EP3295506A1

EP3295506A1 - Device for storing electric energy, method for operating such a device, and method for producing such a device

Info

Publication number: EP3295506A1
Application number: EP16726020.7A
Authority: EP
Inventors: Norbert Pieper
Original assignee: Laird Bochum GmbH
Current assignee: Molex CVS Bochum GmbH
Priority date: 2015-05-13
Filing date: 2016-05-11
Publication date: 2018-03-21
Also published as: WO2016180845A1; DE102015208912A1

Abstract

The invention relates to a device for storing electric energy. The device (1) has at least one electrolyte chamber region, and the electrolyte chamber region is at least partly filled with an electrolyte (10). The device (1) has at least one pressure generating device, and a desired pressure can be provided in the electrolyte chamber region or the pressure in the electrolyte chamber region can be changed by means of the pressure generating device. The invention also relates to a method for operating such a device and to a method for producing such a device.

Description

Device for storing electrical energy, method for operating such a device and method for producing such a device

The invention relates to a device for storing electrical energy, a method for operating such a device and a method for producing such a device.

Known are so-called electrolyte storage devices for electrical energy. These can be designed, inter alia, as a capacitor or battery or accumulator. Such storage devices usually contain a liquid electrolyte. The problem is that this electrolyte passes at high temperatures at least partially in the gaseous state. In this case, gas bubbles can form on the surface of the electrodes, which hinder the desired current flow and thus the desired energy removal. A lifetime can be reduced thereby.

If a high amount of electrical energy is removed from such a storage device in a short time, this can also lead to the current-related heating of partial areas of the surface of the electrodes, which in turn leads to a punctiform one

Gas bubble formation in the range of these surface parts can lead. Also, this can hinder the current drain.

It thus raises the technical problem of a device for storage

electrical energy, a method for operating such a device and a method for producing such a device to provide a

Extend the temperature working range of the device to storage as well as a

Lifespan increased.

The solution of the technical problem results from the objects with the features of claims 1, 9 and 1 1. Further advantageous embodiments of the invention will become apparent from the dependent claims.

It is a basic idea of the invention to provide a pressure generating device which provides a desired pressure in / on the electrolyte-filled region of the

Storage device created or changed. This can cause a boiling point of the Electrolyte can be increased, whereby the unwanted gas bubble formation takes place only at higher temperatures.

A device for storing electrical energy is proposed. The device may be designed as a battery, accumulator or capacitor. The device has at least one electrolyte space area, wherein the electrolyte space area is at least partially filled with an electrolyte. The electrolyte may in particular be formed as a liquid material which is conductive or contains mobile ions.

In this case, the electrolyte-space region can have a constant volume or only a small variable volume. For example, the electrolyte space region may have a volume that can be changed by a maximum of 10%.

The device can thus also be referred to as a capacitive or electrochemical energy store. In addition to the electrolyte space area, the device

Of course, at least two or more than two electrodes. In this connection, connection devices of the device for connecting an external electrical load can be electrically connected to the electrodes. Next, the

Device have at least one separator. The at least one separator may be arranged between two electrodes, in particular between a cathode and an anode in order to separate them mechanically and electrically from one another. The separator may be formed of paper, for example. In this case, the electrolyte space region can be arranged between the at least two electrodes. It is thus possible that both the electrolyte and at least part of the separator are arranged in the electrolyte space area.

Further, the device may comprise at least one housing which separates an enclosed by the housing inner volume of an Au ßenbereich. In particular, the housing can seal the inner volume relative to the outer area. The electrolyte space area may correspond to at least a part of the internal volume or the entire internal volume.

According to the invention, the device has at least one pressure generating device. By the pressure generating means is a desired pressure in the electrolyte Space available. Provision can mean that this pressure is set, for example before the device is put into operation, and then remains constant. In particular, the desired pressure may be an overpressure which is higher than the natural vapor pressure of the electrolyte in a closed system at a designated operating temperature. For the purposes of this invention, an overpressure thus means a pressure which is higher than the vapor pressure of the electrolyte at a designated

Operating temperatur. The intended operating temperature may be, for example, in a range of 20 ° C to 65 ^< €.

Alternatively, the pressure in the electrolyte space region can be changed by the pressure generating device. This means that different pressures, in particular different pressures from a predetermined pressure range, can be set by the pressure-generating device. In particular, the pressure can be variable from the atmospheric or atmospheric pressure to an overpressure. In particular, the

Pressure generating device may be formed and / or arranged such that the pressure in the electrolyte space area can be provided or changed by this.

