suitable contact points, for example for measuring individual cell voltages, for carrying out charge equalization, or the like.

[0012] In previous designs, this was not possible due to the openings in the contact plate being arranged in this area in alignment with the burst openings. The high-voltage battery according to the invention now enables the arrangement in precisely this particularly advantageous area due to its openings or sections being arranged offset from this area, which open in the event of a thermal event, and also offers the advantages already mentioned above in the event of a thermal event in one of the individual battery cells.

[0013] Another particularly advantageous and favorable embodiment of the high-voltage battery according to the invention further provides for the contact plate to be directly mounted on the at least one battery module. This direct mounting on the battery module, thus eliminating the protective layer known from the prior art between the battery module and the contact plate, creates a very efficient structure. On the one hand, the protective layer can be omitted, which is a decisive advantage in terms of manufacturing costs and assembly.In addition, by omitting the protective layer, the flow of gases from the burst openings along the surface of the individual battery cells to the openings and / or sections arranged offset from the burst openings, which open in the event of a thermal event, is made possible with low flow resistance in order to allow the heat to flow away efficiently from the burst opening in all directions, in particular in all angular directions around the burst opening, in the sense described above.

[0014] This omission of this protective layer for thermal and especially electrical insulation, even if it contradicts the general opinion of experts on this topic, does not pose a problem, since electrical insulation is already provided during normal operation. If a thermal event occurs, the possibly lost insulation plays no significant role, since the voltage differences between adjacent components are comparatively small and even a small air gap is sufficient for insulation.

[0015] An exceptionally advantageous embodiment of the high-voltage battery according to the invention can further provide that the contact plate has at least two, in particular exactly two, laminated plastic layers, between which the electrical arrester clips and, if present, the measuring lines are embedded and are exposed in sections on at least one side, typically both sides of the contact plate, to enable electrical contact with the battery terminals. It is precisely this construction of the two laminated plastic layers or plastic films that makes the structure particularly simple, efficient, and cost-effective to manufacture with regard to the design of the high-voltage battery.

[0016] A particularly advantageous embodiment of this variant of the high-voltage battery according to the invention can now further provide that at least one first of the plastic layers has the openings and at least one other second plastic layer lying on the side of the first plastic layer facing away from the individual battery cell has the sections aligned therewith.

[0017] One of the plastic layers can therefore have openings directly adjacent to the battery cell, while the other plastic layer, ideally the layer facing away from the individual battery cell, has sections that only open in the event of a thermal event. This allows hot gases to flow through the openings in one layer to the sections. At the same time, the sections reliably cover the buildup of potential weld spatter during assembly when connecting the arrester clamps to the battery terminals, thus ensuring simple and efficient assembly with a low reject rate.

[0018] It is particularly advantageous if the sections are designed in the form of sections of the contact plate connected to the surrounding material via a few webs, whereby the webs are dimensioned in such a way that they melt or decompose in the event of a thermal event.

[0019] The sections can, for example, be cut with slots across a large part of their circumference, so that they are held in place only by individual webs. They then fulfill their function as a cover for the structure during normal operation and assembly, for example, to prevent welding spatter that can occur during the electrical connection of the battery terminals to the arrester clamps. If a thermal event occurs, the corresponding webs are melted by the hot gases, and the sections open an outlet for the gases.

[0020] According to a very advantageous refinement of this, it can now also be provided that the openings in the layer facing the individual battery cells have a larger cross-section than the sections. This allows the gas to flow very efficiently against the webs and then melt or thermally decompose them accordingly, thus also releasing the opening in the area of the sections in the event of a thermal event.

