Battery with cooling device

Abstract

The invention relates to a battery (1) having an array of a plurality of battery cells (2, 3) arranged side by side and / or one after the other and a cooling device (4) for cooling the battery cells (2, 3), wherein each battery cell (2, 3) has two electrodes (5), and wherein the cooling device (4) has at least one phase change material element (PCM element) (6) which is connected to at least one electrode (5) of the battery cell (2, 3) in a heat-conducting manner. In order to improve the service life of the battery (1) and to ensure trouble-free operation of the battery (1), it is proposed that the PCM elements are distributed among the battery cells in such a way that during a charging and / or discharging process, a first battery cell which heats up to a greater extent than other battery cells and / or is arranged centrally in the array is cooled to a greater extent than a second battery cell which heats up to a lesser extent than the first battery cell and / or is arranged eccentrically in the array.

Description

Technical Field

[0001] The invention relates to a battery having an array consisting of a plurality of battery cells arranged side by side and / or in sequence and a cooling device for cooling the battery cells, wherein each battery cell has two electrodes and wherein the cooling device has at least one phase change material element (PCM element) which is thermally conductively connected to at least one electrode of the battery cell.

[0002] Furthermore, the invention relates to a floor treatment device, in particular a cleaning device, having at least one electrical consumer and a battery for supplying electrical energy to the electrical consumer. Background Art

[0003] Batteries are well known in the prior art. They have one or more battery cells, which are usually surrounded by a battery housing, which also contains a battery management system for monitoring, regulating and protecting the battery, for example, in order to detect the charge state of the battery and to avoid overcharging or complete discharge of the battery cells.

[0004] In the prior art, for example, DE 10 2015 109 954 A1 discloses a battery for use in a cleaning device, wherein the suction air flow generated by the fan of the cleaning device is directed through the battery housing and in the process the suction air flow is passed over the outer circumference of the battery cells. This type of cooling of the battery is therefore dependent on the suction operation of the cleaning device.

[0005] Furthermore, batteries that are cooled by means of a phase change material are known, for example from patent documents US 2011 / 0070474 A1 and US 2017 / 0077487 A1, wherein the phase change material is connected to at least one electrode of the battery cell in a heat-conducting manner.

[0006] In this case, the known cooling device cools all battery cells equally, regardless of their position in the array of battery cells. However, cells located in the center of the array heat up more than battery cells located in the edge area of ​​the array due to the proximity of other hot battery cells. This results in an uneven temperature distribution within the entire array. This in turn leads to uneven aging of the cells and uneven performance of the cells. Since the battery protection circuit cuts off the power supply when the hottest battery cell heats up above a defined temperature, the battery is shut down prematurely, even though, for example, a number of battery cells are still within the permitted range. Summary of the invention

[0007] Based on the above prior art, the technical problem to be solved by the present invention is to prevent the battery from being shut down too early for most of the battery cells of the battery. In addition, the service life and performance of the battery are to be improved.

[0008] In order to solve the above technical problem, it is proposed that phase change material elements (PCM elements) are distributed to the battery cells in such a way that a first battery cell (2) which is heated to a greater extent than other battery cells and / or is arranged centrally in the array is cooled to a greater extent than a second battery cell which is heated to a lesser extent than the first battery cell and / or is arranged eccentrically in the array during a charging process and / or a discharging process, wherein the first battery cell is directly connected to a second battery cell which is not directly adjacent to the first battery cell by means of a heat conducting element.

[0009] According to the invention, the arrangement and construction of the cooling device are improved here compared to the prior art in that the PCM material is individually distributed to the battery cells in such a way that the distribution of the PCM material is adapted to the heat generation of the respective battery cells. Therefore, the battery cells are individually cooled according to their position and / or heat generation, so that the same temperature exists in the battery array regardless of the respective position in the battery. Therefore, the cooling device is preferably composed of a plurality of PCM elements, which are respectively assigned to a plurality of battery cells and cool each or a plurality of battery cells individually according to their heat release. For this purpose, the PCM element of the first battery cell is preferably designed differently from the PCM element assigned to the second battery cell. According to the invention, the battery cell arranged centrally in the array can be connected thermally to the battery cell arranged eccentrically, or the battery cell that heats up more than the other battery cells can be connected thermally to the battery cell with a lower temperature, although they are not directly adjacent in the array. The proposed heat-conducting element is also preferably connected thermally to the PCM element in order to transfer the thermal energy of the battery cell connected to the heat-conducting element to the PCM material. The first, hotter battery cell is therefore cooled on the one hand by the second, cooler battery cell which is connected in a heat-conducting manner and on the other hand by the PCM element which is connected to the heat-conducting element and / or directly to the first battery cell. The electrically insulating material of the heat-conducting element prevents the heat-conducting element from short-circuiting the connected battery cells. The heat-conducting element is preferably made of a plastic which has both heat-conducting and electrical-insulating properties. A uniform temperature distribution over the battery array is achieved by the proposed direct (i.e. without an additional heat conductor arranged in between) heat-conducting connection between the cell which requires more cooling and the cell which requires less cooling.

