DE102019105988A1 - Energy storage cell, energy storage and method for producing an energy storage cell - Google Patents

Abstract

The invention relates to an energy storage cell comprising a closed capsule in which phase change material is arranged, the capsule being made of metal.

Description

The present invention relates to an energy storage cell. The present invention also relates to an energy store. The present invention also provides a method for producing an energy storage cell.

Known energy storage cells are usually implemented as plastic capsules and have a phase change material inside the plastic capsule that is set in such a way that it changes into the liquid phase when heat is supplied (endothermic reaction) and crystallizes again when it cools, thus generating heat releases its surroundings (exothermic reaction). The generic energy storage cells are used primarily in energy storage devices which are essentially constructed as follows and function according to the following principle: a large number of generic energy storage cells are arranged in a tank filled with a liquid, for example water or oil. At a time when there is excess energy, for example during the day when there is solar radiation, the excess energy is used to heat the liquid in the tank. The liquid gives off heat to the energy storage cells, so that the phase change material changes into the liquid phase with an endothermic reaction. If the liquid in the tank cools down to a phase change temperature specific to the phase change material, for example at night, the phase change material crystallizes with an exothermic reaction, with heat being given off or transferred to the liquid.

On the one hand, the energy storage cells must have sufficient tightness against an external pressure of 3 to 4 bar, which prevails in the liquid tank. However, there is also a further impermeability to the phase change material arranged within the energy storage cell. It must therefore also be resistant to chemicals and salt. In general, there is an endeavor to provide the energy storage cells with the largest possible surface area, which is then available for heat exchange with the liquid surrounding them. Therefore, the energy storage cells have hitherto been made spherical or egg-shaped. However, the chaotic, uncontrollable arrangement of the energy storage cells in the tank has proven to be disadvantageous. Furthermore, the known energy storage cells are too sluggish, i. H. the phase transitions of the phase change material as a result of temperature changes are too inert.

It is the object of the present invention to improve the disadvantages from the known prior art, in particular to create an energy storage cell and an energy storage device which is more responsive and can be manufactured inexpensively.

This object is achieved by the features of claim 1, 13 respectively 14th solved.

An energy storage cell is then provided. The energy storage cell can be set up for this or, for example, be arranged in an energy storage device in such a way that the energy storage cell is surrounded and / or flowed around by a liquid such as water, oil or the like. The energy storage cell can function, for example, according to the following principle: up to a certain liquid temperature, the energy storage cell absorbs heat, i. H. Energy from the liquid surrounding and / or flowing around the energy storage cell. The energy storage cell is designed to store the absorbed heat or energy. If necessary, the energy storage cell can release the stored energy again. This can take place, for example, without any control and / or regulating device or external access to the energy storage cell, but preferably exclusively through a temperature sensitivity with regard to the liquid surrounding and / or flowing around the energy storage cell. For example, the energy storage device is a water tank, such as a boiler, which is arranged outdoors and in which the energy storage cell is located. During the day, the water arranged in the water tank can be heated by solar radiation and thereby heat the energy storage cell, which stores the absorbed heat in the form of energy. If the water in the water tank cools down, for example at night, the energy storage cell can release the heat again in order to warm up the water.

The energy storage cell comprises a closed capsule. The capsule can have a closed capsule wall which delimits a cavity, preferably a storage space, in its interior, the capsule wall in particular serving to separate and / or shield the cavity from its surroundings. The capsule is generally not restricted to a specific shape and / or geometry. The capsule can be designed to be fluid-tight with respect to the environment in such a way that no liquid can enter the interior of the capsule from the environment and / or no materials arranged within the capsule, such as phase change materials, can escape into the environment.

Phase change material is arranged in the capsule. Phase change materials are in Generally materials that can store a large part of the thermal energy supplied to them in the form of latent heat. Latent heat is understood to be the enthalpy absorbed or emitted during a phase transition of the first order. This means that phase change materials can store a high proportion of heat and / or cold energy and release it as heat in a phase-shifted manner as required. Phase change materials have the advantage of being able to store very large amounts of heat in a small temperature range around the phase change, for example from solid to liquid, or vice versa, gaseous to solid, or vice versa, or from gaseous to liquid. Phase change materials, or their energy storage capacities, are based on the utilization of the phase change enthalpy, for example during the phase transition solid-liquid (solidification-melting), or vice versa. Phase change materials can include, for example, salts, for example Glauber's salt, sodium acetate, or inorganic compounds, for example paraffin, fatty acids, or the like. Further exemplary phase change materials are water or also metallic phase change materials such as an aluminum-silicon alloy. In general, the phase change material can be selected or adjusted in such a way that it carries out an endothermic reaction when heat is supplied and an exothermic reaction when heat is removed. An endothermic reaction is generally understood to be a reaction in which energy, for example in the form of heat, is absorbed from the environment. The exothermic reaction describes the opposite in which energy, for example in the form of heat, is released to the environment, namely the liquid.

