Prismatic cell and battery module

Abstract

The invention relates to a prismatic cell (10) having a cell housing (12) made of a first material (M1), which has a first cell wall (18, 20) with an openable cell vent opening (38). Here, the battery cell comprises a thermal protection element (44), which comprises a base element (46), which is formed from a second material (M2) having a higher melting point than the first material (M1), and which has two side webs (50), which lie opposite each other, and a base plate (48) having a through-opening (58), which connects the side webs (50) across the respective protection edges (54, 56), according to the invention, the substrate is arranged in a planar manner against the first cell wall or is integrated into the first cell wall such that the through-opening coincides with the openable cell vent opening, and the respective first and second protective edges coincide with at least part of the respective first and second edges (30, 32) or are integrated into the respective first and second edges.

Description

Technical Field

[0001] The present invention relates to a prismatic battery cell, which has a battery cell housing, the battery cell housing comprising first and second battery cell walls opposite to each other in a first direction, third and fourth battery cell walls opposite to each other in a second direction, and fifth and sixth battery cell walls opposite to each other in a third direction. Here, the first battery cell wall is adjacent to the third battery cell wall via a first edge, adjacent to the fourth battery cell wall via a second edge, adjacent to the fifth battery cell wall via a third edge, and adjacent to the sixth battery cell wall via a fourth edge. Here, the first and second edges are respectively longer than the third edge and the fourth edge, wherein the battery cell comprises an openable battery cell exhaust opening arranged in the first battery cell wall. In addition, the present invention also relates to a battery module having such a prismatic battery cell. Background Art

[0002] Prismatic cells, in particular prismatic cells for batteries of motor vehicles, usually have an openable cell exhaust opening, for example a rupture diaphragm, in order to enable a prescribed cell exhaust in the event of a thermal runaway of such a cell. However, in so-called thermal propagation tests carried out to check the propagation behavior of such a cell, it has been shown that in some cases it may happen that the cell does not propagate or exhaust through its own rupture valve provided for this purpose in the event of propagation, but may also damage a larger area around the rupture valve, for example. This makes it difficult to guide the gas escaping from such a propagating cell in a targeted manner and to introduce such gas into a gas exhaust channel at the same time. In this case, if the gas escapes from the cell at a location not provided for this purpose, there is a risk that the escaping gas cannot be discharged in a targeted manner here and in some cases reaches an area where it should not reach. In particular, such gas may come into contact with an adjacent cell and damage and heat the adjacent cell, so that the adjacent cell also thermally runs away. If such an adjacent cell is damaged in a certain housing area, for example by the hot gas of the exhausted cell, this leads to another weak spot in the housing, which may be more easily destroyed by the internal gas pressure in the case of the propagation of the adjacent cell, so that in some cases, the exhaust of the adjacent cell is not even carried out through the rupture valve provided for it, but is additionally or alternatively carried out through the weak spot. As a result, the propagation behavior of multiple cells cannot be controlled at all or only very difficultly. However, a more stable cell construction scheme leads to a higher weight, requires more structural space and higher costs.

[0003] DE 10 2022 001 413 A1 describes a cell housing for a battery cell of a battery module, the cell housing having an inner space and an outer wall, the outer wall having an overpressure element, the overpressure element being designed to discharge particles from the cell when the cell is in thermal runaway. The cell housing comprises a filter plate, which is arranged at the outer wall and at least partially covers the discharge opening of the overpressure element. A spacer element is constructed between the filter plate and the outer wall, by means of which a particle gap is formed for adjusting the particle size. The filter plate comprises a curved side surface, which at least partially extends beyond the outer wall. The gas escape can be directed in a targeted manner in a certain direction by means of the curved side surface.

[0004] Nevertheless, the problems described above still exist. Summary of the invention

[0005] The object of the present invention is to provide a prismatic cell and a battery module which are realized in a way that saves as much construction space as possible, saves weight and is efficient, and allows the prismatic cell to be vented with the highest possible probability through an openable cell venting opening provided for this purpose.

[0006] This object is achieved by a prismatic cell and a battery module having the features according to the respective independent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims, the description and the drawings.

[0007] The prismatic cell according to the present invention comprises a cell housing made of a first material, wherein the cell housing comprises first and second cell walls opposite to each other in a first direction, third and fourth cell walls opposite to each other in a second direction, and fifth and sixth cell walls opposite to each other in a third direction. Here, the first cell wall is adjacent to the third cell wall via a first edge, adjacent to the fourth cell wall via a second edge, adjacent to the fifth cell wall via a third edge, and adjacent to the sixth cell wall via a fourth edge, wherein the first and second edges are respectively longer than the third edge and the fourth edge, wherein the cell comprises an openable cell exhaust opening arranged in the first cell wall. Here, the battery cell has a thermal protection element, which includes a basic element, which is formed by a second material having a higher melting point than the first material, wherein the basic element has a first side web and a second side web opposite to each other in a second direction, and a substrate, which connects the first side web and the second side web across the corresponding first protective edge and the second protective edge and has a through opening, wherein the substrate is arranged to be flat against the first battery cell wall, or integrated into the first battery cell wall, so that the through opening coincides / overlaps with the openable battery cell exhaust opening, and the corresponding first and second protective edges coincide with at least a portion of the corresponding first and second edges, or are integrated into the first and second edges.

