The present invention relates to an energy store device and to the use of a cooling device for cooling a stack of a multiplicity of electrochemical energy store units.
For a connection of cells, in particular Li-ion cells, to a heat sink, it is possible to provide a connection of cooling sheets of various designs to a cooling plate.
Document 102007066944.4 describes inter alia a cooling means for battery flat cells, which exhibits cooling sheets as a thermal path. It is mentioned that the sheets are in thermal contact with the cooling plate; it is sought to produce said contact by sealing.
The patent DE 102 23 782 B4 describes a cooling device for round cells, composed of a base plate and cooling elements which abut against the cells laterally in the longitudinal direction. The cells are connected in a force-fitting manner to the cooling device, and the abutting cooling elements have expansion joints in order to improve the problem of gap formation and of heat transfer.
The lecture “The Impact of Simulation Analysis on the Development of Battery Cooling Systems for Hybrid Vehicles” (by Peter Pichler, Product Manager Battery Systems, MAGNA STEYR Fahrzeugtechnik AG & Co. KG) at the Advanced Automotive Battery Conference (AABC) 2008 describes a modular battery construction in which the heat sink is however already integrated into the modules. Only the connection of the individual cooling ducts is produced during the completion of the battery.
The patent US 2008/0090137 describes a modular construction of a battery in which the module is composed of cells and cooling sheets. The finished battery is air-cooled.
The cooling ducts or the evaporator plate permit, in most cases, a connection of the cells only on one side, which impairs the heat distribution in the cell. Owing to installation space, the contact area for heat transfer to the heat sink is limited, as a result of which the dissipation of heat is hindered, in particular when large amounts of heat are generated. The force-fitting connections to the heat sink such as are used here are cumbersome and in part complex, and at the same time are inferior to cohesive connections. The accessibility for assembly often prevents additional mechanical support, in particular of “coffee bag” cells, for example by means of a frame or form-fitting encapsulation. For positively locking connections, use is made primarily of methods such as soldering or welding, but these damage the cells.
Furthermore, the heat sink or evaporator plate must be redesigned for every design concept of a module or of an entire battery, thus increasing the development expenditure and the number of variants.
Furthermore, the interconnection of individual cooling modules with dedicated heat sinks is cumbersome and increases the risk of leaks. An overall cooling plate for multiple modules can easily reach installation space dimensions which complicate the manufacture thereof. The partially solid construction of the heat sink and the additional connecting elements furthermore has an adverse effect on the overall weight of the battery.
It is the object of the present invention to create an improved device for cooling electrochemical energy store units, and a novel use of a cooling device.
Said object is achieved by means of an energy store device as per claim 1 and the use of a cooling device as per claim 13.
The present invention is based on the realization that the use of modified mass-produced parts and methods based on flat tube coolant coolers or evaporators can permit a reduction in development outlay and production costs. The essence of the invention, aside from improved modularity, is also an increase in heat dissipation, an improvement in the heat distribution in the cell as a result of a connection of heat sinks to multiple sides of the cells, and improved ease of assembly of the connection of the cooling sheet and heat sink. Furthermore, the packaging density can be optimized by means of adapted cooling sheets and a connection of the flat tubes in unused intermediate spaces of the cells. Furthermore, it is possible to attain a reduction in weight and an increase in mechanical stability with a simultaneous simplification of assembly.
It is advantageously possible for development outlay and production costs to be reduced through the use of modified mass-produced parts. The use of a flat-tube cooler or evaporator permits a highly variable, modular construction. A high packaging density can be attained through the optimum utilization of empty spaces. Since a variable arrangement of heat sinks can be attained in accordance with the cooling demand and the conductor position, it is furthermore possible to obtain increased heat dissipation and improved heat distribution in the cell. Aside from the reduction in weight, support of the mechanical stability is obtained with a simultaneous simplification of assembly and improvement in connection quality.