According to the invention, the capsule is made or manufactured from metal. The metals used are, for example, aluminum, brass, steel or copper and alloys thereof. Metals are inexpensive and easy to process. In the case of the metal capsules according to the invention, it has proven advantageous that metals have a high thermal conductivity. This enabled a fast-reacting energy storage cell to be created. Due to the increased thermal conductivity of metal, in particular compared to the previously used material plastic, the phase change material reacted significantly faster, in particular more sensitively, to temperature changes in the liquid surrounding and / or flowing around the capsule. As a result, the thermal conductivity of metals usually by the factor 10 up to 1000 is higher than the thermal conductivity of plastics, the phase change material can react faster to temperature changes in the liquid by this factor. As a result, the energy storage cell is significantly more effective than known energy storage cells made of plastic. Surprisingly, the use of metal as the capsule material has shown that the energy storage cells are also considerably more durable. It has been found that, particularly in long-term behavior, metals are less permeable to the phase change material arranged inside the capsule, so that this cannot diffuse outward into its surroundings, in particular into the liquid surrounding and / or flowing around the capsule.

In an exemplary embodiment of the present invention, the capsule is manufactured by forming, in particular cold forming. During forming, the capsule is generated from a metal blank with targeted plastic, shaping deformation and brought into the desired shape. It has been shown that an energy storage cell capsule according to the invention can be produced in a simple and inexpensive manner by reshaping. Cold forming has proven particularly advantageous, in which the reaction temperature during the process is below, preferably significantly below, the respective recrystallization temperature of the metal used. According to an exemplary development, the capsule is manufactured without thermal joining processes, such as welding or soldering, and / or closed without thermal joining processes. The fact that the capsule can be produced by pure mechanical, plastic shaping deformation of a metal tube, preferably without the need for thermal joining processes, creates a particularly easy-to-implement and cost-effective production process or a particularly easy-to-produce and inexpensive energy storage cell.

According to an exemplary further embodiment of the energy storage cell according to the invention, the capsule is manufactured from a metal blank, such as a metal strip or a metal plate, by deep drawing. Deep drawing is a tensile compression forming process of the metal blank, which is in the form of a plate, a sheet or a sheet, for example, into a hollow body open on one side. In particular, the deep drawing takes place by means of a molding tool, such as a drawing ring, a punch or a holder. The capsule can be manufactured, for example, by means of several successive deep-drawing steps, preferably with different molding tools. Furthermore, deep drawing can be linked to additional, preferably mechanical, forming steps, in particular cold forming steps, in order to generate the desired shape of the capsule. For example, the capsule is produced in a two-stage deep-drawing process and then further cold-formed in order to form the final shape of the capsule and to close it.

According to an exemplary development of the present invention, the capsule delimits a storage space, preferably an energy storage space, in its interior. For example, at least 1% and preferably at most 100% of the storage space is occupied by phase change material, preferably at least 10% and at most 99%, preferably at least 20% and at most 98%, preferably at least 25% and at most 95%, preferably closed at least 30% and at most 90%. For example, depending on the phase change material used, an amount of the phase change material can be selected with regard to the available storage space. It can be provided that the amount of phase change material is matched to the available storage space in such a way that the expansions and compressions of the volume required by the phase material associated with the phase change material-specific and temperature-dependent phase transitions of the phase change material can take place.

In an exemplary development of the energy storage cell according to the invention, the capsule is sealed in a fluid-tight manner. On the one hand, the capsule can be sealed fluid-tight in such a way that no media, such as the liquid that surrounds the capsule, can enter the capsule interior from the environment and, on the other hand, it can be designed in a fluid-tight manner that the phase change material located inside the capsule interior cannot escape from Can leak inside into the environment. The fluid-tight closure of the capsule can be made possible, for example, by a forming process, preferably a cold forming process. The capsule is preferably sealed in a fluid-tight manner without additional thermal joining processes, preferably without welding, soldering or the like.

In a further exemplary embodiment of the present invention, the capsule is sealed fluid-tight in such a way that the tightness of the capsule is maintained in the event of pressure fluctuations in the interior of the capsule, preferably in the storage space, resulting from phase transitions of the phase change material. For example, the capsule is sealed in a fluid-tight manner in such a way that, in addition to the previously filled phase change material, air is also present in the capsule interior, preferably in the storage space, which air compresses or expands during the phase transitions of the phase change material. According to the present invention, however, the capsule is designed to be fluid-tight in such a way that even when the air arranged in the storage space is compressed, the tightness of the capsule is maintained or the capsule is retained without being destroyed.

According to an exemplary development of the energy storage cell according to the invention, the capsule essentially has a preferably elongated bottle shape, in particular the length of which is at least 50%, at least 60% or at least 70% larger than its width across the length. The capsule can have a substantially cylindrical base section, a substantially cylindrical storage section, preferably continuously adjoining the base section, in particular which essentially delimits the storage space, and a neck section which tapers in cross section from the storage section and is preferably frustoconical. It has been found that such a geometric shape of the energy storage cell or the capsule can be easily produced and also results from a large surface available for heat exchange with the liquid, so that a large amount of energy, in particular heat, in the Phase change material arranged storage space can be introduced or discharged therefrom.