[0010] According to a further embodiment, it is proposed that the PCM element assigned to the first battery cell has a higher thermal conductivity than the PCM element of the second battery cell. Thus, the battery cell that needs to be cooled more than the other battery cells is assigned a PCM element that has a higher thermal conductivity than the other PCM elements of the cooling device. The higher the thermal conductivity of the PCM material, the lower the thermal insulation properties of the material, thereby also helping to ensure that heat is released to a greater extent from particularly hot battery cells. In addition, it can be provided that the cooling device has a plurality of PCM elements, which have different phase change materials with different phase change temperatures. By combining different phase change materials, thermal energy can be absorbed more intensively at different phase change temperatures, so that the desired temperature curve of the battery can be adjusted more accurately. For example, at a lower temperature of 35° C., the first PCM material can absorb thermal energy first, wherein when a higher temperature of, for example, 50° C. is reached, the phase change temperature of the second PCM material is reached and more thermal energy can be absorbed. Thus, lower temperatures can initially be tolerated to a greater extent by the cooling device, while in the case of a further increase in the temperature of the battery, a plurality of phase change materials can successively absorb latent heat.

[0011] According to another embodiment of the present invention, it can be provided that the first battery cell has a greater spatial distance relative to adjacent battery cells than the second battery cell. Therefore, battery cells that are heated more or arranged centrally in the battery have a greater distance relative to adjacent battery cells than those battery cells that are heated to a lesser extent (or heated up) or are located, for example, in the edge area of ​​the cell array. The convection component of the heat transfer can be achieved or increased by the larger spatial distance between the cells. As a result, a larger free space is generated between adjacent battery cells, through which, for example, an air flow can be guided. This also promotes the cooling function of the cooling device. In addition, it can also be provided that the battery cells are coated with PCM material using a larger spatial distance, that is, the outer peripheral wall of the battery cells is contacted with PCM material. In this case, the distance between the battery cells can be designed to be correspondingly large so that the PCM material can be arranged in the required amount.

