Battery energy storage device

Abstract

The present invention relates to a battery energy storage device (100), wherein a sealing element (40) is arranged at a through-opening (13) which extends through a housing (10) and in which a busbar (30) extends from an interior (12) to an outer face (17) of the housing (10).

Description

[0001] Battery storage device

[0002] The present invention relates to a battery storage device in which battery cells are accommodated, with a defined discharge for possible outgassing from the battery cells.

[0003] The battery storage device is used as a battery module in a modular structure of a battery storage system, which is used, for example, in mobile applications such as a traction battery in a vehicle.

[0004] Modular battery storage systems are known that have a high energy density and require special safety features to prevent, as far as possible, a spreading chain reaction among the battery cells in the event of thermal runaway, which can occur with some flammable active materials in lithium-ion batteries. These safety features include, among other things, a vent through which hot exhaust gases and their thermal load can be discharged to the outside in a controlled manner.

[0005] If the battery storage system is located on board a vehicle, particularly in the immediate vicinity of a passenger compartment, there are also further safety regulations regarding a permissible thermal load, which is dissipated to a limited extent by exhaust gases in the system environment of the vehicle, such as in particular a maximum temperature or the avoidance of flying sparks from glowing particles on which gases can ignite.

[0006] On the other hand, vehicle construction is constantly striving for space, weight, and cost optimization, which limits the design freedom for constructive solutions that address the aforementioned safety-relevant treatment of outgassing and waste heat in thermally critical incidents. Accordingly, there is a fundamental need for a design to improve the thermal behavior of battery storage systems. It is an object of the invention to design and further develop a battery storage system in such a way that passenger safety is improved in the event of venting of outgassing from thermally overloaded battery cells in the battery storage system.

[0007] The above object is achieved by a battery storage device having the features of claim 1. Further features and details of the invention emerge from the subclaims, the description and the drawings.

[0008] The battery storage device according to the invention comprises a housing for accommodating a plurality of battery cells and at least one gas outlet opening arranged on the housing and serving to discharge outgassing from the battery cells from an interior of the housing to an exterior of the housing. Likewise, the battery storage device has at least one bus bar for the common electrical connection of the battery cells in the housing to an electrical terminal arranged on the exterior of the housing. According to the invention, a sealing means is arranged, in particular, on a passage opening which leads through the housing and in which the bus bar passes between the interior and the exterior of the housing.

[0009] The invention thus provides, for the first time, a seal in the exit area of ​​a busbar or bus bar from a housing. This seals the exit area of ​​the busbar in a gas-tight manner. In the event of outgassing from a battery cell, it can be ensured that no exhaust gas escapes uncontrollably from the housing through the busbar's through-opening. Furthermore, if the housing has no other functional openings besides the gas outlet, it can be ensured that the hot exhaust gas is discharged from the battery storage housing in a controlled manner exclusively via the gas outlet.

[0010] The term “sealing agent” is defined in the present disclosure as a hardening mass comprising a filler and a binder which adheres to the surfaces of suitable materials, forms its own closed, sealing surface and thus ensures a sealing property over underlying elements against the escape of a gas.

[0011] A major advantage of the invention is that it creates the prerequisite for outgassing, i.e., allowing a venting gas to escape from the housing in a defined, directed manner in the event of thermal propagation. In this context, further advantages of the invention include the fact that the hot exhaust gas flows exclusively to the gas outlet via a path specifically provided for this purpose, optionally with a cooling design, in a controlled manner, and does not escape from the housing via another opening for the battery cell wiring. As a further consequence, this makes it possible to suppress as effectively as possible the spread of critical temperatures to neighboring battery cells in the battery storage system and a possible thermal chain reaction among the battery cells.

[0012] According to an advantageous aspect of the invention, the sealing means can be in contact with an inner surface of the housing in an area surrounding the through-opening and enclose the bus bar in the housing. Thus, the through-opening is closed at least from an inner side of the housing. By selecting a sufficiently large area around the through-opening, the sealing means can be processed with relatively high tolerance tolerances, advantageously from a manufacturing perspective, and can be applied to the housing in a manner that is easily accessible from only one side, thereby achieving a sufficiently tight seal.

[0013] According to a building upon this or an alternative aspect of the invention, the sealing means can fill a periphery of the passage opening and enclose the bus bar in the passage opening. Thus, the housing is sealed in a circumferential gap between the passage opening and the bus bar in the passage opening itself. By applying the sealing means only within the passage opening, a sufficiently tight seal can be achieved in a cost-effective manner through minimal use of material. According to a further aspect of the invention, the bus bar can be arranged in a housing section between the plurality of battery cells in the interior of the housing and a housing wall. Thus, the sealing area is expanded both in its extent and functionally with respect to the housing.

