Patent Publication Number: US-2022223963-A1

Title: Battery housing and battery comprising same

Description:
The present invention relates to a battery housing for a vehicle battery, in particular for a truck battery, and to a battery for a vehicle, in particular for a truck, with such a housing. 
     Conventionally, in truck batteries a multiplicity of cell stacks forming electrochemical cells are bonded to a lower wall (base element) of the battery housing by means of an adhesive. For this purpose, usually the entire area of the lower wall is covered with the adhesive and the cell stacks are placed on top in order to improve the vibration resistance of the truck battery during operation. However, with such conventional truck batteries the problem arises that, due to the forces and vibrations occurring during operation (while the truck is driving), although the adhesive adheres well to the cell stacks, it becomes detached from the lower wall, which has the effect that the cell stacks and cell connectors can be damaged and poor results are obtained in battery vibration resistance tests. 
     The present application is therefore based on the object of providing an improved battery housing for vehicle batteries which does not have the disadvantages of the prior art and which is quick, easy and inexpensive to manufacture and which improves the vibration resistance of the battery in use or in operation. 
     The object on which the invention is based is achieved by means of the subjects of the independent patent claims  1  and  16 . Advantageous developments are specified in the dependent claims. 
     Accordingly, a battery housing for a vehicle battery, in particular for a truck battery, is specified, which has the following: a lower housing part for receiving a multiplicity of electrochemical cells, the lower housing part enclosing an interior space, and a housing cover, which can be connected or is connected to the lower housing part in such a way that the interior space is sealed off and closed off from an external environment. The lower housing part has a base element, a multiplicity of projections being arranged in a pattern on at least one area of the base element. 
     The advantages of the invention are obvious. The arrangement of a multiplicity of projections in at least one area of the base element in a pattern ensures that the roughness of the base element is increased on a macroscopic level. An increase in the roughness of the base element leads to the surface of the base element being enlarged. Such a surface enlargement has a positive effect on the vibration resistance of the truck battery thereafter and especially when the battery housing is used in a truck battery, since, by providing or arranging the multiplicity of projections in a pattern, the bonding between an adhesive which connects the multiplicity of electrochemical cells to the lower housing part and in particular to the base element of the lower housing part can be improved. In this way, the adhesive can advantageously be prevented from becoming detached from the base element, which can improve the service life and safety of the battery. 
     Since the multiplicity of projections can be easily formed by means of an injection-molding process when the battery housing is being produced, production costs and times can thus be advantageously reduced. Conventional already manufactured battery housings can also be retrofitted with a multiplicity of projections in at least one area by means of a hot-embossing or hot-stamping process that can be carried out easily and inexpensively. 
     According to a further aspect, the multiplicity of projections can increase the surface of the at least one area of the base element by at least 20%, preferably by at least 25%, particularly preferably by at least 30%, specifically in comparison with the surface of the at least one area of the base element without projections (i.e. the at least substantially flat surface of the at least one area of the base element). 
     Thus, the adhesive surface area can be increased by at least 20% in comparison with a conventional battery housing, which improves the vibration resistance and the bonding capability of the battery housing according to the invention, specifically without requiring a larger installation space and/or more expensive adhesive. 
     According to a further aspect, the multiplicity of projections may extend at least substantially perpendicularly from the base element in the direction of the interior space. An increase in the surface area of the base element can thus be achieved. 
     According to another aspect, the multiplicity of projections may be arranged in a strip pattern. At least some of the strips may extend along the longitudinal direction of the battery housing and/or at least some of the strips may extend along a width direction of the battery housing and/or diagonally to the longitudinal direction and/or width direction of the battery housing. This corresponds to patterns that are simple and thus, advantageously, inexpensive and not complicated to manufacture. 
     According to a further aspect, the pattern may correspond at least substantially to a waffle-like pattern. The projections include at least substantially diamond-shaped recesses into which adhesive can flow. An effect similar to a form fit can thus also be advantageously achieved, which improves the vibration resistance of the battery housing and thus of the battery when the battery housing is inserted. 
     According to a further aspect, the lower housing part may have a multiplicity of side walls, in particular four, which delimit the interior space and which are connected to the base element and extend at least substantially perpendicularly from the base element, which advantageously increases the surface of the base element in the direction of the interior space. 