[0008] Here, the present invention is based on the following multiple insights: On the one hand, it is very advantageous, especially in terms of weight, cost and structural space efficiency, for the cell housing to be formed of a material that is as cost-effective and thin-walled as possible. However, this type of construction scheme is generally unable to withstand the high stresses in the case of thermal runaway of such a cell. However, the design scheme of the cell housing that is more stable as a whole leads to a heavier weight, higher costs and a greater structural space requirement as described. Advantageously, this can be avoided by providing a thermal protection element, which locally strengthens the cell housing of the prismatic cell without having to construct the entire cell housing more firmly. As a result, it is advantageously achieved by means of the thermal protection element, especially in the case of propagation of the cell, to protect and strengthen the weak points of the cell housing. In addition, the present invention is based on the following insight, that is, this weak point of the cell housing is not only around the openable cell exhaust opening on the first side of the prismatic cell, but also, in particular, the edge of the cell housing forms this weak point. This is particularly related to the longitudinal edge of the cell housing adjacent to the first side. Now, precisely the longitudinal edge of the cell housing can be reinforced and thus protected in a targeted manner by means of the protective edge of the thermal protection element, thereby significantly reducing the likelihood of the cell housing splitting in the region of this edge and promoting targeted cell venting in the event of a propagation through the openable cell venting opening provided for this purpose.

[0009] The openable battery cell exhaust opening can be designed as a pressure-dependent and passively openable battery cell exhaust opening. For example, the battery cell exhaust opening can be designed as an overpressure valve and / or a rupture membrane. Since the battery cell is a prismatic battery cell, the battery cell has a substantially square battery cell housing. As a result, the battery cell walls that are opposite to each other in the same direction have substantially the same size and the same geometric structure, in particular a rectangular geometric structure. Accordingly, the first and second edges are also substantially the same length, as are the third and fourth edges. In addition, the edge should also be understood as a rounded edge. Accordingly, this edge is a transition area between two battery cell walls.

[0010] Here, the cell housing separates the interior space of the cell (which may also be referred to as the interior of the cell) from the environment of the cell. Accordingly, the cell housing may have an outer side or an outer surface facing the environment, and an inner side facing the interior of the cell. In addition, the cell comprises two cell electrodes, which may be arranged on any of the cell walls of the cell. For example, the two cell electrodes may also be located on or in the first cell wall, or it is also possible that one cell electrode is arranged on the fifth cell wall and the other on the sixth cell wall.

[0011] Here, the thermal protection element can generally be designed as an independent component, that is to say, designed to be independent from the cell housing and arranged accordingly on the cell housing, or the thermal protection element can also be integrated into the cell housing. In this case, the substrate can be integrated into the first cell wall in such a way that the substrate is, for example, surrounded between the wall elements of the first cell wall and the substrate is located between the two wall elements in the first direction. The substrate can also be integrated into the first cell wall in such a way that the substrate forms part of the first cell wall. In other words, in the area in which the substrate is arranged, the cell wall can be formed only by the substrate. The same applies to the corresponding side tabs and protective edges.

[0012] Furthermore, the thermal protection element can be provided solely by the base element. In other words, the base element can form the thermal protection element. Alternatively, the thermal protection element can additionally have, for example, a coating in addition to the base element, with which the base element is coated. In this case, the thermal protection element is provided or formed by the base element coated with the coating. Here, the coating can be formed of a material different from the second material. For example, the coating can be an anti-corrosion coating. Thus, more material options are provided for the second material.

[0013] Here, the substrate is arranged on the first cell wall or integrated into the first cell wall in such a way that the through-opening coincides with the openable cell exhaust opening. Here, this should be understood to mean that the openable cell exhaust opening is not covered or covered by any part of the substrate. Here, the through-opening can essentially have the same geometry as the openable cell exhaust opening. Here, the edge region that circumferentially limits the through-opening can be arranged on the edge region that circumferentially limits the openable cell exhaust opening, or be adjacent to the edge region. The boundary contour of the through-opening can in particular be directly adjacent to the boundary contour of the openable cell exhaust opening.

[0014] It is also preferred that, apart from the through-opening, the base element has no further openings or holes or the like. For example, the thermal protection element can have an outer contour representing the boundary contour of the thermal protection element, wherein the thermal protection element is designed as a continuous wall within its outer contour, apart from the through-opening. As a result, the protective effect of the thermal protection element can be maximized. As a result, the thermal protection element can cover the area of ​​the cell housing in a planar manner and effectively prevent the cell housing from cracking or breaking or otherwise being damaged in the event of cell propagation, or at least significantly reduce the probability thereof.

[0015] In another advantageous design of the present invention, the first side tab is flatly attached to the third cell wall or integrated into the third cell wall, and the second side tab is flatly attached to the fourth cell wall or integrated into the fourth cell wall. Similar to the substrate, the side tab can also be a plate-shaped element. That is, what is common to the substrate and the side tab is that they each have a length and width greater than their thickness, wherein the thickness of the substrate and the side tab is also referred to as wall thickness. Here, the thickness of the substrate extends in a first direction, while the thickness of the side tab extends in a second direction. Here, the side tab can in principle have any geometric structure, but preferably also has a rectangular geometric structure. For example, the base element can be designed in the form of a U-shaped profile with a through opening in the substrate. The two sides of the "U" of the U-shaped profile are provided by two side tabs.

[0016] The side tabs can also be integrated into the cell housing as already described for the base plate. That is, the first side tab can also be integrated into the third cell wall and form a part of it or be embedded in a wall element of the third cell wall, and the second side tab can be integrated into the fourth cell wall or form a part of it or be embedded in a wall element of the fourth cell wall.

