Energy storage device for a motor vehicle

Abstract

The invention relates to a method for producing an energy storage device having a plurality of energy storage cells which are accommodated in an energy storage housing arrangement, whereby a temperature control region is formed between at least two rows of energy storage cells, the invention relates to a method for controlling the temperature of an energy storage device in a temperature control region of an energy storage device, and the energy storage device has an energy storage device temperature control device having at least one temperature control channel, the temperature control channel being arranged in the temperature control region, comprising the following steps: arranging a plurality of energy storage cells in an energy storage housing arrangement into at least two energy storage cell rows; introducing a flexible temperature control channel hose into the temperature control region; introducing a temperature control channel overpressure into the temperature control channel hose in order to form a temperature control channel; introducing an energy storage filling material into the energy storage housing device, and thereby enclosing the temperature control channel at least partially or completely by the energy storage filling material.

Description

Field of the Invention

[0001] The present invention relates to a method for manufacturing an energy storage device for a motor vehicle and an energy storage device manufactured by means of this method. Background Art

[0002] From DE102020119450A1, a battery module with condensation and propagation protection, a traction battery with such a battery module, and an electrified motor vehicle with such a traction battery are known.

[0003] Next, the present invention will be explained by means of an energy storage device configured as a traction battery for an electrified motor vehicle, which should not be construed as limiting the present invention to such an application. In an electrified motor vehicle, the traction battery is an important cost driver on the premise of a corresponding electric driving range, so that a cost-appropriate manufacture of such an energy storage device is advantageous. In addition, such an energy storage device has a relatively high weight compared to other components of an electrified motor vehicle.

[0004] In addition to components for storing energy in chemical bond form (so-called energy storage battery cells), the energy storage device also has other components, especially for temperature control of these energy storage battery cells. The present invention focuses on the temperature control function, or the manufacture of a structure for providing such a function. As is well known, temperature control channels, that is, components for guiding a temperature control medium to heat or cool energy storage battery cells, are constructed as "rigid" components in such an energy storage device. Here, such a rigid component should be understood as a metal component or a plastic component, which is arranged such that its shape does not change significantly either during the manufacture of the energy storage device or during the planned operation of the energy storage device. Therefore, the temperature control channels can be formed by so-called cooling serpentine tubes, which are brought into their shape by a forming method before being placed into the energy storage device. Such formed cooling serpentine tubes are then placed into the energy storage device as rigid components. Thus, the rigid components for temperature control have a high weight. In addition, each component, especially components of a so-called energy storage module (energy storage battery cells and components for cooling them), must be dimensionally accurate, because due to the large number of components, deviations occur in the geometric extension dimensions of the energy storage module. Summary of the Invention

[0005] Against this background, the object of the present invention is to provide a method for manufacturing an improved energy storage device, which object is solved by the method according to claim 1 and by an energy storage device manufactured by means of this method according to claim 6. Preferred improvements of the present invention are respectively the technical solutions of the dependent claims.

[0006] The present invention provides a method for manufacturing an energy storage device, wherein the energy storage device has a plurality of energy storage battery cells. In the context of the present invention, an energy storage device should be understood as a device for receiving and outputting electric power in the form of current and voltage and for storing this electric power in the form of chemical binding energy, and such a device can also be understood as a so-called secondary battery. Preferably, such an energy storage device is configured as a so-called traction battery for an electrified motor vehicle, the traction battery having an energy storage module that includes energy storage battery cells and a temperature control device for cooling and / or heating these energy storage battery cells, and the traction battery having an energy storage housing device for accommodating the energy storage module. Further preferably, these energy storage battery cells of the energy storage device are configured as battery-type energy storage battery cells, which may generate waste heat during their discharge or charge, and further preferably, these energy storage battery cells are configured as so-called round battery cells. In particular, such a round battery cell has a substantially circular cross-section and, in terms of its chemical structure, such an energy storage battery cell can be configured as a lithium-ion energy storage battery cell. In the planned installation position of the energy storage device, the energy storage battery cells are preferably erected and oriented such that the cylindrical axis of such an energy storage battery cell or all the energy storage battery cells in the energy storage device are vertically oriented in the planned installation position. Further preferably, such an energy storage battery cell can also be lying down and thus be horizontally oriented with respect to its cylindrical axis. Further preferably, such energy storage battery cells are arranged side by side in a plurality of rows or, in particular in the case of horizontal orientation, are stacked in the energy storage housing device.