According to a further embodiment, the approach according to the invention can be used in particular for prismatic hard-case cells and “coffee bag” cells. An increase in heat dissipation is attained through the direct connection of the cells to the heat sink. Furthermore, an adaptation of cooling capacity can be attained by means of a variable number of flat tubes. The approach according to the invention advantageously permits tolerance compensation and flexibility in the cell assembly. Furthermore, owing to the low transfer resistances, cooling of battery cells with comparatively high inlet temperatures is made possible.
The approach according to the invention thus yields the further advantages of cohesive, reliable joining of the flat tubes to a collecting tank, improved heat dissipation in the cell as a result of direct connection to the heat sink, and a cooling capacity which meets demand through the variable number of flat tubes.
In a further embodiment of the invention, the approach described here can be used in particular for “coffee bag” cells. Through the direct connection of the cell or the cell conductor to the heat sink, an increase or improvement in the heat dissipation in the cell can be realized.
A further embodiment of the invention yields the advantages of improved assembly, a larger contact surface and latching of the energy store module into a structural component or the like.
The present invention provides an energy store device having the following features: a multiplicity of cooling ducts which are arranged spaced apart from one another and substantially parallel in a plane and which are formed such that a cooling fluid can flow through them; at least one collecting tank which is arranged in the plane with and substantially perpendicular to the multiplicity of cooling ducts and is connected to said cooling ducts in order to receive the cooling fluid therefrom or deliver the cooling fluid thereto; and a stack of a multiplicity of electrochemical energy store units which are arranged such that in each case at least one energy store unit of the multiplicity of electrochemical energy store units is arranged between two adjacent cooling ducts of the multiplicity of cooling ducts.
The energy store device is composed of an electrochemical energy store unit and at least one cooling device. Said energy store device may be used in a vehicle with hybrid or electric drive. The electrochemical energy store unit may be a battery or an accumulator battery and comprise for example lithium-ion cells. The cooling device may be a heat sink for the electrochemical energy store unit. The cooling ducts may be arranged adjacent to one another and connected at their respective ends to collecting tanks. The collecting tanks can receive a cooling fluid from, and deliver the cooling fluid back to, a cooling circuit. Each electrochemical energy store unit may have two opposite larger main surfaces and four smaller side surfaces. The side surfaces may form edge regions. The stack may be designed such that the main surfaces of adjacent electrochemical energy store units bear against or face towards one another. In different embodiments, the cooling ducts may make contact with the electrochemical energy store units in different regions thereof. The cooling ducts may be formed by cooling tubes.
In one embodiment of the energy store device, the multiplicity of cooling ducts may be formed as flat tubes. Flat tubes have the advantage that they can be fitted more effectively into the recesses between adjacent electrochemical energy store units.
In a further embodiment of the energy store units, each of the multiplicity of electrochemical energy store units may have a projection in at least one tapered edge region. Said projections may be designed such that recesses are formed in each case between the projections of the multiplicity of electrochemical energy store units. The electrochemical energy store units may for example each have a casing, and the projections may be formed by sealing formations of the casings. Such sealing formations are used for example in the case of “coffee bag” cells to close off the cell casing. In this case, the cooling ducts may be arranged between the sealing formations. The multiplicity of electrochemical energy store units may also each have at least one current conductor which may form the projection. In this case, the cooling ducts may be arranged between the current conductors.
Furthermore, insulators may be arranged between the projections and the cooling ducts. The insulators may be formed as a material piece or as a lacquer. The insulators can prevent an undesired flow of current between the conductor and the cooling device.
In one embodiment, cooling sheets may be arranged between adjacent electrochemical energy store units. Here, the cooling sheets may be thermally coupled to the cooling ducts. Here, the cooling sheets and cooling ducts may be in contact such that the cooling ducts can dissipate heat from the electrochemical energy store units via the cooling sheets. There may be a force-fitting or cohesive connection between the cooling sheet and energy store unit and between the cooling sheet and tube.
