DE102019101281A1 - Accumulator and soil cultivation device with an accumulator - Google Patents

Abstract

The invention relates to an accumulator (1) with at least one accumulator cell (4) having two electrical poles (3) and a cooling device (5) for cooling the accumulator cell (4). In order to advantageously cool such an accumulator (1), it is proposed that the cooling device (5) have a phase change material (6, 7) which is thermally connected to at least one electrical pole (3) of the accumulator cell (4). A soil cultivation device (2) with such an accumulator (1) is also proposed.

Description

Subject of the invention

The invention relates to an accumulator with at least one accumulator cell having two electrical poles and a cooling device for cooling the accumulator cell.

Furthermore, the invention relates to a soil tillage implement with an electrical consumer, an accumulator with at least one accumulator cell having two electrical poles for providing electrical energy for the electrical consumer and a cooling device for cooling the accumulator cell.

State of the art

Accumulators are well known in the prior art. These have one or more battery cells, which are usually surrounded by a battery housing, which also accommodates a battery management system that is used to monitor, regulate and protect the battery, for example to detect the state of charge of the battery and overcharge or complete discharge of the battery Avoid accumulator cells.

Relative to an accumulator for a cleaning device, it is in the prior art, for example, from DE 10 2015 109 954 A1 known to pass a suction air flow, which is generated by a blower of the cleaning device, through the accumulator housing and thereby pass a circumferential surface of the accumulator cells. The battery cells are cooled over their circumferential surface, the outer windings of the battery cells being fundamentally better cooled than the inner windings. This inhomogeneous cooling effect must be taken into account when designing the battery.

Furthermore, it is from the JP 2002-291669 A Known to cool the electrical poles of the battery by means of an exhaust air stream from a cleaning device, thermal energy of the pole being transferred to the air stream.

In both cases, the cleaning device having the accumulator is designed such that the accumulator is cooled by the suction air flow of the cleaning device. The cooling device of the accumulator therefore does not function independently of the suction operation of the cleaning device.

Description of the invention

Starting from the aforementioned prior art, it is an object of the invention to provide an accumulator with a cooling device which enables effective cooling of the accumulator, regardless of the operation of the device, for example soil cultivation device, in which the accumulator is inserted. In particular, the cooling device of the rechargeable battery is intended to effect effective cooling of the rechargeable battery both during a charging operation and during an unloading operation.

To solve the problem, an accumulator is first proposed, the cooling device of which has a phase change material (PCM material) which is thermally connected to at least one electrical pole of the accumulator cell.

