Patent Application
20240371576
This application claims the benefit of German Patent Application Number 10 2023 111 690.8 filed on May 5, 2023, the entire disclosure of which is incorporated herein by way of reference.
The invention relates to ventilation concepts for energy storage modules.
More specifically the invention relates to measures that allow a more uniform thermal load within energy storage modules.
Electrical energy storage modules are well known and typically combined into larger units of energy storage systems, e.g., for independent power supplies, energy storage for renewable energies or energy buffers for providing enough power for peak loads.
Suitable energy storage modules include battery based modules and—especially useful for fast charging and discharging—ultracapacitor based modules.
CN 210 925 775 U discloses a super capacitor energy storage module where plurality of capacitors are arranged in parallel, and the upper and lower ends of the capacitors are fixedly connected with interfaces of laminated busbars.
There are no venting holes in the laminated busbars.
CN 206 711 772 U discloses a super capacitor module that has a plurality of parallel supercapacitor units. The supercapacitor units are connected via busbars. Cooling is effected by a radiator that is attached to the top laminated busbar.
CN 112 310 522 A discloses a supercapacitor energy storage module that comprises a frame, batteries or capacitors, an upper laminated busbar, a lower laminated busbar and a front cover plate. The plurality of batteries or capacitors are arranged in the frame in an array manner. No venting holes are present in the laminated busbars.
CN 218 215 014 U discloses a supercapacitor energy storage module. The supercapacitor energy storage module comprises heat dissipation plates that are located on the two end faces of the supercapacitor cells. Heat is conducted between the pole columns of the supercapacitor single bodies and the heat dissipation plates and heat dissipation holes are formed in the heat dissipation plates so that air circulation can be facilitated to take away heat. The heat dissipation holes are arranged relative to each other such that a laminar fluid flow may flow between the heat dissipation plates directly along the shortest path between the heat dissipation plates.
It is an object of the invention to provide measures that allow a more uniform distribution of thermal load within energy storage modules.
The object may be achieved by the subject-matter of one or more embodiments described herein.
The invention provides a support structure for an energy storage module
the support structure being configured for supporting a plurality of energy storage cells, the support structure comprising:
wherein the bottom plate and the top plate are spaced apart along a vertical direction that is orthogonal to both the bottom plate and the top plate,
wherein the bottom plate member includes a plurality of bottom ventilation holes and/or the top plate member includes a plurality of top ventilation holes,
wherein the respective ventilation holes are arranged such that, when viewed along the vertical direction through an arbitrarily chosen ventilation hole, only a holefree portion of the respective plate member is visible through that chosen ventilation hole.
Preferably, at least one bottom ventilation hole and at least one top ventilation hole are arranged relative to each other such that, when viewed along the vertical direction through an arbitrarily chosen ventilation hole of one of the bottom plate and the top plate, no ventilation hole of the other of the bottom plate and the top plate is in alignment with the arbitrarily chosen ventilation hole along the vertical direction.
Preferably, the bottom plate member and/or the top plate member include a plurality of cell mounting portions that are configured for mounting a plurality of energy storage cells, and, when viewed along the vertical direction, each ventilation hole is arranged in a horizontal plane defined by the bottom plate member and/or the top plate member and in a gap portion that is defined between neighboring mounting portions.
Preferably, a fluid path length of a laminar fluid flow entering through an arbitrary chosen bottom ventilation hole and exiting through an arbitrarily chosen top ventilation hole is greater than a plate distance between the bottom plate and the top plate that is measured parallel to the vertical direction, or such that such that a fluid path length of a laminar fluid flow entering through an arbitrary chosen top ventilation hole and exiting through an arbitrarily chosen bottom ventilation hole is greater than a plate distance between the bottom plate and the top plate that is measured parallel to the vertical direction.
The invention provides an energy storage unit for an energy storage module, the energy storage unit comprising a support structure and plurality of energy storage cells each energy storage cell being fixed to one of the mounting portions.
Preferably, a group of three or four neighboring energy storage cells define therebetween at least one vertical flow path that extends between the bottom plate member and the top plate member.
