Battery module and battery-powered vehicle having a battery module

Abstract

The present invention relates to a battery module, in particular for battery-powered vehicles, comprising a housing, a plurality of battery cells arranged in the housing, and one or more fixing materials for fixing the battery cells to one another and / or to the housing. The at least one fixing material contains an additive, wherein, above a predefined temperature of the fixing means, the additive or a decomposition product of the additive exits the fixing material in a gaseous state, and wherein the battery module comprises at least one sensor which is arranged inside the housing and by means of which the additive or the decomposition product of the additive can be detected.

Description

[0001] battery module and

[0002] battery-electric vehicle with battery module

[0003] The present invention relates to a battery module, in particular for battery-electrically powered vehicles, comprising a housing, a plurality of battery cells arranged in the housing and one or more fixing materials for fixing the battery cells to each other and / or to the housing.

[0004] The invention further relates to a battery-electrically powered vehicle comprising one or more such battery modules.

[0005] Electrically powered vehicles typically use a battery system with one or more battery modules as energy storage. The battery modules contain a large number (e.g., 500 or more) of individual battery cells, which are designed as secondary cells (accumulators) for repeated charging and discharging cycles.

[0006] Various malfunctions during vehicle operation and / or charging can cause so-called "thermal events" in one or more battery cells. A thermal event is defined as any situation in which such a malfunction leads to an unwanted and uncontrolled temperature increase in the affected battery cell, potentially resulting in the release of flammable substances from the cell and, in the worst case, a fire that can quickly spread from the affected cell to the entire battery module. This potential hazard exists, among other things, in battery modules based on lithium-ion batteries, which are currently used in most battery-electric vehicles.The problem of thermal events is not limited to vehicles, but can also arise in the same way in stationary applications of battery modules, e.g. in battery storage systems in buildings, which are used particularly in connection with photovoltaic systems.

[0007] To limit the consequences of a thermal event in a battery module, measures are already known to detect it as early as possible. In particular, temperature sensors are used to warn the driver and / or initiate automatic countermeasures based on a temperature increase in the battery module. However, temperature sensors have the disadvantage that even when multiple sensors are used in a battery module, a temperature increase in a single cell is only detected with a time delay, which can be critical depending on the position of the temperature sensor.

[0008] The invention is therefore based on the objective of proposing a battery module in which a thermal event can be registered as quickly and reliably as possible.

[0009] This problem is solved in the battery module of the type mentioned at the outset according to the invention in that at least one fixing material contains an additive, wherein above a predetermined temperature of the fixing agent the additive or a decomposition product of the additive escapes from the fixing material in a gaseous state, and that the battery module comprises at least one sensor arranged inside the housing with which the additive or the decomposition product of the additive can be detected.

[0010] According to the invention, an additive is used which, above a predetermined temperature characteristic of a thermal event in a battery cell, either escapes from the fixing material or decomposes. Both the heat transfer from the affected battery cell to the immediately adjacent fixing material and the distribution of the escaped additive or decomposition product within the battery module by diffusion occur significantly faster than a temperature increase within the battery module. The gaseous additive or decomposition product can therefore be detected very quickly by a suitable sensor, even if this sensor is located within the battery module at a distance from the affected battery cell.

[0011] The at least one sensor can, in principle, be any type of sensor capable of detecting the additive or its decomposition product with sufficient sensitivity. Regarding selectivity, the choice of sensor is relatively uncritical, as the battery module is not expected to be affected by interference from other gaseous substances besides the normal operating atmosphere.

[0012] Preferably, the at least one sensor is a gas sensor. Various types of gas sensors capable of detecting certain gaseous substances are known to those skilled in the art. The at least one sensor can, in particular, be a chemical gas sensor or a physical gas sensor, preferably an optical, thermal, thermochemical, thermophysical, gravimetric, resistive, capacitive, potentiometric, or amperometric gas sensor.

[0013] The predetermined temperature above which the additive or a decomposition product of the additive escapes from the fixing material in a gaseous state can be selected depending on the type of battery cells and the normal operating conditions of the battery module, corresponding to the temperature at which a thermal event is to be expected. Preferably, the predetermined temperature is approximately 70 °C, more preferably approximately 80 °C. These temperatures are particularly suitable as threshold values ​​for battery cells based on lithium-ion batteries.