[0007] In the context of the present invention, such an energy storage housing device should be understood as a device that at least partially, but preferably completely, surrounds these plurality of energy storage battery cells and is further preferably provided for - especially in a motor vehicle - positioning the energy storage device and thus the plurality of energy storage battery cells and, in addition, protecting the energy storage battery cells from external influences. Figuratively speaking, such an energy storage housing device can be understood as a battery housing.

[0008] As described above, the plurality of energy storage battery cells are accommodated in the energy storage device housing means such that an energy storage battery cell row is obtained. Preferably, at least two energy storage battery cell rows are arranged adjacent to each other in the energy storage device housing means, so that the energy storage battery cells in the two energy storage battery cell rows do not come into contact with each other. Instead, a so-called temperature control region is formed between the two energy storage battery cell rows. Geometrically, such a temperature control region can in particular be understood as an intermediate space between two adjacent energy storage battery cell rows. Functionally, a device can be arranged in this temperature control region by means of which heat can be removed (cooled) from the energy storage battery cells of the two energy storage battery cell rows, or by means of which heat can also preferably be supplied (heated) to these energy storage battery cells. In particular, such heating or cooling takes place such that these energy storage battery cells can operate within a preset temperature window. In particular, a temperature control channel is geometrically arranged between two adjacent energy storage battery cell rows, and this temperature control channel is part of the so-called energy storage device temperature control means. Thus, in a preferred embodiment, the energy storage module is constructed such that when the energy storage battery cells are arranged next to each other in the longitudinal direction to form an energy storage battery cell row, in the width direction of the energy storage module, the energy storage battery cell rows and the temperature control channels alternate. In a further preferred embodiment, in this width direction, every two energy storage battery cell rows are arranged directly adjacent to each other, and then a temperature control channel is arranged directly adjacent or in contact with at least one of these energy storage battery cell rows. Further preferably, for this embodiment, a layout structure is obtained in the width direction in which one temperature control channel, then two energy storage battery cell rows, and then again one temperature control channel are arranged, and so on.

[0009] In the sense of the present invention, such an energy storage device temperature control means should be understood as a device for cooling, heating or for cooling and heating the energy storage battery cells in the energy storage device housing means, and in particular for this purpose the energy storage device temperature control means has at least one temperature control channel. Thus, such a temperature control channel is in particular a channel for guiding - preferably liquid - temperature control medium, wherein this temperature control medium is arranged to absorb the heat of the energy storage battery cells in one or more energy storage battery cell rows adjacent to the temperature control channel or to output heat to the energy storage battery cells. Further preferably, the energy storage device is provided with a plurality of temperature control channels, wherein preferably such a temperature control channel is adjacent to two energy storage battery cell rows respectively, and further preferably, such a temperature control channel at least partially contacts the energy storage battery cell row arranged adjacent to the temperature control channel, so that in particular good heat conduction can be achieved and small installation space requirements can be met.

[0010] Against this background, the present invention proposes a method for manufacturing an energy storage device, by which an energy storage device with improved characteristics compared to the energy storage devices known from the prior art can be manufactured. In particular, an energy storage device with high dimensional accuracy and good heat transfer in the temperature control device of the energy storage can be realized. In particular, in order to manufacture such an improved energy storage device, the proposed method includes the following steps:

[0011] - In particular, in the energy storage housing device, a plurality of energy storage battery cells are arranged in at least two rows of energy storage battery cells, but preferably in a plurality of rows of energy storage battery cells, wherein in such a row of energy storage battery cells, the plurality of energy storage battery cells are arranged in sequence in the longitudinal direction. Therefore, preferably in such a row of energy storage battery cells, at least two, but preferably a plurality of energy storage battery cells are arranged in sequence, that is, arranged in sequence in this longitudinal direction. Further preferably, these rows of energy storage battery cells are arranged spaced apart from each other in the width direction. In particular, since each two rows of energy storage battery cells are arranged spaced apart from each other, that is, geometrically separated by a temperature control region, these rows of energy storage battery cells can be precisely arranged in the energy storage housing device. Compared with a device having a temperature control channel tube configured as a rigid member (such as the temperature control channel tube known from the prior art, and in this device, the temperature control channel tube is in direct contact with two rows of energy storage battery cells, especially for heat transfer), the inevitable manufacturing deviations accumulate into a total geometric deviation, especially the total deviation in this width direction. In contrast, in the proposed manufacturing method, the rows of energy storage battery cells are first positioned independently of the cooling channels and are thus precisely positioned, especially in the energy storage battery cell housing.

[0012] In addition, in the proposed manufacturing method, a flexible temperature control channel hose is arranged in the region between two adjacent rows of energy storage battery cells, that is, arranged in this temperature control region. Here, the flexibility of the temperature control channel hose is selected such that the temperature control channel hose does not have its final shape, the so-called unstretched state, when it is introduced into the temperature control region, but obtains the final shape, the so-called stretched state, only in subsequent manufacturing steps. Preferably, in a plurality of temperature control regions of the energy storage device, and preferably in all temperature control regions, such a temperature control channel hose is respectively arranged, and in addition, the only such temperature control channel hose can also be guided through a plurality of or all such temperature control regions. Preferably, the temperature control channel hose is at least substantially composed of a stretchable plastic material. In particular, by introducing the flexible temperature control channel hose, the precise positioning of the rows of energy storage battery cells is maintained.

[0013] After introducing the at least one temperature control channel hose, an overpressure (so-called temperature control channel overpressure) is applied to the temperature control channel hose, where the overpressure relates to the pressure ratio between the internal volume of the temperature control channel hose and the environment directly surrounding this internal volume, in short, the pressure ratio between the inside and the outside of the temperature control channel hose. Furthermore, the temperature control channel hose is selected such that the temperature control channel hose causes the formation of the temperature control channel hose, that is, causes an increase in the volume of the temperature control channel hose, and preferably, the temperature control channel hose is formed at least to a certain extent, or its volume increases until the temperature control channel hose at least partially or preferably completely contacts two adjacent energy storage battery unit rows, and thereby at least substantially fills the temperature control region. Preferably, under the action of the temperature control channel overpressure, the temperature control channel hose increases in its volume by more than 5%, preferably by more than 15%, and preferably by more than 30%, and further preferably, the temperature control channel overpressure is less than 50 bar, preferably less than 10 bar, and further preferably less than 5 bar. In particular due to the elasticity of the temperature control channel hose, the temperature control channel hose preferably can completely, but at least partially, abut against the energy storage battery unit rows, and thereby a particularly large contact area is formed between the critical surfaces of the temperature control device and these energy storage battery units of the energy storage battery unit rows.

[0014] Furthermore, it is proposed that after introducing the temperature control channel hose and preferably also after applying the temperature control channel overpressure, an accumulator filling material is introduced into the accumulator housing device, where the accumulator filling material thus at least partially or completely surrounds the temperature control channel, such that this temperature control channel is at least partially or completely accommodated in the accumulator filling material. Further preferably, the accumulator filling material is introduced into the accumulator housing device in liquid form. Further preferably, the accumulator filling material is brought into a foamy consistency, or preferably introduced into the accumulator housing device as a foam. Further preferably, the accumulator filling material and the temperature control channel hose, especially in its expanded state, are at least partially sectionally connected in a material-locking manner, and particularly preferably, after the accumulator filling material has solidified, the accumulator filling material holds at least one temperature control channel hose in the shape that the temperature control channel hose had in the stretched state.