In an exemplary embodiment of the energy storage cell according to the invention, the capsule is sealed in a fluid-tight manner by the action of mechanical force from the outside, preferably without additional thermal joining processes, preferably without welding, soldering or the like. It can be provided that the fluid-tight closure of the capsule takes place without the influence of temperature from the outside, that is to say without additional heating or cooling in relation to an ambient temperature. For example, the capsule is closed in a fluid-tight manner by compressing and / or rotating and / or folding, in particular folding over, at least part of the neck section. Provision can be made for the semi-finished capsule product formed from the metal blank, preferably cold-formed, to be compressed on the neck section, for example by means of a folding, clamping and / or twisting device, in such a way that the capsule is closed off, for example by means of a folding, Clamping and / or twisting device is compressed in such a way that the capsule is sealed fluid-tight. For example, it can be provided, in particular in order to increase the tightness of the capsule, that the compressed part of the neck section is twisted, in particular twisted.

In an exemplary development of the present invention, the capsule, preferably on the neck section, is designed in an intermediate production state as a blank, preferably after deep-drawing, open to the outside at one end to enable the capsule to be filled with phase change material. According to a As an example further development, a preferably chemical- and / or salt-resistant seal, such as a sealing plug, is inserted into the opening and / or a preferably chemical- and / or salt-resistant varnish, such as a sealing and / or protective varnish, is inserted into the opening before the capsule is closed. The seal can be arranged and / or designed in such a way that the seal is compressed when an external force acts to close the capsule, in particular when compressing and / or twisting, preferably twisting, the capsule, in particular the neck section. Furthermore, a preferably chemical and / or salt-resistant lacquer, in particular a sealing lacquer and / or a protective lacquer, can be applied from the outside to the capsule in the area of the compressed neck section. In particular, the lacquer seals the capsule in the area of the neck section, preferably in the area of its compressed opening. A UV-curing acrylic varnish, for example, which is resistant to chemicals and / or salt, can be used as the varnish. It should be clear that other paints can be used which are suitable for the use of the present invention.

According to an exemplary development of the energy storage cell according to the invention, the capsule, preferably at the neck section, is additionally closed by an induction welding, diffusion welding or cold welding process. It has been found that this increases the tightness of the capsule. Particularly in areas of application of the energy storage cell where high external pressures and / or internal pressures act on the capsule, the additional welding of at least part of the neck section, preferably in the area of the opening through which the phase material was filled into the capsule, has proven to be advantageous, in particular Proven in terms of longevity. With the welding process used to seal the capsule, it must be ensured that the heat generated during welding or other production-related influences do not influence the phase change material in such a way that a phase transition is caused. Furthermore, the additional welding production process for closing the capsule can be advantageous if a phase change material is selected that is particularly volatile and / or particularly material-degrading in at least one physical state.

In a further exemplary embodiment of the energy storage cell according to the invention, the capsule has a preferably circumferential notch on its outer circumference. For example, the notch is provided on the outer circumference of the cylindrical bottom section of the capsule. Furthermore, it can be provided that the bottom section is made essentially from solid material. Furthermore, a recess can be made on an end face of the capsule on the base section. For example, the recess is shaped like a blind hole and / or has a circular cross section. The recess can extend in the longitudinal direction of the capsule up to an end wall of the capsule, which is preferably located in the region of the transition from the bottom section and the storage section and on which the phase change material rests. In an exemplary development, the inside diameter of the recess is matched to an outside diameter of the closed, preferably compressed and / or twisted, in particular twisted, neck section. Both the notch and the recess simplify the production and / or handling and / or the transport of the energy storage cell according to the invention. The notch can serve, for example, as a pinch groove in order to grip the energy storage cell during its manufacture or during transport, for example to handle it. By providing the recess on the bottom section and by coordinating the corresponding dimensions of recess and neck section, it is possible to mount two energy storage cells according to the invention on one another, in particular to plug them onto one another. The elongated bottle shape of the energy storage cell according to the invention has also proven to be advantageous, since even with an energy storage cell pair arrangement stacked on top of one another, a sufficiently large surface area is required for heat / energy exchange between the environment and the interior of the capsule, in particular the phase change material, is provided.

According to an exemplary development, the capsule has an essentially constant wall thickness in the range from 0.125 mm to preferably 0.5 mm. For example, the bottom section can be made of solid material and / or have the preferably circumferential notch and / or the recess on the bottom section. The material thickness can be selected, for example, depending on the metal used for the capsule. In the event that brass is selected as the material, a material thickness in the range from 0.15 to 0.35 mm can be. For steel, exemplary wall thicknesses are in the range from 0.13 mm to 0.3 mm. When using aluminum alloys, such as AlSi1MgCuMn, exemplary wall thicknesses are in the range from 0.2 mm to 0.5 mm. Exemplary storage volumes of the energy storage cell, i.e. volume of the storage space bounded by the capsule, are in the range from 1 ml to 50 ml, preferably in the range from 2 ml to 40 ml, preferably in the range from 3 ml to 30 ml or 20 ml exemplary diameter of the capsule, which is essentially round in cross section, in the region of FIG mm to 50 mm, preferably in the range from 7 mm to 40 mm, preferably in the range from 10 mm to 30 mm or 25 mm.