[0014] The choice of additive is determined by the predetermined temperature at which the additive or its decomposition product exits the fixing material. Suitable additives within the scope of the invention are, in particular, plasticizers, i.e., compounds that are commonly used as plasticizers in various plastics. Preferably, the additive is selected from the group comprising dicarboxylic acid alkyl esters, in particular phthalic acid esters, tricarboxylic acid alkyl esters, phosphoric acid alkyl esters, fatty acid alkyl esters, soft resins, and camphor.

[0015] Advantageously, the housing of the battery module includes a base plate on which the battery cells are arranged, the fixing means comprising an adhesive for fixing the battery cells to the base plate.

[0016] In a preferred embodiment of the invention, the adhesive comprises the additive, preferably in a quantity of 0.5 to 30 wt.%.

[0017] The adhesive is typically selected from the group comprising epoxy resins and polyurethanes.

[0018] It may also be provided that the fixing means or means include a potting compound for fixing the battery cells to each other.

[0019] According to a further preferred embodiment of the invention, the potting compound comprises the additive, preferably in a quantity of 0.5 to 30 wt.%.

[0020] The potting compound typically comprises a polyurethane, preferably a thermoplastic polyurethane (TPU).

[0021] If the battery module according to the invention comprises both an adhesive for fixing the battery cells to the base plate and a potting compound for fixing the battery cells to one another, the additive can be contained only in the adhesive, only in the potting compound, or in both the adhesive and the potting compound. The battery cells are advantageously designed as cylindrical cells with a substantially cylindrical shape and are arranged parallel to and perpendicular to each other on a base plate of the housing. Advantageously, in this case, the lower end faces of the battery cells are fixed to the base plate with the adhesive, and the potting compound fills the space between the cylindrical cells and fixes them to one another.

[0022] In principle, a single sensor is sufficient within the scope of the invention, which can be arranged at any point within the housing of the battery module. In the event of a thermal event, the escaping additive or decomposition product is rapidly distributed throughout the entire housing by diffusion, so that the thermal event can be detected very quickly.

[0023] Alternatively, the battery module can include multiple sensors located at different points within the housing. This can potentially further accelerate the detection of the additive or decomposition product. It also ensures redundancy in case of sensor failure.

[0024] The battery cells of the battery module according to the invention are preferably lithium-ion batteries. However, the invention is not limited to this type of battery cell, but is applicable to all types of battery cells where the problem of a thermal event exists.

[0025] The invention further relates to a battery-electrically powered vehicle comprising one or more battery modules according to the invention. The vehicle is preferably a motor vehicle, in particular a passenger vehicle.

[0026] Particular advantages and preferred embodiments of the vehicle according to the invention have already been explained in connection with the battery module according to the invention. However, the invention is not limited to use in vehicles, but also includes battery modules for stationary applications, in particular as battery storage systems in buildings.

[0027] These and other advantages of the invention will be explained in more detail using the exemplary embodiment described below with reference to the figures.

[0028] They show in detail:

[0029] Fig. 1: a schematic cross-sectional view of a battery module according to the invention; and

[0030] Fig. 2: a schematic top view of a battery module according to the invention.

[0031] An embodiment of a battery module according to the invention is shown in a schematic cross-sectional view in Figure 1 and is designated as a whole by 10. The battery module 10 comprises a housing 12 and battery cells 14 arranged in the housing, which are designed as cylindrical cells with a substantially cylindrical shape. The battery cells 14 are arranged parallel and perpendicular to each other on a base plate 16 of the housing 12.

[0032] In this embodiment, the battery cells 14 are lithium-ion batteries for use of the battery module 12 in a battery-electric vehicle, although the invention is not limited to this type of battery cell and this application.

[0033] The battery cells 14 are fixed to the base plate 16 of the housing 12 via their lower end faces using an adhesive 18. The adhesive 18 comprises, for example, a thermally conductive adhesive based on an epoxy or polyurethane. The battery module 10 also includes a potting compound 20 as a further fixing material, which is placed between the individual battery cells 14 and fixes them together. The potting compound 20 comprises, for example, a thermoplastic polyurethane (TPU).