[0015] In a preferred embodiment, at least one temperature control channel hose is led out from the temperature control area, and preferably, the temperature control channel hose is thus led into a so-called collecting area. In particular, in this area, which is preferably still inside the accumulator housing device, the temperature control channel hose is adjacent to at least one row of accumulator cells on only one side, or even not adjacent to any row of accumulator cells. Further preferably, in this area, a plurality of temperature control channel hoses are connected to each other in a fluid-guiding manner by means of a rigid member (the so-called collecting pipe), and further preferably, they are connected to each other in a fluid-guiding manner by means of at least one temperature control channel collecting hose (the temperature control channel collecting hose is implemented flexibly like such a temperature control channel hose). Preferably, the collecting area extends at least substantially in the width direction of the energy storage module. In particular, such a design of the present invention enables the temperature control device to be connected to a flexible and thus easily manufacturable temperature control channel hose or a rigid plastic member as well.

[0016] In a preferred embodiment of the present invention, the temperature control channel hose, at least within the temperature control area, expands by more than 5% under the application of a temperature control channel overpressure compared to the state without the application of the temperature control channel overpressure. Preferably, this expansion relates to the volume occupied by the temperature control channel hose in the non-stretched state (non-stretched: without the application of the temperature control channel overpressure / stretched: with the application of the temperature control channel overpressure). In particular, by means of such expansion, the temperature control channel in the non-stretched state can be particularly easily introduced into the temperature control area because the space occupied by the temperature control channel is significantly smaller than in its stretched state. In addition, through the "large" expansion, good contact between the accumulator cells in the row of accumulator cells and the accumulator temperature control device can be achieved.

[0017] In a preferred embodiment of the present invention, the accumulator filling material and the temperature control channel hose are coordinated with each other such that the accumulator filling material and the temperature control channel hose form a material-locking connection, at least in the temperature control area and at least in some sections, especially when the accumulator filling material has partially or completely solidified. Further preferably, the accumulator filling material hardens after being introduced, especially when the accumulator filling material has at least partially surrounded the temperature control channel hose. In particular, through the material-locking connection between the accumulator filling material and the temperature control channel hose and the hardening of the accumulator filling material, the temperature control channel hose is at least substantially permanently maintained in its stretched state by the accumulator filling material, so that the temperature control channel is thus accurately introduced into the temperature control area.

[0018] In a preferred embodiment of the present invention, the temperature control channel hose, especially after applying an overpressure in the temperature control channel, comes into contact with at least one energy storage battery cell in the energy storage battery cell row, preferably a plurality or preferably all of the energy storage battery cells, and further preferably, this contact is a planar contact. Figuratively speaking, the elastic temperature control channel, especially under the influence of the overpressure in the temperature control channel, conforms to the energy storage battery cells grouped into an energy storage battery cell row, and is in planar contact with them here. In particular, a large contact area can be achieved through such a planar contact, especially in combination with cylindrical energy storage battery cells, and thus good heat transfer to the temperature control device can be achieved.

[0019] Furthermore, the present invention provides an energy storage device for a motor vehicle and preferably a motor vehicle energy storage device, preferably a motor vehicle traction battery, wherein the energy storage device is manufactured according to the method in the claims explained previously. Brief Description of the Drawings

[0020] The present invention will be explained in more detail below with the aid of at least partially schematic drawings, which show a plurality of individual features and combinations of features. It should be noted that the present invention can also be implemented by other combinations of features in addition to the combinations of features shown. The drawings show:

[0021] Figure 1 A schematic top cross-sectional view showing three energy storage battery cell rows with two unstretched temperature control channel hoses;

[0022] Figure 2 A schematic top cross-sectional view showing three energy storage battery cell rows with two stretched temperature control channel hoses;

[0023] Figure 3 A schematic flow chart showing the proposed manufacturing method. Detailed Description of the Preferred Embodiments

[0024] Figure 1 A cross-sectional top view of a part of the energy storage device, especially an energy storage module, is shown, in which the first energy storage battery cell row 1, the second energy storage battery cell row 2, and the third energy storage battery cell row 3 can be seen. These energy storage battery cell rows 1, 2, 3 are formed by arranging cylindrical energy storage battery cells next to each other in the energy storage housing device 11. In the energy storage housing device 11, only a single side wall is shown exemplarily. A first temperature control region 4 and a second temperature control region 5 are formed between the three energy storage battery cell rows 1, 2, 3. In the manufacturing step shown, the first temperature control channel 6 or the second temperature control channel 7 is also placed in these two temperature control regions 4, 5 in an unstretched state.