[0012] Depending on the type of phase change material of the PCM element, a certain heat transfer from the associated battery cell to the PCM element is controlled. Each phase change material has a characteristic phase change temperature, such as a melting temperature, which represents the transition between a first state and a second state of the phase change material. When the phase change material is heated to a temperature, such as a temperature above its material-specific melting temperature, the phase change material absorbs the energy of the battery cell and changes from a first aggregate state, such as a crystalline state, to a second aggregate state, such as a liquid state. Due to the heat absorbed in this process, the phase change material cools the battery cell that is thermally conductive to the PCM element, especially through the poles and / or the outer peripheral surface. The phase change material can also be present as a PCM-polymer composition, wherein the polymer used for the composition can be, for example, polyethylene, especially low-density polyethylene (LDPE) or polymethyl methacrylate (PMMA). Such compositions are advantageously low-leakage or non-leakage, have high mechanical strength and are resistant to thermal deformation, so that such compositions can be used, for example, as sheet materials. In addition, such compositions also have improved thermal conductivity. The phase change material of the cooling device is preferably a phase change material with a high specific heat capacity greater than 2kJ / (kgK). The advantage of this phase change material is that heat energy can be stored for a long time with low loss. The latent heat of melting absorbed by the phase change material after reaching the melting temperature is, for example, significantly greater than the heat energy that can be stored due to the specific heat capacity of the phase change material (in the absence of phase change effect). When the phase change material is loaded with heat energy, the material is melted, for example, and a lot of heat energy can be absorbed in the process. The stored heat energy is then released when the phase change material solidifies, wherein a large amount of heat energy previously absorbed is released to the environment as solidification heat. In a small temperature range predetermined by the melting temperature or solidification temperature of the phase change material, a large amount of heat energy is stored in a relatively small mass. In addition, due to the use of the metastable state of the phase change material, heat energy can be stored without insulation and with very little loss. For example, all phase change materials whose melting temperature is in the typical temperature range for battery operation can be used as phase change materials for the cooling device of the battery. It can be particularly preferably noted here that it is desirable to heat the battery to a certain extent at the beginning of the charging or discharging operation of the battery so that the battery can be charged or discharged within the optimal operating temperature range. The battery usually has the best performance at a higher temperature, such as 50°C or higher, and the service life is shortened due to the high temperature. In order to achieve the optimal operating temperature range in the aforementioned sense, the battery should be heated as quickly as possible. Therefore, it is not desirable to cool the battery immediately by the cooling device at the beginning of the charging or discharging operation, which will delay the reaching of the optimal operating temperature range and thus reduce the efficiency of the battery. The phase change material of the cooling device advantageously ensures that the battery can be heated first to the optimal operating temperature range and absorbs the heat of the battery intensified when the phase change temperature of the phase change material is reached. In this case, it is appropriate that the phase change temperature of the phase change material is just above the optimal operating temperature range of the battery.Furthermore, a uniform temperature distribution within the array of battery cells can be promoted by selecting different phase change materials for the multiple PCM elements of the cooling device. In contrast to the convective cooling of the battery cells used in the prior art, the PCM elements of the cooling device according to the invention are not activated before the phase change temperature is reached. Only when the phase change temperature is reached does the phase change material begin to undergo a phase change and extract thermal energy from the battery cell until the maximum thermal energy absorption of the phase change material is reached. The phase change material is advantageously connected to the battery cell in such a way that gas can escape from the battery cell. Accordingly, the valve of the battery cell is opened in order to prevent so-called "thermal runaway". Alternatively, the phase change material can also completely cover the valve of the battery cell, as long as a predetermined breaking point in the phase change material is retained, which breaks under mechanical load or temperature increase associated with the escape of gas and allows the gas to escape from the battery cell unhindered. The battery according to the invention can be, for example, a lithium-ion battery or also a so-called post-lithium-ion battery using technologies such as lithium-sulfur batteries. Other battery types can also benefit from the invention.

[0013] The phase change material preferably has a phase change temperature greater than 25°C and less than 80°C. It is particularly recommended that the phase change material has a phase change temperature greater than 40°C and less than 60°C. The phase change temperature is preferably so high that the battery reaches the optimal operating temperature range before reaching the phase change temperature of the phase change material. This may be the case, for example, at about 50°C. Below the phase change temperature, the battery is first heated as usual during charging or discharging operation, so that the battery has the smallest possible internal resistance. Only when the temperature of the battery is so high that the disadvantages of premature aging of the battery or possible reduction in operating time are no longer outweighed by the advantages of the increased operating temperature, the phase change material absorbs the thermal energy of the battery and, for example, changes from a crystalline state to a liquid state. It should be noted that different phase changes may occur, such as a phase change from a solid to a liquid state, a phase change between two different crystal structures, or a phase change between a liquid phase and a gas phase.

[0014] The PCM element can be designed as a film or a plate or can be embedded in a film or a plate. In particular, when the PCM element is designed in a plate shape, the PCM element can be detachably arranged on the battery, so that the PCM element can be taken out after the charging process or discharging process of the battery and the stored heat can be removed. Thereafter, the PCM element can be reconnected to the battery or replaced by a PCM element that is not loaded with heat energy. The battery can be reused more quickly by designing the PCM element as a replaceable type. It is not necessary to wait for a phase change in the PCM element before the battery can be charged or discharged again.

[0015] It is further proposed that the first battery cell is provided with a PCM element which has a greater layer thickness and / or a greater surface area and / or a lower phase transition temperature than the PCM element of the second battery cell. The PCM elements of the battery cooling device can therefore differ from battery cell to battery cell. Battery cells that are heated more, for example battery cells arranged in the center of the array, can, for example, have a PCM element which has a greater PCM material thickness and / or a greater contact area with the battery cell and / or a lower phase transition temperature. As a result, the phase change material assigned to these battery cells can absorb individually adjusted thermal energy and absorb latent heat at a lower temperature. The cooling device can therefore be particularly individually adapted to the requirements of the respective battery cell. In particular, the proportionate contact area of ​​the PCM element with the outer circumference of the battery cell and / or with the surface of the pole can be adjusted, wherein a larger contact area between the PCM element and the respective battery cell can achieve a stronger cooling of the battery cell. The thickness of the PCM element can also improve the cooling effect, because more PCM material also correspondingly achieves a stronger cooling of the battery cell. Furthermore, the proposed lower phase change temperature for battery cells requiring greater cooling makes it possible for the cooling effect of the PCM material to begin earlier during the heating of the battery cells.