For example, the pressure in the electrolyte space area may be provided or changed by applying pressure to that space area. It is possible that at least a part of the pressure-generating device or the entire

Pressure generating device is arranged in the inner volume of the housing.

In particular, the pressure in the electrolyte space region may be provided or changed such that the boiling point of the electrolyte is increased compared to the boiling point at atmospheric pressure or normal pressure. In particular, the pressure can be provided or changed in such a way that a boiling temperature of the electrolyte is higher than the intended operating temperature of the storage device.

For example, the pressure generating means may be provided by one or more gas reservoir volumes or volumes provided in the housing. In this case, the electrolyte can be filled with a filling pressure in the electrolyte space area. After filling, the housing can be closed under the filling pressure. The filling pressure is chosen such that the gas reservoir volume is reduced during filling and that pressure is exerted on the electrolyte or on the electrolyte space area after the closure of the housing by the gas reservoir volume. The gas reservoir volume can be designed, for example, as a CO 2 bubble. This does not require complex structural separation, for example by a membrane, the

Pressure generating device of the electrolyte space area.

Overall, a simple extension of the results in an advantageous manner

Operating temperature range of the device for storing electrical energy. In particular, can be provided by the pressure provided an increased boiling temperature of the electrolyte. By changing the pressure, the

Boiling temperature can also be changed.

In particular, it results in an advantageous manner that the device for storing electrical energy at high temperatures can also be operated with higher peak currents without locally and temporarily forming gas bubbles in the electrolyte as a result of partial internal heating, whereby the performance and service life would be impaired.

In a preferred embodiment, the pressure generated by the pressure generating device is temperature-dependent variable, in particular dependent on an operating temperature or a temperature of the electrolyte. In particular, the pressure generated by the pressure generating device with increasing

Increase temperature and / or decrease with decreasing temperature. Preferably, the pressure generating device is designed such that a change in the

Temperature due to physical laws or effects causes a change in the pressure generated. For example, the change in temperature may be a change in a volume or a size of the

Effect pressure generating device. These temperature-related size or

Volume change may then cause a change in the pressure in the electrolyte space area. In particular, no expensive temperature sensing and control operations are required to effect the temperature dependent variation of the pressure generated.

This advantageously results in e.g. with rising

Operating temperatures of the pressure in the electrolyte space area can be increased, which also increases the boiling temperature.

In a further embodiment, the at least one

Pressure generating device at least one hollow body or is as a hollow body educated. A volume of the hollow body is variable, in particular enlargeable or reducible. For example, at least one cavity of the hollow body may at least partially be enclosed or surrounded by a deformable wall element. The at least one cavity is at least partially filled with a fluid.

Alternatively, the at least one cavity has a negative pressure. The negative pressure refers to a pressure that is less than the pressure in the electrolyte space region and / or less than an ambient pressure. Further, the hollow body may comprise at least one spring element which is biased at negative pressure. The at least one spring element is in this case arranged and / or formed that under

Preload an expansion force is exerted on the hollow body, the one

Increases the volume of the hollow body causes or can cause. The

Expansion force is greater than that resulting from the negative pressure

Compression force. Preferably, the cavity is evacuated, that is, vacuumized. The spring element may e.g. be exerted by an elastic wall element and / or by a spring element arranged in the hollow body. Thus, the spring element can be designed as a spring, in particular as a steel spring, which is arranged in the hollow body or cavity.

The pressure generating device may, for. B be designed as a bladder. Such a bladder body may, for example, be formed as a hollow sphere or as a hollow ellipsoid.

In addition to the at least one deformable wall element, the

Pressure generating device comprise further deformable or non-deformable wall elements which surround or surround the at least one cavity. One

deformable wall element can in this case in particular be designed and / or arranged such that the volume of at least one cavity at

Change deformation, especially zoom in or out, can. One

deformable wall element may in particular be elastically deformable. It is conceivable z. B., that a wall element is formed of elastic plastic. Alternatively, however, the wall element can also consist of a deformable metal membrane. The wall element may be gas-tight and liquid-tight. In particular, the conversion element can not allow the passage of the electrolyte in the gaseous or liquid state. An elastic wall element can for example be formed as a diaphragm be. Alternatively, the elastic wall element made of stainless steel or from

Be formed aluminum foil.