According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, an energy store is provided. The energy store can be set up, for example, to absorb and store the excess energy in the event of an energy surplus, and to release it again when required.

The energy store comprises a fluid-tight tank that is at least partially filled with a liquid such as water, oil or the like. The liquid essentially serves as an energy carrier or energy receiver from which or to which energy is given off or transferred.

According to the invention, at least one energy storage cell, preferably a plurality, in particular several hundreds or thousands of energy storage cells, is arranged in the tank, which energy storage cells are configured in accordance with one of the previously described aspects or exemplary embodiments.

According to the invention, the capsule is made or manufactured from metal. The metals used are, for example, aluminum, brass, steel or copper and alloys thereof. Metals are inexpensive and easy to process. In the case of the metal capsules according to the invention, it has proven advantageous that metals have a high thermal conductivity. This enables a fast-reacting energy storage cell to be created. Due to the increased thermal conductivity of metal, in particular compared to the previously used material plastic, the phase change material reacted significantly faster, in particular more sensitively, to temperature changes in the liquid surrounding and / or flowing around the capsule. As a result, the thermal conductivity of metals usually by the factor 10 up to 1000 is higher than the thermal conductivity of plastics, the phase change material can react faster to temperature changes in the liquid by this factor. As a result, the energy storage device is significantly more effective than known energy storage devices. Surprisingly, the use of metal as the energy storage cell material has shown that the energy storage devices are also considerably more durable. It has been found that, particularly in long-term behavior, metals are less permeable to the phase change material arranged inside the capsule, so that this cannot diffuse outward into its surroundings, in particular into the liquid surrounding and / or flowing around the capsule and arranged inside the tank.

According to an exemplary development, the pressure in the tank is above one bar, in particular above 2 bar, 3 bar or 4 bar. The pressure can, for example, be a liquid pressure, such as a water pressure, which can arise from the fluid column present in the tank. Furthermore, the pressure can arise due to the weight of the plurality of energy storage cells lying on top of one another and act on one or more of the plurality of energy storage cells. In particular, the weight-dependent pressure on the energy storage cells increases in the gravitational direction.

According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a method for producing an energy storage cell is provided. The energy storage cell can be set up for this or, for example, be arranged in an energy storage device in such a way that the energy storage cell is surrounded and / or flowed around by a liquid such as water, oil or the like. The energy storage cell can function, for example, according to the following principle: up to a certain liquid temperature, the energy storage cell absorbs heat, i. H. Energy from the liquid surrounding and / or flowing around the energy storage cell. The energy storage cell is designed to store the absorbed heat or energy. If necessary, the energy storage cell can release the stored energy again. This can take place, for example, without any control and / or regulating device or external access to the energy storage cell, but preferably exclusively through a temperature sensitivity with regard to the liquid surrounding and / or flowing around the energy storage cell. For example, the energy storage device is a water tank, such as a boiler, which is arranged outdoors and in which the energy storage cell is located. During the day, the water arranged in the water tank can be heated by solar radiation and thereby heat the energy storage cell, which stores the absorbed heat in the form of energy. If the water in the water tank cools down, for example at night, the energy storage cell can release the heat again in order to warm up the water.

According to the invention, phase change material is introduced into a capsule and the capsule is closed. According to the method according to the invention, the capsule is made of metal. The metals used are, for example, aluminum, brass, steel or copper and alloys thereof. Metals are inexpensive and easy to process. In the case of the metal capsules according to the invention, it has proven advantageous that metals have a high thermal conductivity. This could a responsive energy storage cell can be created. Due to the increased thermal conductivity of metal, in particular compared to the previously used material plastic, the phase change material reacted significantly faster, in particular more sensitively, to temperature changes in the liquid surrounding and / or flowing around the capsule. As a result, the thermal conductivity of metals usually by the factor 10 up to 1000 is higher than the thermal conductivity of plastics, the phase change material can react faster to temperature changes in the liquid by this factor. As a result, the energy storage cell is significantly more effective than known energy storage cells made of plastic.

Surprisingly, the use of metal as the capsule material has shown that the energy storage cells are also considerably more durable. It has been found that, particularly in long-term behavior, metals are less permeable to the phase change material arranged inside the capsule, so that this cannot diffuse outward into its surroundings, in particular into the liquid surrounding and / or flowing around the capsule.