[0014] According to a further aspect of the invention, the sealing agent can substantially fill the housing section and substantially enclose the bus bar, sealing the interior of the housing in a gas-tight manner from the outside. This can further ensure that any flammable gas does not come into contact with the bus bar, which, due to its thermal conductivity, may have already heated up to flammable temperatures and glowed during a thermal incident in the battery cell in question. Accordingly, ignition of a flammable exhaust gas through direct contact with a hot bus bar or busbar can be avoided. For example, the sealing agent can fill an outer housing section up to the housing wall in order to seal the interior of the housing from the housing section in which the bus bar is arranged.By sealing a larger area around the manifold, which also includes the passage opening, the ignition of a combustible exhaust gas in connection with a high temperature of a manifold is safely excluded.

[0015] According to an advantageous aspect of the invention, the housing can be composed of at least two housing elements at a component boundary, and the sealing means can be in contact with an inner surface of the housing in a region surrounding the component boundary. Thus, a gas-tight seal of the housing to an inner side of the component boundary between the housing elements is achieved.

[0016] According to a subsequent or alternative aspect of the invention, the housing can be composed of at least two housing elements at a component boundary, and the sealing means can be arranged between opposing interfaces of the housing elements. This optionally or additionally achieves a gas-tight seal of the interior of the housing at the component boundary between the housing elements.

[0017] According to an advantageous aspect of the invention, the sealant may comprise an inorganic, particularly mineral, filler. This is inexpensive and readily available.

[0018] According to an advantageous aspect of the invention, the sealing agent may comprise a silicon oxide-based ceramic composite. This increases the strength of the sealing layer.

[0019] According to an advantageous aspect of the invention, the sealant may comprise a high-temperature-resistant binder. Preferably, a binder is selected that is non-combustible after curing at temperatures above 1000°C.

[0020] According to an advantageous aspect of the invention, the sealing agent can have an adhesive property or be an adhesive. This ensures the integrity of the seal on the housing elements, whose adhesion also withstands mechanical influences such as vibrations or similar in mobile applications.

[0021] According to an advantageous aspect of the invention, the sealing means can have an electrically insulating property. This prevents a short circuit from occurring between the bus bar and the housing parts that are enclosed and contacted by the seal.

[0022] Further advantages, features, and details of the invention will become apparent from the following description, which describes embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. They show schematically:

[0023] Fig. 1 is a schematic side sectional view of a modular battery storage device according to an embodiment of the invention, Fig. 2 is a schematic top plan view of an opened battery storage device according to the same embodiment of the invention.

[0024] Fig. 1 schematically shows a sectional view through a modular battery storage device 100 in a vertical plane S, the course of which is marked in Fig. 2. Fig. 2 shows, orthogonally to Fig. 1, a schematic plan view of an open state of the battery storage device 100 in a horizontal plane D, the course of which is marked in Fig. 1.

[0025] The battery cells 20—illustrated here as pouch cells—are housed in an interior space 12 of a housing 10. On the left and right sides shown, the battery cells 20 are held and fixed in the housing 10 by a carrier 15 made of a ceramic material.

[0026] A plurality of adjacent battery cells 20 are combined in groups and electrically connected to one another within the group via cell contacts 23 in parallel connection to bus bars 30. The groups of battery cells 20 are in turn electrically connected to one another in series connection via the bus bars 30. At the outer groups of battery cells within the housing 10, a wiring of the battery cells 20 ends in potential connections 31 with a positive and a negative potential, which represent the electrical connection poles of the modular battery device 100. Several of these modular battery devices 100 in turn form a larger battery storage device, such as a traction battery of a vehicle or the like. To provide the connections 31, the bus bars 30 of the respective outer groups of battery cells 20 emerge from the housing 10 via a respective through-opening 13.

[0027] Gas outlet openings 16 are arranged on an underside of the housing 10, i.e., at a floor of the interior 12, and are assigned to the groups of battery cells 20. In the event of an ignition or a similar thermally critical incident that causes outgassing, i.e., escaping exhaust gases from a battery chemistry in the battery cells 20, the gas can escape downward from the interior 12 through the gas outlet openings 16—represented by the arrows—as part of a pressure reduction. In an exhaust duct (not shown in detail), the gas is released to an outside 17 or an environment of the battery storage device 100 via detours that lead to a cooling of the gas temperature.