It is conceivable that the hollow body is formed as a single body. This may mean, in particular, that the at least one hollow body is designed as a body separated from the housing. However, it is also conceivable that at least one wall element of the hollow body is provided by the housing of the device or is mechanically connected to the housing. If the hollow body is formed as a single body, then it can likewise be mechanically connected to the housing,

for example, glued or welded, be.

The at least one hollow body can be arranged in the electrolyte space area or adjacent to the electrolyte space area. In particular, the hollow body can be arranged such that a change in volume of the hollow body results in a pressure change in the electrolyte space region.

For example, the hollow body can be arranged in a bottom region of the housing and thus under the electrodes.

Next example, the hollow body may be arranged such that the

Electrodes of the device for storing electrical energy are at least partially or completely located in an enclosed by the hollow body interior.

For example, the hollow body may be arranged such that it at least partially surrounds or surrounds the electrodes. Alternatively, the hollow body may be located at least partially or completely in an inner area enclosed by the electrodes. For example, the electrodes may be arranged such that they at least partially surround or surround the hollow body.

Also, the hollow body of at least a part of an electrode can be formed.

These embodiments can be chosen in particular when the

Electrodes and the / the separator (s) are film-like and wound into a roll. In this case, the roller can be enclosed by the hollow body. Alternatively, the hollow body may be enclosed by the roller. Also, at least one section a film, for example, the cathode film, the anode film or the separator film, be double-walled and thus provide the hollow body. A length of the double-walled portion may be selected such that at least one complete revolution of the wound-up electrode or the wound-up separator is provided in the wound-up state.

Preferably, the pressure generating device can be provided as at least partially or completely filled bladder with the fluid. This can then be arranged in the inner volume of the housing. When the temperature rises, a volume of the hollow body will increase, whereby the pressure on the electrolyte space increases and thus increases the boiling temperature of the electrolyte.

Further, the at least one cavity of the hollow body gas and / or

be liquid-tight.

A pressure generating device designed as a hollow body or a pressure generating device comprising the hollow body can in this case be advantageously used for

Providing a (constant) pressure in the electrolyte space area or for the temperature-dependent change in the pressure can be used.

In a further embodiment, a boiling temperature of the fluid is lower than the boiling temperature of the electrolyte. The fluid may in particular be a further electrolyte or a non-electrolytic liquid. That the boiling temperature of the fluid is lower than the boiling temperature of the electrolyte may mean that the fluid boils at the same pressure at a lower temperature compared. This in turn can lead to a volume of the fluid increases with increasing temperature, in particular with a rise above the boiling temperature, while the electrolyte is still in the liquid state. By changing the volume of the boiling fluid, the volume of the hollow body can be increased and a pressure in the electrolyte space can be increased, which in turn leads to the increase of the boiling temperature of the electrolyte.

Thus, the fluid may be a fluid whose gas amount and gas pressure increase with increasing temperature. This results in an advantageous manufacturing technology easy to manufacture and easy to install pressure generating device that allows a temperature-dependent change in the pressure in the electrolyte space area.

In a further embodiment, the fluid is liquid or gaseous at a reference pressure and a reference temperature. The reference temperature may be, for example, in a temperature range of -20 ° C to 65 ^. In the case of a liquid fluid results in an advantageous manner that the electrolyte at reference pressure and

Reference temperature can be filled without form, as no compression of the fluid is possible and necessary.

This results in an advantageous manner further that the permissible operating temperature range of the memory device can be extended to the top.

The fluid may e.g. be one of the following compound or consist of a mixture of two or more of the following compound whose boiling point is below the boiling point of the electrolyte:

Acetaldehyde, acetic acid, acetone, acetonitrile, ammonia, aniline, anisole, benzaldehyde, benzene, bromine, butane, 1-butanol, carbon disulfide, chlorine, chlorobenzene, 1-chlorobutane, chloroethane, chloroethylene, cyclohexane, cyclohexanol, cyclohexanone, decane, dibutyl ether, Dichloromethane, dimethyl ether, dimethyl sulfoxide, 1,4-dioxane, dipropyl ether, ethanol, ethyl acetate, ethylene glycol, heptane, hexafluorobenzene, hexane, 1-hexanol,

Hydrogen fluoride, methyl iodide, isobutane, methanol, methyl acetate, methyl formate, N-methylaniline, N-methylformamide, nitrobenzene, nitromethane, 1-octanol, pentane, 1-pentanol, phenol, propane, 1-propanol, 2-propanol, pyridine, pyrrole , Pyrrolidine, styrene, sulfur dioxide, tetrachlorethylene, carbon tetrachloride, toluene, trichlorethylene, trichloromethane,

Trimethylamine, water, o-xylene, m-xylene, p-xylene.