According to an exemplary development of the method according to the invention, the capsule is shaped from a metal strip of predefined thickness. The resulting wall thickness of the capsule can be influenced via the predefined thickness of the metal strip. According to an exemplary development, the metal strip is formed into a cylindrical blank by deep drawing. The deep drawing can be divided into at least two deep drawing steps. The metal wall is formed by deep drawing in such a way that the blank is designed to be open towards one end face. Furthermore, the blank can be sculpted on the open end face, that is, enlarged in its cross-section, preferably continuously or abruptly, cut off, drawn in and then rotated to a predetermined length to form an essentially bottle-shaped semi-finished product. The semi-finished product, for example, already has essentially the final shape of the energy storage cell or the capsule. Furthermore, it can be provided that the capsule is filled with phase change material via the open face, it being possible for several filling processes to be provided depending on the phase change material. Furthermore, the capsule can be closed by the action of mechanical force from the outside and, if necessary, sealed and / or sealed, for example by means of a seal such as a sealing plug and / or a lacquer, for example a sealing lacquer and / or a protective lacquer such as a UV-curing acrylic lacquer.

According to an exemplary development, the method is designed in such a way that it realizes the energy storage cell in accordance with one of the previously described aspects and exemplary embodiments.

Preferred embodiments are given in the subclaims.

• 1 eine schematische Ansicht einer erfindungsgemäßen Energiespeicherzelle;
• 2 eine schematische Ansicht eines Rohlings zum Herstellen einer erfindungsgemäßen Energiespeicherzelle;
• 3 eine Schnittansicht eines Rohlings nach 2 nach einem Verarbeitungsschritt;
• 4 eine Schnittansicht des Rohlings gemäß der 2 und 3 nach einem weiteren Bearbeitungsschritt
• 5 eine Schnittansicht des Rohlings gemäß den 2 bis 4 nach einem weiteren Bearbeitungsschritt;
• 6 eine Schnittansicht des Rohlings gemäß den 2 bis 5 nach einem weiteren Bearbeitungsstand;
• 7 eine Schnittansicht des Rohlings gemäß den 2 bis 6 nach einem weiteren Bearbeitungsschritt;
• 8 eine Schnittansicht eines Halbfabrikats einer erfindungsgemäßen Energiespeicherzelle;
• 9a eine Schnittansicht einer erfindungsgemäßen Energiespeicherzelle gemäß der Linie IX-IX aus 1;
• 9b eine Schnittansicht eines nach 8 ausgebildeten Halbfabrikats in einer schematisch dargestellten Bearbeitungsstation;
• 9c eine Schnittansicht des Halbfabrikats in der Bearbeitungsstation nach 9b nach einem Bearbeitungsschritt; und
• 10 eine Schnittansicht einer erfindungsgemäßen Energiespeicherzelle gemäß einer weiteren beispielhaften Ausführung.

In the following, further properties, features and advantages of the invention will become clear by means of a description of preferred embodiments of the invention with reference to the accompanying exemplary drawings, in which:

• 1 a schematic view of an energy storage cell according to the invention;
• 2 a schematic view of a blank for producing an energy storage cell according to the invention;
• 3 a sectional view of a blank according to 2 after a processing step;
• 4th a sectional view of the blank according to FIG 2 and 3 after a further processing step
• 5 a sectional view of the blank according to FIG 2 to 4th after a further processing step;
• 6th a sectional view of the blank according to FIG 2 to 5 after a further processing status;
• 7th a sectional view of the blank according to FIG 2 to 6th after a further processing step;
• 8th a sectional view of a semifinished product of an energy storage cell according to the invention;
• 9a a sectional view of an energy storage cell according to the invention along the line IX-IX 1 ;
• 9b a sectional view of an after 8th trained semi-finished product in a processing station shown schematically;
• 9c a sectional view of the semi-finished product in the processing station according to 9b after a processing step; and
• 10 a sectional view of an energy storage cell according to the invention according to a further exemplary embodiment.

In the following description of exemplary embodiments, the energy storage cell according to the invention is generally given the reference number 1 Mistake.

Based on 2 to 9a is with reference to the illustrated manufacturing stages of the energy storage cell according to the invention 1 also the method according to the invention for producing the energy storage cell 1 described in 1 in a side view and in 9a in a sectional view along the line IX-IX according to 1 is shown. According to the invention, the energy storage cell comprises 1 a capsule made of metal 3 , in the phase change material 5 ( 9 ) is arranged. The capsule 3 essentially comprises the following sections or components: an essentially cylindrical bottom section 7th ; one on the bottom portion 7th subsequent, essentially cylindrical storage section 9 ; and one to the storage section 9 subsequent neck section 11 , which also essentially has a round cross-section and its cross-sectional dimension starting with the storage section 9 continuously decreases in sections, i.e. away from the storage section 9 tapered towards. At the transition between storage sections 9 and neck section 11 is a substantially frustoconical transition 13 educated. In 1 already recognize that the capsule 3 in the area of the neck section 11 is compressed and / or twisted, preferably closed in a fluid-tight manner exclusively under the action of external mechanical force. Are indicated in 1 several folding areas 15th in the neck section 11 , to which even closer in terms of 9b , 9c is received.

2 shows an exemplary metal blank 17th , from which the energy storage cell according to the invention 1 is made by forming, in particular cold forming, preferably deep drawing. With the metal blank 17th can it be a metal band ( 1 ) or a metal plate or something similar.