According to the invention, the battery cell is now cooled by means of a phase change material via its electrical poles, which are usually exposed to a greater thermal load than the peripheral surface. As a result, the accumulator cell can be cooled homogeneously, in particular homogeneously over all layers of a winding geometry. Furthermore, it is also possible to cool a plurality of accumulator cells of the accumulator with the same success regardless of their position within the accumulator. The warm contact of the poles of an accumulator cell with a phase change material also enables a material-dependent design of the cooling device, an increased heat transfer being able to be controlled depending on the type of phase change material once a defined temperature of the phase change material has been reached. Each phase change material has a characteristic phase transition temperature, for example melting temperature, which indicates the transition between a crystalline state and a molten state of the phase change material. When the phase change material is heated to a temperature which is above the melting temperature, the phase change material absorbs the energy and changes from a first state of aggregation, in particular a crystalline state, to a second state of aggregation, in particular a liquid state. Due to the heat of fusion absorbed in the process, the phase change material cools the pole of the battery cell connected to it, and consequently also the entire battery cell. The phase change material can also be designed as a PCM polymer composition, the polymers used for the composition being, for example, polyethylenes, in particular low density polyethylene (LDPE), or polymethyl methacrylate (PMMA). Such compositions are advantageously low-exudation or exudation-free, mechanically strong and Resistant to heat, so that they can be manufactured as sheet material, for example. In addition, such compositions also have improved thermal conductivity. The phase change material of the cooling device is preferably one with a high specific heat capacity of greater than 2 kJ / (kgK). The phase change materials are characterized by the fact that this thermal energy can be stored with little loss and for a long time. The latent heat of fusion, which is absorbed by the phase change material after the melting temperature is reached, is substantially greater than the amount of thermal energy that can be stored due to the specific heat capacity of the phase change material (without its phase change effect). When the phase change material is charged with thermal energy, the material is melted, and a great deal of thermal energy can be absorbed. The stored thermal energy is then released again when the phase change material solidifies, the previously absorbed large amount of thermal energy being released into the environment as solidifying heat. In the small temperature range predetermined by the melting temperature or solidification temperature of the phase change material, a large amount of thermal energy is stored in a relatively small mass. In addition, due to the use of metastable states of the phase change material, the thermal energy can be stored without thermal insulation and with very little loss. All phase change materials whose melting temperature is in a temperature range that is typical for the operation of an accumulator are fundamentally possible as the phase change material for the cooling device of the accumulator. It can be particularly preferably noted that a certain warming of the battery is desired at the start of its charging or discharging operation in order to charge or discharge the battery in an optimal temperature working range. The accumulator usually has an optimal performance at higher temperatures, for example 50 ° C or more, while the service life is reduced by high temperatures. In order to achieve an optimal temperature working range - in the aforementioned sense - the accumulator should warm up as quickly as possible. Immediate cooling of the battery at the beginning of the charging or discharging operation by the cooling device would delay the achievement of the optimal temperature working range and would accordingly reduce the efficiency of the battery. The phase change material of the cooling device now advantageously ensures that the battery can first heat up to an optimal temperature working range, and then, when the melting temperature of the phase change material is reached, heat of the battery is increasingly absorbed. It is recommended that the melting temperature of the phase change material is immediately above the optimal temperature working range of the battery. By cleverly selecting the phase change materials, all the battery cells of the battery preferably also show a temperature curve which is homogeneous with respect to one another. Compared to convective cooling of the battery cells used in the prior art, the phase change material of the cooling device according to the invention is not active up to the melting temperature. Only when the melting temperature is reached does the phase change material begin its phase change and remove thermal energy from the battery cell until a maximum thermal energy absorption of the phase change material is reached.

The phase change material is advantageously connected to the battery cells in such a way that gas can escape from the battery cells. Accordingly, a valve of the battery cell is kept free to prevent a so-called "thermal runaway". Alternatively, the phase change material can also completely cover the valve of the battery cell, provided that a predetermined breaking point is then provided in the phase change material, which breaks when the mechanical stress or temperature increase associated with a gas leak occurs, and gas can escape unhindered from the battery cell. The accumulator in the sense of the invention can, for example, be a lithium-ion battery or also a so-called post-lithium-ion battery that uses lithium-sulfur technology or the like. Other batteries can also benefit from the invention.

It is proposed that the accumulator have a cell connector which connects the electrical poles of at least two accumulator cells to one another in an electrically and thermally conductive manner and is thermally conductively connected to the electrical poles on the one hand and to the phase change material on the other. In this configuration, the electrical poles of the battery cells are not directly connected to the phase change material of the cooling device. Rather, the poles are first thermally and electrically conductively coupled to the cell connector, which in turn is then connected to the phase change material of the cooling device, which absorbs the thermal energy of the battery cells.

It is proposed that the phase change material make direct contact with the cell connector and / or that the phase change material contact an electrically insulating heat-conducting element arranged between the cell connector and the phase change material. In the event that the phase change material is designed to be electrically insulating, it can also be connected directly to a plurality of cell connectors, the heat of the battery being dependent on the Cell connectors are transferred directly to the phase change material, while at the same time the electrically insulating property of the phase change material prevents the phase change material from short-circuiting the poles of the battery cells. If, on the other hand, the phase change material is electrically conductive - or also independently of it - an electrically insulating heat-conducting element can additionally be provided between the cell connector and the phase change material, so that the accumulator has at least one electrically insulating and thermally conductive layer which comprises the cell connector or the accumulator cells thermally connects with the phase change material. The electrical insulation prevents the battery cells from being short-circuited.