[0017] However, it is very advantageous and preferred that the thermal protection element is designed as a component that is independent of the cell housing. Advantageously, this makes it possible to also retrofit conventional cells with such a thermal protection element. The thermal protection element can, for example, be simply arranged on the outside of the cell housing, as will be explained in more detail later. As a result, this advantageous protection mechanism can also be provided as a retrofit solution for existing cells. In addition, the manufacturing process for existing cells can be retained and the construction and installation solution of the thermal protection element can be simply supplemented. This makes it possible to manufacture prismatic cells in a particularly simple and efficient manner.

[0018] Therefore, another very advantageous design of the present invention is that the thermal protection element is a component independent of the cell housing and is arranged on the outside of the cell housing. That is, in this example, the base plate is arranged to be flat against the outside of the first cell wall, the first side tab is arranged to be flat against the outside of the third cell wall, and the second side tab is arranged to be flat against the outside of the fourth cell wall. As a result, the first protective edge covers the first edge of the cell housing on the outside, and the second protective edge covers the second edge of the cell housing on the outside. As a result, it is possible to significantly more effectively prevent the cell housing from cracking in this edge area and gas from escaping through this edge when the cell is propagating.

[0019] According to another design of the present invention, the thermal protection element is a component independent of the cell housing and is arranged on the inner side of the cell housing in the interior of the cell housing. In principle, there is also the possibility of arranging the thermal protection element in the interior of the cell housing. At this time, the thermal protection element or the base element is also arranged to be flat against the corresponding cell wall as described above, but now, it is arranged on the inner side relative to the cell housing. As a result, the enhanced effect can be achieved in the same way. However, at this time, the integration in the cell housing can be carried out during the manufacturing process of the cell housing. This makes it difficult to use the thermal protection element as a retrofit solution. However, this variant also has the great advantage that when the thermal protection element is arranged in the internal space of the cell, the thermal protection element can be significantly more stably maintained at the cell housing under the propagation of the cell. As a result, it is also possible to more effectively prevent the cell housing from melting in the area where the thermal protection element is arranged.

[0020] Preferably, the first material is aluminum. Aluminum has the great advantage that it is very light and cost-effective and allows simple production of the cell housing. For example, the cell housing can be constructed using a drawing process.

[0021] According to another advantageous design of the present invention, the second material has a melting point of at least 1300° C., in particular at least 1400° C. This is based on the knowledge that high temperatures in the range of 800° C. to 1300° C. occur during the propagation of the battery cell. As a result, the thermal protection element can advantageously withstand such high temperatures. Preferably, the second material is a metal or an alloy. In principle, other materials, such as ceramics, can also be considered. However, the great advantage of metallic materials is that the material generally enables a significantly thinner-walled thermal protection element construction scheme. As a result, the thermal protection element can be provided in a particularly space-saving manner. Particularly preferably, the thermal protection element or its base element is formed of steel or stainless steel. Here, stainless steel is particularly preferred because it is particularly corrosion-resistant compared to aluminum, and therefore for corrosion protection, the base element does not have to be provided with an additional coating. Therefore, the thermal protection element can be formed completely of stainless steel, for example.

[0022] In another very advantageous embodiment of the invention, the base element and in particular the thermal protection element has a wall thickness of a maximum of 2 mm or a maximum of 1 mm, preferably a maximum of 0.5 mm. The base element can thus be provided in a particularly space-saving manner. Depending on the material and requirements, even smaller wall thicknesses are conceivable, for example in the range of 0.2 mm to 0.4 mm, or even wall thicknesses of less than 0.2 mm, for example in the range of 0.05 mm. Therefore, the construction of such a thin-walled thermal protection element hardly results in a greater weight, and there is basically no additional structural space requirement. As a result, the thermal protection element can be particularly easily integrated, for example, also into a battery module having a plurality of prismatic cells, without having to change the module structure or additionally position other components.

[0023] In another advantageous embodiment of the present invention, the first protective edge covers a large part of the first edge along the third direction, and the second protective edge covers a large part of the second edge along the third direction. In principle, it is also conceivable that the first and second protective edges each cover more than a large part of the first or second edge, or even completely cover the first or second edge along the third direction. Here, covering on the inside as well as on the outside is also feasible. Here, there is also the possibility of integrating the thermal protection element into the cell housing, and thus the first protective edge is correspondingly embedded in the first edge, and the second protective edge is embedded in the second edge, or the corresponding protective edge represents or at least largely forms the corresponding edge of the cell housing.

[0024] The corresponding edges of the cell housing can thus be protected and reinforced particularly well with the aid of the protective edge. For example, if the cell electrodes of a prismatic cell are located in or on the first cell wall, it is preferred that the openable cell exhaust opening is located between the two cell electrodes in the third direction, and that the two cell electrodes are arranged as far as possible on the first cell side or on the edge of the first cell wall in the third direction. In this case, the substrate can extend to the cell electrodes or almost to the cell electrodes in the third direction, for example, except for a predetermined distance, which is less than 1 cm, in particular less than 0.5 cm. If the cell electrodes are not on or in the first cell wall, but on other cell walls of the cell housing, the substrate can also extend along the third direction over the entire length of the first cell wall along the third direction. Correspondingly, in this case, the protective edge can also extend along the third direction over the entire first and second edges of the cell housing. Advantageously, this provides maximum edge protection.

