Temperature-control module for a battery cell, cell arrangement having a temperature-control module and a battery cell, and battery store

Abstract

The invention relates to a temperature-control module (6) for controlling the temperature of at least one battery cell (2) of a battery store (1), comprising: a flexible outer casing (8) which is deformable under pressure from the outside, in particular when the volume of the at least one battery cell (2) changes; a fluid channel (10) which is formed inside the outer casing (8) and within which a temperature-control fluid flows in order to exchange heat energy with the at least one battery cell (2); and at least one compensation chamber (12) into which temperature-control fluid flows depending on a pressure acting on the outer casing (8). The invention further relates to a cell arrangement (20) and to a battery store (1).

Description

[0001] Temperature control module for battery cell, cell assembly with temperature control module and battery cell, and battery storage

[0002] Description

[0003] The disclosure relates to a temperature control module for temperature control of at least one battery cell of a battery storage system, comprising a flexible outer shell which is deformable under external pressure, in particular when the volume of the at least one battery cell changes, and a fluid channel formed inside the outer shell, within which a temperature control fluid flows to exchange heat energy with the at least one battery cell.

[0004] Background of the Revelation

[0005] A high-voltage storage system in a hybrid or electric vehicle is an energy storage system that stores electrical energy in the form of direct current at high voltage. This stored energy is typically used to power at least one of the vehicle's electric motors. These high-voltage storage systems are typically composed of individual battery cells, such as lithium-ion cells, or modules configured in a battery pack.

[0006] Battery cells exist in various designs and dimensions for this purpose. Circular cylindrical cells (round cells) or flat cells, such as prismatic cells or so-called pouch cells, are used. Flat cells, such as pouch cells or prismatic cells, are particularly preferred with regard to better heat dissipation and stackability.

[0007] When cycling such battery cells, mechanical deformation can be observed during the charging and discharging phases. This means that within a charge-discharge cycle, a battery cell undergoes a volume increase. The volume of a battery cell also increases over its lifetime. This phenomenon is referred to as "swelling." In cylindrical battery cells, this growth acts inwards, particularly due to the high mechanical integrity of the casing. In pouch and prismatic battery cells, however, the forces caused by the volume growth, which can deform the casing or encapsulation, act outwards.

[0008] During operation, high-voltage storage systems typically require temperature control (i.e., cooling and / or heating) to ensure battery performance and lifespan. In high-voltage storage systems for electric vehicles, battery cells are cooled and / or heated, for example, by means of cooling coils or cooling modules containing coolant / cooling fluid / temperature control fluid located between or on the battery cells. The coolant usually flows through the cooling coils or modules to exchange heat energy with the battery cells, thus maintaining their temperature—that is, heating or cooling them to a predetermined operating temperature.

[0009] It is known from the prior art to use such cooling concepts or cooling or temperature control modules to compensate for volume growth. For example, WO 2020 / 221 856 A1 discloses a pressure module for a battery cell, wherein the pressure module is an elastomeric component for swelling compensation with simultaneous cooling or heating function for rechargeable batteries.

[0010] However, in prior art concepts, compensating for volume growth always involves compression of a cooling channel through which the coolant flows. This means that as the battery cells expand due to swelling, the components responsible for temperature control and cooling are deformed, reducing the cross-sections of the cooling channels inside these components. Consequently, the volume flow through the cooling channels decreases, which in turn reduces the cooling capacity and ultimately the performance of the high-voltage storage system. Summary of the disclosure

[0011] The tasks and objectives of this disclosure are to eliminate or at least mitigate the disadvantages of the prior art. In particular, a temperature control module or cooling structure for at least one, preferably prismatic or pouch, battery cell is to be provided, which ensures sufficient and consistent temperature control or cooling of the battery cell throughout its entire service life.

[0012] The tasks and objectives with regard to a generic temperature control module are solved, as disclosed, by the subject matter of claim 1. The disclosure is thus based on the knowledge of how to accommodate the expansion of the battery cells during swelling without compressing a laterally positioned temperature control module or a laterally positioned cooler to such an extent that no or insufficient volume flow can pass through the cooling channel.

[0013] The temperature control module is accordingly configured / adapted, as disclosed, to include at least one compensation chamber into which temperature control fluid flows depending on the pressure acting on the outer shell. This means that if the at least one battery cell expands over its lifetime due to swelling, it presses against the outer shell of the temperature control module. Due to its flexibility, the outer shell deforms, which in turn compresses the fluid channel inside the temperature control module. Consequently, the flow cross-section of the fluid channel decreases, resulting in a reduced volume flow rate within the fluid channel. The temperature control performance of the temperature control module would thus decrease.