     According to a further aspect, the lower housing part may also have a multiplicity of partition walls, which divide the interior space into a multiplicity of cell chambers. Each cell chamber is designed to receive an associated electrochemical cell. 
     According to a further aspect, the at least one area may be arranged at a distance from the side walls and/or the partition walls, so that a gap is arranged between the multiplicity of projections and the side walls or the partition walls. In particular, the gap may be formed circumferentially around the multiplicity of projections. As a result, it can advantageously be prevented that forces and/or vibrations which act on the base element are transmitted to the side walls, which can lead to the formation of cracks. 
     According to a further aspect, the at least one area may correspond to the entire surface area of the base element in the direction of the interior space, or may correspond to a surface area of the base element in a cell chamber, which is advantageously accompanied by an improved surface enlargement or increased roughness of the base element. As a result, the bonding effect of the adhesive on the base element can be improved in an inexpensive manner. 
     According to a further aspect, a cross section of the multiplicity of projections may be formed as at least substantially triangular, semicircular, rectangular or in the form of a sawtooth profile. 
     According to a further aspect, the surface of the multiplicity of projections may be roughened (for example on a microscopic level), which can advantageously lead to a further increase in the surface. 
     The object on which the invention is based is also achieved by a battery for a vehicle, in particular a battery for a truck, according to the subject matter of claim  16 , the battery having the following: a battery housing, as described above, and a multiplicity of electrochemical cells, the multiplicity of electrochemical cells being arranged in the interior space of the lower housing part and connected to the base element in a material-bonding manner by means of an adhesive which is arranged on the base element of the lower housing part. By means of such an arrangement, a battery or a truck battery which is advantageously formed as vibration-resistant can be advantageously provided. In particular, as a result of the multiplicity of projections, the bonding effect of the adhesive on the base element of the lower housing part can be improved. 
     According to a further aspect, the adhesive may be a hot-melt adhesive or an epoxy-resin adhesive. 
     According to a further aspect, the multiplicity of projections can increase the surface of the at least one area of the base element by at least 20%, preferably by at least 25%, particularly preferably by at least 30%, in such a way that the adhesive surface area increases by at least 20%, preferably by at least 25%, particularly preferably by at least 30%. As a result, detachment of the adhesive or the adhesive layer from the base element can be advantageously prevented. 
     The invention will be discussed in more detail below, also with regard to further features and advantages, on the basis of the description of embodiments with reference to the appended drawings. 
    
    
     
       In the drawings: 
         FIG. 1  shows a schematic representation of a battery; 
         FIGS. 2 to 8  show schematic representations of a plan view of a lower housing part of the battery; and 
         FIGS. 9 a    to  11  show schematic representations of a cross section through a cell chamber in the battery housing. 
     
    
    
     Aspects of the battery housing according to the invention and the battery according to the invention are described in more detail below with reference to the representations in  FIGS. 1 to 11 . Elements and functions that are the same or have the same effect are provided with the same or similar reference signs. 
     In each of the drawings, the dimensional relationships in the figures and/or the number of elements shown does not necessarily coincide with the actual dimensional relationships or the actual number of elements shown. The dimensional relationships between the figures also do not necessarily have to coincide. 
     In the following, the battery and the battery housing are described in such a way that relative terms refer to the installed state of the battery. For example, “in an upper area” means in an upper area as seen in the installed state, “in a lateral area” means in an area which is located in a front, rear, left-hand or right-hand area as seen in the installed state and in a direction of travel, and “in a lower area” means in a lower area as seen in the installed state. 
     Batteries which are provided with a battery housing according to the present invention are used in particular as starter batteries in vehicles. The battery may be arranged in a front area of the vehicle as seen in the direction of travel, in a rear area of the vehicle and/or in an area below the seats, in particular below the driver&#39;s seat. 
     The vehicle may be an aircraft or watercraft, a track-guided vehicle, an off-road vehicle or, preferably, a road vehicle, whereby a road vehicle can be understood to be a passenger car, in particular a truck, a bus or a mobile home. 
     If the battery is used in a truck, it is also conceivable that it is arranged at a location outside the driver&#39;s cab, and in particular may be attached to a fifthwheel pick-up plate of the truck. 
     The battery described below is based on lead-acid technology. However, it is also conceivable that the battery is based on other technologies, such as NIMH, lithium-ion or nickel-cadmium technology. 