[0034] Figure 2 shows a top view of the battery module 10 without the upper part of the housing 12, i.e., a top view of the battery cells 14 and the potting compound 20. For the sake of clarity, the schematically represented battery module 12 comprises only a relatively small number of battery cells 14; in practice, typical battery modules can contain over 500 battery cells. Likewise, for the sake of clarity, other typical components of a battery module, such as the electrical contacts, coolant circuit, etc., for which corresponding openings are provided in the housing, are not shown in the figures.

[0035] The battery module 10 further comprises a sensor 22, in particular a gas sensor, which is arranged within the housing 10. The adhesive 18 and / or the potting compound 20 comprise an additive which, above a predetermined temperature, e.g., above 80 °C, escapes from the adhesive 18 and / or the potting compound 20, optionally in the form of a decomposition product, and is distributed in a gaseous state by diffusion within the housing 12. The additive or the decomposition product is detected by the sensor 22, so that the presence of a thermal event in one of the battery cells 14 can be detected very quickly.

[0036] Sensor 22 is connected to a control system not shown in the figures. In the event of a thermal event detected by sensor 22 in battery module 10, the control system can issue a warning message to the driver of the battery-electric vehicle and / or initiate automatic measures to limit the consequences of the thermal event, such as introducing an extinguishing agent into battery module 10. (Reference symbol list)

[0037] Battery module

[0038] Housing

[0039] Battery cells

[0040] base plate

[0041] Adhesive

[0042] potting compound

[0043] sensor

Claims

patent claims 1. Battery module (10), in particular for battery-electric vehicles, comprising a housing (12), a plurality of battery cells (14) arranged in the housing and one or more fixing materials (18, 20) for fixing the battery cells to each other and / or to the housing, characterized in that at least one fixing material contains an additive, wherein above a predetermined temperature of the fixing agent the additive or a decomposition product of the additive escapes from the fixing material in a gaseous state, and that the battery module comprises at least one sensor (22) arranged inside the housing with which the additive or the decomposition product of the additive can be detected.

2. Battery module (10) according to claim 1, wherein the at least one sensor (22) is a gas sensor.

3. Battery module (10) according to claim 2, wherein the at least one sensor (22) is a chemical gas sensor or a physical gas sensor, preferably an optical, thermal, thermochemical, thermophysical, gravimetric, resistive, capacitive, potentiometric or amperometric gas sensor.

4. Battery module (10) according to any one of the preceding claims, wherein the additive or a decomposition product of the additive leaches from the fixing material above a temperature of approximately 70 °C, preferably above a temperature of 80 °C.

5. Battery module (10) according to any one of the preceding claims, wherein the additive comprises a plasticizer, preferably selected from the group consisting of dicarboxylic acid alkyl esters, in particular phthalic acid esters, tricarboxylic acid alkyl esters, phosphoric acid alkyl esters, fatty acid alkyl esters, soft resins and camphor.

6. Battery module (10) according to one of the preceding claims, wherein the housing (12) comprises a base plate (16) on which the battery cells (14) are arranged, and wherein the fixing means or means comprise an adhesive (18) for fixing the battery cells to the base plate.

7. Battery module (10) according to claim 6, wherein the adhesive (18) comprises the additive, preferably in a quantity of 0.5 to 30 wt.%.

8. Battery module (10) according to claim 6 or 7, wherein the adhesive (18) is selected from the group comprising epoxy resins and polyurethanes.

9. Battery module (10) according to one of the preceding claims, wherein the fixing means or means comprise a potting compound (20) for fixing the battery cells (14) to one another.

10. Battery module (10) according to claim 9, wherein the potting compound (20) comprises the additive, preferably in a quantity of 0.5 to 30 wt.%.

11. Battery module (10) according to claim 9 or 10, wherein the potting compound (20) comprises a polyurethane, preferably a thermoplastic polyurethane (TPU).

12. Battery module (10) according to any one of the preceding claims, wherein the battery cells (14) are designed as round cells with a substantially cylindrical shape and are arranged on a base plate (16) of the housing (12) parallel to each other and perpendicular to the base plate.

13. Battery module (10) according to one of the preceding claims, comprising several sensors (22) arranged at different locations within the housing (12).

14. Battery module (10) according to any of the preceding claims, wherein the battery cells (14) are lithium-ion accumulators.

15. Battery-electrically powered vehicle comprising one or more battery modules (10) according to any of the preceding claims. * * *

Images