[0014] As mentioned above, according to the disclosure, the temperature control fluid can flow into the at least one equalization chamber when pressure is applied to the outer shell. This means that the at least one equalization chamber allows the necessary flow cross-section of the temperature control fluid-carrying components (fluid channel and equalization chamber) to be maintained for adequate temperature control of the battery cell. In other words, by providing the at least one equalization chamber, a reduction in the flow cross-section of the fluid channel can be compensated for, which in turn ensures adequate temperature control of the battery cell.

[0015] Advantageous embodiments are claimed in the dependent claims and are explained below.

[0016] In a preferred embodiment, at least one sealing element (bulkhead) can be arranged between the fluid channel and the at least one compensation chamber, which opens and closes depending on the pressure acting on the outer shell. Particularly preferably, the at least one sealing element can be configured to open from the outside when the pressure on the outer shell increases. The at least one sealing element thus functions as a self-acting sealing mechanism, which allows the temperature control fluid to flow into the at least one compensation chamber when the pressure on the outer shell of the temperature control module increases, thereby maintaining the flow cross-section for the temperature control fluid.

[0017] According to a particularly advantageous embodiment, the at least one compensation chamber can be designed as a compensation channel extending over the entire length of the fluid channel. That is, the compensation channel can preferably be designed to extend parallel to the fluid channel. It can be advantageous if closure elements are arranged at several defined points along the fluid channel or along the compensation channel, so that the temperature control fluid can flow uniformly from the fluid channel into the compensation channel at these points.

[0018] Preferably, the at least one closure element can be designed as a pressure equalization membrane which, when the pressure on the outer shell increases, opens a flow path / opening through which the temperature control fluid flows from the fluid channel into the at least one equalization chamber. Furthermore, it can be advantageous for the pressure equalization membrane to rupture and thus open the opening when the pressure acting on the outer shell exceeds a predetermined threshold. In an alternative embodiment as disclosed, the at least one closure element can be designed as a flap mechanism which, when the pressure on the outer shell increases, opens a flow path / opening through which the temperature control fluid flows from the fluid channel into the at least one equalization chamber. Preferably, the flap mechanism can be arranged on an inner surface of the outer shell via a fixed connection and a loose connection.The flap mechanism can have a hinge section which is fixedly arranged on the inside of the outer shell. Furthermore, the flap mechanism can have a support section. The support section can preferably be arranged on an inside of the outer shell opposite the hinge section, so that the flap mechanism is rotatably attached to the outer shell via the hinge section and can be moved between a closed state, in which a closing flap of the flap mechanism closes the opening between the fluid channel and the at least one compensation chamber, and a released state, in which the closing flap releases the opening. In other words, the flap mechanism can have a closing flap, one end section of which is rotatably arranged on the outer shell via the hinge section.In the locked position, the other end section of the closure flap rests on the support section, whereas in the unlocked position, the other end section of the closure flap is spaced away from the support section, thus opening the passage between the fluid channel and the at least one compensating chamber. In a further development as disclosed, it is also conceivable that the flap mechanism has two closure flaps which are pivotally hinged to opposite inner surfaces of the outer shell and can be pivoted from the locked position to the unlocked position when pressure on the outer shell increases.

[0019] According to one embodiment disclosed, the at least one compensation chamber can be arranged in a vertical direction of the temperature control module next to the fluid channel. The at least one compensation chamber can be located above and / or below the fluid channel. That is, according to the disclosure, the at least one compensation chamber can be arranged above or below the fluid channel. Alternatively, one compensation chamber can be arranged above and one below the fluid channel.

[0020] Furthermore, it can be advantageous if the at least one compensation chamber is arranged in a lateral direction of the temperature control module next to the fluid channel. That is, the at least one compensation chamber can be formed on a side surface of the fluid channel facing either the at least one battery cell or the side facing away from it. In other words, the at least one compensation chamber can be arranged between the at least one battery cell and the fluid channel or on a side of the fluid channel facing away from the battery cell.

[0021] Furthermore, according to the disclosure, at least one compensation chamber can be formed adjacent to the fluid channel in the vertical direction and at least one in the horizontal direction. In other words, according to the disclosure, any number of compensation chambers can be arranged. The compensation chambers can also be positioned arbitrarily around the fluid channel. The arrangement of the respective compensation chambers can thus be optimized according to requirements. For example, to prevent level equalization in the fluid channel, a compensation chamber can be formed below the fluid channel.