In practice, you choose a fluid that is easy to handle and builds up a reasonable amount of pressure.

For example, the electrolyte may be acetonitrile with a boiling point of 81 .6 ^. The fluid may be acetone with a boiling point of 56 ° C. Alternatively, the fluid may be n-pentane with a boiling point of 36 ^. In the case of acetone as a fluid, the fluid remains liquid and does not boil when a

Operating temperature is less than 56 ° C. There is still no strong pressure increase in the electrolyte space area. Only at an operating temperature above 56 'Ό boils the fluid and can greatly expand the hollow body. This can increase the pressure in the electrolyte space area. The increase may cause the fluid to boil due to the increased pressure itself.

A capacitor without the proposed pressure generating device and with an acetonitrile electrolyte can only be used up to a low current load

Operating temperature of 81 ° C are operated. At higher operating temperatures, harmful gas bubbles form. Typical manufacturer specification for the maximum

Operating temperature of such a capacitor is 65 ° C (at high current load) to 85 ° C (at low current load). Will in this case of a static

Operating temperature of the capacitor of 65 'Ό assumed, the electrolyte may by (temporary) peak current load only selectively from 65 ° C to up to 81 .6 ^, ie by 16.6 ° C warm. It is assumed here that high peak currents increase the operating temperature at least temporarily. In addition, he begins to form harmful gas bubbles.

In the case of an existing pressure generating device, in particular a filled with acetone hollow body, the acetone is at the static operating temperature Θ'Ό above its boiling point and thus develops an overpressure of

9 ^< € / (0.289 ^< € / KPa) = 31 .14 KPa. At 31 .14 KPa overpressure, the acetonitrile electrolyte boils only at 81 .6 ° C + 31 .14 KPa ^* (0.316 ° C / KPa) = 91.44 ° C.

Thus, for example, by a peak current load, the electrolyte now up to 91.44 ° C, ie to 26.44 ^q C, warm until it begins to form harmful gas bubbles. Thus, the allowable heating by eg peak currents from 16.6 ^ to 26.44 ° C, ie by about 10 ° C, can be increased. In other words, with the same static operating temperature, significantly higher peak currents can flow without suffering from the disadvantages described by gas bubbles.

In the case of medium to small flows, there is no limit to gas bubble formation for the maximum operating temperature of the condenser, since the acetone in the hollow body is always about 31 KPa pressure above the gas pressure of the acetonitrile electrolyte (this is independent of the current (static) operating temperature is the Reference pressure). In other words, the electrolyte theoretically never reaches its boiling point in this case. Unless otherwise limited, for example due to mechanical and / or chemical effects, this can be prevented such an improved capacitor at temperatures well above its

Operate electrolyte boiling temperature (for example, based on the atmospheric pressure normal).

The described advantages apply equally to capacitors, batteries and accumulators with liquid electrolytes.

Furthermore, the following advantage results: electrolytes based on acetonitrile are known to be stable even at very low temperatures, e.g. even at -40 ° C, still have a good functionality. By using a pressure-generating device, the temperature range of application of this attractive electrolyte can now be significantly extended towards the top. Especially in the automotive industry and in the military sector reaching to the lowest possible and highest possible temperatures

Operating temperature ranges strongly in demand.

In a further embodiment, the hollow body, in particular at least one deformable wall element of the hollow body, is prestressed under a reference pressure of the electrolyte space region. In this case, upon compression of the hollow body by external action due to the bias of the hollow body, a compression-opposing force is applied. This force can be from an elastic

Wall element and / or a fluid-filled cavity and / or exercised by a spring element arranged in the hollow body.

The reference pressure may in this case be lower than a boiling pressure of the electrolyte, in particular lower than a minimum boiling pressure of the electrolyte in one

predetermined temperature range. This temperature range may range, for example, from 50 'Ό (including up to 100 ° C). In particular, the hollow body may be biased such that increases the volume of the hollow body at pressures which are lower than the reference pressure. At higher pressures than the reference pressure can be exerted by the hollow body, in particular by the deformable wall element, a pressure on a surrounding area. In other words, the hollow body, in particular the at least one deformable wall element can be elastically deformed at the reference pressure and due to the

Deformation exert a predetermined back pressure. If such a hollow body is arranged in the inner volume of the housing, then, for example, the electrolyte can be introduced under a filling pressure into the electrolyte space area or the inner volume such that the deformable wall element elastically deforms and then exerts a pressure on the electrolyte space area.