Preferably, the vertical flow path has provided on one of its end portions one ventilation hole and on its opposite end portion a holefree portion of the respective plate member.
Preferably, a group of three neighboring energy storage cells is arranged such that, when viewed along the vertical direction, the energy storage cells are located so as to form vertices of an equilateral triangle, and center axes of the vertical flow path and one ventilation hole are located at the center of the equilateral triangle.
Preferably, a group of four energy storage cells is arranged such that, when viewed along the vertical direction, the energy storage cells are located so as to form vertices of a rhombus, and center axes of the vertical flow path and one ventilation hole are located at the center of a triangle formed by a group of three neighboring energy storage cells of the four neighboring energy storage cells.
Preferably, a group of at least four energy storage cells define therebetween a horizontal flow path that extends parallel to and between the bottom plate member and the top plate member.
Preferably, the horizontal flow path includes the ventilation holes on either a top portion or a bottom portion.
Preferably, a second group of at least four energy storage cells define therebetween a second horizontal flow path that extends parallel to and between the bottom plate member and the top plate member as well as parallel to the horizontal flow path.
Preferably, the second horizontal flow path includes the ventilation holes on the opposite side of the top portion or bottom portion compared to the horizontal flow path.
The invention provides an energy storage module comprising an energy storage unit and a housing structure in which the energy storage unit is accommodated, wherein the housing structure comprises at least one intake plenum for cooling fluid and an exhaust plenum for the cooling fluid, and the intake plenum and the exhaust plenum are arranged to direct the flow of cooling fluid between the bottom plate member and the top plate member.
Preferably, at least one of the intake plenum and/or the exhaust plenum includes a fan.
Laminated busbars are thought to be the future in manufacturing of energy storage modules. While not necessarily in broad application just yet, the prospect of successfully implementing this concept can be significant game changer in mass producing energy storage modules. While certainly viable from an electrical stand point, laminated busbars pose a challenge regarding thermal management within the energy storage module.
Conventionally, busbars are comparatively large slabs of a highly conductive metal (typically aluminum) that are welded to the individual storage cells. This approach is easy and in terms of thermal management allows for enough space of airflow that can cool not only the cells but also the busbars themselves.
In the laminated busbar concept, the individual slabs are incorporated in a laminate structure formed from less heat conductive material such as epoxy. In one approach the laminate structure includes special heat conductive layers that allow a better distribution of heat.
In addition, in some approaches heat dissipation holes are formed in the laminate to sort of emulate the more open structure formed by plain busbars. The known approach basically follows the rule that the more heat dissipation holes are present, the better for cooling the storage cells.
However, this approach neglects some important properties of energy storage cells, when they are brought together in this fashion. While energy storage cells are mass manufactured to a certain specification, different energy storage cells-even from the same fabrication line-differ slightly in their properties.
There is considerable effort using management systems to “equalize” the storage cells and avoid too much imbalance in their properties, as this may cause severe or even catastrophic malfunctions of the energy storage module.
It is known that thermal load causes aging of the storage cells which may cause deterioration of the overall performance of the respective cell, e.g., due to a loss in useable capacity.
The ideas presented herein aim at a more uniform aging of the storage cells by reducing the temperature difference between individual cells in the storage module.
In contrast to the known measures, the ventilation holes are arranged in a pattern that does provide enough cooling, but also reduces the temperature difference between individual cells.
The applicant has performed computer simulations of the temperature difference between individual cells. Reference is made to the enclosed simulation results which are incorporated in this disclosure by reference. Key indicators are the maximum cell temperature increase in K, the difference between the maximum and minimum cell temperature in K and the thermal resistance in K/W.
The maximum cell temperature increase is up to 6 K for no ventilation holes or too much ventilation holes. The optimal ventilation hole pattern reduces the temperature increase by nearly 1 K or 17%. Also the spread between the maximum and minimum cell temperature can be reduced by almost 1 K or nearly 20%. Most strikingly, the thermal resistance is more or less independent of the current and—for the optimal ventilation hole pattern—is consistently 10% less than the comparative examples.