[0025] In another advantageous design of the present invention, the first and / or second side tabs have such a height along the first direction, that is, the height is at least 5 mm, in particular at least 1 cm and / or at most half the wall height of the third cell wall along the first direction. Here, the wall height of the third cell wall also substantially corresponds to the wall height of the fourth cell wall. Thus, depending on the positioning of the first cell wall, the side tabs preferably extend downward or upward to a maximum of half the cell height or housing height of the cell along the first direction. Here, it is not necessary for the third and fourth cell walls to be completely covered by the side tabs along the third direction. This is based on the understanding that, for example, when a prismatic cell is located in a cell stack together with a plurality of other prismatic cells, the third and fourth cell walls in the cell complex are covered and supported laterally by other components that can be arranged between the cells, in particular so-called cell separation elements. Due to the support by other components, it is almost impossible to achieve exhaust of the cells through the third and fourth cell walls, especially in the central area of ​​the cell walls, in the case of propagation. In addition, the design is based on the knowledge that such a cell separation element does not usually extend in the third direction over the entire height of the cell or the cell housing, and that, for example, the edge regions of the third and fourth cell walls, which are adjacent to the first cell wall or the first and second edges, respectively, are not covered by such a cell separation element. Therefore, it is precisely this edge region of the third and fourth cell walls that forms a weak point. Advantageously, this weak point can be covered by the side tabs of the base element. For this purpose, it is completely sufficient for the height of the corresponding tabs along the first direction to be in the range of, for example, 1 to 2 cm. Therefore, along the first direction, the side tabs can be limited to a height of about 1 cm to 5 cm, in particular 1 cm to 2 cm.

[0026] In another advantageous design scheme of the present invention, the first side web extends along the first direction over the entire third battery cell wall, and / or the second side web extends along the first direction over the entire fourth battery cell wall, in particular, wherein the basic element has a first basic web and a second basic web opposite to the substrate in the first direction, wherein the first side web is connected to the first basic web via a third protective edge, and the second side web is connected to the second basic web via a fourth protective edge, wherein the first and second basic webs are respectively arranged on the second battery cell side, or integrated into the second battery cell side, and the corresponding third and fourth protective edges respectively overlap with at least a part of the corresponding fifth edge connecting the third and second battery cell sides and the sixth edge connecting the fourth and second battery cell sides, or are integrated into the fifth edge and the sixth edge.

[0027] Therefore, the side tabs can also extend in the first direction over the entire third and fourth cell walls. As a result, the cell walls can also be additionally stabilized and protected from damage during cell exhaust. It is also possible in particular to surround the base element in addition to the second lower cell side and thereby also correspondingly stabilize and protect the fourth edge connecting the third and second cell sides and / or the fifth edge of the cell housing connecting the fourth and second cell sides, i.e., they are covered by the corresponding third or fourth protective edge, or the protective edge is integrated into the housing edge. However, the surrounding of the fourth and fifth edges can be used in particular to produce a mechanical anchoring of the thermal protection element.

[0028] It is also conceivable that the two base tabs are designed as a common base tab, which is flat against the second cell side. However, if the two base tabs are independent of each other and not connected to each other, the production of the thermal protection element and the installation on the cell housing are simplified. Here, it is also preferred that the base tab is arranged flat on the second cell side, but the second cell side does not completely cover the entirety of the cell side in the second direction.

[0029] In another advantageous embodiment of the invention, at least one notch or through-opening is arranged in the first and / or second side tab, in particular in the lower half of the first or second side tab facing away from the substrate, but not necessarily limited to the lower half. For example, the two side tabs can be designed in the lower half with a locally reduced wall thickness to provide such a recess, or even have one or more through-openings, such as holes, that pass through the corresponding side tabs in the second direction. As a result, the thermal protection element can be designed to be simpler and more cost-effective, which is advantageous when the side tab extends along the first direction over the entire third or fourth battery cell side. Thus, an additional stabilizing effect can be provided without having to specifically bear more weight and material.

[0030] According to another advantageous design of the present invention, the thermal protection element is bonded and / or clamped on the cell housing and / or is held on the cell housing by friction locking. In principle, the connection schemes can also be combined with each other in any manner. Bonding is particularly advantageous here because a stable connection can be provided between the thermal protection element and the cell housing without having to provide additional elements, such as locking lugs or clamping elements, on the thermal protection element and / or on the cell housing. However, it is also conceivable that the thermal protection element is clamped on the cell housing. For this purpose, the thermal protection element and / or the cell housing can be designed to have a corresponding locking mechanism, which can achieve that the thermal protection element is held on the cell housing by locking, especially form-locking locking. In this case, it is preferred that this type of clip or locking structure is provided on the first cell wall, for example in the region of the openable cell exhaust opening or its edge, and correspondingly on the substrate of the thermal protection element. It is also conceivable to clamp by friction locking. In this case, the frictional connection can also be provided in particular by further components which locally press the thermal protection element against the cell housing of the prismatic cell. For example, when the prismatic cells are arranged in a cell complex having a plurality of cells, the side tabs can be clamped in the region between the cells. Alternatively or additionally, such a battery module including prismatic cells can also have, for example, a cell cover or a further cover structure which holds the thermal protection element against the cell housing and is arranged, for example, in a first direction above the first cell wall and the base plate of the thermal protection element. Such a component can press the thermal protection element downward against the cell housing in the first direction.

[0031] Furthermore, the present invention also comprises a battery module having a prismatic cell according to the invention or one of its embodiments.