Is, while maintaining the filling pressure, after filling the housing

sealed, so is provided by the hollow body, a desired pressure on the electrolyte space area. This desired pressure can in particular be chosen such that the boiling temperature of the electrolyte is increased in comparison to the boiling point under atmospheric or atmospheric pressure.

In a further embodiment, at least one part of the housing, in particular at least one housing wall, of the device for storage is elastically deformable such that pressure can be exerted on the electrolyte space area by the housing, in particular if it exceeds a predetermined volume.

In particular, it is possible to elastically deform the housing before being filled with the electrolyte, whereby a volume of the electrolyte space area is increased. Then electrolyte can be filled in this space area. Upon completion of filling, the elastic deformation of the housing may be at least partially reversed, thereby providing a desired pressure on the electrolyte space area.

This results in an advantageous manner providing a desired pressure without additional resources.

In a further embodiment, the pressure generating device has at least one piston. The piston can in particular be designed and / or arranged such that upon movement of the piston, the pressure in the electrolyte space region can be changed. The piston may in particular be a movable piston. This can for example be operated manually and / or by the force of a spring, such as a steel spring, and / or actorgestützt. In this case, the housing may have at least one outlet valve, which forms an overpressure outlet valve. This is in normal operation, in particular at operating pressures below a predetermined outlet pressure, in the electrolyte space area, separated by at least part of the piston fluidly from the electrolyte space area. However, if the pressure in the electrolyte space area increases beyond this predetermined outlet pressure, the piston performs a movement such that the outlet valve is released, ie there is a fluidic connection between the electrolyte space area and the outlet valve.

Thus, both a pressure generating device and an exhaust valve release device are provided by the piston.

Furthermore, the device may comprise a device for temperature detection.

Likewise, the device may comprise a control and evaluation device. It is conceivable that through the control and evaluation the

Pressure generating device is driven such that a desired

temperature-dependent pressure in the electrolyte space area is adjusted.

Of course, embodiments are also conceivable in which various of the above-explained pressure generating means are combined.

Further proposed is a method for operating a device according to one of the embodiments described in this invention. According to the invention, a desired pressure is provided in the electrolyte space area. In particular, this pressure may be greater than the atmospheric or atmospheric pressure. Thus, the pressure provided can be chosen such that the boiling point of the

Increased electrolyte compared to the atmospheric or atmospheric pressure. The pressure can for example be provided by the illustrated hollow body and / or the housing due to an elastic deformation pressure on the electrolyte region and thus in the electrolyte space area exerts.

Alternatively, the pressure in the electrolyte region is changed. The change can be made, for example, by increasing a volume of the illustrated hollow body. In a further embodiment, the pressure is changed depending on the temperature.

In particular, the pressure is increased with increasing temperature and / or at decreasing Temperature reduced. This results in an advantageous manner an extension of the temperature range.

Further proposed is a method for manufacturing a device according to an embodiment described in this invention. According to the invention, at least one electrolyte space area is provided, wherein the electrolyte space area is at least partially filled with an electrolyte. For example, a housing may be provided wherein the electrolyte space area corresponds to a portion of the interior volume or the entire internal volume. Next will be at least one

Pressure generator provided, wherein by the pressure generating means, a desired pressure in the electrolyte space area available or pressure in the electrolyte space area is variable.

In the inner volume, at least a part or even the complete pressure generating device can also be arranged. This can be done, for example, before the filling of the electrolyte.

This results in an advantageous manner a simple production of a

Device according to the invention.

In a further embodiment, at least one hollow body is provided as pressure generating device, wherein a volume of the hollow body is variable.

For example, a cavity of the hollow body is at least partially enclosed by a deformable wall element.

Further, at least one cavity of the hollow body is at least partially or completely filled with a fluid. Alternatively, a vacuum is provided in the cavity. In particular, the cavity may be evacuated. Next, the hollow body is arranged in an interior of a housing of the pressure generating device.

The hollow body can be arranged in particular in a bottom region of the housing. It is conceivable that at least a part of the hollow body is formed by the housing or by a part mechanically connected to the housing. Also, a part of the hollow body can be mechanically connected to the housing. In a further embodiment, the filling of the electrolyte takes place, in particular temporally, after the arrangement of the hollow body in the internal volume. Next is the

Electrolyte filled under pressure. In particular, the filling pressure of the electrolyte can be selected such that the hollow body elastically deforms, wherein the elastically deformed hollow body in the elastically deformed state due to the desired

Return to the original form exerts a pressure on the electrolyte space area.