In 3 the metal capsule is shown in an intermediate stage of manufacture. In a first deep-drawing step, the metal blank became 17th according to 2 an essentially cylindrical one towards one end face 19th open capsule blank 3 ' manufactured. The capsule blank 3 ' includes one of the open end faces 19th opposite bottom 21st , the outside of which is slightly curved, preferably concave. The floor 21st opens into a circumferential capsule wall 23 whose wall thickness is from the floor 21st towards the open front 19th decreasing essentially continuously. The remaining wall thickness of the floor 21st can be set as desired by means of the production method according to the invention, depending on the requirements placed on the wall thickness of the energy storage cell according to the invention 1 . In 3 it can be seen that the capsule blank 3 ' is essentially hollow, that is, the encircling capsule wall 23 surrounds a cavity 25th .

In 4th is a capsule blank 3 " shown by a further forming step, in particular cold forming step, preferably deep-drawing step, of the capsule blank 3 ' to 3 is formed. The capsule blank 3 " differs from the capsule blank 3 ' essentially by the axial dimension, that is to say its dimension in the direction of extent of the capsule blank 3 " . Furthermore, is on the front side open to the environment 19th to see that the circumferential front wall 27 , which the capsule wall 23 limited in the longitudinal direction, unevenly, that is not flat, shaped.

5 shows the in a capsule blank 3 "' after a further processing step of the capsule blank 3 " according to 4th . The capsule blank 3 "' differs from the capsule blank 3 " to 4th essentially by the fact that the capsule blank 3 "' at the open end 19th is sculpted to a tulip-shaped end 29 to build. Cold forming processes such as tumbling or rolling are used, for example. Between the tulip-shaped end 29 and the duct wall area with a smaller cross-section 23 of the metal capsule blank 3 "' is an essentially circumferential kink 31 provided, the longitudinal extent of which is small, preferably only a few millimeters, in particular less than 10 mm.

An in 6th Metal capsule blank shown 3 ^IV is made by the in 5 shown capsule blank 3 "' in the area of the tulip-shaped end 29 to the front 19th was cut flat to form a flat, smooth ring-front wall structure 27 to create.

In 7th is a further production stage of the metal capsule 3 and with the reference number 3 ^V marked. The metal capsule semi-finished product 3 ^V differs from the capsule blank 3 ^IV on the one hand by the fact that the floor area 21 ' compared to the curved surface 21st according to the 3 to 6th was leveled and as a substantially flat floor surface 21 ' is designed. Furthermore, the tulip-shaped end section is essentially 29 of the metal capsule blank 3 ^IV drawn inward and elongated, around the neck section 3 to reshape, being at the transition between the neck section 11 and memory section 9 a substantially frustoconical transition 13 is formed. Furthermore, it can be provided that the metal capsule semi-finished product 3 ^V for example, cut to length by turning and / or brought to a predetermined axial length, that is to say longitudinal extension. According to the metal capsule semi-finished product 3 ^V in 8th it can be seen that there are no further processing steps compared to the metal capsule semi-finished product 3 ^V to 7th more were made. That was the cavity 25th about the at the Face 10 provided opening with the phase change material 5 filled, which can for example be in liquid or solid-like form. To exemplary embodiments and the properties of the phase change materials used according to the invention 5 reference is made to the description above in order to avoid repetition. It can be seen that the cavity 25th for example between 40% to 60% with the phase change material 5 is occupied, the filling quantity depending on the phase change material to be selected 5 is set and between 1% to 100% of the memory space 25 ' specified volume.

In 9a is finally the energy storage cell according to the invention 1 in a sectional view along the line IX-IX in 1 shown, the metal capsule semi-finished product 3 ^V to 8th in the area of the neck section 11 was compressed and / or twisted under the action of mechanical force from the outside. This is the neck section 11 so strongly compressed and / or twisted that the capsule 3 is fluid-tight with respect to the environment. This means that this is inside the capsule 3 arranged and the storage space 25 ' evidencing phase change material 5 can not get to the outside, and the energy storage cell 1 surrounding and / or flowing around liquid (not shown) into the interior of the capsule 3 can get.

Regarding the 9b to 9c becomes an exemplary processing station, such as a folding, clamping and / or twisting station 33 shown by means of the capsule 3 , especially the semi-finished metal capsule product 3 ^V to form the final metal capsule 3 is compressed and / or twisted, in particular twisted. The folding and / or twisting station 33 is like that with phase change material 5 filled metal capsule semi-finished product 3 ^V , shown schematically in sectional view. The folding and / or twisting station 33 is essentially rotationally symmetrical with respect to a longitudinal axis A. educated. During the processing of the capsule semi-finished product 3 ^V in the folding and / or twisting station 33 is a longitudinal axis of the capsule, with respect to which it is formed rotationally symmetrical, coaxial to the longitudinal axis A. the folding and / or twisting station 33 oriented. The semi-finished metal capsule product is held 3 ^V by, for example, circumferential holding jaws 35 . The holding jaws 35 form a circumferential line contact, for example ( 9b) or a surface contact essentially in the area of the transition 13 between memory section 9 and neck section 11 ' . The jaws 35 are essentially made of solid material and their positioning with regard to the distance to the longitudinal axis A. relocate to different dimensions of metal capsule semi-finished products 3 ^V edit.