[0032] The advantages described for the prismatic cell according to the invention and its embodiments apply in the same manner to the battery module according to the invention.

[0033] In another very advantageous embodiment of the battery module, the battery module comprises at least one component which contacts at least a part of the thermal protection element and holds the thermal protection element on the cell housing on the outside by means of friction and / or form fit. Advantageously, clamping, in particular additional clamping or fixing, of the thermal protection element on the cell housing can thereby be provided.

[0034] For example, the component can be another battery cell, in particular another battery cell according to the present invention or one of its embodiments, and / or a battery cell separation element arranged between second battery cells, wherein at least one of the battery cells is a prismatic battery cell according to the present invention or one of its embodiments, and / or the component can be a module cover and / or a housing bottom and / or a carrier plate for a battery cell connector, and / or a cooling plate, etc.

[0035] For example, a battery module may include a plurality of prismatic cells, in particular a plurality of cells according to the present invention or cells according to an embodiment of the present invention, which are arranged side by side in a stacking direction, wherein the stacking direction corresponds to the second direction defined above. Between each two cells arranged adjacent to each other in the stacking direction, a cell separation element may be arranged. Here, the cell separation element may be designed as a planar element having a length and a width in a first direction and a third direction, which are significantly greater than its thickness in the second direction. It is also preferred that the cell separation element has a height in a first direction, which is less than the height of the third and fourth cell walls in the first direction. Here, the cell separation element may have a distance from the corresponding first cell side of the adjacent cell in the first direction. The above-mentioned cover, such as a battery housing cover or a module cover or a cooling plate of a carrier plate for a cell connector is preferably arranged in the first direction above and / or below a cell stack having a plurality of cells, in particular so that the corresponding first cell wall faces the cover or plate. Here, such a plate or such a cover may also be mounted on the cell stack or fixed relative to the cell stack, for example, it may be bolted on the end side, etc.

[0036] The invention also includes a battery, in particular a motor vehicle battery, comprising at least one battery module according to the invention or one of its embodiments. The battery can also have a plurality of such battery modules. For example, the battery can be designed as a high-voltage battery. For example, the battery cell can be designed as a lithium-ion battery cell.

[0037] Furthermore, the invention relates to a motor vehicle having a battery module according to the invention or one of its embodiments.

[0038] The motor vehicle according to the invention is preferably designed as a car, in particular as a passenger car or a commercial vehicle, or as a bus or a motorcycle.

[0039] The invention also includes combinations of features of the described embodiments. Therefore, the invention also includes implementations which each have a combination of features of a plurality of the described embodiments, as long as these embodiments are not described as mutually exclusive. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The embodiments of the present invention are described below. As shown in the figure:

[0041] Figure 1 A schematic perspective view showing a prismatic battery cell according to one embodiment of the present invention;

[0042] Figure 2 A schematic perspective view showing a prismatic battery cell according to another embodiment of the present invention;

[0043] Figure 3A schematic cross-sectional view of a prismatic cell according to one embodiment of the present invention is shown;

[0044] Figure 4 A schematic cross-sectional view showing a prismatic battery cell according to another embodiment of the present invention;

[0045] Figure 5 A schematic diagram showing a battery module having a plurality of prismatic cells according to an embodiment of the present invention; and

[0046] Figure 6 A schematic perspective view shows a prismatic battery cell according to another embodiment of the present invention. DETAILED DESCRIPTION

[0047] The embodiments described below are preferred embodiments of the present invention. In the embodiments, the described components of the embodiments are respectively individual features of the present invention that can be regarded as independent of each other, and these features also improve the present invention independently of each other. Therefore, the present disclosure should also include feature combinations that are different from the illustrated embodiment feature combinations. In addition, the embodiments may also be supplemented by other features in the already described features of the present invention.

[0048] In the figures, the same reference numerals respectively denote elements with the same function.

[0049] Figure 1 1 shows a schematic perspective view of a prismatic cell 10 according to an exemplary embodiment of the present invention. The cell 10 has a cell housing 12. The cell housing 12 encloses an interior space 14 (see Figure 3 and Figure 4 ) and separates the interior space 14 from the environment 16 of the cell 10. Here, the cell housing 12 has: a first cell wall 18 and a second cell wall 20 opposite in the z direction; a third cell wall 22 and a fourth cell wall 24 opposite to the third cell wall 22 (see Figure 3 and Figure 4 a fifth cell wall 26 and a sixth cell wall 28 opposite to the fifth cell wall 26 in the y direction. In the above, the z direction shown is also referred to as the first direction, the y direction is referred to as the third direction, and the x direction is referred to as the second direction.

[0050] Here, the first cell wall 18 adjoins the third cell wall 22 via a first edge 30, the fourth cell wall 24 via a second edge 32, the fifth cell wall 26 via a third edge 34, and the sixth cell wall 28 via a fourth edge 36. Here, the edges 30, 32 are longitudinal edges, and the edges 34, 36 are transverse edges, which are shorter in the x-direction than the longitudinal edges 30, 32 in the y-direction.