     Batteries based on lead-acid technology are particularly suitable for use as starter batteries in vehicles. Furthermore, such batteries can likewise be used wherever relatively high currents are required in a short period of time. 
     The battery for a vehicle or the battery for a truck according to the present invention has a battery housing  100  and a multiplicity of electrochemical cells, which are arranged and received in the battery housing  100 . 
     The battery housing  100  may be divided into a lower housing part  110  and a housing cover  120 , which can be connected to one another in such a way that an interior space defined and enclosed by the battery housing  100  is closed off and sealed off from an external environment. In particular, the housing cover  120  may be welded to the lower housing part  110 . Alternatively, it is also conceivable to tightly connect the housing cover  120  to the lower housing part  110  and close them off by means of one or more screw connections and/or clamping elements. 
     At least one positive and one negative battery terminal  122 , which are electrically connected to the multiplicity of electrochemical cells, may be arranged or inserted in the housing cover  120 . Furthermore, a degassing opening, which can be closed off or is closed off with a degassing plug, and/or a filling opening, which can be closed off or is closed off with a closing plug, may be arranged in the housing cover  120 . 
     The lower housing part  110  is formed in such a way that it receives a multiplicity of electrochemical cells and at least substantially defines or encloses the interior space of the battery housing  100 . For this purpose, the lower housing part has a multiplicity of side walls, in particular four, which delimit (in particular enclose) the interior space and which are connected to a base element  112 . In particular, the multiplicity of side walls extend substantially perpendicularly from the base element  112 , so that the interior space is at least substantially defined by the multiplicity of side walls and the base element  112 . 
     The base element  112  and the side walls may be formed integrally, which is advantageously easy and inexpensive to manufacture (for example by an injection-molding process). However, it is equally also conceivable to form the base element  112  as an insert which can be cast into the side walls, as a result of which the material of the base element  112  can advantageously be selected independently of the material of the side walls. 
     Advantageously, for example, depending on the type of adhesive that is to be used, the material of the insert may be selected in such a way that a bonding effect of the adhesive on the insert or the base element that is as optimum as possible can be achieved. 
     Furthermore, a multiplicity of partition walls  114   i ,  114   ii , which divide the interior space into a multiplicity of cell chambers  20 , may be arranged in the lower housing part  110 . 
     In particular, a longitudinal partition wall  114   ii  arranged along a longitudinal direction L of the battery or battery housing  100  and/or one or more transverse partition wall  114   i  or partition walls  114   i  arranged parallel to one another in width direction B of the battery or battery housing  100  may be arranged. 
     For example, as indicated in the schematic representations in  FIGS. 2 to 8 , the interior space of the lower housing part  110  may be divided by means of a longitudinal partition  114   ii  and two transverse partition walls  114   i  spaced apart from one another at an equal distance into six cell chambers  20  of at least substantially the same size. 
     Although this is not explicitly shown in the figures, it is of course also conceivable that, depending on the requirement and the required number of electrochemical cells, the battery housing  100  or the lower housing part  110  has more or fewer than six cell chambers  20 . 
     It is also conceivable that the partition walls  114   i ,  114   ii  have a length which at least substantially corresponds to the width of the battery housing  100  or the length of the battery housing. However, it is equally also conceivable that the length of the partition walls  114   i ,  114   ii  is formed in such a way that it corresponds to the width or length of a cell chamber. In other words, the lower housing part  110  indicated in  FIG. 2  may be divided either by means of a (large) longitudinal partition wall  114   ii  and two transverse partition walls  114   i  which are spaced apart from one another in the longitudinal direction L. Equally well, however, three longitudinal partition walls  114   ii  and four transverse partition walls  114   i  spaced apart from one another could be arranged. In both cases, for example six cell chambers  20  of at least substantially the same size can be defined. 
     The lower housing part  110  is also designed to receive a multiplicity of electrochemical cells and to arrange them therein. In particular, in each case an electrochemical cell may be received in an associated cell chamber  20  and arranged therein. 
     Each of the electrochemical cells has a cell stack which is formed from a multiplicity of positive electrode plates and negative electrode plates, as well as a multiplicity of separators, which electrically isolate the positive electrode plates from the negative electrode plates. In this connection, for example, each separator may be formed as a separator pocket, in each of which a positive electrode plate is received. 