[0022] According to an advantageous embodiment, the at least one compensation chamber can be configured as a separate housing component attached to the outer shell. In other words, the temperature control module can be implemented as a two-part component. Put another way, the temperature control module can be composed of two components: the outer shell defining the fluid channel and the separate housing component defining the at least one compensation chamber. The two components can be detachably or permanently connected. Such a two-part composition of the temperature control module is particularly advantageous for simplified manufacturing, especially of the at least one closure element.

[0023] In a preferred embodiment, an expansion tank can also be provided, which is fluidically connected to the fluid channel, so that when the pressure on the outer shell increases, temperature control fluid flows into the expansion tank. The expansion tank thus represents an additional measure for changing the fill level in the fluid channel.

[0024] In other words, the disclosure relates to a temperature control or cooling module for at least one battery cell, comprising sections (closures) within the cooling module that are separated at the beginning of the battery cell's service life. As the cooling module deforms due to cell swelling, coolant can flow through these sections (closures), thereby maintaining at least the potential flow rate. The closures can be oriented horizontally or vertically. Furthermore, the design of the closures can vary. The cooling module can also be implemented as a two-part component, simplifying the manufacturing process for the closures. A further benefit is the potential extension of the system's service life, as both the mechanical parameters and the cooling performance can be optimized.

[0025] Furthermore, the disclosure relates to a cell arrangement for a battery storage system comprising two battery cells, between which a temperature control module according to the disclosure is arranged. Preferably, a spacer element can be arranged on each of the battery cells on the sides facing away from the temperature control module.

[0026] Furthermore, the disclosure relates to a battery storage system, in particular a high-voltage storage system, for an electric vehicle with a plurality of cell arrangements as disclosed. The cell arrangements can be arranged side by side and one behind the other in the battery storage system.

[0027] Brief description of the characters

[0028] The disclosure is explained in more detail below with reference to preferred embodiments and the figures. Figure 1 shows a schematic view of a temperature control module according to a first embodiment at the beginning of a battery cell's service life cycle;

[0029] Fig. 2 shows a schematic view of the temperature control module according to the first embodiment as disclosed, at the end of the battery cell's service life cycle;

[0030] Fig. 3 shows a schematic view of a temperature control module according to a second embodiment as disclosed, at the beginning of a battery cell's lifetime cycle;

[0031] Fig. 4 shows a schematic view of the temperature control module according to the second embodiment as disclosed, at the end of the battery cell's service life cycle;

[0032] Fig. 5 shows a schematic view of a temperature control module according to a third embodiment as disclosed, at the beginning of a battery cell's lifetime cycle;

[0033] Fig. 6 shows a schematic view of the temperature control module according to the third embodiment as disclosed, at the end of the battery cell's service life cycle; and

[0034] Fig. 7 is a schematic view of a battery storage device according to the disclosure.

[0035] The figures are schematic and serve only to illustrate the disclosure. Identical elements are identified by the same reference numerals. The features of the different embodiments are interchangeable. Detailed description of preferred embodiments

[0036] Fig. 1 schematically shows a battery cell 2 arranged in a battery storage system 1, which will be described in more detail below, at the beginning of its life cycle. The battery storage system 1 is installed in an electric vehicle to provide electrical energy to an electric drive motor of the electric vehicle. For this purpose, a plurality of battery cells 2 are arranged in a battery storage housing 4 of the battery storage system 1. As disclosed, the battery cells 2 are designed as prismatic cells.

[0037] To temper, i.e., to heat or cool, battery cell 2, as shown in Fig.

[0038] Figure 1 shows a temperature control module 6 according to a first embodiment. The temperature control module 6 has a flexible outer shell 8 which defines a fluid channel 10 inside. A temperature control fluid flows in the fluid channel 10 to exchange thermal energy with the battery cell 2. If, for example, the battery cell 2 is to be heated to operating temperature when starting the electric vehicle, the temperature control fluid flowing in the fluid channel 10 consequently transfers thermal energy to the battery cell 2. To cool the battery cell 2, the temperature control fluid absorbs thermal energy from the battery cell 2.