Furthermore, the cooling sheets may have, at a level of the tapered edge region, a bend in the direction of a projection of an adjacent electrochemical energy store unit. Adequate space is thus provided for the tubes to be fitted between the edge regions of the electrochemical energy store units.
In a further embodiment, the cooling sheets arranged between adjacent electrochemical energy store units may be folded and, at a level of the tapered edge region, have a bend in the direction of the projections of adjacent electrochemical energy store units. Here, a cross section of the cooling ducts may have a wedge shape which corresponds to a recess formed by the tapered edge region of two adjacent electrochemical energy store units.
Furthermore, each of the multiplicity of cooling ducts may have a cooling projection. The multiplicity of electrochemical energy store units may be arranged such that in each case at least one electrochemical energy store unit of the multiplicity of electrochemical energy store units is arranged between two adjacent cooling projections of the multiplicity of cooling ducts. It is thus possible for the cooling projections to be arranged between the electrochemical energy store units and for the cooling ducts to be situated outside the electrochemical energy store units. For this purpose, the cooling ducts may be arranged in or on a cooling plate.
In a further embodiment, in each case one central region of the at least one electrochemical energy store unit of the multiplicity of electrochemical energy store units may be arranged between two adjacent cooling ducts of the multiplicity of cooling ducts. In this way, a single cooling device may advantageously suffice for cooling the stack of electrochemical energy store units.
The present invention furthermore provides the use of a cooling device having a multiplicity of cooling ducts which are arranged spaced apart from one another and substantially parallel in a plane and which are formed such that a cooling fluid can flow through them, and at least one collecting tank which is arranged in the plane with and substantially perpendicular to the multiplicity of cooling ducts and is connected to said cooling ducts in order to receive the cooling fluid therefrom or deliver the cooling fluid thereto for the purpose of cooling a stack of a multiplicity of electrochemical energy store units. The approach according to the invention thus provides a novel use of a cooling device composed of modified mass-produced parts.
Advantageous exemplary embodiments of the present invention will be explained in more detail below with reference to the appended drawings, in which:
In the following description of the preferred exemplary embodiments of the present invention, the same or similar reference numerals will be used for elements of similar function illustrated in the various drawings, wherein a repeated description of said elements will not be given. Likewise, for clarity, if an identical element appears multiple times in a figure, in each case only one of the identical elements is provided with the relevant reference numeral.
The energy store 300 may also have more or fewer energy store units 310 and cooling sheets 330 than shown in
In
By contrast, in the energy store device 600 shown in
The connection of cells 310 via cooling sheets 330 to the heat sink 100 with flat tubes 130, as has been illustrated in conjunction with the exemplary embodiments from
Already mass-produced flat-tube coolers or evaporators 100 are produced without a corrugated fin profile and with possibly modified collecting tanks 110, 120 adapted in terms of width to the cells 310 and/or the cooling sheets 330 and in terms of overall length to the respectively desired number of cells 310. The use of said modified mass-produced parts reduces the development outlay and production costs and permits a highly variable modular construction.
The cells 310 are connected, for example by adhesive bonding, to the cooling sheets 330. The cooling sheets 330 are adapted to a surface of the cells 310 or to a geometry of a casing of the cells 310, as shown for example in
The cooling sheets 330 may be connected to the flat tubes 130 for example by adhesive bonding. The flat tubes 130 run through the unused intermediate space 340 between the cells, in particular along the sealing edges 320 in the case of “coffee bag” cells. In this way, the available installation space can be optimally utilized and the packaging density can be increased.