     Furthermore, if the battery is formed as an AGM battery (absorbent glass mat battery), a multiplicity of fiberglass or fleece mats, in which the battery acid is completely absorbed, may be arranged. This means that the battery can be operated dry and in any position. However, it is equally conceivable to provide or form a wet battery with a liquid electrolyte. 
     Optionally, the cell stacks may also be arranged in an additional cell housing. 
     In order to increase the vibration resistance of the battery, the cell stacks or the cell housing are connected to the base element  112  in a material-bonding manner. In particular, the cell stacks are bonded onto the base element  112 . 
     A hot-melt adhesive, a two-component adhesive or an adhesive based on epoxy resin is suitable for example as the adhesive. 
     The battery housing  100  (i.e. lower housing part  110  and/or housing cover  120 ) may in particular be made of a polyolefin or a copolymer which comprises a polyolefin. In particular, the battery housing  100  may be made of polypropylene, polyethylene, polypropylene-polyethylene copolymer, and the like. 
     In order to prevent the material-bonding connection between the cell stack or the cell housing and the base element  112  from loosening due to vibrations and forces during operation, a multiplicity of projections  10  that can improve the vibration resistance of the battery are arranged on the surface area of the base element  112  facing the interior space of the battery housing  100 . 
     The multiplicity of projections  10  are arranged in a pattern at least on an area of the base element  112 . In other words, at least in a plan view (i.e. a plane defined by the longitudinal direction L and width direction B of the battery housing  100 ) of the base element  112 , the multiplicity of projections  10  forms a pattern in at least one area. 
       FIGS. 2 to 8  each show an exemplary lower housing part  110 , which has partition walls  114   i ,  114   ii  which divide the interior space of the battery housing  100  into six cell chambers  20  of at least substantially the same size. 
     Although not explicitly shown in the figures, it is of course also alternatively conceivable that no partition walls  114   i ,  114   ii  are provided, or a different number of partition walls  114   i ,  114   ii , which divide the interior space of the battery housing  100  into a different number of cell chambers  20 . For example, an area in which the multiplicity of projections  10  are arranged may be formed in such a way that it extends at least substantially over the entire surface area of the base element  112 . 
     Also in  FIGS. 2 to 8 , the three upper cell chambers  20  seen in the width direction B are formed without a gap  22  and the three lower cell chambers  20  seen in the width direction B are formed with a gap  22 . However, this is only an exemplary representation and can be chosen as desired, depending on the requirements. For example, it may be that none of the cell chambers  20  have a gap  22  (i.e. the multiplicity of projections  10  extend in all of the cell chambers  20  or in the interior space up to the respective side walls or partition walls  114   i ,  114   ii ) or all of the cell chambers  20  are formed in such a way that a gap  22  is formed between the respective cell walls or partition walls  114   i ,  114   ii  and the multiplicity of projections  10  (i.e. the projections  10  do not extend up to the partition wall  114   i ,  114   ii  or side wall of the battery housing  100 ). In particular, the gap  22  may be formed circumferentially around the multiplicity of projections  10 . 
     It is also conceivable that—unlike as shown in  FIGS. 2 to 8 —either all of the areas are arranged with a gap  22  to the side walls or partition walls  114   i ,  114   ii  or all of the projections  10  extend up to the partition walls  114   i ,  114   ii  or side walls (i.e. without a gap  22 ). 
     As indicated in  FIG. 2  by way of example, the pattern may take the form of a strip pattern. As shown in  FIG. 2 , the multiplicity of projections  10  extend parallel to one another and in the width direction B of the battery housing  100 . 
     As indicated in  FIG. 2 , a multiplicity of projections are arranged in six areas, which at least substantially correspond to the surface area of the base element  112  in a corresponding cell chamber  20 . 
     The multiplicity of projections may extend from the partition wall  114   ii  up to a side wall of the lower housing part  110 , as is indicated for example in the upper three cell chambers  20 . 
     However, it is equally conceivable, as indicated in the lower three cell chambers  20  of  FIG. 2 , that the multiplicity of projections  10  are set at a distance from the side walls or partition walls  114   i ,  114   ii  by a gap  22 . 