Immediately above the holding jaws 35 in the axial direction A. viewed has the folding and / or twisting station 33 a folding, clamping and / or rotating unit 37 on. This is essentially made of solid material and essentially perpendicular to the axial direction A. movable back and forth or around the longitudinal axis A. rotatable by at least 10 °, preferably by at least 20 °, preferably by at least 30 ° or preferably by at least 45 °, in particular by a maximum of 360 °, 270 °, 180 or a maximum of 135 °. It can be seen that the folding and / or rotating unit 37 at least two cooperating diametrically with respect to the longitudinal axis A. opposing jaws 39 , 41 has at least one of the at least two jaws 39 , 41 is movably mounted to the neck portion 11 ' to jam, in particular to fold, and / or twist. The jaws 39 , 41 so grip the neck portion 11 ' on, or the metal capsule semi-finished product is in such a way in the folding and / or twisting station 33 added that each one is essentially in the axial direction A. extending clamping surface 40 , 42 the jaws 39 , 41 immediately below the face 19th of the metal capsule semi-finished product 3 ^V the neck section 11 ' squeezes and / or twisted. To the respective clamping surfaces 40 , 42 closes a respective shaping surface 43 , 45 to that of the neck section 11 ' is also facing, but at an angle with respect to the axial direction A. is oriented so that after squeezing the neck section 11 ' by means of the clamping jaws 39 , 41 a cross-sectional dimension in the neck section that tapers continuously at least in sections 11 (please refer 9c ) results. Referring to 9c is the metal capsule 3 to see which by means of the folding and / or twisting station 33 is completed fluid-tight. As with 1 addressed, fold areas arise 15th at the neck section 11 and are so interlocked and / or pressed together that the capsule 3 at the front 19th is completed fluid-tight.

To seal the metal capsule 3 Further measures can be taken to improve this. For example, before compressing and / or twisting the neck portion 11 in the one at the front 19th Formed opening a chemical and / or salt-resistant seal, such as a sealing plug, from above into the neck portion 11 be inserted. In the event of an external force as a result of the clamping jaws moving towards one another 39 , 41 the seal is compressed, preferably compressed so that it is between the fold areas 15th resulting spaces are occupied and filled to ensure the fluid tightness of the capsule 3 to increase. Furthermore, a preferably chemical and / or salt-resistant lacquer, for example a UV-curing acrylic lacquer, can be applied from the outside the capsule 3 for example in the area of the compressed neck section 11 ' be applied to this, which causes a kind of seal to ensure the fluid tightness of the capsule 3 to increase. In an exemplary embodiment, in addition to the purely mechanical production steps for producing the energy storage cell according to the invention 1 nor an induction welding, diffusion welding or cold welding process step can be used around the compressed and / or twisted part of the neck portion 11 ' to close, in particular to seal, by thermal joining at least in sections.

The energy storage cell according to the invention 1 can with a preferably circumferential notch 47 be provided, for example, on the outer circumference of the bottom portion 7th is introduced. The notch 47 For example, which can be referred to as a pinch groove, a paragraph 49 include, as a profile recess from the outer circumference of the bottom section 7th is realized and which in one with respect to the longitudinal axis A. angled bevel 51 which in turn merges into the outer circumference of the bottom section 7th flows out. The notch 47 can be used to power the energy storage cell 1 during manufacture or during transport or during any other type of handling, for example when it is arranged in an energy store according to the invention (not shown). Furthermore, on an end face on the base section 21 ' a recess in the bottom section 7th be introduced, which has, for example, a sack block shape and coaxial to the longitudinal axis A. is oriented. The depression 53 extends in the axial direction A. essentially constant with the formation of a bottom wall 55 which for one reason 57 the deepening 53 and for another reason 59 of storage space 25 ' forms, the phase change material 5 on the ground 59 and this is preferably completely occupied. In particular with regard to the arrangement of the energy storage cell according to the invention 1 in an energy store according to the invention, the depression has become 53 proved beneficial. For example, an outer diameter of the compressed and / or twisted neck section 11 ' to an inner diameter of the recess 53 be coordinated so that two adjacent energy storage cells 1 can be mounted on top of one another, in particular plugged onto one another. This allows a targeted, predefined arrangement or orientation of the energy storage cells 1 realize each other in the energy store. Due to the placement of the recess 53 essentially below the phase change material 5 and due to the elongated bottle shape of the energy storage cell according to the invention 1 is also in the stacked arrangement of two energy storage cells 1 ensures that a sufficiently large surface area of the energy storage cell 1 is available, which for a heat transfer or heat transfer between the environment and storage space 25 ' or phase change material 5 is available.