Further, after the filling process, the housing can be closed in a fluid-tight manner, wherein the filling pressure is maintained in the internal volume. In this case, a desired pressure is provided in the electrolyte space area by the hollow body.

In an alternative embodiment, a housing of the device for storing electrical energy is elastically deformed such that a volume of the electrolyte space region is increased. Then, the electrolyte is filled in the electrolyte space area. After filling, the elastic deformation of the housing is at least partially reversed. Also in this case, because of the desired return to the original state, pressure may be applied to and thus in the electrolyte space area

to be provided.

The invention will be explained in more detail with reference to several embodiments. The figures show:

1 shows a schematic cross section through a device according to a first

Embodiment in a first state,

FIG. 2 shows a schematic cross section through the device shown in FIG. 1 in a further state, FIG.

3 shows a schematic cross section through an embodiment according to the invention in a further embodiment,

4 shows a schematic cross section through a device according to the invention in a further embodiment, 5 shows a schematic cross section through a device according to the invention in a further embodiment during filling,

6 shows a schematic cross section through the device shown in FIG. 5 in a state after filling, FIG.

7 shows a schematic cross section through a device according to a further embodiment,

8 shows a schematic cross section through a hollow body,

9 shows a schematic cross section through a device according to a further embodiment,

Fig. 10 is a schematic plan view of an electrode assembly with hollow body.

The following designate like reference numerals with the same or similar technical features.

In Fig. 1 is a schematic cross section through an inventive device 1 for storing electrical energy is shown. The device 1 comprises a fluid-tight housing 2, a first electrode 3 formed as a cathode, a further electrode 4 designed as an anode and a separator 5, the separator 5 being arranged between the electrodes 3, 4. The housing 2 comprises an internal volume 6, wherein the internal volume 6 comprises a bottom area 7 and an upper part 8. In the upper part 8, the electrodes 3, 4 and the separator 5 are arranged. In the bottom region 7, a hollow body 9 is arranged, wherein the hollow body 9 is formed like a hollow lens. In the inner volume 6 of the housing 2, an electrolyte 10 is arranged, which surrounds the electrodes 3, 4, the separator 5 and the hollow body 9.

The hollow body 9 has an inner volume 1 1 by a fluid, in particular acetone, is arranged. At a first temperature TO, the hollow body 9 has a first volume. In the inner volume 6 of the housing 2 in this case there is a first pressure pO. The prevailing in the inner volume 6 pressure pO thus denotes the pressure in the electrolyte space area. In Fig. 1 it is shown that the hollow body 9 is formed as a separate element from the housing 2.

2, the device 1 shown in FIG. 1 is in a further state,

illustrated in particular at a further temperature T1, wherein the further temperature T1 is higher than the first temperature TO. The fluid arranged in the inner volume 1 1 of the hollow body 9 may have a boiling temperature which is lower than that

Boiling temperature of the electrolyte is 10. If the temperature increases to the further temperature T1, the boiling temperature of the fluid can be exceeded, while the boiling temperature of the electrolyte is greater than the further temperature T1. In this case, the inner volume 1 1 of the hollow body 9 can increase, since the fluid in the interior 1 1 passes into the gaseous state. By increasing the volume, the pressure in the inner volume 6 of the housing 2 increases to a further pressure p1, which is greater than the first pressure pO. This in turn also increases the boiling temperature of the electrolyte 10th

In FIGS. 1 and 2 it is shown that a maximum volume of the hollow body 9 is selected such that it does not emerge from the bottom area 7.

FIG. 3 shows a cross section through a device 1 according to the invention in a further embodiment. The device 1 shown in Fig. 3 is substantially, as the device 1 shown in FIGS. 1 and 2, formed. In contrast to the device 1 shown in FIGS. 1 and 2, the hollow body 9 is formed by a bottom wall 12 of the housing 2 and an elastically deformable wall element 13.

FIG. 4 shows a schematic cross section through a device 1 according to the invention in a further embodiment. This device 1 also comprises electrodes 3, 4, a separator 5, a housing 2, an internal volume 6, which is subdivided into an upper region 8 and a bottom region 7. In contrast to the devices 1 shown in FIGS. 1 to 3, the device 1 illustrated in FIG. 4 comprises a piston 14 which is arranged in the bottom region 7. The piston 14 may in this case have a piston surface which corresponds to a cross-sectional area of the inner volume 6. Further, the piston 14 may have a piston rod 15 which is led out of the housing 2. Thus, the piston by spring force, manually or actuator supported be actuated from outside ßerhalb the housing 2. By moving the piston 14, the pressure in the inner volume 6 and thus in the electrolyte space region can be changed.