[0051] An openable cell venting opening 38 of the cell 10 is arranged in the first cell wall 18, which is designed, for example, as a rupture valve or a rupture membrane. Here, the openable cell venting opening is arranged centrally in the first cell wall 18 in the y direction and also centrally in the x direction. In addition, the cell 10 comprises two cell electrodes 40, 42. In the example shown here, the cell electrodes are also arranged on the first cell wall 18. In principle, however, the cell electrodes can also be arranged on any other cell wall of the cell 10. The described cell walls 18, 20, 22, 24, 26, 28 are preferably made of aluminum. Advantageously, the cell 10 comprises a thermal protection element 44. The thermal protection element has a base element 46, which consists of a base plate 48, a first side web 50 and a second side web 52, wherein the second side web 52 is shown here as a dotted line, since according to Figure 1 , the second side tab is located on the back cell wall 24. Here, the two side tabs 50, 52 are connected to each other via a base plate 48, in particular across the corresponding first protective edge 54 and the second protective edge 56. The base plate 48 has a through opening 58, which has essentially the same geometric structure as the openable cell exhaust opening 38 and is arranged superimposed on the openable cell exhaust opening. Therefore, the base plate 48 is flat against the first cell wall 18, in particular in this example, on the outside against the cell wall 18, that is, on the outside 60 of the cell housing 12. The first side tab 50 is flat, in particular also on the outside against the third cell wall 22, and correspondingly, the second side tab 52 is on the outside, in particular also flat against the fourth cell wall 24. Therefore, the protective edges 54, 56 cover a portion of the edges 30, 32 of the cell housing 12 in the y direction, for example at least one third. The thermal protection element 44 or at least its base element 46 is formed here by a second material M2, which has a significantly higher melting point than the first material M1 of the cell housing 12, which is preferably aluminum. For example, the second material M2 can be steel or preferably stainless steel. Optionally, a protective layer can also be arranged on the base element 46. This protective layer can, for example, also be located only on the side of the base element 46 facing the cell housing 12 to provide corrosion protection. However, the thermal protection element 44 can also be formed only by the described base element 46. For example, the thermal protection element 44 can be designed as a protective plate made of thin-walled stainless steel, which has, for example, a melting temperature of about 1500° C. and a wall thickness in the range of 0.2 mm to 0.4 mm. As a result and by the described geometric design of the protective plate 44, the environment of the rupture valve, that is, the openable cell exhaust opening 38, can be specifically protected not only mechanically but also thermally, without limiting the battery module 62 with extremely narrow tolerances in terms of its function (see Figure 5). For example, the protective plate 44 can simply be placed from above onto the battery cell, that is to say the battery cell housing 12, and be bonded together with an insulating film (which is not shown here, however) which additionally surrounds the battery cell housing 12. It is also conceivable to mechanically clamp the thermal protection element 44, for example, on the edge of the rupture valve 38. In any case, it can now be advantageously achieved by the thermal protection element 44 that in the event of propagation, the thin-walled battery cell or the battery cell housing 12 made of aluminum is adequately protected so that propagation can proceed in a targeted manner only through the holes of the rupture valve 38 and thus in particular adjacent batteries are protected from further propagation. The cell separation element 64 (see Figure 5 ) can also reliably perform its intended work and protect adjacent cells from thermal runaway.

[0052] Conventional prismatic cells can thus be made more reliable by this simple optimization measure. The thermal protection element 44 can also be provided as a retrofit solution, so that previously used cells can also be used. So-called thermal runaways, in which a propagating cell infects more and more other cells, can be significantly delayed or, in the best case, even completely prevented by providing such a protection element 44.

[0053] Here, the base plate 48 and the side tabs 50, 52 have a length L in the y direction, and the side tabs 50, 52 have a height H in the z direction. The third cell wall 22 and correspondingly the fourth cell wall 24 have a length l in the y direction and a height h in the z direction. The length L of the base plate and the side tabs 50, 52 is, for example, at least one third of the length l of the third cell wall 22 in the y direction, or also in a larger range, such as, for example, in Figure 2 , for example, extending over at least half of the length l of the third side wall 22. The thermal protection element 44 can also extend over the entire area between the cell electrodes 40, 42 in the y direction, or optimally can also extend over the entire length l of the cell 10 or the third side wall 22, especially when the cell electrodes 40, 42 are arranged on the other cell wall. The side tabs 50, 52 can also be designed to have different heights H in the z direction, such as by Figure 2 Explanatory.

[0054] Here, Figure 2 In particular, a battery cell 10 according to another embodiment of the present invention is shown, which can be used with Figure 1 The cell 10 in the embodiment is designed identically, except for the following differences, namely, the thermal protection element 44 has a greater length L and the side tabs 50, 52 have a greater height H. The height H of the side tabs 50, 52 can be, for example, in the range of 0.5 mm to 2 cm and in this example extends to a maximum of half the height h of the cell 10 or the third cell wall 22. This is because when installed in the module 62 (see Figure 5), the cell 10 is always protected laterally in the region of its third side 22 and fourth side 24 by the cell separator element 64 already described, so that in this region the exhaust of the cell 10 is always made more difficult by the cell separator element 64. The side tabs 50, 52 can also be longer in the z direction, such as according to Figure 6 As described.

[0055] Here, the height H and the length L of the thermal protection element 44 can be adjusted according to the situation and can also be varied independently of one another, that is, Figure 1 The heat protection element 44 shown in the figure can be designed to have the length L shown here, but the side tabs 50, 52 can be designed to have a greater height H, such as in Figure 2 The height H of the side gussets 50, 52 shown in FIG. While maintaining its height H, Figure 2 The thermal protection element 44 shown in FIG. 4 can also be designed to be shorter in the y direction, for example, as in Figure 1 As shown in .