[0016] It is further proposed that the battery has a cell connector which electrically and thermally connects the electrodes of at least two battery cells to one another and which is thermally connected to the electrodes on the one hand and to the PCM element on the other hand. In this embodiment, the electrodes of the battery cells are not directly connected to the PCM element of the cooling device. Instead, the electrodes are firstly coupled thermally and electrically to the cell connector, wherein the cell connector is then in turn connected to the phase change material of the cooling device which absorbs the thermal energy of the battery cells.

[0017] In particular, it is proposed that the PCM element directly contacts the cell connector or that the PCM element contacts an electrically insulating, heat-conducting element which is additionally arranged between the cell connector and the PCM element. In the case where the phase change material itself is designed to be electrically insulating, the phase change material can be directly connected to the cell connector, wherein the heat of the battery is transferred directly from the cell connector to the phase change material, while the PCM element is prevented from short-circuiting the poles of the battery cell by the electrically insulating properties of the phase change material. Conversely, if the phase change material is electrically conductive or whether it is electrically conductive or not, an electrically insulating, heat-conducting element can be additionally arranged between the cell connector and the PCM element, so that the battery has at least one electrically insulating and heat-conducting layer which connects the cell connector or the battery cell to the phase change material in a heat-conducting manner. Short-circuiting of the battery cells is prevented by electrical insulation.

[0018] In addition to the above-mentioned battery, the present invention also proposes a ground treatment device, in particular a cleaning device, which has at least one electrical consumer and a battery for providing electrical energy to the electrical consumer, wherein the battery is designed as described above. Therefore, the battery of the ground treatment device according to the present invention has a cooling device with at least one PCM element, which is thermally connected to at least one battery cell, which heats up more than other battery cells in the array or is arranged centrally in the array. The battery can be a battery that is non-detachably connected to the ground treatment device, or it can also be a battery that is detachably connected to the ground treatment device, which can be removed and replaced. The ground treatment device can be an autonomously moving automatic ground treatment device, such as a cleaning robot. However, alternatively, the ground treatment device can also be a ground treatment device driven by a battery and manually guided. The ground treatment device in the sense of the present invention is, for example, a cleaning device, but it can also be a care device, such as a polishing device or a waxing device. In the sense of the present invention, the ground treatment device also includes, for example, a mowing device. Other features and advantages of the ground treatment device according to the present invention are as described above with respect to the battery according to the present invention. To avoid repetition, reference is made to the previous description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described in detail below based on embodiments. In the accompanying drawings:

[0020] Figure 1 A ground processing device according to the present invention is shown;

[0021] Figure 2 A longitudinal section through a ground processing device according to the present invention is shown;

[0022] Figure 3 An exemplary structure of a battery is shown;

[0023] Figure 4 A schematic sectional view of a battery according to a first embodiment of the present invention is shown;

[0024] Figure 5 Show according to Figure 4 A top view of a battery;

[0025] Figure 6 A schematic top view of a battery according to a further embodiment is shown. DETAILED DESCRIPTION

[0026] Figure 1 and Figure 2A floor treatment device 9 designed as an autonomously moving vacuum robot is shown. Although the invention is explained here with reference to an automatic cleaning device, the invention can also be applied to a floor treatment device 9 that is manually guided by a user. Figures 2 to 6 The battery 1 shown in FIG. 1 is independent of the type of ground processing device 9 for which the corresponding battery 1 is used to supply energy.

[0027] Here, according to Figure 1 and Figure 2 The exemplary floor treatment device 9 of has motor-driven wheels 15 for moving the floor treatment device 9 and at least one floor treatment element 14, here for example a motor-driven cleaning roller, which has a plurality of bristle bundles for acting on the surface to be treated. The floor treatment element 14 is associated with a suction opening 19, which is acted upon by the negative pressure of a fan 16 via a flow channel 20. The fan 16 is driven by a motor, which is an electrical consumer 10 of the floor treatment device 9. The fan 16 conveys the suction material from the surface to be treated through the flow channel 20, wherein the suction material is blocked by a filter element 18 in a suction material chamber 17, so that only cleaned air can flow to the fan 16. The fan 16 of the floor treatment device 9 and, if necessary, other electrical consumers 10 are provided with a battery 1 for energy supply.

