DE102020112110A1 - Battery module with cell gas supply, battery system and motor vehicle - Google Patents

Abstract

The invention relates to a battery module (1) for a battery system (16) for a motor vehicle (2), comprising a module housing (3) with a module interior (5) formed by a housing wall (4), several battery cells (5) arranged in the module interior (5). 6) and a cooling fluid for cooling the battery cells (6), the battery cells (6) being bathed in the cooling fluid. At least one gas routing device (7) for guiding cell gas and at least one sensor device (8) are arranged in the module interior (5), the sensor device (8) being designed for detecting cell gas in the at least one gas guiding device (7). The invention also relates to a battery system (16) for a motor vehicle (2) and a motor vehicle (2) with a battery module (1) or battery system (16) according to the invention.

Description

The present invention relates to a battery module for a motor vehicle. The invention also relates to a battery system with a plurality of battery modules and a motor vehicle with a generic battery system.

Electrically operated motor vehicles usually have a battery for receiving, storing and providing electrical energy. In particular, so-called battery systems are used as the battery. Conventional battery systems for electrically operated motor vehicles have a large number of battery cells which are connected to one another via their arresters. Furthermore, such battery systems have power electronics, which often also have a battery management system (BMS) for controlling and monitoring the battery system.

Battery cells based on Li-ions have proven to be particularly advantageous for battery systems. Such battery cells have a relatively high power density and relatively little wear.

Conventional cylindrical or prismatic cells based on Li-ions have a cylindrical or prismatic design with a rigid cell wall. More modern battery cells for motor vehicles are increasingly being designed as so-called pouch cells. For receiving, storing and providing electrical energy, pouch cells have an active part which is arranged within a cell interior formed by a flexible cell wall. The active part can be connected to other pouch cells via arresters. The cell wall has connecting seams, such as weld seams or adhesive seams, for forming a closed cell interior for sealing the cell interior.

Battery cells are subject to continuous aging, which can be accelerated by improper use, such as short circuit, deep discharge, overheating, rapid charging, high discharge currents or the like. When a battery cell ages, chemical reactions and conversions take place on and in electrodes, as well as between electrodes and an electrolyte of the battery cell. As a result, gases form inside the battery cell and thus ensure a rise in pressure within the battery cell.

To reduce aging, battery systems have a device for temperature control, e.g. a cooling device. By means of the cooling device, for example, cell walls of the battery cells can be cooled via cooling fluid lines. In alternative battery systems, the battery cells are washed around by the cooling fluid.

In conventional cylindrical or prismatic cells, the cell wall is designed to be relatively rigid, so that an increase in pressure within the battery cell initially leads to an increase in the voltage within the cell wall. To avoid overpressure within the battery cell, which in extreme cases can lead to the cell wall of the battery cell and a module wall of a battery module comprising several battery cells bursting, such battery cells often have an overpressure valve in order to vent gases from the battery cell at a critical overpressure. In particular, prismatic cells can contain devices which interrupt the flow of current in the cell when the internal cell pressure is too high. This is more difficult with pouch cells and cylindrical cells, so that when the cell envelope is opened, these cells allow the gas to escape without this being detected directly e.g. by voltage, current flow, temperature behavior or tension pressure of the cells. In addition, battery systems of this type often have a cooling device for cooling the battery modules and the battery cells.

In the case of pouch cells, the cell wall is made of a more flexible material, such as a metal foil coated with an insulator, in particular a plastic, in particular an aluminum foil, so that an increase in pressure within the battery cell leads to an expansion of the battery cell. Conventional connection seams of pouch cells cannot withstand an overpressure comparable to that of cylindrical cells. Therefore, pouch cells usually do not have any pressure relief valves. Nevertheless, it is of great importance to reliably detect failure of the connection seams, since open battery cells dry out and can negatively affect a complete battery cell system due to their increasing internal resistance.

From the pamphlets US 2012/0133521 A1 and US 2018/0287223 A1 Battery cell systems based on stacked pouch cells are known in which a change in the curvature of a pouch cell can be determined by means of strain gauges (DMS). In this way, the accumulation of cell gases within the pouch cell can be detected. the US 2013/0330577 A1 discloses a battery cell system with a stack of pouch cells, in which state variables of the pouch cells are determined and an external pressure is exerted on the stack by means of a pressure device in order to maintain or increase the efficiency of the battery cell system.