The piston 14 is preferably arranged such that an external pressure, for example an atmospheric air pressure, can act on the piston 14. This energy can be saved for the pressure build-up. It is also conceivable to press a fluid-tight elastic membrane through a piston rod 15 in the electrolyte space region and thus to increase the pressure in the electrolyte space area.

In this embodiment, the device 1, a non-illustrated

Temperature sensor and a likewise not shown control and evaluation include, wherein the movement or position of the piston 14 can be adjusted in such a temperature-dependent manner by the control and evaluation, that in the

Interior 6 arranged electrolyte does not boil.

FIG. 5 shows a schematic cross section through a device 1 according to the invention in a further embodiment. The device 1 shown in FIG. 5 also comprises electrodes 3, 4, a separator 5, a housing 2 and a

Inner volume 6 of the housing 2. Side walls 16 of the housing are formed wavy. In Fig. 5 is shown by arrows 17, that the housing 2 is elastically deformed such that the inner volume 6 is increased in comparison to the elastic undeformed state. This can, for example, by applying tensile forces on the

Side walls 16 take place. Also shown is an electrolyte container 18, is filled by the electrolyte 10 in the inner volume 6 of the housing 2 in the deformed state. This is done through an opening 19 in a cover 20 of the housing 2. Im

Inner volume 6 in this case preferably prevails first vacuum and at the end of the filling process, a filling pressure which is equal to or greater than the atmospheric pressure pO.

The vacuum results in an advantageous manner that the electrolyte can be filled bubble-free and gapless. For example, a separator formed of paper can thus be completely impregnated.

In Fig. 6, the device 1 shown in Fig. 5 is shown in a state after filling. After filling, the opening 19 of the lid 20 became fluid-tight locked. Due to the tendency of the elastically deformed housing 2 to return to its original state, the inner volume 6 decreases in comparison to the inner volume 6 set in FIG. 5 during filling. This is schematically represented by arrows 21. By this reduction of the inner volume 6, the pressure p1 in the inner space 6 increases, so that it is higher than the filling pressure PO.

FIG. 7 shows a schematic cross section through a device 1 according to a further embodiment. This is essentially the same as the embodiment of the device 1 shown in FIG. 1. Therefore, reference may be made to the explanation of this embodiment. In contrast to that shown in Fig. 1

Embodiment, the hollow body 9 is formed in the bottom portion 7 through the housing walls of the housing 2 and an intermediate wall 22 which is disposed in the interior space 6. This intermediate wall comprises elastic sections 23 and rigid section 24. The internal volume 11 of the hollow body 9 can increase when the middle rigid section 24 moves in the direction of the upper area 8, in particular in the direction of the housing cover, due to the elastic sections 23. By enlarging the

Inner volume 1 1 increases the pressure in the inner volume 6 of the housing 2. This can in turn increase the boiling temperature of the electrolyte 10.

Fig. 8 shows a schematic cross section through a hollow body 9. This is formed as an ellipsoidal hollow body 9, wherein the wall elements may consist of stainless steel sheet.

9 shows a schematic cross section through a device 1 according to a further embodiment. This is essentially the same as the embodiment of the device 1 shown in FIG. 4. Therefore, reference may be made to the explanation of this embodiment. In contrast to the embodiment shown in Fig. 4, the housing 2 in the bottom portion 7 a hollow cylindrical extension 25, in the inner volume of the piston 14 and the piston rod 15 can move. The hollow cylindrical extension 25 has an outlet opening 26 in the wall area. This outlet opening 26 is not fluidly with the

Inner volume 6 of the housing 2 connected when the surface of the piston 24 is above the upper end of the outlet opening 26. This is particularly the case when a pressure in the internal volume 6 is less than a predetermined outlet pressure. If the pressure in the inner volume 6 rises above the outlet pressure, a movement takes place of the piston 14 away from the inner volume 6, wherein the outlet opening 26 can be at least partially or completely released. Thus, a fluidic connection between the inner volume 6 and outlet opening 26 is made and electrolyte can escape from the inner volume 6. As a result, an unwanted damage to the housing 2 can be avoided in an advantageous manner. The combination of piston 14 and outlet opening 26 thus serves as a pressure relief valve.