It is further proposed that the phase change material have a melting temperature of greater than 25 ° C and less than 80 ° C. In particular, it is proposed that the phase change material have a melting temperature of greater than 40 ° C and less than 60 ° C. The melting temperature is preferably so high that the accumulator reaches an optimal temperature working range before the melting temperature of the phase change material is reached. This can be the case, for example, at approximately 50 ° C. Below the melting temperature, the battery is initially heated as usual during a charging or discharging operation, so that it has the lowest possible internal resistance. Only when the temperature of the battery is so high that the disadvantages of premature aging or reduction of a possible operating time of the battery are no longer outweighed by the advantages of the increased operating temperature, does the phase change material absorb the thermal energy of the battery as heat of fusion and assume, for example, a crystalline one State into a liquid state. It should be mentioned here that other phase transitions can also take place, for example phase transitions between two different crystalline structures or a phase transition between a liquid and a gaseous phase.

It can be provided that the cooling device has several phase change materials with different melting temperatures. By combining different phase change materials, thermal energy can be absorbed when different melting temperatures are reached, so that a desired temperature profile of the battery can be set more precisely. For example, at a lower temperature of 35 ° C, a first phase change material can initially absorb thermal energy, and when a higher temperature of, for example, 50 ° C is reached, the melting temperature of a second phase change material is reached and an even greater amount of thermal energy can be absorbed. Thus, lower temperatures can initially be tolerated to a greater extent by the cooling device, while a plurality of phase change materials can then absorb thermal energy in succession as the temperature of the rechargeable battery increases.

The phase change material can be designed as a film or plate or can be embedded in a film or plate. In particular in the case of a plate-shaped design of the phase change material, the phase change material can be arranged detachably on the accumulator, so that the phase change material can be removed after the accumulator has been charged or discharged and the stored heat can be extinguished. The phase change material can then be reconnected to the accumulator or replaced by a phase change material that is not charged with thermal energy. Due to the interchangeably designed type of phase change material, the accumulator can be used again more quickly. It is not necessary to wait for the phase change.

Furthermore, it can be provided that the accumulator has an array of a plurality of accumulator cells arranged next to and / or one behind the other, an accumulator cell which is arranged in the center of the array and / or has a higher temperature than other accumulator cells of the array Phase change material with a larger layer thickness and / or surface area and / or lower melting temperature than the phase change material of the other battery cells is assigned. The phase change material of the battery can thus vary from battery cell to battery cell. Accumulator cells of the accumulator that heat up more, e.g. those that are in the middle of an array, i.e. Battery packs are arranged, for example, can have a greater material thickness and / or a lower melting temperature. As a result, the phase change material assigned to these accumulator cells can absorb a higher amount of thermal energy or absorb thermal energy even at lower temperatures. The cooling device can thus be adapted particularly individually to the individual requirements of the battery cells.

It is proposed that the phase change material of the cooling device also contacts protective electronics of the accumulator in a heat-conducting manner. According to this configuration, not only the poles of the battery cells, but also the protective electronics are thermally conductively connected to the phase change material, that is to say those components which, in addition to the battery cells, are also get particularly warm. An optimal functioning of the protective electronics can thus be ensured.

An embodiment can further provide that one and / or more battery cells are surrounded by a thermally insulating material, the thermally insulating material surrounding at least one cell peripheral surface of the battery cell. In particular, it can be provided that the thermally insulating material also surrounds the phase change material assigned to the poles. Optionally, additional thermally insulating material can thus be arranged around the cell peripheral surface and possibly also around the phase change material. It can thereby be achieved that the battery cells are initially heated to operating temperature more quickly during a charging or discharging operation and then cooled via their poles when the melting temperature of the phase change material is reached. This leads to faster heating of the battery cell to an optimal operating temperature and targeted dissipation of thermal energy if the battery cell becomes too warm, which is preferably the case when the melting temperature of the phase change material is reached. As proposed, the thermally insulating material can, for example, surround only the peripheral surface of the battery cell or the entire battery.