From the pamphlet US 2014/0045036 A1 a battery cell system is known with a system housing on which a pressure sensor for determining an internal pressure in the system housing is arranged. Operation of the battery system can be controlled on the basis of measured values from the pressure sensor. The pamphlet US 2017/0162923 A1 discloses a battery system having a plurality of battery cells which are surrounded by a system housing. A cooling liquid that washes around the battery cells is arranged in the system housing. The cooling liquid can be pumped from the system housing through a heat exchanger and into a cooling liquid tank using a pump. A liquid level in the coolant tank can be measured using a fill level sensor. An increase in pressure in the system housing due to escaping cell gas causes a change in the liquid level in the coolant tank.

Known battery cell systems have the disadvantage that only insufficient monitoring of the state of the battery cells is guaranteed. A leakage of cell gas is not possible in most battery cell systems or only possible with larger amounts of cell gas and with a disadvantageous time delay.

It is therefore the object of the present invention to remedy or at least partially remedy the disadvantages described above in a battery module, a battery system and a motor vehicle. In particular, it is the object of the present invention to create a battery module for a battery system for a motor vehicle, a battery system for a motor vehicle and a motor vehicle, which ensure improved detection of the escape of cell gas in a simple and inexpensive manner.

The above problem is solved by the patent claims. Accordingly, the object is achieved by a battery module for a motor vehicle with the features of independent claim 1, a battery system with the features of independent claim 8 and by a motor vehicle with the features of the independent claim 10. Further features and details of the invention emerge from the subclaims, the description and the drawings. Features and details that are described in connection with the battery module according to the invention naturally also apply in connection with the battery system according to the invention and the motor vehicle according to the invention and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always or can be made to the individual aspects of the invention.

According to a first aspect of the invention, the object is achieved by a battery module for a battery system for a motor vehicle. The battery module has a module housing with a module interior formed by a housing wall, a plurality of battery cells arranged in the module interior and a cooling fluid for cooling the battery cells, the battery cells being bathed by the cooling fluid. According to the invention, at least one gas guiding device for guiding cell gas and at least one sensor device are arranged in the module interior, the sensor device for detecting cell gas being designed in the at least one gas guiding device.

The module interior is formed by the housing wall of the module housing. The module housing is preferably designed to protect the battery cells arranged in the module interior from mechanical impacts, pressure or the like. The module housing is preferably designed to be gas-tight. It is preferred according to the invention that the module housing has a pressure relief valve for releasing excess pressure in order to avoid an excessive pressure increase in the module interior and thus a possible bursting of the housing wall in the event of a strong escape of cell gas. The module housing is preferably made of metal and / or a fiber-reinforced plastic or the like. The battery cells are preferably arranged next to one another and / or stacked on top of one another in the module interior.

Gaps are formed between adjacent battery cells. The cooling fluid is arranged in the intermediate spaces. The cooling fluid is preferably designed as a cooling liquid. The module housing preferably has a cooling fluid inlet for feeding the cooling fluid into the module interior and a cooling fluid outlet for discharging the cooling fluid from the module interior. The cooling fluid inlet and the cooling fluid outlet are preferably coupled in fluid communication with a cooling system. The cooling system preferably has a cooling fluid pump and a heat exchanger. The heat exchanger is preferably designed as a radiator cooler and more preferably for arrangement behind a radiator grille of a motor vehicle. The cooling system further preferably has a cooling fluid reservoir for storing the cooling fluid. For better monitoring of the battery module, the cooling system preferably has a temperature sensor for measuring a temperature of the cooling fluid and / or a pressure sensor for measuring the pressure in the cooling fluid reservoir. The temperature sensor is preferably arranged in the area of the cooling fluid outlet. Another temperature sensor is preferably arranged at the coolant inlet.

The gas routing device is arranged in the module interior. The gas guide device can, for example, be part of the housing wall of the module housing and / or as part of a cell wall of a cell housing of a battery cell and / or as an independent component, such as a separate tube or the like, for example. The gas guide device can be formed, for example, by an edge, in particular with an angle facing the module interior of less than 180 °, preferably between 90 ° and 120 °, of a wall. The gas routing device is preferably designed and set up in such a way that it absorbs cell gas flowing out of the battery cells and guides it to the sensor device. The sensor device is preferably arranged in an upper region of the module housing, preferably in the module interior, in order to be able to better detect the cell gas rising in the cooling fluid.

A battery module according to the invention has the advantage over conventional battery modules that the outflowing cell gas of the battery cells can be concentrated on the sensor device with simple means and in a cost-effective manner, so that even small amounts of cell gas early, namely already within the system interior, and without Time delay can be reliably detected. By detecting the cell gas at an early stage, countermeasures such as intensifying the cooling and / or switching off one or more battery modules or the like can be carried out by a battery management system of the battery module or a battery system having a plurality of battery modules. In this way, further damage to the battery module or battery system and consequential damage to the motor vehicle can be avoided in a significantly more reliable manner than with conventional battery modules.