[0028] The battery 1 is cooled by means of a cooling device 4. Figure 3 A possible structure of a battery 1 having a plurality of battery cells 2, 3 is shown in the figure. The battery 1 is designed as a so-called "battery pack", which has an array consisting of a plurality of battery cells 2, 3, which are arranged side by side or one after the other. Here, each battery cell 2, 3 is designed as a cylinder, for example, but can also have other different shapes. The battery cells 2, 3 have a cell outer circumference 12, which corresponds to the cylindrical outer circumference here. The battery cells 2, 3 have electrodes 5 on the cell end sides 13, and the electrodes 5 are connected to each other via cell connectors 7 (see Figure 4 ) interconnection. Here, the negative pole 5 of the battery cells 2, 3 is connected to the positive pole 5 of the adjacent battery cells 2, 3. The cell connector 7 is usually made of metal and is electrically and thermally conductive. Figure 4 As shown in FIG. 1 , the cell connectors 7 protrude on both sides of the battery 1 . The battery 1 also has a battery management system 11 which essentially contains a protection circuit 22 which, among other functions, has the task of protecting the battery cells 2 , 3 from overcharging or complete discharge.

[0029] The following reference Figures 4 to 6 An exemplary embodiment of a battery 1 according to the present invention is explained in more detail.

[0030] Figure 4A schematic cross-sectional view of a row of a battery 1 according to a first embodiment is shown. The battery 1 has a plurality of battery cells 2, 3, wherein here only a single row of an array consisting of a plurality of battery cells 2, 3 arranged side by side and in succession is shown by way of example. Specifically, the battery 1 comprises a first battery cell 2 which is arranged centrally in the array and which is heated relatively more during operation of the battery 1, and a second battery cell 3 which is arranged eccentrically in the array and which here belongs to the edge region of the battery 1. The second battery cell 3 is heated or warmed to a lesser extent than the first battery cell 2. The battery cells 2, 3 are arranged at a distance d1 equidistant from each other. The poles 5 of the battery cells 2, 3 are connected both thermally and electrically by means of a cell connector 7. On the side of the cell connector 7 facing away from the poles 5 there is a cooling device 4 which here has a plurality of PCM elements 6. These PCM elements 6 are made of an electrically insulating material so that the battery cells 2, 3 cannot be short-circuited with each other. The PCM elements 6 of the first battery cell 2 here have, by way of example, a different phase change material than the second battery cell 3. It is proposed here that the PCM elements 6 of the first battery cell 2 have a lower phase change temperature than the PCM elements 6 of the second battery cell 3, so that when the battery 1 is heated up, the thermal energy can be discharged earlier from the first battery cell 2 which is heated up more. Although not shown here, the PCM elements 6 of the first battery cell 2 can alternatively also have a larger contact area or a greater thickness (more PCM material) than the PCM elements 6 of the second battery cell 3. In addition, according to Figure 4 and Figure 5 In the example of , the two innermost first battery cells 2 are also thermally connected to each of the outermost second battery cells 3 by means of a heat-conducting element 8. As a result, the two innermost first battery cells 2 are cooled both by the outermost second battery cells 3 and by the associated PCM element 6. The heat-conducting element 8 is designed to be electrically insulating so that the heat-conductingly connected poles 5 of the first battery cell 2 and the second battery cell 3 are not short-circuited. The heat-conducting element 8 can be manufactured, for example, as a film or plate made of silicone rubber or polyamide. In principle, all materials having a thermal conductivity of at least 0.5 W / (mK) and at the same time a specific resistance of at least 10 Ωm are suitable for constructing the heat-conducting element 8. Preferably, the heat-conducting element 8 has a specific resistance greater than 1 x 10 6Ωm insulating material. The shape and size of the heat-conducting element 8 can be adapted to the distance between the first battery cell 2 and the second battery cell 3 in the battery 1, wherein the heat-conducting element 8 preferably does not contact the battery cells 2 and 3 located in the middle. However, according to other embodiments, it can also be provided that the other first battery cell 2 arranged in the middle is also connected to the second battery cell 3 located outside by the heat-conducting element 8 in a heat-conducting manner. Although not shown, a heat-conducting element 8 can also be arranged between the cell connector 7 and the PCM element 6, which has electrical insulation properties and also ensures heat conduction between the poles 5 of the battery cells 2 and 3 and the PCM element 6. The PCM element 6 is insulated relative to the cell connector 7 by the electrical insulation provided thereby, so that the poles 5 of the battery cells 2 and 3 cannot be short-circuited. In this case, the phase change material of the PCM element 6 can be electrically conductive. The heat can be dissipated in a targeted manner by the heat-conducting connection of the phase change material of the PCM element 6 of the cooling device 4 with the pole 5 of the battery 1. Therefore, efficient and especially uniform cooling of the entire battery 1 can be achieved. In addition to the poles 5, for example, the protective circuit 22 can also be connected to the cooling device 4, that is, thermally connected to the PCM element 6. Optionally, in addition to the poles 5, the cell outer surface 12 can also be thermally connected to the PCM element 6, so that the battery cells 2, 3 are cooled not only via the cell end faces 13, but also via the generally larger cell outer surface 12.