[0025] In Figure 2 it is shown Figure 1The same view of the energy storage device shown in [Figure] after a further manufacturing step. In this further manufacturing step, the first temperature control channel 8 and the second temperature control channel 9 are shown in a stretched state. Here, by applying an overpressure to the temperature control channels, the transition of the temperature control channels from their non-stretched states 6, 7 to their stretched states 8, 9 is achieved. When applying the overpressure to the temperature control channels, there is an overpressure inside the respective temperature control channel hoses relative to the environment directly surrounding the temperature control channel hoses. Due to the flexible material of these temperature control channel hoses, these temperature control channel hoses expand under the action of the overpressure of the temperature control channels and conform to the energy storage battery cell rows 1, 2, 3, thereby achieving a large contact area between the energy storage battery cell rows 1, 2, 3 and the temperature control channels 8, 9 respectively. The still free area 10 in the accumulator housing device 11 is an area that is filled with accumulator filling material in a further manufacturing step.

[0026] In Figure 3 a simplified flow chart of the method for manufacturing an energy storage device according to the present invention is shown.

[0027] The first method step 101 includes arranging a plurality of energy storage battery cells in the accumulator housing device 11 into at least two energy storage battery cell rows 1, 2. The second method step 102 includes introducing flexible temperature control channel hoses into at least one temperature control region 4 between at least two energy storage battery cell rows. The third method step 103 includes introducing an overpressure of the temperature control channels into at least one temperature control channel hose, thereby transitioning the temperature control channel hose from its non-stretched state 6 to its stretched state 8, and thereby forming at least one temperature control channel by means of the temperature control channel hose.

[0028] The fourth method step 104 includes introducing accumulator filling material into the still free area 10 in the accumulator housing device 11, where such an area 10 can be unfilled, partially filled, or completely filled with accumulator filling material.

[0029] In other words, it is known from the prior art that the cooling of the cylindrical battery cells of a high-voltage energy storage device is achieved by means of so-called inter-cell cooling, by means of cooling serpentines made of aluminium (so-called aluminium cooling serpentines) arranged between the energy storage battery cells and additionally by means of a fluid guide on their sides, where this lateral fluid guide can be understood as a collecting area or collecting channel. Furthermore, it is known to implement one or more aluminium cooling serpentines in electrical insulation from the energy storage battery cells by means of a plastic coating. The cylindrical battery cells arranged in rows are adhesively bonded to at least one adjacent aluminium cooling serpentine arranged therewith via their circumferential surfaces or are connected to the aluminium cooling serpentine in a material-locking manner. The individual aluminium cooling serpentines arranged in the intermediate spaces between the energy storage battery cells and connected to the energy storage battery cells are connected at their axial ends and are thus connected to one another via an interface to form a fluid guide (inflow and return flow), which is the collecting area explained above. Furthermore, a module (aluminium cooling serpentine, energy storage battery cell) provided with such a cooling structure can be structurally filled and foamed with foam material or other suitable filling material in a further process step. Due to the material-locking connection of a large number of rigid bodies (aluminium cooling serpentines, energy storage battery cells), the inevitable manufacturing tolerances of these rigid bodies can accumulate to a relatively large overall tolerance.