According to a preferred further development of the invention, it can be provided in the case of a battery module that the sensor device is arranged completely or partially in the gas routing device. In the context of the invention, this is understood in particular to mean that a sensor or a detection head of the sensor device is arranged in the gas guide device. Accordingly, it can be provided according to the invention that the sensor device protrudes into the gas guide device and / or forms part of a wall of the gas guide device. This has the advantage that, with simple means and in a cost-effective manner, the cell gas arranged in the gas guiding device can be detected better and thus at an early stage even in very low concentrations.

It is preferred according to the invention that the sensor device has a detector float for swimming on the cooling fluid and / or at least one detector lamella and / or a spectrometer for detecting the cell gas in the gas guide device. In the context of the invention, a detector float is understood to mean a device which is designed to float on the cooling fluid. In this case, the gas routing device is preferably designed such that the cooling fluid is displaced from the gas routing device by an increase in the cell gas and a cooling fluid level in the gas routing device thus falls. This can be detected by means of the detector float. In the context of the invention, a detector lamella is understood to mean a device which is arranged within the gas guiding device and can be deflected differently depending on the surrounding medium, such as, for example, cooling fluid and cell gas. This deflection can be detected, for example, by means of a circuit which can be opened and closed by the detector lamella. The sensor device preferably has a plurality of such detector lamellae in order to increase the sensitivity of the sensor device. An IR spectrometer is preferred as the spectrometer in the context of the invention. Using a spectrometer, precise statements can be made about the type of gas detected. It can thus also be determined whether the detected gas is cell gas or ambient air flowing in from the outside. This has the advantage that reliable detection of cell gas is provided with simple means and in a cost-effective manner.

The module housing further preferably has a housing cover with an inside of the cover facing the module interior, the at least one gas guide device extending on the inside of the cover. In the context of the invention, a housing cover is understood to mean a housing wall that delimits the module interior at the top. The housing cover can be detachable or fixedly, in particular permanently, connected to one or more adjacent housing walls. The gas routing device is preferably arranged on the housing cover in such a way that the gas routing device runs from the edge, preferably from corners, of the housing cover to a surface center point of the housing cover. This has the advantage of being easy to use as well as in an inexpensive manner Concentration of the cell gas inside the module interior and thus an improved detection of the cell gas is guaranteed.

In a particularly preferred embodiment of the invention, the inside of the cover is concave and / or pyramidal or conical. According to the invention, it can be provided that the entire housing cover is concave and / or pyramidal or conical. Such a curvature or incline of the housing cover has the advantage that a concentration of the cell gas within the module interior and thus an improved detection of the cell gas is ensured with simple means and in a cost-effective manner.

The inside of the lid preferably has a coating. The coating is preferably designed as a nano-coating. More preferably, the coating is, for example, hydrophilic or lipophilic, in order to promote wetting of the inside of the lid with cooling fluid and thus to improve the flow of cell gas. This has the advantage that a concentration of the cell gas within the module interior and thus an improved detection of the cell gas is ensured with simple means and in a cost-effective manner.

According to a preferred embodiment of the invention, the gas routing device has a circumferentially closed gas routing line or a gas routing channel open on the longitudinal side. According to the invention, it can be provided that the gas guide device is designed partly as a gas guide line and partly as a gas guide channel. In the context of the invention, a gas guide line is a device which has a gas inlet and a gas outlet and is designed to guide the cell gas from the gas inlet to the gas outlet. A gas guide channel is designed to receive cell gas via the open side. The gas guide channel is preferably arranged such that the open side points downwards so that cell gas flowing upwards can flow into the gas guide channel, with cell gas also being able to flow out of the gas guide channel via the open side in the case of particularly large cell gas flows. This has the advantage that a concentration of the cell gas within the system interior and thus an improved detection of the cell gas is ensured with simple means and in a cost-effective manner.

According to a second aspect of the invention, the object is achieved by a battery system. The battery system has a system interior formed by a system housing and a plurality of battery modules arranged in the system interior. According to the invention, at least one of the battery modules is designed as a battery module according to the invention.

Several or all of the battery modules are preferably designed as battery modules according to the invention. It is preferred here that the gas routing devices of a plurality of battery modules are coupled to one another in a fluid-communicating manner. More preferably, at least two battery modules have a common sensor device, so that manufacturing costs of the battery system are reduced.