Embodiments of the invention are described in more detail with reference to the accompanying schematic drawings that are listed below.
Referring to
The housing structure 12 is generally known and preferably configured as a 19″ housing structure so it can be mounted in a typical 19″ rack. The housing structure 12 is configured such that there is some air space around the energy storage unit 14 so as to allow airflow for cooling.
The housing structure 12 may comprise a first intake plenum 16. The first intake plenum 16 may be arranged on the right side of the housing structure 12. The first intake plenum 16 may include a fan for generating airflow towards the energy storage unit 14 or may redirect airflow from the 19″ rack towards the energy storage unit 14.
The housing structure 12 may comprise a second intake plenum 18. The second intake plenum 18 may be arranged on the back side of the housing structure 12. The second intake plenum 18 may include a fan for generating airflow towards the energy storage unit 14 or may redirect airflow from the 19″ rack towards the energy storage unit 14.
The housing structure 12 may comprise an exhaust plenum 20. The exhaust plenum 20 may be arranged on the left side of the housing structure 12 or in general opposite the first intake plenum 16. The exhaust plenum 20 may include a fan for generating airflow away from the energy storage unit 14 or may redirect the airflow.
The airflow is in general from the first intake plenum 16 towards the exhaust plenum 20, e.g., from right to left in this example. In case of both intake plena 16, 18 being present, the airflow is in general diagonal from the right-back towards the left-front (where back and front are up and down in the drawing plane as the drawing is in top view).
The energy storage unit 14 comprises a bottom plate member 22 and a top plate member 24. Since the bottom plate member 22 and the top plate member 24 are similar in structure, only the top plate member 24 is described in more detail for the sake of brevity.
The top plate member 24 is preferably electrically isolating. The top plate member 24 is configured as a laminated structure 26. The laminated structure 26 may include a plurality of layers. A bottom layer may be insulating and is preferably made of e.g., fiber composite or circuit board material, or foil. Another layer may include a plurality of busbar members that electrically connect pairs of energy storage cells 28 in the desired configuration but are electrically isolated from each other. This layer may be an epoxy layer, for example. Preferably, the energy storage cells 28 are ultracapacitors.
For example all energy storage cells 28 may be coupled in series. It is also possible to have multiple stacks of energy storage cells 28 that are coupled in series, where the stacks are coupled in parallel or vice versa.
A top layer may cover the busbar layer and again be made of insulating material, e.g. the same material as the bottom layer.
The energy storage unit 14 may include a plurality of energy storage cells 28 that are electrically coupled by the bottom and top plate members 22, 24.
A first group of neighboring energy storage cells 28 can be arranged so as to form vertices of an equilateral triangle 30. In the center of the triangle 30 a ventilation hole 33 is formed in the top plate member 24, for example. Furthermore, the three neighboring energy storage cells 28 define a vertical flow path 32 for cooling air. The vertical flow path 32 has on its one end portion the ventilation hole 33 and on its other end portion a holefree or solid portion of the bottom plate member 22. The ventilation hole 33—as well as the vertical flow path 32—is preferably arranged in the center of the equilateral triangle 30.
Furthermore, it is possible for a group of four energy storage cells 28 to form vertices of a rhombus 34. Specifically, the rhombus 34 can be seen as two triangles 36 joined together at their respective base. The triangles 36 need not be equilateral but are preferably equilateral triangles 30.
In other words, the group can be seen as a composition of two of the first groups where two energy storage cells 28 are shared with each of the triangles 36. It is also possible for the energy storage cells 28 to define a horizontal flow path 38. The horizontal flow path 38 may extend along a line 40, where to the right and left of the line 40 energy storage cells 28 are arranged such that a connecting line between their terminals 42 is parallel to the line 40.
The horizontal flow path 38 includes at least one ventilation hole 33, where a preferred number is from 4 to 7 along a specific horizontal flow path 38.
Referring to
This results in a more uniform temperature distribution between the energy storage cells 28 as illustrated in
Referring to
Referring to
While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 111 690.8 | May 2023 | DE | national |