[0021] A further very advantageous embodiment of the high-voltage battery according to the invention can further provide that the contact plate is arranged between an upper housing part of a battery housing and the at least one battery module, wherein the distance between the contact plate and the upper housing part is less than 15 mm, in particular less than 10 mm. Such a comparatively small distance, which is also designed analogously to the philosophy described above without an intermediate protective layer, electrical insulation or the like, allows sufficient space to allow venting gases to flow out if necessary. On the other hand, the small distance of preferably only 5 to 8 mm from the upper side of the contact plate allows the contact plate to bulge accordingly in the area located above the burst openings of the individual battery cells and to rest against the upper housing part.This creates more space for the gases escaping from the burst opening and also allows the contact plate, supported by the upper housing section, to withstand adverse thermal conditions in this area for a little longer than without this support from the upper housing section. This further improves the diversion effect to the openings and / or sections offset from the burst openings, which open in the event of a thermal event. The discharge clamps, which are firmly connected to the battery terminals, also ensure that the contact plate adheres well to the battery modules in the lateral area of the battery module. This ultimately allows the gases to flow in the area of the bulge in the middle of the structure above the battery module and then flow out via the openings or the opening sections via the path of least resistance.This helps to optimize the inventive effect described at the beginning.

[0022] According to a very advantageous development, the battery modules of the high-voltage battery according to the invention can comprise prismatic individual battery cells, as already described above, which are stacked in each of the modules to form a cell stack. The contact plate can then cover one or, for example, two modules arranged parallel with respect to the stacking direction in order to electrically interconnect them and to contact them for the electrical power extraction or charging of the individual battery cells.

[0023] Such a high-voltage battery can in principle be used in various fields of application; this design, which is very advantageous in terms of safety, can particularly preferably be used in a vehicle, for example an electrically powered motor vehicle.

[0024] Further advantageous embodiments of the high-voltage battery according to the invention also emerge from the exemplary embodiment which is described in more detail below with reference to the figures.

[0025] Showing: Fig. 1 shows a schematically indicated vehicle with a high-voltage battery according to the invention; Fig. 2 a plan view of a possible embodiment of a high-voltage battery according to the invention; Fig. 3 a schematic sectional view of a battery module of the high-voltage battery according to the invention in a regular operating state; and Fig. 4 a representation analogous to that in Fig. 3 in case of a thermal event.

[0026] In the presentation of the Fig. Figure 1 shows a highly schematic representation of a vehicle, designated 1, which is intended to be at least partially electrically powered. Within the vehicle 1, a high-voltage battery 2 is located for storing electrical drive power. The term "high-voltage battery" refers to batteries with a direct voltage of more than 60 V and is based on the definition in ECE R100.

[0027] In the presentation of the Fig. 2 shows a plan view of a possible embodiment of such a high-voltage battery 2. This essentially consists of two battery modules 3, 4, which in the exemplary embodiment shown here are each composed of a stack of prismatic individual battery cells 5, only some of which are provided with a reference symbol. The two stacks of individual battery cells 5, which form the battery modules 3 and 4, are arranged parallel to one another with respect to the respective stacking direction S and, purely by way of example, are clamped together between two jointly used pressure plates 6, 7 in the stacking direction S. In the exemplary embodiment shown here, a first side of each of the individual battery cells 5 points upwards and is accordingly shown in the illustration of the Fig. 2. This first side of the respective single battery cell 5 comprises two battery terminals 8, 9 and centrally between these battery terminals 8, 9 a burst opening designated 10. These elements 8, 9, 10 are shown in the illustration of Fig. 2 are only designated accordingly on the individual battery cell 5 shown bottom right, but are present analogously on all individual battery cells 5.

[0028] Within the high-voltage battery 2, the individual battery cells 5 are now covered with a contact plate 11 and are electrically interconnected via this. In order to Fig. 2, in order to make at least some of the individual battery cells 5 more visible, only a central section of this contact plate 11 is shown in the stacking direction S. In reality, this contact plate 11 extends from one end plate 6 to the other end plate 7, thus completely covering the two battery modules 3, 4 of the high-voltage battery 2 and contacting their battery poles 8, 9 in the desired interconnection.