10 shows a schematic plan view of an electrode arrangement 27 with hollow body 9. The electrode arrangement 27 comprises electrodes 3, 4 formed as films and a separator 5 formed as a film, which is arranged between the electrodes 3, 4. The films are wound up here. Of course, the electrode arrangement 27 can also have a plurality of foil-type electrodes 3, 4 and foil-like separators 5. In particular, in this case, the wickeiförmige electrode assembly 27 may have a plurality of contacts for electrically contacting the electrodes 3, 4. Around the wickeiförmige electrode assembly 27 around a hohizylinder- or hollow-ring-shaped hollow body 9 is arranged, wherein a jacket of the hollow cylinder is hollow, for example, double-walled, or the annular body is hollow. FIG. 10 shows that the hollow body 9 completely or almost completely encloses the electrode arrangement 27.

LIST OF REFERENCE NUMBERS

1 device for storing electrical energy

2 housings

3 electrode

4 electrode

5 separator

6 interior, interior volume

7 floor area

8 Upper area

9 hollow body

10 electrolyte

1 1 internal volume of the hollow body

12 bottom wall

13 Deformable wall element

14 pistons

15 piston rod

6 Corrugated side wall

17 arrow

18 electrolyte tank

19 opening

20 lids

21 arrows

22 partition wall

23 elastic section

24 rigid section

25 hoizylindförmiger extension

26 outlet opening

27 electrode arrangement

First pressure

p1 further pressure

Claims

claims

1 . Device for storing electrical energy, the device (1) having at least one electrolyte space area, wherein the electrolyte space area is at least partially filled with an electrolyte (10),

characterized in that

the device (1) has at least one pressure generating device, wherein a desired pressure in the electrolyte space region can be provided by the pressure generating device or the pressure in the electrolyte spatial region can be changed.

2. Device according to claim 1, characterized in that of the

Pressure generating device generated pressure is temperature-dependent variable.

3. Apparatus according to claim 1 or 2, characterized in that the at least one pressure generating device has at least one hollow body (9) or as a hollow body (9), wherein a volume of the hollow body (9) is variable, wherein at least one cavity of the hollow body (9) is at least partially filled with a fluid or at least one cavity of the hollow body (9) has a negative pressure and the hollow body (9) has at least one spring element which is biased at negative pressure.

4. Apparatus according to claim 3, characterized in that a boiling temperature of the fluid is lower than the boiling temperature of the electrolyte (10).

5. Apparatus according to claim 3 or 4, characterized in that the fluid at a reference pressure and a reference temperature is liquid or gaseous.

6. Device according to one of claims 3 to 5, characterized in that the hollow body (9) is biased under a reference pressure of the electrolyte space region.

7. Device according to one of claims 1 to 6, characterized in that

at least a part of a housing (2) of the device (1) is designed to be elastically deformable such that pressure is applied to the electrolyte through the housing (2). Space is exercisable.

8. Device according to one of claims 1 to 2 or 7, characterized in that the pressure generating means comprises at least one piston (14).

9. A method of operating an electrical energy storage device according to any one of claims 1 to 8, characterized in that a desired pressure in the electrolyte space area provided or the pressure in the electrolyte region is changed.

10. The method according to claim 9, characterized in that the pressure

is changed depending on the temperature.

1 1. Method for producing an apparatus (1) for storing electrical energy according to one of claims 1 to 8, characterized in that at least one electrolyte space area is provided, wherein the electrolyte space area is at least partially filled with an electrolyte (10), wherein at least one pressure generating device is provided, wherein a desired pressure in the electrolyte space area can be provided by the pressure generating device or the pressure in the electrolyte space area can be changed.

12. The method according to claim 1 1, characterized in that as

Pressure generating device at least one hollow body (9) is provided, wherein a volume of the hollow body (9) is variable, wherein at least one cavity of the hollow body (9) is at least partially filled with a fluid or wherein provided in a cavity of the hollow body (9), a negative pressure is, wherein the hollow body (9) in an inner space (6) of a housing (2) of the device (1) for storing electrical energy is arranged.

13. The method according to claim 12, characterized in that the filling of

Electrolyte (10) after the arrangement of the hollow body (9), wherein the electrolyte (10) is filled under pressure.

14. The method according to any one of claims 1 1 to 13, characterized in that a housing (2) of the device (1) for storing electrical energy in such a way is elastically deformed, that a volume of the electrolyte space is increased, wherein in the electrolyte space region of the electrolyte (10) is filled.