Battery housings for lithium-ion batteries

Abstract

A battery housing for a lithium-ion battery of a motor vehicle is provided, for arrangement in the engine compartment of the motor vehicle, the battery housing comprising at least one mechanically stable outer shell having a plurality of walls corresponding to the shape of the battery; at least one layer of solid thermal insulation material for protecting the battery from heat from the region of the internal combustion engine; at least one first groove connectable to an air line to the surrounding environment; and at least one second groove connectable to a line associated with at least one cooling system of the vehicle.

Description

Technical Field

[0001] The invention relates to a housing for a lithium-ion battery for a motor vehicle. Background Art

[0002] Lithium-ion batteries are becoming increasingly important in the automotive sector. They are used, in particular, as energy storage devices in hybrid vehicles. They offer various advantages over conventional batteries, for example in terms of specific energy and specific power.

[0003] However, the service life and operation of lithium-ion batteries depend heavily on the ambient temperature. Lithium-ion batteries should not be exposed to temperatures below 0°C and above 60°C and should ideally be within a temperature range of 10°C to 40°C. The temperature sensitivity here depends on the specific technology of the battery, that is, in particular on the chemical composition (composition of the electrolyte, material of the electrodes, etc.) and the corresponding power requirements. In addition, lithium-ion batteries require high mechanical safety standards because they can catch fire or even explode if mechanically damaged or destroyed, for example in an accident. In addition, some lithium-ion batteries require ventilation.

[0004] The aforementioned disadvantages complicate the installation of lithium-ion batteries in motor vehicles. For crash safety reasons, lithium-ion batteries are typically not installed in the engine compartment, but rather underneath the vehicle, in the underbody area or the luggage compartment. In this case, if a lithium-ion battery fails, connecting the battery to the vehicle interior is also complicated. Furthermore, monitoring the temperature of the lithium-ion battery is complicated, for example, by the long coolant paths. Therefore, the present invention aims to provide a method for arranging lithium-ion batteries more efficiently than conventional arrangements. Summary of the Invention

[0005] This object is achieved by a battery housing having the features of claim 1. Further advantageous embodiments and developments of the invention are apparent from the independent and dependent claims, the drawings and the illustrative examples.

[0006] A first aspect of the invention relates to a battery housing for a lithium-ion battery for a motor vehicle, comprising: at least one mechanically stable outer shell having a shape corresponding to the shape of the battery; at least one layer comprising a solid thermally insulating material; at least one first groove connected to an air line to the surrounding environment; and at least one second groove connected to a line associated with at least one cooling system of the vehicle.

[0007] The battery housing according to the present invention is advantageous because it enables the placement of lithium-ion batteries in the engine compartment of a motor vehicle. In this case, a mechanically stable shell provides protection against mechanical stresses. The layer comprising a solid thermal insulation material advantageously thermally separates the lithium-ion battery from the area of the internal combustion engine or other heat-generating devices in the motor vehicle's engine compartment. Furthermore, the first slot is designed to conduct air, which advantageously allows for heat dissipation. Furthermore, the first slot forms a cavity that also requires protection from mechanical stresses. Additional slots may also be designed as air slots. The second slot is also used to dissipate heat using a coolant when the temperature exceeds a temperature window favorable for the lithium-ion battery, or alternatively, to supply heat when the temperature drops below a temperature window favorable for the lithium-ion battery. Additional slots may also be provided for the use of coolant. According to the present invention, a shape of the housing corresponding to the shape of the battery should be understood to mean that the number of surfaces of the housing corresponds to the number of surfaces of the battery, even though the housing is necessarily larger than the battery.

[0008] The mechanically stable shell can comprise one, or optionally, multiple, material layers. It is designed to absorb mechanical forces, particularly during accidents, without significantly deforming during these events, thereby protecting the lithium-ion battery protected by the battery housing from mechanical damage. The shell material preferably comprises metal. In a particularly preferred embodiment, the material comprises steel. Alternatively, for example, the material can also be aluminum. In another possible embodiment, the material comprises plastic.

[0009] The solid thermal insulation material preferably comprises a thermoplastic. Suitable materials are polystyrene, for example, in particular as foam in the form of expanded polystyrene, or suitable copolymers comprising styrene.