[0029] The contact plate 11 consists of two in the illustration of the Fig. 3 and Fig. 4 visible plastic films 12, 13, which will be discussed in more detail later. Arrester clips 14 are now provided within the contact plate 11 and are shown here with a thick dashed line. They are arranged in such a way that they typically protrude upwards and downwards from the contact plate 11 in sections. Via these arrester clips 14, which have different geometries depending on the arrangement, the battery poles 8, 9 of the individual battery cells 5 are contacted in a manner known per se in order to electrically connect them, for example, in series or parallel to one another. Individual groups can also be connected in parallel and these groups can be connected in series with one another or vice versa. All of this is possible by appropriately adapting the shape of the arrester clips 14.In the exemplary embodiment shown here, the arrester clips 14 in the outer region are essentially L-shaped, while the arrester clips 14 in the central region connect, as straight arresters, the battery poles 8, 9 of individual battery cells 5, each of which is assigned to a different battery module 3, 4. In the respective central region of the parts of the contact plate 11 related to the respective battery module 3, 4, measuring lines designated 15 are laminated between the foils 12, 13 of the contact plate 11. These lines can be used, for example, to monitor individual cell voltage.

[0030] The special feature of the structure shown here lies in the areas designated 16, which are designed either as openings 16a and / or as sections 16b, which open in a similar manner to the burst openings 10 in the event of a thermal event. These openings 16a and / or sections 16b, which are collectively designated 16, will be discussed in more detail below.

[0031] The representation in Fig. 3 shows a schematic cross-section through a part of the high-voltage battery 2. One of the individual battery cells 5 can be seen, which, analogously to the illustration in Fig. 2 has the battery poles 8, 9 on the first side facing upwards and the burst opening 10 in the central area, schematically indicated here by a weakened material. The contact plate, designated overall by 11, consists, as already indicated above, of a first lower plastic film 13 and a plastic film 12 laminated to the first plastic film 13 and arranged above it. The arrester clips 14 are laminated between these films and are exposed via corresponding openings in these films opposite the battery poles 8, 9 and, in the representation chosen here, also upwards. After the contact plate 11 has been placed in place, the exposed areas of the arrester clips 14 can be mechanically connected to the corresponding battery poles 8, 9 by welding and electrically contacted.

[0032] In the center of the area shown here and thus above the burst opening 10 are the measuring lines designated 15, which are designed, for example, as a flexible printed circuit board and laminated between the two foils 12, 13.

[0033] The area of the opening and / or section designated 16 is now crucial for functionality. In the preferred embodiment shown here, the opening designated 16a is provided for this purpose in the lower first film 13. In the second film 12, above this opening 16a, the section designated 16b is provided, which opens in the event of a thermal event. For this purpose, it can, for example, be provided with slits running around most of its circumference, so that only small webs leave this section 16b with the material of the second film 12. These webs melt in the event of a thermal event, thus also creating an opening 16c in the upper second film 12 (cf. Fig. 4), with a slightly smaller cross-section than the opening 16a. This design, with the slightly larger cross-sectional area of the opening 16a than that of section 16b, serves to optimize the flow of hot gases to the webs in the event of a thermal event, thus safely releasing section 16b and thus creating a corresponding opening 16c.

[0034] Above the contact plate 11, a housing upper part 17 or cover of a battery housing can also be seen, which surrounds the entire high-voltage battery 2. Such a housing upper part 17 can be made, for example, from a sheet metal, for example as a stamped part, deep-drawn part, or the like.

[0035] Purely schematically, the illustration in Fig. 4, which is otherwise analogous to the representation in Fig. 3, the behavior of the contact plate 11 in the event of a thermal event in the individual battery cell 5 shown here will be explained. Due to the thermal event in the individual battery cell 5, an excess pressure develops within it, so that hot gases laden with molten droplets and sparks, the so-called venting gases, flow out through the now opened burst opening 10. These venting gases are shown here purely as an example by a few arrows and are designated by the reference numeral 18. These venting gases 18 therefore flow out of the burst opening 10 and press the central region of the contact plate 11 above the burst opening 10 against the upper housing part 17.The upper housing part 17, which is arranged comparatively closely above the contact plate 11, so that only a gap of the order of 5 to 8 mm remains here, then supports the material of the contact plate 11 in this area, dissipates part of the heat into the upper housing part and thus ensures that the central area of the contact plate 11 does not burn immediately but remains intact for a certain time. Due to the discharge clamps 14, the material of the contact plate 11 cannot immediately move upwards to the sides, so that an area is created in which the hot venting gases 18 from the affected individual battery cell 5 can flow through the centrally curved contact plate in all directions, i.e. at an angle of 360° around the circumference of the burst opening 10, between the contact plate 11 and the first side of the battery modules 5.They then flow to the opening 16a, causing the webs that held the section 16b to decompose or burn, thus creating the structure shown in the . Fig.4, also in the upper second film 12 of the contact plate 11. The venting gases 18 are not discharged to just one of the openings and / or sections 16, as shown here, but to all surrounding openings and / or sections 16, so that the venting gas 18 is distributed in different directions and the thermal energy is dissipated relatively evenly. This even dissipation of thermal energy results in a large-scale decomposition and / or combustion of the films 12, 13 of the contact plate 11, so that thermal energy is distributed over a relatively large area compared to the structures according to the prior art and is partially "used up" by the decomposition of the films 12, 13.The thermal load per unit area in the vicinity of the individual battery cell 5 affected by the thermal event is thus reduced compared to conventional designs, so that the overall risk of a thermal chain reaction, i.e. the thermal runaway of adjacent individual battery cells due to strong heating, is significantly reduced, which serves the safety of the entire high-voltage battery 2.