Instead of connecting the phase change material directly to the poles or the cell connector of the battery cells, possibly with the interposition of an electrically insulating heat-conducting layer, the battery cells can also be mounted separately on a circuit board, the phase change material then being connected to the circuit board in a heat-conducting manner, so that the phase change material contacts the circuit board.

Furthermore, it is possible for the cooling device to have a further cooling element in addition to the phase change material, for example the cooling device of the battery can also have one or more Peltier elements for active cooling of the poles of the battery cells. Furthermore, in addition to the phase change material, it is also possible to convectively cool the accumulator or its accumulator cells, i.e. to apply an air flow. The air flow can be used before and / or during a charging or discharging operation of the rechargeable battery in order, for example, to dissipate an amount of energy already absorbed by the phase change material more quickly. For example, the accumulator or a charger for the accumulator can have a blower. It is also conceivable that a Peltier element further reduces the temperature of the air flow if an ambient temperature is too high for the phase change material to cool down. If the temperature of the accumulator is too low to represent an optimal operating temperature, the temperature can be increased additionally or alternatively by heating elements or a blower can be controlled so that a cooling air flow is reduced. The effect of the phase change material can also be enhanced by using a conventional heat storage device such as polypropylene (PP) or by dissipating heat from the phase change material into the environment via additional heat-conducting materials, for example via heat-conducting elements thermally coupled to the accumulator housing.

In addition to the previously described accumulator, the invention also proposes a tillage device with an electrical consumer, an accumulator with at least one accumulator cell having two electrical poles for providing electrical energy for the electrical consumer and a cooling device for cooling the accumulator cell, the accumulator as is previously described. The accumulator of the soil tillage implement according to the invention thus has a cooling device with a phase change material which is thermally connected to at least one electrical pole of the accumulator cell. The accumulator can be an accumulator permanently connected to the tillage implement, or also an accumulator releasably connected to the tillage implement, which can be removed and exchanged. The further features and advantages of the tillage implement result, as previously described in relation to the accumulator according to the invention.

Figure list

• 1 ein erfindungsgemäßes Bodenbearbeitungsgerät,
• 2 einen Längsschnitt durch ein erfindungsgemäßes Bodenbearbeitungsgerät,
• 3 einen erfindungsgemäßen Akkumulator,
• 4 den Akkumulator gemäß 3 entlang der Schnittlinie IV,
• 5 einen Akkumulator gemäß einer zweiten Ausführungsform,
• 6 einen Akkumulator gemäß einer dritten Ausführungsform,
• 7 einen Akkumulator gemäß einer vierten Ausführungsform.

The invention is explained in more detail below on the basis of exemplary embodiments. Show it:

• 1 a soil tillage implement according to the invention,
• 2nd 2 shows a longitudinal section through a tillage implement according to the invention,
• 3rd an accumulator according to the invention,
• 4th the accumulator according 3rd along the section line IV,
• 5 an accumulator according to a second embodiment,
• 6 an accumulator according to a third embodiment,
• 7 an accumulator according to a fourth embodiment.

Description of the embodiments

The 1 and 2nd show a soil tillage implement 2nd , which is designed as a self-propelled vacuum robot. Although the invention is explained here on the basis of an autonomous cleaning device, the invention can also be used with differently designed tillage devices 2nd Find. Related to the further in the 3rd to 7 shown accumulators 1 , the designs are independent of the type of soil tillage implement 2nd , for the energy supply of the respective accumulator 1 serves.

The tillage implement 2nd according to the 1 and 2nd has a housing 21 , electric motor driven wheels 14 for moving the tillage implement 2nd and at least one tillage element 15 , here for example an electromotive driven cleaning roller, which carries a plurality of bristle tufts for acting on a surface to be cleaned. The tillage element 15 is a suction mouth 19th assigned which via a flow channel 20 from the vacuum of a blower 16 is acted upon. The blower 16 is driven by a motor, which is an electrical consumer 13 of the soil tillage implement 2nd represents. The blower 16 conveys suction material from the surface to be cleaned through the flow channel 20 , the suction material in a suction chamber 17th with a filter 18th is retained, so that only cleaned air to the blower 16 can flow. The blower 16 and possibly also other electrical consumers 13 of the soil tillage implement 2nd is an accumulator for energy supply 1 assigned.