[0056] Furthermore, the side tabs 50 , 52 can be designed to be different in size, in particular with regard to their height H. For example, the first side tab 50 can have a greater height H in the z-direction than the second side tab 52 , or vice versa.

[0057] Figure 3 A schematic cross-sectional view of a battery cell 10 according to an embodiment of the present invention is shown. The battery cell 10 can be designed as described above. In this example, the thermal protection element 44 is arranged on the battery cell housing in a manner that it is flat on the outside and abuts against the battery cell housing 12 as described above. As can be seen in particular here, the openable battery cell exhaust opening can be designed with a surrounding edge R that is raised in the z direction. In this case, the boundary contour K surrounding the through-opening 58 in the base element 46, in particular in the base plate 48, can directly adjoin the edge R of the openable battery cell exhaust opening 38.

[0058] Such a protective plate 44 can be adapted in size to the corresponding cell or its cell housing 12 without significant expenditure and can be applied from the outside to the cell, or more precisely to its cell housing 12. For future cells, such a protective plate 44 can also be taken into account in the structure of the cell 10 and can therefore also be installed inside the cell 10, such as, for example, in the Figure 4 As schematically shown in FIG.

[0059] Here, Figure 4 A schematic diagram of a cell 10 is shown according to an exemplary embodiment of the present invention, according to which a thermal protection element 44 , which can be designed as described above, is now arranged on the inner side 61 of the cell housing 12 .

[0060] That is, therefore, the thermal protection element 44 is located in the interior 14 of the cell housing 12. Nevertheless, the thermal protection element is also arranged flat on the corresponding cell walls 18, 22, 24 and thus in particular protects the edges 54, 56 between the first cell wall 18 and the corresponding third cell wall 22 or fourth cell wall 24. In this case, the outer contour K of the through-opening 58 lies directly on the edge R of the openable cell exhaust opening 38, in particular below the edge R in the z direction.

[0061] Figure 5 A schematic diagram of a battery module 62 according to an exemplary embodiment of the present invention is shown. In this case, the battery module 62 has a cell stack 66, which has a plurality of cells 10 arranged side by side in a stacking direction. The cells 10 can be constructed as described above. In this case, the stacking direction corresponds to the x direction shown.

[0062] In addition, the battery module 62 includes a plurality of cell separator elements 64, wherein such a cell separator element 64 is arranged between two battery cells 10 adjacent to each other in the stacking direction. It does not extend over the total height h of the corresponding battery cell 10 or its third and fourth cell walls 22, 24, but is designed to be slightly shorter in the z direction. It is therefore very advantageous that the side tabs 50, 52 of the corresponding thermal protection element 44 cover at least the areas of the corresponding third and fourth cell walls 22, 24 in the z direction that are not covered by the cell separator elements 64. Here, the tabs 50, 52 may also overlap with the cell separator elements 64, which is exemplary for Figure 5 The two battery cells 10 on the right side are shown.

[0063] Furthermore, the cell stack 66 can be arranged in a housing which is not shown here. Accordingly, the cell stack 66 can also be delimited in the z direction on the bottom, in the x direction on the left and right and in the y direction in the front and rear by corresponding housing walls or housing plates or other components. In the z direction, above the cell stack 66, corresponding plate-shaped components such as housing covers, carrier plates for cell connectors (which are also referred to as busbar carriers), etc. can also be arranged. The remaining cell walls of the cell housing 12, in particular the second cell wall 20, the fifth cell wall 26 and the sixth cell wall 28, can be stabilized by the housing walls. Thus, in combination with the described thermal protection element 44, the cell housing 12 can be fully or almost fully stabilized and, thereby, in the case of propagation of such a cell 10, a targeted escape of gas from the cell exhaust openings 38 provided for this purpose can be promoted.

[0064] Figure 6 A schematic perspective view of a battery cell 10 according to another embodiment of the present invention is shown, wherein the battery cell 10 can be Figure 1 and Figure 2The invention is designed as described, except for the differences described below: in this example, the first side web 50 extends along the z direction over the entire third cell wall 22, and / or the second side web 52 extends along the z direction over the entire fourth cell wall 24, in particular, the base element 46 has a first base web 68 and a second base web 70 which are opposite to the base plate 48 in the z direction, wherein the first side web 50 is connected to the first base web 68 via a third protective edge 72, and the second side web 52 is connected to the second base web 70 via a fourth protective edge 74, wherein the first base web 68 and the second base web 70 are respectively arranged on the second cell side 20, in particular in a planar manner, the corresponding third protective edge 68 and the fourth protective edge 70 respectively overlap with at least a portion of the corresponding fifth edge 76 connecting the third cell side 22 and the second cell side 20 and the sixth edge connecting the fourth cell side 24 and the second cell side 20, wherein the sixth edge is shown as a dotted line.

[0065] As a result, the cell walls 22, 24 can also be additionally stabilized and protected from damage during venting of the cell 10. In particular, it is also possible here to surround the base element 46 in addition to the second lower cell side 20 and thereby also to correspondingly stabilize the fourth edge 76 and / or the fifth edge 78 of the cell housing 12 and provide a mechanical anchoring for the thermal protection element 44.