The battery system according to the invention has all the advantages that have already been described for a battery module according to the first aspect of the invention. Accordingly, the battery system according to the invention has the advantage over conventional battery systems that the outflowing cell gas of the battery cells can be concentrated on the sensor device with simple means and in a cost-effective manner, so that even small amounts of cell gas early, namely already within the module interior, and can be reliably detected without a time delay. By detecting the cell gas at an early stage, countermeasures, such as, for example, increasing the cooling and / or switching off one or more battery modules or the like, can be carried out by a battery management system of the battery system. In this way, further damage to the battery system and consequential damage to the motor vehicle can be avoided significantly more reliably than in conventional motor vehicles with known battery systems.

It is preferred according to the invention that the battery modules are bathed in the cooling fluid, with at least one gas routing device for guiding cell gas and at least one sensor device being arranged in the system interior outside the battery modules, and with the sensor device for detecting cell gas being formed in the at least one gas routing device. Such a battery system has improved cooling of the battery modules, since the cooling fluid washes around the battery modules both from the outside and from the inside. An additional gas routing device and an additional sensor device outside the battery modules have the advantage that the cell gas is concentrated within the system interior and thus improved detection of the cell gas is ensured with simple means and in a cost-effective manner. Furthermore, this provides a redundancy through which the operational reliability of the battery system is further improved.

According to a third aspect of the invention, the object is achieved by a motor vehicle. The motor vehicle has a drive system with an electric motor. According to the invention, the motor vehicle has a battery module according to the invention or a battery system according to the invention. The motor vehicle is preferably designed as an electric vehicle or a hybrid vehicle.

The electric motor is preferably designed to drive the motor vehicle. Accordingly, the electric motor is preferably used as an auxiliary electric motor for supporting an internal combustion engine of the motor vehicle for jointly driving the motor vehicle and / or as Drive electric motor designed for the sole purpose of driving the motor vehicle.

The battery module or battery system is preferably designed to provide the electrical energy for operating the electric motor.

The motor vehicle according to the invention has all the advantages that have already been described for a battery module according to the first aspect of the invention and for a battery system according to the second aspect of the invention. Accordingly, the motor vehicle according to the invention has the advantage over conventional motor vehicles that the outflowing cell gas of the battery cells can be concentrated on the sensor device with simple means and in a cost-effective manner, so that even small amounts of cell gas early, namely already within the module interior or system interior , and can be reliably detected without a time delay. By detecting the cell gas at an early stage, countermeasures such as intensifying the cooling and / or switching off one or more battery cells or one or more battery modules or the like can be carried out by a battery management system of the battery module or the battery system. In this way, further damage to the battery module or battery system and consequential damage to the motor vehicle can be avoided in a significantly more reliable manner than in conventional motor vehicles with known battery modules or battery systems.

• 1 in einer perspektivischen Ansicht ein Batteriemodul gemäß einer bevorzugten ersten Ausführungsform,
• 2 in einer Seitenansicht das Batteriemodul aus 1,
• 3 in einer perspektivischen Ansicht ein Batteriemodul gemäß einer bevorzugten zweiten Ausführungsform,
• 4 in einer Seitenansicht das Batteriemodul aus 3,
• 5 in einer Draufsicht eine Deckelinnenseite eines Gehäusedeckels gemäß der bevorzugten zweiten Ausführungsform, und
• 6 in einer Seitenansicht eine bevorzugte Ausführungsform eines erfindungsgemäßen Kraftfahrzeugs.

A battery module according to the invention, a battery system according to the invention and a motor vehicle according to the invention are explained in more detail below with reference to drawings. They each show schematically:

• 1 in a perspective view a battery module according to a preferred first embodiment,
• 2 in a side view of the battery module 1 ,
• 3 in a perspective view a battery module according to a preferred second embodiment,
• 4th in a side view of the battery module 3 ,
• 5 a top view of a cover inside of a housing cover according to the preferred second embodiment, and
• 6th in a side view a preferred embodiment of a motor vehicle according to the invention.

Elements with the same function and mode of operation are in the 1 until 6th each provided with the same reference numerals.

In 1 is a battery module 1 according to a preferred first embodiment shown schematically in a perspective view. 2 shows the battery module 1 the end 1 schematically in a side view. The battery module 1 has a module housing 3 with a housing wall 4th on which a module interior 5 includes. An upper case wall 4th is as a housing cover 12th educated. The housing cover 12th is essentially plate-shaped. In the module interior 5 are several battery cells 6th arranged. The battery cells 6th are surrounded by a liquid cooling fluid.