     In particular, a gap  22  between the multiplicity of projections  10  and the corresponding side walls or partition walls  114   i ,  114   ii  can advantageously ensure that forces and vibrations that act on the base element  112  are not so easily transmitted to the side walls or partition walls  114   i ,  114   ii , as a result of which the risk of crack formation in the side walls or partition walls  114   i ,  114   ii  and/or the transition area from the base element  112  to the side walls or partition walls  114   i ,  114   ii  can be reduced. 
       FIG. 3  shows a further embodiment of the pattern in which the multiplicity of projections  10  may be arranged. In particular, the projections  10  may be arranged in a longitudinal strip pattern, so that the multiplicity of projections  10  extend substantially along the longitudinal direction L of the battery housing  100  and parallel to one another. As already described above, the multiplicity of projections  10  may either extend completely up to the side walls or partition walls  114   ii , or a gap  22  may be formed between the side walls or partition walls  114   i ,  114   ii  and the multiplicity of projections  10 . 
       FIG. 4  shows another pattern, in which a multiplicity of projections are arranged in a checkered pattern. The distances between the projections  10  may be chosen to be greater than in the case of a pure strip pattern, in order to ensure that the adhesive can flow into the depressions enclosed by the projections. Just as with respect to  FIG. 2  and  FIG. 3 , in the case of the pattern according to  FIG. 4  a gap  22  may be provided or arranged between the multiplicity of projections  10  and the corresponding partition walls  114   i ,  114   ii  or side walls. 
       FIG. 5  shows an embodiment in which the multiplicity of projections  10  extend diagonally, i.e. at an angle (which is not perpendicular) to the longitudinal direction L or width direction B. 
     The pattern may equally well be, as indicated in  FIG. 6 , a waffle-like pattern or, as indicated in  FIG. 7 , a pattern in which the multiplicity of projections  10  extend at least substantially circularly and/or partially circularly from a central region of the at least one area, or the pattern may be formed in a substantially serpentine-shaped manner, as indicated in  FIG. 8 . 
     However, other patterns, such as for example a regular or irregular zigzag shape, of the projections  10  are also conceivable. 
     Even if it is not explicitly shown in the figures, it should be noted that the shape of the pattern is not limited to the patterns described above. 
     Even if it is not explicitly shown in the figures, different areas may have different patterns. It is also conceivable to form different patterns of projections  10  in one area. 
     In particular, the intended aim is that, by means of the multiplicity of projections  10 , the surface of the base element  112  is enlarged and thus the roughness of the base element  112  increases, as a result of which a better adhesive effect can be achieved. 
     This can ensure that, even if vibrations occur during operation of the battery, the adhesive specifically does not become detached from the base element  112 , which can lead to damage to the electrochemical cells and/or the battery housing  100 . 
     It may therefore be advantageous if at least 5 projections  10 , in particular at least 10 projections  10 , in particular at least 20 projections  10 , are arranged in a corresponding area. Different areas may have a different number of projections  10 . The larger the area (or the surface of the area) on which the multiplicity of projections  10  are formed, the more projections  10  (depending on their orientation) can tend to be arranged. 
     The arrangement of at least one area with a multiplicity of projections  10  arranged in a pattern can reduce the surface of the corresponding area of the base element  112  by at least 25%, in particular at least 30%, in particular at least 40%, of the surface area of the corresponding area of the base element  112  without projections  10 , which also increases the adhesive surface area. This significantly increases the adhesive strength and thus also the resistance to vibrations of the battery. 
     Although it is not explicitly shown in the figures, it is conceivable that at least one projection  10  of the multiplicity of projections  10  has a multiplicity of notches along the direction of extent of the projection  10 , in such a way that the projection  10  at least substantially has a peak/valley profile along its direction of extent. As a result, the surface can advantageously be enlarged further and, at the same time, a form fit can be formed between the surface of the base element  112  and the adhesive. 
     The projections  10  may have a cross-sectional shape as shown or indicated for example in  FIGS. 9 a , 9 b , 10 a , 10 b    and  11 . The term cross section refers to a section through the multiplicity of projections  10  perpendicular to their direction of extent. For example,  FIG. 3  shows a section parallel to the width direction B and seen along the longitudinal direction L through the multiplicity of projections  10 . 