As shown in
“Coffee bag” cells 310 can be mechanically supported, together with the cooling sheets 330 connected thereto, already at a preparatory state by means of frames, form-fitting encapsulation or sealing compounds. Here, those points which, during later assembly, will be connected to the flat tubes 130 for heat transfer remain recessed. Such a construction may already have integrated therein connecting elements such as for example latching hooks, clips or the like, which enable the individual segments to be plugged together in a simple manner. Furthermore, the cells can also be insulated from one another in this way. One or more flat-tube coolers or evaporators 100 can subsequently be mounted, in the described way, on a stack of cells 310 thus constructed. As a result of the spacing between the flat tubes 130, the flat-tube cooler or evaporator 100 can be inserted or mounted into the stack or the cooling sheets 330 in a simple manner. This is illustrated in conjunction with the assembly illustration from
Alternatively, cooling plates instead of flat tubes 130 may be mounted, with correspondingly modified cooling sheets 330.
A further possibility would be to connect the flat tubes 130 directly to the cell 310 if a thickness of the cell housing or of the cell casing exhibits good heat conduction corresponding to that of the cooling sheet 330. Corresponding exemplary embodiments following this approach are illustrated in
The casing cooling of battery cells 310 via flat tubes 130 to collecting tanks 110, 120 described in conjunction with
Again, it is possible for already mass-produced flat-tube coolers or evaporators without a corrugated fin profile and with possibly modified collecting tanks to be used and correspondingly adapted. It is also possible for existing production plants, such as for example through-type furnaces, to be used together with parts which are widely used nowadays, such as coolant coolers.
The cells 310 are connected directly, for example by adhesive bonding, to the flat tubes 130. The positioning is central, and not in contact with the whole of the casing surface of the cell 310. The heat dissipation from the surface which is not in contact takes place by heat conduction via the cell casing. Depending on the demanded cooling capacity, it is possible for one or more flat-tube coolers or evaporators to be arranged around the cells 310; it is alternatively also possible for the width of the tubes 130 to be adapted if the battery cell 310 itself cannot provide adequate internal heat conduction. The flat tubes 130 may be operated with coolant or refrigerant. The use of tubes 130 instead of cooling plates reduces the weight of the cooling system as a whole. For thermal contacting, it is possible, if necessary, for the cell assembly composed of cooler and cells 310 to be provided with a housing and to be sealed as a cohesive unit. The housing may remain on the cell assembly, for example as an insulation box, or may be removed after the hardening of the sealing compound.
Alternatively, thermal contacting of the cell assembly may also be realized by means of a clamping device. Here, there is merely contact, and no cohesive connection, between the flat tube 130 and cell 310. Here, the clamping device may be formed as a belt or as a clamping sheet. For electric insulation with respect to the battery cells 310 which may be at potential, the cooler may be provided with protective coatings such as for example lacquer.
It is alternatively possible for cooling plates with cooling sheets to be mounted. A further possibility would be to connect the flat tubes 130 to the cell 310 via cooling sheets.
In the exemplary embodiment, shown in conjunction with
It is alternatively possible for cooling plates with cooling sheets to be mounted. A further possibility would be to connect the flat tubes 130 to the cell 310 via cooling sheets, or to connect the flat tubes 130 directly to the cell casing.
For the cooling of battery cells 310 via flat tubes 130 to collecting tanks, it is possible, as per the exemplary embodiments from
The flat tubes 130 may also be formed as a single extruded part and, for example in the form of a plate 1910 with tubes 130 mounted thereon, may also be mounted on the opposite side of the conductor. In this way, the cooling system can simultaneously perform a structural function. The flow ducts may be situated either in the tubes 130 or in the plate 1910. A plurality of cells with cooling sheets may be combined to form a module with one extruded part.
The cooling sheets 330 may be of rounded form in the bend region. In the case of the folded cooling sheet 330, said region is thus tubular and can serve as a receptacle 2010 for pins or the like. Said inserted pins may for example be latched into a receptacle of the housing or of some other structural part. This permits simple assembly of the module in an overall construction.
The described exemplary embodiments have been selected merely by way of example and may be combined with one another.
Number | Date | Country | Kind |
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10 2009 052 254.9 | Nov 2009 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2010/066990 | 11/8/2010 | WO | 00 | 8/15/2012 |