[0066] Furthermore, in this example, at least one notch or through-opening 80, 82 is arranged in the first side tab 50 and / or the second side tab 52. The through-opening in the first side tab 50 is denoted by 80, and the through-opening in the second side tab 52 is denoted by 82. Thus, the two side tabs 50, 52 can be designed to have one or more through-openings 80, 82, such as holes, which pass through the corresponding side tabs 50, 52 in the x-direction. As a result, the thermal protection element 44 can be designed to be lighter and more cost-effective, which is particularly advantageous when the side tabs 50, 52 extend along the z-direction over the entire third cell side 22 or the fourth cell side 24. Thus, an additional stabilizing effect can be provided without having to bear more weight and material.

[0067] Here, the through openings 80, 82 can have any geometric shape in principle. To illustrate this situation, the opening 80 in the first side piece 50 is exemplarily designed as an angle, especially a rectangle, and the opening 82 in the second side piece 52 is exemplarily circular, such as a perfect circle or an ellipse.

[0068] It is also possible to provide the opening 80 only in the first side tab 50 or only in the second side tab 52. Additionally or alternatively, the first side tab 50 can also be designed with a circular opening, and additionally or alternatively, the second side tab 52 can have an angular opening. A variety of other opening geometries are also conceivable, such as triangles, hexagons, etc., or free forms are conceivable.

[0069] In summary, the example shows how propagation protection for prismatic cells can be provided by the present invention.

Claims

1. A prismatic battery cell (10), comprising a battery cell housing (12) made of a first material (M1), wherein: The battery cell housing (12) has: - a first cell wall (18) and a second cell wall (20) which are opposite to each other in a first direction (z), - a third cell wall (22) and a fourth cell wall (24) which are opposite to each other in the second direction (x), - a fifth cell wall (26) and a sixth cell wall (28) that are opposite to each other in the third direction (y), -in, The first cell wall (18) is adjacent to the third cell wall (22) via a first edge (30), adjacent to the fourth cell wall (24) via a second edge (32), adjacent to the fifth cell wall (26) via a third edge (34), and adjacent to the sixth cell wall (28) via a fourth edge (36). - wherein the first edge (30) and the second edge (32) are respectively longer than the third edge (34) and the fourth edge (36), - wherein the battery cell (10) comprises an openable battery cell vent opening (38) arranged in the first battery cell wall (18), It is characterized in that The battery cell (10) has a thermal protection element (44), which includes a base element (46), which is formed from a second material (M2) having a higher melting point than the first material (M1), wherein the base element (46) comprises a first side web (50) and a second side web (52) which are arranged opposite each other in the second direction (x), and a base plate (48) which connects the first side web (50) and the second side web (52) across the corresponding first protective edge (54) and the second protective edge (56) and has a through opening (58), -Wherein, the substrate (48) is arranged to be flat against the first battery cell wall (18) or integrated into the first battery cell wall (18), so that the through opening (58) coincides with the openable battery cell exhaust opening (38), and the corresponding first protective edge (54) and the second protective edge (56) coincide with at least a part of the corresponding first edge (30) and the second edge (32), or are integrated into the first edge and the second edge.

2. The prismatic battery cell (10) according to claim 1, It is characterized in that The first side web (50) lies flat against the third cell wall (22) or is integrated into the third cell wall, and the second side web (52) lies flat against the fourth cell wall (24) or is integrated into the fourth cell wall.

3. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The thermal protection element (44) is a component independent of the cell housing (12) and is arranged on the outer side (22) of the cell housing (12).

4. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The thermal protection element (44) is a component that is independent of the cell housing (12) and is arranged in the interior (14) of the cell housing (12) on the inner side (61) of the cell housing (12).

5. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The second material (M2) has a melting point of at least 1300° C., in particular wherein the second material (M2) is a metal, preferably steel or stainless steel.

6. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The base element ( 46 ) has a wall thickness of at most 1 mm, preferably at most 0.5 mm.

7. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The first protective edge (54) covers most of the first edge (30) along the third direction (y), and the second protective edge (56) covers most of the second edge (32) along the third direction (y).

8. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The first side web (50) extends along the first direction (z) over the entire third cell wall (22), and / or the second side web (52) extends along the first direction (z) over the entire fourth cell wall (24), in particular wherein the base element (46) comprises a first base web (68) and a second base web (70) which are arranged opposite to the base plate (48) in the first direction (z), wherein the first side web (50) is connected to the first base web (68) via a third protective edge (72), and the second side web (52) is connected to the first base web (68) via a fourth protective edge (74 ) is connected to a second base connecting piece (70), wherein the first base connecting piece (68) and the second base connecting piece (70) are respectively arranged on the second battery cell side (20) or integrated into the second battery cell side, and the corresponding third protective edge (72) and the fourth protective edge (74) respectively overlap with at least a part of the corresponding fifth edge (76) connecting the third battery cell side (22) and the second battery cell side (20) and the sixth edge (78) connecting the fourth battery cell side (24) and the second battery cell side (20), or are integrated into the fifth edge and the sixth edge.

9. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that At least one recess or through-opening (80, 82) is arranged in the first side web (50) and / or the second side web (52), in particular in the lower half of the first side web (50) or the second side web (52) facing away from the base plate (48).

10. The prismatic cell (10) according to any one of the preceding claims, It is characterized in that The thermal protection element (44) is on the battery cell housing (12) - are bonded; and / or - entrapment; and / or - Held by friction locking.

11. A battery module (62) comprising a prismatic cell (10) according to any one of the preceding claims, It is characterized in that The battery module (62) comprises at least one component (64) which contacts at least a part of the thermal protection element (44) and holds the thermal protection element (44) on the outside of the cell housing (12) by means of friction and / or form fit.

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