The accumulator 1 is by means of a cooling device 5 chilled. A possible construction of an accumulator 1 with a variety of battery cells 4th is in 3rd shown. The accumulator 1 is designed as a so-called "battery pack", which is an array of a large number of battery cells 4th has, which are arranged side by side and one behind the other. Every accumulator cell 4th is cylindrical, for example, but could also have a different shape. The accumulator cells 4th have a cell peripheral area 12th , which corresponds to the circumferential surface of the cylinder. The accumulator cells have on the front sides 4th about electrical poles 3rd that match their electrical potential with cell connectors 8th are interconnected. There is a negative pole in each case 3rd a first battery cell 4th to a positive pole 3rd a second battery cell 4th connected. The accumulator 1 also has a battery management system 22 on which, among other things, protective electronics 10th includes, among other things, the task of overloading or completely discharging the battery cells 4th to prevent. The cell connector 8th usually consists of metal and is electrically and thermally conductive. As in the 4th to 7 shown, the cell connector sits 8th on both sides of the accumulator 1 away.

The following are exemplary embodiments of an accumulator according to the invention 1 with reference to the 4th to 7 explained in more detail. The figures each show a section through an accumulator 1 .

4th shows the in 3rd shown accumulator 1 along the section line IV. The accumulator 1 has several accumulator cells 4th on. The poles 3rd the accumulator cells 4th are by means of the cell connector 8th both thermally and electrically connected. On the Poles 3rd opposite side of the cell connector 8th there is an electrically insulating heat-conducting element 9 , which provides electrical insulation with the best possible thermal conductivity. For example, there is the heat-conducting element 9 from an electrically non-conductive thermal paste, a thermal oil, silicone oil, zinc oxide or the like. Furthermore, the heat-conducting element 9 can also be a thermal pad made of silicone rubber or polyamide. Basically are for the formation of the heat-conducting element 9 All materials are suitable that have a thermal conductivity of at least 0.5 W / (mK) and at the same time have a specific electrical resistance of at least 10 Ω m. The heat-conducting element preferably has 9 an insulation material with a specific electrical resistance of more than 1 × 10 ⁶ Ω m. The shape and size of the thermal element 9 can match the shape and size of the cell connector 8th be adjusted. The heat-conducting element preferably covers 9 the assigned cell connector 8th complete in each case. On the one of the cell connector 8th opposite side of the heat-conducting element 9 is the thermal element 9 a cooling device 5 assigned which is a phase change material 6 having. The phase change material 6 the cooling device 5 is about the thermal element 9 and the cell connector 8th thermally conductive with the assigned poles 3rd the accumulator cells 4th connected. At the same time is the phase change material 6 through the electrically insulating heat-conducting element 9 opposite the cell connector 8th electrically isolated so that the phase change material 6 which according to the in 4th illustrated embodiment all cell connectors 8th or heat-conducting elements 9 connects the poles 3rd the accumulator cells 4th cannot short circuit. Due to the thermally conductive connection of the poles 3rd of the accumulator 1 to the phase change material 6 the cooling device 5 the heat can be dissipated there, specifically at the poles 3rd where the accumulator cells 4th are usually the warmest. This is an effective and in particular also homogeneous cooling of the entire accumulator 1 possible. In addition to the Poles 3rd can also be used for protection electronics 10th to the cooling device 5 be connected, that is thermally conductive with the phase change material 6 be connected. Optionally, in addition to the poles 3rd also the cell circumference area 12th thermal to the phase change material 6 be connected so that the battery cells 4th not just about their poles 3rd end faces, but rather over the large cell circumference area 12th be cooled. The phase change material 6 , also called PCM or latent heat storage, has for example a specific heat capacity of at least 2 kJ / (kgK). Here is the phase change material 6 For example, sodium acetate trihydrate, which has a melting temperature of 58 ° C. The phase change material 6 takes the heat of the heated battery cells 4th and goes into the liquid state at the melting point of 58 ° C given here as an example. Due to the phase change taking place, the phase change material 6 a large amount of heat energy from the accumulator 1 record, tape. In addition to the proposed sodium acetate, other salts or paraffins can also be used as the storage medium, for example dipotassium hydrogen phosphate hexahydrate. The phase change material 6 nucleating agents are added which cause crystallization of the phase change material 6 can cause to be able to release the stored thermal energy again. Depending on the optimal operating temperature for the battery 1 can be a phase change material 6 can be selected with a higher or lower melting temperature. It should be weighed against each other that a higher temperature of the accumulator 1 optimal performance of the battery 1 ensures, however, the operating life and lifespan of the accumulator from a certain temperature 1 be significantly reduced. Preferably the temperature of the accumulator 1 not be significantly higher than 60 ° C. Accordingly, a phase change material is recommended 6 with a melting temperature in a temperature range of in particular 40 ° C to 60 ° C. When operating the accumulator 1 the battery cells heat up during a charging or discharging process 4th , the phase change material 6 has not yet reached the melting point. The phase change material 6 already absorb thermal energy according to its specific heat capacity, but there is still no phase transition, for example from solid to liquid. Only when the battery cells 4th to the extent that they are heated, namely preferably above a defined optimum operating temperature, the melting temperature is exceeded from here, for example, 58 ° C., so that the phase transition begins and the phase change material 6 can now absorb significantly more thermal energy. The specific phase change enthalpy is compared to the specific heat capacity of the phase change material 6 relatively high, for example, 226 kJ / kg for sodium acetate trihydrate.