[0031] The phase change material of the PCM element 6 assigned to the second external battery cell 3 has, for example, a specific heat capacity of at least 2 kJ / (kg·K). The phase change material is, for example, sodium acetate trihydrate, which has a melting temperature of 58° C. The phase change material absorbs the heat of the heated battery cell 3 and in the process changes to a liquid state at a melting point of 58° C. given here as an example. Due to the phase change, the phase change material can absorb a large amount of thermal energy from the battery cell 3. In addition to the proposed sodium acetate trihydrate, other different salts or paraffins, such as dipotassium hydrogen phosphate hexahydrate, can also be used as heat storage media. The phase change material of the PCM element 6 assigned to the first battery cell 2 preferably has a lower phase change temperature than the phase change material of the PCM element assigned to the second external battery cell 3, so that more heat can be removed from the first battery cell 2 than from the second battery cell 3. For example, the first battery cell 2 can be equipped with a phase change material with a phase change temperature between 40° C. and 50° C.

[0032] Phase change materials are usually added with nucleating agents, which can cause the crystallization of the phase change material so that the stored thermal energy can be released again. Depending on the optimal operating temperature of the battery 1, a phase change material with a higher or lower phase change temperature can be selected. What needs to be balanced here is that a higher temperature of the battery 1 ensures the best performance of the battery 1, but from a certain temperature, the operating time and service life of the battery 1 may be significantly reduced. Preferably, the temperature of the battery 1 should not be significantly higher than 60°C. Accordingly, phase change materials with a phase change temperature in the temperature range of 40°C to 60°C are suitable. During the operation of the battery 1, during the charging process or the discharging process, the battery cells 2, 3 heat up, wherein the phase change material of the PCM element 6 has not yet reached the phase change temperature at first. Here, the phase change material 6 can absorb thermal energy in accordance with its specific heat capacity without a phase change, for example, from solid to liquid. When the battery cells 2, 3 are heated to a certain extent, that is, preferably exceeding the defined optimal operating temperature of the battery 1, the phase change temperature of the phase change material associated with the first battery cell 2 is exceeded, so that the phase change begins and the phase change material can absorb significantly more thermal energy. When the second battery cell 3 also reaches the specific phase change temperature of its associated phase change material at a later time, the second battery cell 3 is also cooled by the corresponding PCM element 6.

[0033] If in addition according to Figure 5 , the first battery cell 2 in the middle is directly connected to only one second battery cell 3, wherein the second battery cell 3 is an edge cell of the array of batteries 1. The battery cells 2, 3 arranged in the middle are not in contact, at least not in thermal contact. However, different embodiments can also provide that a plurality of non-directly adjacent battery cells 2, 3 are connected via such a thermally conductive element 8.

[0034] It is important that the inner battery cells 2 which heat up more during the charging and / or discharging process are cooled more than the outer battery cells 3 which heat up less in comparison. Figure 4 and Figure 5 Many other embodiments are conceivable, in which the battery cells 2, 3 can, for example, have different distances d1, d2 relative to each other, and / or the PCM elements 6 can have different thermal conductivities, wherein the PCM element 6 associated with the first battery cell 2 preferably has a higher thermal conductivity.