The features disclosed in the above description, the figures and the claims can be important both individually and in any combination for realizing the invention in the various configurations.

List of reference symbols

1

Energy storage cell

3

capsule

3 ^I , 3 ^II , 3 ^III , 3 ^IV

Capsule blank

3 ^V

Capsule semi-finished product

5

Phase change material

7th

Floor section

9

Memory section

11

Neck section

13

crossing

15th

Folding area

17th

Metal band

19th

Face

21st

Floor area

23

Capsule wall

25th

cavity

27

Front wall

29

tulip-shaped end

31

Kink

33

Folding and / or twisting station

35

Holding jaw

37

Folding and / or rotating unit

39, 41

Jaw

40, 42

Clamping surface

43, 45

Shaping surface

47

score

49

paragraph

51

chamfer

53

deepening

55

Bottom wall

57.59

reason

A.

Axial direction

Claims (16)

Energy storage cell (1) comprising a closed capsule (3) in which the phase change material (5) is arranged, the capsule (3) being made of metal. Energy storage cell (1) according to Claim 1 , the capsule (3) being produced by forming, in particular cold forming. Energy storage cell (1) according to Claim 1 or 2 wherein the capsule (3) is made from a metal blank (17), such as a metal strip or plate, by deep drawing. Energy storage cell (1) according to one of the preceding claims, the interior of the capsule (3) delimiting a storage space (25 ') which is occupied to at least 1% and preferably to a maximum of 100% with phase change material (5). Energy storage cell (1) according to one of the preceding claims, wherein the capsule (3) is sealed in a fluid-tight manner in particular by forming, preferably cold forming. Energy storage cell (1) according to Claim 5 wherein the capsule (3) is sealed fluid-tight in such a way that the tightness of the capsule (3) is maintained in the event of pressure fluctuations resulting from phase transitions of the phase change material (5). Energy storage cell (1) according to any one of the preceding claims, wherein the capsule (3) essentially has the shape of a bottle, in particular the capsule (3) having an essentially cylindrical bottom section (7), preferably continuously adjoining the bottom section (7) has a cylindrical storage section (9) and a neck section (11) which tapers in cross section starting from the storage section (9) and is preferably frustoconical. Energy storage cell (1) according to one of the Claims 5 to 7th wherein the capsule (3) is sealed fluid-tight by the action of mechanical force from the outside, wherein in particular the capsule (3) is sealed fluid-tight by compressing and / or rotating at least part of the neck section (11). Energy storage cell (1) according to one of the preceding claims, wherein the capsule, preferably on the neck section (11), is designed in an intermediate state as a blank, preferably after deep-drawing, to an end face open to the outside in order to fill the capsule (3) To enable phase change material (5), wherein a preferably chemical and / or salt-resistant seal, such as a sealing plug, is inserted into the opening before closing the capsule (3), which is preferably arranged and designed in such a way that the seal is exposed to external forces is compressed to close the capsule (3), and / or a preferably chemical and / or salt-resistant lacquer is applied from the outside to the capsule (3) in the area of the compressed neck section (11). Energy storage cell (1) according to one of the Claims 5 to 9 , wherein the capsule, preferably at the neck section (11), is additionally closed by an induction welding, diffusion welding or cold welding process, in particular the compressed and / or twisted part of the neck section (11) being additionally closed by the induction welding, diffusion welding or cold welding process is completed. Energy storage cell (1) according to one of the preceding claims, wherein the capsule (3) has a preferably circumferential notch (47) on its outer circumference and a recess (53) on a bottom section-side end face, in particular an inner diameter of the recess (53) being equal to an outer diameter of the closed neck portion (11) is matched. Energy storage cell (1) according to one of the preceding claims, wherein the capsule (3) has an essentially constant wall thickness in the range from 0.125 mm to preferably 0.500 mm, with the bottom section (7) in particular being made of solid material. Energy storage device comprising a fluid-tight tank that is at least partially filled with a liquid and in which at least one, preferably a plurality of, according to one of the Claims 1 to 12 formed energy storage cell (1) is arranged, in particular in the tank a pressure of over 1 bar, in particular of over 2 bar, 3 bar or 4 bar prevails. Method for producing an energy storage cell, in which phase change material (5) is introduced into a capsule (3) and the capsule (3) is closed, the capsule (3) being made of metal. Procedure according to Claim 14 , in which the capsule (3) is formed from a metal strip (17) of predefined thickness, in particular the Metal strip (17) is formed into a cylindrical blank (3 ') by deep drawing, which is designed to be open towards one end face (19), in particular the blank (3') being sculpted, cut off, drawn in and drawn on the open end face (19) Finally, it is rotated to a predetermined length to form a substantially bottle-shaped semi-finished product (3 ^v ), in particular the capsule (3) being filled with phase change material (5) via the open end face (19) and being closed by the action of mechanical force from the outside and possibly sealed and / or sealed. Procedure according to Claim 14 or 15th , which is designed such that it the energy storage cell (1) according to one of the Claims 1 to 12 realized.

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