5 shows a further embodiment of an accumulator according to the invention 1 . Here are the accumulator cells 4th by means of their poles 3rd again on cell connectors 8th connected. The cell connectors 8th are in direct contact with the phase change material 6 which, according to this embodiment, is designed to be electrically insulating, so that the phase change material 6 which here is all the cell connectors 8th contacted together, no electrical short circuit of the poles 3rd the accumulator cells 4th can bring about. An additional electrically insulating heat conducting element 9 , as before in 4th shown is therefore not necessary.

6 shows a further possible embodiment of an accumulator 1 , the cooling device 5 two different phase change materials 6 , 7 has, which are plate-shaped and, as in 5 already shown, the cell connector 8th contact immediately. Those accumulator cells 4th which are centered within the array of battery cells 4th are arranged from a different phase change material 7 cooled than the battery cells on the outside 4th which is thermally conductive with the phase change material 6 are connected. The battery cells arranged in the middle of the array 4th usually experience higher heating than the external battery cells 4th . Hence the phase change material 7 this centrally arranged accumulator cells 4th designed so that it has a lower melting temperature than the phase change material 6 , which the external battery cells 4th assigned. Alternatively or additionally, it is also possible for the phase change material 7 has a greater layer thickness and / or surface area than the phase change material 6 . For example, the phase change material 7 have a melting point at about 30 ° C while the phase change material 6 begins a phase transition at 58 ° C. The phase change material 7 the lower melting point can be, for example, sodium sulfate decahydrate (Glauber's salt), which has a melting point of 32.5 ° C. A modification of the embodiment according to 6 could also provide that the internal battery cells 4th in heat-conducting contact with two different phase change materials 6 , 7 stand so that the same battery cell 4th Heat on two different phase change materials 6 , 7 can deliver, namely, for example, a first with a lower melting temperature and a second with a higher melting temperature.