[0035] Figure 6A partial top view of a battery 1 according to a further possible embodiment is shown, which has an array of a plurality of first battery cells 2 and second battery cells 3. The first battery cells 2 and the second battery cells 3 have different distances d1, d2 relative to one another, wherein a battery cell 2 arranged centrally in the array has a greater distance d2 relative to the other battery cells 2, 3 than, for example, a second battery cell 3 arranged eccentrically. The schematic diagram shown shows only a partial area of ​​the battery 1. The outer second battery cell 3 shown here can of course be surrounded by further second battery cells 3. The different distances d1, d2 are present here, for example, in two different orientations of the array.

[0036] In this embodiment, a PCM element 6 is also provided which is in contact with the cell outer circumference 12 of the battery cell 2 or 3, although this is not necessary and is only exemplary. Here, for example, the first battery cell 2 among the five has a PCM element 6 with a greater material thickness than the remaining battery cells 3. With this design, the first battery cell 2 is cooled more than the second battery cell 3, that is, on the one hand, because the PCM element 6 is thicker and therefore has more phase change material, and on the other hand, because the distance d2 to the adjacent battery cells 2, 3 is greater, so that in addition to cooling by means of the PCM element 6, convection cooling can also be performed through the larger free space in the array.

[0037] The embodiments shown here are merely exemplary for the present invention. Of course, subcombinations of the described variants are also possible.

[0038] Reference numerals list

[0039] 1 Battery

[0040] 2 First battery unit

[0041] 3 Second battery unit

[0042] 4 Cooling device

[0043] 5-pole

[0044] 6 PCM components

[0045] 7-unit connector

[0046] 8 Thermal Conductive Components

[0047] 9 Ground handling equipment

[0048] 10 Electrical consumption

[0049] 11 Battery Management System

[0050] 12 Unit outer surface

[0051] 13 Unit end side

[0052] 14 Ground handling elements

[0053] 15 Wheels

[0054] 16 Fan

[0055] 17 Suction chamber

[0056] 18 Filter element

[0057] 19 Suction port

[0058] 20 Flow channels

[0059] 21 Shell

[0060] 22 Protection circuit

[0061] d1 distance

[0062] d2 distance

Claims

1. A battery (1) comprising an array of a plurality of battery cells (2, 3) arranged side by side and / or in sequence and a cooling device (4) for cooling the battery cells (2, 3), wherein: Each battery cell (2, 3) has two electrodes (5), and the cooling device (4) has at least one phase change material element (6) which is connected to at least one electrode (5) of the battery cell (2, 3) in a heat-conducting manner, characterized in that the phase change material elements (6) are assigned to the battery cells (2, 3) in such a way that during a charging process and / or a discharging process, a first battery cell (2) which is heated to a greater extent than other battery cells (2, 3) and / or is arranged centrally in the array is cooled to a greater extent than a second battery cell (3) which is heated to a lesser extent than the first battery cell and / or is arranged eccentrically in the array, wherein the first battery cell (2) is directly connected to a second battery cell (3) which is not directly adjacent to the first battery cell (2) by means of a heat-conducting element (8).

2. The battery (1) according to claim 1, characterized in that The first battery cell (2) is provided with a phase change material element (6) which has a greater layer thickness and / or a greater surface area and / or a lower phase change temperature than the phase change material element (6) of the second battery cell (3).

3. The battery (1) according to claim 1, characterized in that The outer peripheral wall of the battery cells (2, 3) is in direct contact with the phase change material element (6).

4. The battery (1) according to claim 1, characterized in that A cell connector (7) is provided, which connects the electrodes (5) of at least two battery cells (2, 3) to each other in an electrically and thermally conductive manner and is thermally connected to the electrodes (5) on the one hand and to the phase change material element (6) on the other hand.

5. The battery (1) according to claim 4, characterized in that The phase change material element (6) directly contacts the cell connector (7), or the phase change material element (6) contacts an electrically insulating heat conductive element (8) arranged between the cell connector (7) and the phase change material element (6).

6. The battery (1) according to claim 1, characterized in that The phase change material element (6) is designed to be electrically insulating.