[0030] In contrast, the present invention proposes a manufacturing method which provides for the use of a flexible cooling serpentine which is not made of a rigid material such as aluminium, so that the fluid guide can be achieved by means of a flexible plastic hose or hollow body (so-called temperature control channel hose). The at least one temperature control channel hose is designed to be flexible and thus does not perform structural functions such as positioning the energy storage battery cells or achieving a specific minimum spacing between two adjacent rows of energy storage battery cells, but this temperature control channel hose only performs a sealing function for the medium guide, i.e. for the guide of the temperature control medium or cooling medium during the intended operation of the energy storage device. For this purpose, it is proposed that the energy storage battery cells, in particular configured as cylinders, are first arranged in rows of energy storage battery cells, and then the flexible temperature control channel hose, which is still in an unstretched state at this point in time, is positioned between two adjacent rows of energy storage battery cells, which is repeated as often as necessary until all the areas provided therefor are provided with such a temperature control channel hose. At least one such positioned temperature control channel hose is filled with a medium, and under the action of the resulting temperature control channel overpressure, the temperature control channel hose expands and thus adheres to the circumferential surface of the energy storage battery cell.

[0031] In this stretched state of at least one temperature control channel hose, the energy module is then filled with a reservoir filling material. By this filling, preferably all remaining intermediate spaces are filled. Here, the nature of the reservoir filling material is such that the reservoir filling material establishes an adhesive connection with at least one temperature control channel hose. Thus, even if the filling pressure or the overpressure in the temperature control channel drops, the temperature control channel remains unobstructed for fluid guidance after curing. The possible connections of a plurality of individual temperature control channels (so-called lateral fluid guides) can also be implemented as plastic parts and filled together. Thereby, in a preferred embodiment, the entire fluid guide can be implemented as consisting of at least one thin, light and inexpensive plastic component. The strength of the temperature control channel is controlled at least substantially by the reservoir filling material here.

[0032] List of reference numerals

[0033] 1, 2, 3 First, second, third energy storage battery cell rows

[0034] 4, 5 First, second temperature control regions

[0035] 6, 7 First, second temperature control channel hoses in the unstretched state

[0036] 8, 9 First, second temperature control channel hoses in the stretched state

[0037] 10 Region to be filled with the reservoir filling material

[0038] 101 First step

[0039] 102 Second step

[0040] 103 Third step

[0041] 104 Fourth step

Claims

1. A method for manufacturing an energy storage device, the energy storage device having a plurality of energy storage battery cells, the energy storage battery cells being accommodated in an energy storage housing device, whereby a temperature control region is formed between at least two rows of the energy storage battery cells, and the energy storage device has an energy storage temperature control device with at least one temperature control channel hose, wherein, such a temperature control channel hose is arranged in the temperature control region, the method comprising the steps of: - arranging the plurality of energy storage battery cells in the energy storage housing device into at least two rows of energy storage battery cells; - introducing a flexible temperature control channel hose into the temperature control region; - introducing a temperature control channel overpressure into the temperature control channel hose to form a temperature control channel; - introducing an energy storage filler material into the energy storage housing device, and thereby at least partially or completely surrounding the temperature control channel hose with the energy storage filler material.

2. The method for manufacturing an energy storage device according to claim 1, characterized in that, the temperature control channel hose is led out from the temperature control region into a region which is in the energy storage device, and in which the temperature control channel hose is adjacent to at least one energy storage device only on one side, or is not adjacent to any energy storage device.

3. The method for manufacturing an energy storage device according to any one of the preceding claims, characterized in that, the temperature control channel, at least within the temperature control region, expands by more than 1% when the temperature control channel overpressure is applied as compared to the state without the application of the temperature control channel overpressure.

4. The method for manufacturing an energy storage device according to any one of the preceding claims, characterized in that, the energy storage filler material forms a material-locking connection with the temperature control channel at least within the temperature control region and at least in some sections.

5. The method for manufacturing an energy storage device according to any one of the preceding claims, characterized in that, after the application of the temperature control channel overpressure, the temperature control channel is in surface contact with at least one energy storage battery cell.

6. An energy storage device for a motor vehicle, wherein, the energy storage device is manufactured according to the method of any one of the preceding claims.

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