7 shows a further embodiment of the invention. According to this embodiment each cell connector 8th the accumulator cells 4th with two different phase change materials 6 , 7 in contact, so that preferably different melting points of the phase change materials 6 , 7 can be used to optimally heat from the battery cells 4th dissipate. In addition, it would also be, as already in 6 shown, possible that only individual battery cells 4th with two different phase change materials 6 , 7 are in heat-conducting contact, for example those that heat up particularly and / or are placed inside the battery cell array. The execution according to 7 also has a thermally insulating material 11 on which the accumulator cells 4th including the cell connector 8th and the cooling device 5 with the phase change materials 6 , 7 surrounds. The thermally insulating material 11 leads to the accumulator cells 4th when starting a charging or discharging operation, warm up faster to an optimal operating temperature and the defined melting points of the phase change materials 6 , 7 can be reached faster. On the one hand, this allows the accumulator to work efficiently 1 can be achieved at the optimal operating temperature, and on the other hand a limitation of the operating temperature of the battery 1 through that of the phase change materials 6 , 7 absorbed thermal energy after reaching the specific melting points.

Reference list

1

accumulator

2nd

Tillage implement

3rd

pole

4th

Accumulator cell

5

Cooling device

6

Phase change material

7

Phase change material

8th

Cell connector

9

Thermal element

10th

Protection electronics

11

thermal insulating material

12th

Cell peripheral area

13

electrical consumer

14

wheel

15

Tillage element

16

fan

17th

Suction chamber

18th

filter

19th

Suction mouth

20

Flow channel

21

casing

22

Battery management system

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015109954 A1 [0004]
• JP 2002291669 A [0005]

Claims (11)

Accumulator (1) with at least one accumulator cell (4) having two electrical poles (3) and a cooling device (5) for cooling the accumulator cell (4), characterized in that the cooling device (5) has a phase change material (6, 7), which is thermally connected to at least one electrical pole (3) of the battery cell (4). Accumulator (1) after Claim 1 , characterized by a cell connector (8) which electrically and thermally conductively connects the electrical poles (3) of at least two battery cells (4) and is thermally conductively connected on the one hand to the electrical poles (3) and on the other to the phase change material (6, 7) . Accumulator (1) after Claim 2 , characterized in that the phase change material (6, 7) makes direct contact with the cell connector (8) and / or in that the phase change material (6, 7) is an electrically insulating heat-conducting element arranged between the cell connector (8) and the phase change material (6, 7) (9) contacted. Accumulator (1) after Claim 1 or 2nd , characterized in that the phase change material (6, 7) is electrically insulating. Accumulator (1) according to one of the preceding claims, characterized in that the phase change material (6, 7) has a melting temperature of greater than 25 ° C and less than 80 ° C, in particular greater than 40 ° C and less than 60 ° C . Accumulator (1) according to one of the preceding claims, characterized in that the cooling device (5) has a plurality of phase change materials (6, 7) with mutually different melting temperatures. Accumulator (1) according to one of the preceding claims, characterized in that the phase change material (6, 7) is designed as a film or plate or that the phase change material is embedded in a film or plate. Accumulator (1) according to one of the preceding claims, characterized in that the accumulator (1) has an array of a plurality of accumulator cells (4) arranged next to and / or one behind the other, an accumulator cell (4) which is centered in the array is arranged and / or has a higher heating than other battery cells (4) of the array, a phase change material (6, 7) with a layer thickness and / or surface area larger than the phase change material (6, 7) of the other battery cells (4) and / or is assigned lower melting temperature. Accumulator (1) according to one of the preceding claims, characterized in that the phase change material (6, 7) of the cooling device (5) also contacts protective electronics (10) of the accumulator (1) in a heat-conducting manner. Accumulator (1) according to one of the preceding claims, characterized in that one and / or more accumulator cells (4) are surrounded by a thermally insulating material (11), the thermally insulating material (11) at least one cell peripheral surface (12) of the accumulator cell (4) surrounds, in particular the thermally insulating material (11) also surrounding the phase change material (6, 7) assigned to the poles (3). Soil cultivation device (2) with an electrical consumer (13), an accumulator (1) with at least one battery cell (4) having two electrical poles (3) for providing electrical energy for the electrical consumer (13) and a cooling device (5) for Cooling of the battery cell (4), characterized in that the battery (1) is designed according to one of the preceding claims, wherein the cooling device (5) comprises a phase change material (6) which is thermally conductive with at least one electrical pole (3) of the battery cell ( 4) is connected.

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