[0010] The second tank of the battery housing according to the present invention is preferably connected to a line of the vehicle's internal combustion engine's cooling system. Advantageously, this connection allows for cooling of the lithium-ion battery as needed when the temperature, due to heat from the internal combustion engine area, exceeds the temperature window favorable for lithium-ion batteries. Alternatively, this connection allows for heating as needed when the temperature drops below the temperature window favorable for lithium-ion batteries. In this case, the coolant flow is activated. The coolant can be water or some other conventional coolant.

[0011] The second tank of the battery housing according to the present invention is preferably connected to the line of the vehicle's air conditioning system. Advantageously, this connection allows for cooling of the lithium-ion battery as needed when the heat from this area becomes too great and is no longer neutralized by the layers of insulating material and by air cooling. In this case, as an alternative to activating the aforementioned coolant, the connection can be such that only the air conditioning system is connected or that the air conditioning system can be connected to the second tank, depending on the operating state of the respective motor vehicle.

[0012] The battery housing according to the invention is preferably a component of a packaged battery.

[0013] The battery housing according to the present invention is preferably at least partially an integral part of the vehicle. In this case, the battery housing can occupy the position where the vehicle battery (i.e., lead-acid battery) is conventionally arranged. In this case, the arrangement of the battery housing according to the present invention—including the lithium-ion battery enclosed therein—advantageously enables close connection to the coolant line or the line of the vehicle air conditioning system. The lithium-ion battery can partially assume the functions of the lead battery. As a result, the provided lead battery can be smaller than a conventional one and can be arranged in some other part of the vehicle.

[0014] A second aspect of the present invention relates to a motor vehicle having a battery housing for a lithium-ion battery according to the present invention. The advantages of the vehicle correspond to those of the battery housing according to the present invention. In particular, the vehicle has a hybrid drive, and more specifically, a mild hybrid drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention is explained in more detail with reference to the accompanying drawings, in which:

[0016] Figure 1 A schematic diagram shows an arrangement of a lithium-ion battery having an embodiment of a battery housing according to the present invention;

[0017] Figure 2 Shown Figure 1 An enlarged view of the arrangement area 10 is shown in FIG;

[0018] Figure 3 Shown Figure 1 An enlarged view of the arrangement area 30 is shown in FIG. DETAILED DESCRIPTION

[0019] Figure 1 The invention shows an arrangement 1 of a lithium-ion battery 2 of a motor vehicle with a battery housing 3. Specifically, the vehicle is a motor vehicle with a hybrid drive, wherein the lithium-ion battery is used in particular for driving an electric motor, for example in a mild hybrid drive.

[0020] The battery housing 3 corresponds in shape to the batteries 2 to be housed, but is necessarily larger than the batteries 2. Specifically, the battery housing 3 is cuboidal, with several flat walls corresponding to the surfaces of a cube. The battery housing 3 has a reversibly closable wall on one side to accommodate the batteries 2. Alternatively, the battery housing 3 can be open on this side. Connections are provided in the battery housing 3 for connecting to air and cooling lines.

[0021] The battery housing 3 is separated from the outside by a mechanically stable outer shell 4. In the figures shown, the shell 4 is composed of a single layer of material, but it can also be composed of two or more layers of material. In one embodiment, the shell 4 can also have ribs and brackets, which help to increase the stability of the shell. The material of the shell 4 preferably comprises metal. In this case, the material can be an alloy, in particular steel, but alternatively, it can also be composed of, for example, a specific metal such as aluminum. The shell 4 can also include plastic, and plastic and metal parts can also be assembled together.

[0022] The battery housing 3 has a first groove 5 and a second groove 6. In particular, both grooves 5 and 6 are air grooves. Figure 2 As shown in Figure 1 The enlarged detail 10 clearly shows a first channel 5 formed between the shell 4 and a layer of solid insulation material 7. The first channel 5 has supports 8 between the shell 4 and the layer 7. These are used to ensure the stability of the first channel 5 and the entire battery housing 3. The second channel 6 is formed between the layer of solid insulation material 7 and the encapsulated battery cells 2. The second channel 6 has a plurality of supports 9 to separate the battery cells 2 and thus form a second air channel 6. The second channel 6 can also be separated by a wall in the direction of the battery cells 2 relative to the area of the battery cells 2.

[0023] In particular, the layer 7 of solid insulating material comprises a thermoplastic. In this case, the layer 7 may for example consist of a foam based on expanded polystyrene, such as an expanded polystyrene copolymer.