[0039] As can be seen in Fig. 1, the temperature control module 6 according to the first embodiment also has two equalization channels 12. That is, the outer shell 8 of the temperature control module 6 defines the fluid channel 10 and the two equalization channels 12 internally. A first equalization channel 12A is arranged above the fluid channel 10 in the vertical direction of the temperature control module 6. The second equalization channel 12B, on the other hand, is arranged below the fluid channel 10 in the vertical direction of the temperature control module.

[0040] A shut-off valve 14 is arranged between the fluid channel 10 and the equalization channels 12. The shut-off valve 14 ensures fluidic separation between the fluid channel 10 and the adjacent equalization channels 12, preventing any temperature control fluid from flowing from the fluid channel 10 into one of the equalization channels 12. The shut-off valve 14 is an example of a shut-off element as disclosed.

[0041] In the first embodiment shown in Fig. 1, the closing flap 14 is configured. It is pivotally connected to the outer shell 8 at one end section, allowing the closing flap 16 to pivot between a closed state, as shown in Fig. 1, and a released state, as shown in Fig. 2 and described in more detail below. In the closed state, the closing flap 14 rests with its free end section on a support section 16 arranged on the outer shell 8, thereby closing the interface between the fluid channel 10 and the equalization channel 12. Consequently, no temperature control fluid can flow from the fluid channel 10 into the equalization channel 12 in the closed state.

[0042] Fig. 2 shows the temperature control module 6 according to the first embodiment and the battery cell 2 at the end of its service life. As mentioned above, the battery cell 2 is a prismatic battery cell. As indicated in Fig. 2, the volume of such prismatic battery cells increases over their service life or service life due to gas formation and the formation of a protective layer at the electrodes, as well as changes in morphology. Due to this increase in volume, the battery cell 2 exerts pressure against the temperature control module 6 at the end of its service life. The flexible outer shell 8 of the temperature control module 6 allows for deformation of the outer shell 8, which is accompanied by a reduction in the flow cross-section of the fluid channel 10.

[0043] When, as shown in Fig. 2, the battery cell 2 presses against the temperature control module 6 and the outer casing 8 deforms, the closing flaps 14 pivot into the release position. This means that the closing flaps 14 lift off their respective support sections 16 and open a flow path between the fluid channel 10 and the respective compensation channel 12. The temperature control fluid can then flow from the fluid channel 10 into the compensation channels 12, thus compensating for the reduction in the flow cross-section of the fluid channel 10 and ensuring sufficient temperature control performance. Fig. 3 shows a temperature control module 6 according to a second embodiment at the beginning of the life cycle of the battery cell 2. As can be seen in Fig. 3, the temperature control module 6 according to the second embodiment has a compensation channel 12, which is arranged next to the fluid channel 10 in a lateral direction perpendicular to the vertical direction of the temperature control module 6.The compensating channel 12 extends over the entire height of the fluid channel 10.

[0044] A pressure equalization membrane 18 is arranged between the fluid channel 10 and the equalization channel 12. This membrane fluidically separates the fluid channel 10 from the equalization channel 12, preventing any temperature control fluid from flowing from the fluid channel 10 into the equalization channel 12. The pressure equalization membrane 18 therefore represents an example of a closure element as disclosed.

[0045] If, as shown in Fig. 4, the volume of the battery cell 2 increases towards the end of its life cycle, causing the outer shell 8 to deform, the pressure equalization membrane 18 opens a flow path between the fluid channel 10 and the equalization channel 12 to compensate for the reduced flow cross-section of the fluid channel 10. The pressure equalization membrane 18 can open this flow path reversibly (temporarily) or irreversibly (permanently). For example, the pressure equalization membrane 18 can be designed to rupture when the pressure on the outer shell 8 exceeds a predetermined threshold.

[0046] Figures 5 and 6 show a temperature control module 6 according to a third embodiment. Figure 5 shows a state at the beginning of the battery cell 2's life cycle, whereas Figure 6 shows a state at the end of the battery cell 2's life cycle. According to the third embodiment, the temperature control module 6 has a first equalization channel 12A, which is arranged laterally next to the fluid channel 10, and a second equalization channel 12B, which is arranged vertically above the fluid channel 10 and the first equalization channel 12A.