[0036] The venting gas 18 thus follows the described path of least pressure loss to the area outside the respective battery module 3, 4 and relieves thermal stress in all directions in the area of the burst opening 10 through the lateral venting. The arrangement of several of the openings and / or sections 16 distributed over the surface of the contact plate 11 also ensures that the heat is dissipated quickly and evenly, which reduces the thermal load per unit area, as already mentioned above, and per unit time.

Claims

[1] High-voltage battery (2) with at least one battery module (3, 4) comprising a plurality of individual battery cells (5) which have at least one of the battery poles (8, 9) and a burst opening (10) on a first side, wherein all first sides of the individual battery cells (5) of the battery module (3, 4) are covered by a contact plate (11) which has electrical conductor clips (14) for the electrically conductive connection of the battery poles (8, 9), wherein the contact plate (11) has a plurality of openings and / or sections (16, 16a, 16b) which release openings (16c) in the event of a thermal event in the battery module (3, 4), characterized by that the openings and / or sections (16, 16a, 16b) are formed offset from the burst openings (10), wherein both battery poles (8, 9) of the individual battery cell (5) are arranged on the first side, wherein the burst opening (10) is arranged between the battery poles (8, 9). [2] High-voltage battery (2) according to claim 1, characterized by that the contact plate (11) has measuring lines (15), in particular in the form of a flexible printed circuit board, aligned with the burst openings (10) of the individual battery cells (5). [3] High-voltage battery (2) according to claim 1 or 2, characterized by that the contact plate (11) is placed directly on at least one battery module (3, 4). [4] High-voltage battery (2) according to one of claims 1 to 3, characterized by that the contact plate (11) has at least two, in particular exactly two, plastic layers (12, 13) laminated to one another, between which the arrester clips (14) are embedded and partially exposed on at least one of the sides of the contact plate (11). [5] High-voltage battery (2) according to claim 4, characterized bythat at least a first of the layers (13) has the openings (16a) and at least one other second layer (12) lying on the side of the first layer (13) facing away from the single battery cell (5) has the sections (16b) in alignment therewith. [6] High-voltage battery (2) according to claim 5, characterized by that the openings (16a) have a larger cross-section than the sections (16b). [7] High-voltage battery (2) according to one of claims 1 to 6, characterized by that the sections (16b) are designed in the form of sections (16b) of the contact plate (11) connected to the surrounding material via a few webs, wherein the webs are dimensioned such that they melt and / or decompose in the event of a thermal event. [8] High-voltage battery (2) according to one of claims 1 to 7, characterized bythat the contact plate (11) is arranged between an upper housing part (17) of a battery housing and the at least one battery module (3, 4), wherein the distance between the contact plate (11) and the upper housing part (17) in the intended use is less than 15 mm, preferably less than 10 mm. [9] High-voltage battery (2) according to one of claims 1 to 8 characterized by prismatic individual battery cells (5) which are stacked to form a cell stack in the at least one battery module (3, 4). [10] Vehicle (1) with a high-voltage battery (2) according to one of claims 1 to 9.

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