[0024] The grooves 5, 6 may be in fluid communication with each other, thereby allowing air circulation between the grooves. Figure 3 It is shown that the grooves 5, 6 are preferably connected to air lines leading to the surrounding environment. For this purpose, the battery housing has a first air connection 11 and a second air connection 12. In this case, the first air line 13 will be connected to the first air connection 11 and will be used here to convey air from the surrounding environment into the battery housing 3. In this case, the second air line 14 will be connected to the second air connection 12 and will be used here to discharge air from the battery housing 3 to the surrounding environment. For this purpose, the grooves 5, 6 have a partition wall 15, which helps to create an air circulation ( Figure 3 ). There can also be multiple air connections, for example for each slot 5 , 6 .

[0025] Figure 1 Also shown is a third tank 16 which can be connected to the vehicle's cooling system and is formed in the battery housing 3. For this purpose, the battery housing 3 has a first coolant connection 17 and a second coolant connection 18. Figure 1 , third tank 16 is connected via a first coolant connection 17 to a first cooler line 19 of a cooling system of a motor vehicle and via a second coolant connection 18 to a second cooler line 20 of a cooling system of a motor vehicle, in particular a cooling system of an internal combustion engine of a motor vehicle. The connection to the cooler system does not necessarily have to be used to cool battery 2, but can also be used at low external temperatures to heat battery 2 by transferring heated coolant into battery housing 3.

[0026] As an alternative to the pipeline of the coolant system of the motor vehicle, the third tank 16 can also be connected to the pipeline of the air conditioning system of the motor vehicle. In this case, cold air or warm air can enter the battery housing 3 as needed.

[0027] In another embodiment of the battery housing 3, there is only one air slot in the form of the first slot 5. Alternatively, there can be only one air slot in the form of the second slot 6. The slots 5 and 6 provided for ventilation can also be selectively fluidically connected to the cooling system or air conditioning system of the internal combustion engine. This fluid connection can also be formed between the third slot 16 and the first slot 5 and / or the second slot 6. If the connection between the slots 5 and / or 6 and the cooling system or air conditioning system is established, the connection of one or both of the slots 5 and 6 to the air lines 13 and 14 will be closed. If only one slot 5 or 6 is connected to the cooling system or air conditioning system, the fluid connection between the slots 5 and 6 will be closed.

[0028] In another embodiment of the battery housing 3 , the battery 2 is a component of the battery housing 3 . In another embodiment, the battery housing 3 is integrated into the engine compartment of the respective vehicle, wherein the battery 2 can be reversibly accommodated in the battery housing 3 .

[0029] Reference Signs List

[0030] 1. Layout

[0031] 2 Lithium-ion batteries

[0032] 3 Battery housing

[0033] 4 Battery housing shell

[0034] 5 First Slot

[0035] 6 Second slot

[0036] 7 Solid insulation material layer

[0037] 8 bracket

[0038] 9 Support

[0039] 10 First Details

[0040] 11 First air connection

[0041] 12 Second air connection

[0042] 13 First air line

[0043] 14 Second air line

[0044] 15 partition wall

[0045] 16 Third slot

[0046] 17 First coolant connection

[0047] 18 Second coolant connection

[0048] 19 First coolant line

[0049] 20 Second coolant line

[0050] 30 Second Detail

Claims

1. A battery housing for a lithium-ion battery of a motor vehicle, comprising: at least one mechanically stable outer shell having a shape corresponding to the shape of the battery; at least one layer comprising a solid thermal insulation material for protecting the battery from heat in the area of the internal combustion engine; at least one first slot formed between the housing and the solid insulation material and connected to an air line leading to the surrounding environment; and at least one second tank formed between the solid insulation material and the lithium-ion battery and connected to a line associated with at least one cooling system of the vehicle.

2. The battery case according to claim 1, wherein The solid thermal insulation material comprises a thermoplastic.

3. The battery case according to claim 1 or 2, wherein: The material of the housing includes metal.

4. The battery case according to claim 1 or 2, wherein: The material of the housing includes steel.

5. The battery case according to claim 1, wherein The second tank is connected to a line of the cooling system of the internal combustion engine of the vehicle.

6. The battery case according to claim 1, wherein The second tank is connected to a line of the vehicle's air conditioning system.

7. The battery case according to claim 1, wherein The battery housing is an integral part of the battery.

8. The battery case according to claim 1, wherein The battery housing is at least partially a component of the vehicle.

9. A motor vehicle having a battery housing for a lithium-ion battery according to any one of claims 1 to 8.

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