7. A battery (1) comprising an array of a plurality of battery cells (2, 3) arranged side by side and / or in sequence and a cooling device (4) for cooling the battery cells (2, 3), wherein: Each battery cell (2, 3) has two electrodes (5), and the cooling device (4) has at least one phase change material element (6) which is connected to at least one electrode (5) of the battery cell (2, 3) in a thermally conductive manner, characterized in that the phase change material elements (6) are assigned to the battery cells (2, 3) in such a way that during a charging process and / or a discharging process, a first battery cell (2) which is heated to a greater extent than other battery cells (2, 3) and / or is arranged centrally in the array is cooled to a greater extent than a second battery cell (3) which is heated to a lesser extent than the first battery cell and / or is arranged eccentrically in the array, wherein the phase change material element (6) assigned to the first battery cell (2) has a higher thermal conductivity than the phase change material element (6) of the second battery cell.

8. The battery (1) according to claim 7, characterized in that The first battery cell (2) is directly connected to a second battery cell (3) which is not directly adjacent to the first battery cell (2) by means of a heat conducting element (8).

9. The battery (1) according to claim 7, characterized in that The first battery cell (2) is provided with a phase change material element (6) which has a greater layer thickness and / or a greater surface area and / or a lower phase change temperature than the phase change material element (6) of the second battery cell (3).

10. The battery (1) according to claim 7, characterized in that The outer peripheral wall of the battery cells (2, 3) is in direct contact with the phase change material element (6).

11. The battery (1) according to claim 7, characterized in that A cell connector (7) is provided, which connects the electrodes (5) of at least two battery cells (2, 3) to each other in an electrically and thermally conductive manner and is thermally connected to the electrodes (5) on the one hand and to the phase change material element (6) on the other hand.

12. The battery (1) according to claim 11, characterized in that The phase change material element (6) directly contacts the cell connector (7), or the phase change material element (6) contacts an electrically insulating heat conductive element (8) arranged between the cell connector (7) and the phase change material element (6).

13. The battery (1) according to claim 7, characterized in that The phase change material element (6) is designed to be electrically insulating.

14. A battery (1) comprising an array of a plurality of battery cells (2, 3) arranged side by side and / or in sequence and a cooling device (4) for cooling the battery cells (2, 3), wherein: Each battery cell (2, 3) has two electrodes (5), and the cooling device (4) has at least one phase change material element (6) which is connected to at least one electrode (5) of the battery cell (2, 3) in a heat-conducting manner, characterized in that the phase change material elements (6) are assigned to the battery cells (2, 3) in such a way that a first battery cell (2) which is heated to a greater extent than other battery cells (2, 3) and / or which is arranged centrally in the array is cooled to a greater extent during a charging process and / or a discharging process than a second battery cell (3) which is heated to a lesser extent than the first battery cell and / or which is arranged eccentrically in the array, wherein the first battery cell (2) has a greater spatial distance (d2) from adjacent battery cells (2, 3) than the second battery cell (3).

15. The battery (1) according to claim 14, characterized in that The first battery cell (2) is directly connected to a second battery cell (3) which is not directly adjacent to the first battery cell (2) by means of a heat conducting element (8), or the phase change material element (6) provided to the first battery cell (2) has a higher thermal conductivity than the phase change material element (6) of the second battery cell.

16. The battery (1) according to claim 14, characterized in that The first battery cell (2) is provided with a phase change material element (6) which has a greater layer thickness and / or a greater surface area and / or a lower phase change temperature than the phase change material element (6) of the second battery cell (3).

17. The battery (1) according to claim 14, characterized in that The outer peripheral wall of the battery cells (2, 3) is in direct contact with the phase change material element (6).

18. The battery (1) according to claim 14, characterized in that A cell connector (7) is provided, which connects the electrodes (5) of at least two battery cells (2, 3) to each other in an electrically and thermally conductive manner and is thermally connected to the electrodes (5) on the one hand and to the phase change material element (6) on the other hand.

19. The battery (1) according to claim 18, characterized in that The phase change material element (6) directly contacts the cell connector (7), or the phase change material element (6) contacts an electrically insulating heat conductive element (8) arranged between the cell connector (7) and the phase change material element (6).

20. The battery (1) according to claim 14, characterized in that The phase change material element (6) is designed to be electrically insulating.

21. A ground treatment device (9) having at least one electrical consumer (10) and a battery (1) for supplying electrical energy to the electrical consumer (10), characterized in that: The battery ( 1 ) is designed according to any one of the preceding claims 1 to 20 .

22. The ground processing device (9) according to claim 21, characterized in that The floor treatment equipment (9) is a cleaning equipment.

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