     The term “cross-sectional shape” is understood in this connection to mean the outline of a projection  10  which is formed in the direction of extent onto the (vertical) section of the projection  10 . 
     This outline may in particular be triangular, with the individual projections being able to be arranged directly adjacent to one another, as indicated for example in  FIGS. 9 a    and  9   b.    
     However, it is equally conceivable to arrange the individual projections  10  at a distance from one another, as a result of which the distribution of the adhesive between the projections  10  can be facilitated. It is also conceivable to arrange the projections  10  at non-uniform distances from one another. For example, smaller distances between the projections  10  may be formed in areas close to the partition walls  114   i ,  114   ii  or side walls, in order to counteract a shear effect in peripheral areas (or more stressed areas), and larger distances between the projections  10  may be formed in a central area (or less stressed area). 
     Another possible cross-sectional shape of the projections  10 , not shown in the figures, is for example also a sawtooth profile, which corresponds to a special shape of the triangular profile in which the cross section for example rises obliquely on the left side and runs straight down on the right side (perpendicular to the base element  112 ), that is to say an asymmetrical triangle. 
     Furthermore, as indicated in  FIGS. 10 a  and 10 b   , the projections  10  may also have a semicircular shape. In this case, the cell stacks can for example be aligned and arranged more easily. 
     The projections  10  according to  FIGS. 10 a  and 10 b    may also be arranged at a distance from one another, even if this is not explicitly shown in the figures. 
     Alternatively, it is also conceivable that the projections  10  may have a substantially rectangular cross section, as indicated in  FIG. 11 . 
     In summary, various areas in which a multiplicity of projections  10  can be arranged in various of the patterns and cross-sectional shapes described above may be formed on the base element  112 . It is also conceivable to provide or arrange different patterns in different cross-sectional shapes in one area (for example on a surface area of the base element  112  which is assigned to a cell chamber  20 ). 
     The height of the projections  10  can be a maximum of 5 mm, in particular a maximum of 3 mm, particularly preferably a maximum of 2 mm, in order not to unnecessarily restrict or reduce the available interior space. 
     Thus, all of the patterns and cross-sectional shapes described above can be freely combined with one another and are not limited to the embodiments shown in the figures. 
     The embodiments described above have been described in such a way that the surface area of the base element  112  is enlarged as a result of a multiplicity of projections  10 . However, it is equally conceivable to arrange a multiplicity of recesses in a pattern instead of the projections  10  (i.e. a case of being formed in complementary manner). A combination of projections and recesses is also conceivable. 
     The multiplicity of projections  10  can be introduced into the base element  112  easily and inexpensively by means of an injection-molding process during the manufacture of the battery housing  100  or the lower housing part  110 . However, it is also conceivable to retrofit battery housings  100  that have already been manufactured and to provide them with a multiplicity of projections  10  by means of a hot-embossing process or hot-stamping process. A multiplicity of projections  10  can thus be arranged in an easy and inexpensive manner. 
     Alternatively, it could also be conceivable to form the projections  10  from open-pored foam, so that the adhesive can flow into the open pores. In addition, by means of such an embodiment, a certain elasticity and damping capacity could be introduced into the base element  112 , which can have the effect that forces and/or vibrations which arise during operation of the battery and act on the battery housing  100  can be at least partially absorbed and damped. This could advantageously improve the safety of the battery. 
     It is also conceivable that the surface of the multiplicity of projections  10  is additionally roughened further (on a microscopic level), as a result of which a further surface enlargement can be achieved, which leads to an enlarged adhesive surface area. 
     Briefly summarized, it is intended that at least such a multiplicity of projections  10  should be arranged on the base element  112  in at least one area that an enlargement of the adhesive surface area of the at least one area by at least 20%, in particular at least 30%, preferably at least 40%, can be achieved. 
     At this point it should be noted that all of the parts described above, considered individually or in any combination, in particular the details shown in the drawings, are claimed as being essential to the invention. Amendments thereto are familiar to a person skilled in the art. 
     LIST OF DESIGNATIONS 
     
         
           10  Projection/projections 
           20  Cell chamber 
           22  Gap 
           100  Battery housing 
           110  Lower housing part 
           112  Base element 
           114   i ,  114   ii  Partition walls 
           120  Housing cover 
           122  Battery terminal 
         B Width direction 
         L Longitudinal direction