[0047] A first pressure equalization membrane 18A is provided as a sealing element between the fluid channel 10 and the first equalization channel 12A. Furthermore, a second pressure equalization membrane 18B fluidically separates the fluid channel 10 from the second equalization channel 12B. If the pressure on the outer shell 8 increases due to the volume increase of the battery cell 2, the pressure equalization membranes 18A and 18B can rupture to maintain the flow cross-section necessary for adequate temperature control of the battery cell 2. It is advantageous if the two pressure equalization membranes 18A and 18B rupture depending on different applied pressures. That is, the first pressure equalization membrane 18A is designed to rupture when a first threshold value is exceeded, so that the temperature control fluid initially flows from the fluid channel 10 into the first equalization channel 12A. If the pressure on the outer shell 8 continues to rise and exceeds a second threshold value, i.e.,If the volume of battery cell 2 continues to increase, the second pressure equalization membrane 18B may rupture, allowing the temperature control fluid to flow into the second equalization channel 12B as well. The temperature control module 6 according to the third embodiment therefore enables a staged provision of the flow cross-section.

[0048] As mentioned above, the battery cell 2 is arranged in the battery storage housing 4 of the battery storage unit 1. As shown in Fig. 7, the battery cell 2 is arranged within a cell arrangement 20 in the battery storage housing 4. According to the disclosure, a plurality of cell arrangements 20 are accommodated in the battery storage housing 4.

[0049] The cell arrangement 20 comprises two battery cells 2, a temperature control module 6 as disclosed, and two spacer elements 22. Specifically, the cell arrangement 20 includes a first spacer element 22A, a first battery cell 2A, the temperature control module 6, a second battery cell 2B, and a second spacer element 22B, arranged side by side in that order. The temperature control module 6 is therefore configured to compensate for the volume increase of the two battery cells 2A and 2B by providing additional flow cross-sections. (Reference numeral list)

[0050] 1 battery storage

[0051] 2 battery cells

[0052] 2A first battery cell

[0053] 2B second battery cell

[0054] 4 battery storage housings

[0055] 6 Temperature control module

[0056] 8 Outer shell

[0057] 10 Fluid channel

[0058] 12 Compensation channel

[0059] 12A first equalization channel

[0060] 12B second equalization channel

[0061] 14. Locking flap (locking element)

[0062] 16th edition section

[0063] 18 Pressure equalization membrane (closing element) 18A First pressure equalization membrane

[0064] 18B second pressure equalization membrane

[0065] 20 cell arrangement

[0066] 22 spacer element

[0067] 22A first spacer element

[0068] 22B second spacer element

Claims

Claims 1. Temperature control module (6) for temperature control of at least one battery cell (2) of a battery storage device (1) with a flexible outer shell (8) which is deformable under external pressure, in particular when the volume of the at least one battery cell (2) changes, and a fluid channel (10) formed inside the outer shell (8) in which a temperature control fluid flows to exchange heat energy with the at least one battery cell (2), characterized by at least one equalization chamber (12) into which temperature control fluid flows depending on a pressure acting on the outer shell (8).

2. Temperature control module (6) according to claim 1, characterized in that at least one closure element (14, 18) is arranged between the fluid channel (10) and the at least one compensation chamber (12), which opens depending on the pressure acting on the outer shell (8).

3. Temperature control module (6) according to claim 2, characterized in that the at least one closure element (14, 18) opens from the outside when pressure increases on the outer shell (8).

4. Temperature control module (6) according to one of the preceding claims 1 to 3, characterized in that the at least one compensation chamber is designed as a compensation channel (12) over the entire length of the fluid channel.

5. Temperature control module (6) according to one of the preceding claims 2 to 4, characterized in that the at least one closure element is designed as a pressure equalization membrane (18) which, when pressure increases on the outer shell (8), releases a flow path through which the temperature control fluid flows from the fluid channel (10) into the at least one equalization chamber (12).

6. Temperature control module (6) according to one of the preceding claims 2 to 4, characterized in that the at least one closure element is a A flap mechanism (14) is formed which, when pressure increases on the outer shell (8), releases a flow path through which the temperature control fluid flows from the fluid channel (10) into the at least one compensation chamber (12).

7. Temperature control module (6) according to one of the preceding claims 1 to 6, characterized in that the at least one compensation chamber (12) is arranged in a height direction and / or width direction of the temperature control module (6) next to the fluid channel (10).

8. Temperature control module (6) according to one of the preceding claims 1 to 7, characterized in that the at least one compensation chamber (12) is formed by a separate housing component which is attached to the outer shell (8).

9. Cell arrangement (20) for a battery storage system (1 ) with two battery cells (2) between which a temperature control module (6) according to one of the preceding claims 1 to 8 is arranged.

10. Battery storage (1), in particular high-voltage storage, for an electric vehicle with a plurality of cell arrangements (20) according to claim 9.

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