On the vertical edges of the module housing 3 are in the module interior 5 several gas guiding devices 7th arranged, which is up over the housing cover 12th extend beyond. The gas guiding devices 7th are as completely closed gas ducts 14th formed, the gas guide lines 14th preferably openings for receiving the cell gas from the battery cells 6th exhibit. Examples are on the gas routing devices 7th different sensor devices 8th such as a detector float 9 , two detector blades 10 as well as a spectrometer 11 arranged. According to alternative embodiments of the battery module according to the invention 1 several identical or exclusively identical sensor devices can also be used 8th with a battery module 1 be used.

In 3 is a battery module 1 according to a preferred second embodiment shown schematically in a perspective view. 4th shows the battery module 1 the end 3 schematically in a side view. In this preferred second embodiment, the housing cover is 12th pyramid-shaped, the gas guide devices 7th through inner edges of the housing cover 12th as gas ducts 15th are formed and thus from the lower corners of the housing cover 12th to a tip 19th of the housing cover 12th get lost. Further gas routing devices 7th are also used as gas ducts 15th formed and extend from the centers of lower edges 20th of the housing cover 13th to the top 19th .

In 5 is the inside of the lid 13th a housing cover 12th according to the preferred second embodiment of the battery module according to the invention 1 shown schematically. In this view they are used as gas ducts 15th trained gas guiding devices 7th which stand out from the lower edges 20th to the top 19th extend towards, particularly clearly recognizable. At the top 19th is the sensor device 8th arranged. Ascending cell gas is via the gas guide devices 7th to the top 19th and thus to the sensor device 8th steerable.

6th shows a preferred embodiment of a motor vehicle according to the invention 2 schematically in a side view. The car 2 exhibits a drive system 17th with an electric motor 18th and a battery system according to the invention 16 on. The battery system 16 has a system case 21 on which a system interior 22nd forms. In the system interior 22nd are several battery modules according to the invention 1 arranged.

List of reference symbols

1

Battery module

2

Motor vehicle

3

Module housing

4th

Housing wall

5

Module interior

6th

Battery cell

7th

Gas guiding device

8th

Sensor device

9

Detector float

10

Detector lamella

11

spectrometer

12th

Housing cover

13th

Inside of the lid

14th

Gas duct

15th

Gas duct

16

Battery system

17th

Drive system

18th

Electric motor

19th

top

20th

lower edge

21

System housing

22nd

System interior

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 2012/0133521 A1 [0009]
• US 2018/0287223 A1 [0009]
• US 2013/0330577 A1 [0009]
• US 2014/0045036 A1 [0010]
• US 2017/0162923 A1 [0010]

Claims (10)

A battery module (1) for a battery system (16) for a motor vehicle (2), comprising a module housing (3) with a module interior (5) formed by a housing wall (4), a plurality of battery cells (6) arranged in the module interior (5) and a Cooling fluid for cooling the battery cells (6), the battery cells (6) being bathed in the cooling fluid, characterized in that at least one gas routing device (7) for routing cell gas and at least one sensor device (8) are arranged in the module interior (5), wherein the sensor device (8) is designed for detecting cell gas in the at least one gas guide device (7). Battery module (1) Claim 1 , characterized in that the sensor device (8) is arranged completely or partially in the gas guide device (7). Battery module (1) Claim 1 or 2 , characterized in that the sensor device (8) has a detector float (9) for swimming on the cooling fluid and / or at least one detector lamella (10) and / or a spectrometer (11) for detecting the cell gas in the gas guide device (7). Battery module (1) according to one of the preceding claims, characterized in that the module housing (3) has a housing cover (12) with an inside (13) of the cover facing the module interior (5), the at least one gas guide device (7) being on the inside of the cover (13) extends. Battery module (1) Claim 4 , characterized in that the inside of the lid (13) is concave and / or pyramidal or conical. Battery module (1) Claim 4 or 5 , characterized in that the inside of the lid (13) has a coating. Battery module (1) according to one of the preceding claims, characterized in that the gas routing device (7) has a circumferentially closed gas routing line (14) or a gas routing channel (15) open on the longitudinal side. Battery system (16) for a motor vehicle (2), comprising a system interior (22) formed by a system housing (21) and a plurality of battery modules (1) arranged in the system interior (22), characterized in that at least one of the battery modules (1) is used as a battery module (1) is designed according to one of the preceding claims. Battery system (16) Claim 8 , characterized in that the battery modules (1) are bathed in the cooling fluid, with at least one gas guide device (7) for guiding cell gas and at least one sensor device (8) being arranged in the system interior (22) outside the battery modules (1), the sensor device (8) is designed to detect cell gas in the at least one gas guiding device (7). Motor vehicle (2), having a drive system (17) with an electric motor (18), characterized in that the drive system (17) has a battery module (1) according to one of the Claims 1 until 7th or a battery system (16) according to one of the Claims 8 or 9 having.

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