[0028] A sealing agent 40 is introduced into outer housing sections 14 of the housing 10 on the left and right sides shown, filling the outer housing sections 14 of the housing 10 and enclosing the wiring of the busbar arrangement 30 up to the through-openings 13. The sealing agent 40 is in contact with the inner walls of the housing 10 and fills the area around the through-openings 13 such that the through-openings 13 are enclosed in a gas-tight manner. Thus, a volume of the interior 12 of the housing 10 is sealed against gas escape by the sealing agent in the housing sections 14 on the left and right sides, and venting is only possible in a controlled manner through the provided gas outlet openings 16, preferably into a housing section (not shown) for further exhaust gas treatment.Furthermore, the sealing agent 40 creates a thermal barrier between the bus bars 30 and the volume of the interior space 12.

[0029] The sealant 40 is preferably an inorganic, high-temperature-resistant, single-component adhesive, such as that used for sealing flame barriers. It is suitable for bonding metals and other low-absorption materials, comprises a ceramic composite, and is temperature-resistant up to 1100°C, particularly non-flammable.

[0030] In the top view of Fig. 2 of the opened battery storage device 100, a housing cover 11 of the housing 10 and the carrier 15 for securing the battery cells 20, which are visible from above, have been removed. Likewise, the outer housing sections 14 are not yet filled with the sealing agent 40, whereby the conductor structure as well as the terminals 31 of the bus bar 30 are visible from above.

[0031] The sealing agent 40 can be introduced into the outer housing sections 14 during assembly of the modular battery storage device 100, before or after inserting and connecting the conductor structure of the bus bars 30. The filling of the sealing agent 40 is in contact with an inner surface of the housing 10 at least in the vicinity of the passage opening 13, so that the passage opening 13 is closed to the inside of the housing 10.

[0032] Additionally or alternatively, the filling of the sealing agent 40 is introduced into a gap between the passage opening 13 and the bus bar 30 passing through it, so that the housing 10 is closed in a gap around the bus bar 30 in the passage opening 13.

[0033] The housing 10 is a multi-part housing 10 having a housing cover 11 and a component boundary G shown in Fig. 1 between an interface 10g of the housing 10 and an interface 11g of the housing cover 11. The filling of the sealing agent 40 is in contact with an inner surface of the housing 10 at least in the vicinity of the component boundary G, so that a gap between the component boundary G and the inner surface of the housing 10 is closed. Additionally or alternatively, the filling of the sealing agent 40 is introduced into a gap between the interface 10g of the housing 10 and the interface 11g of the housing cover, so that the housing 10 is closed in the gap of the component boundary G at the interfaces 10g, 11g.

[0034] Alternatively, the battery storage device 100 may also have cylindrical or differently shaped battery cells 20 and the representative gas outlet openings 16 may also exit from the housing 10 to a different side and they do not have to lead to the outside 17, but may first lead into another housing section.

[0035] The above explanations of the embodiments describe the present invention exclusively by way of examples. Of course, individual features of the embodiments can be freely combined with one another, provided they are technically feasible, without departing from the scope of the present invention.

[0036] 10 housings

[0037] 10g interface of the housing at the component boundary

[0038] 11 Housing cover

[0039] 11g Interface of the housing cover at the component boundary

[0040] 12 Interior

[0041] 13 Passage opening

[0042] 14 Housing section filled with sealant

[0043] 15 battery cell carriers

[0044] 16 gas outlet openings

[0045] 17 Outside

[0046] 20 battery cells

[0047] 23 cell contacts

[0048] 30 collection managers

[0049] 31 potential connections

[0050] 40 sealants

[0051] 100 battery storage device

[0052] G Component boundary between housing and housing cover

[0053] D Plane of the top view in Fig. 2

[0054] S plane of the sectional view in Fig. 1

Claims

Patent claims 1. A battery storage device (100), comprising: a housing (10) for accommodating a plurality of battery cells (20); at least one gas outlet opening (16) leading through the housing (10) for discharging outgassing from the battery cells (20) from an interior space (12) of the housing (10) to an exterior space (17) of the housing (10); at least one bus bar (30) for the common electrical connection of the battery cells (20) in the housing (10) to an electrical terminal (31) arranged on the exterior space (17) of the housing (10); characterized in that a sealing means (40) is arranged at a passage opening (13) leading through the housing (10) and in which the bus bar (30) passes between the interior space (12) and the exterior space (17) of the housing (10).

2. Battery storage device (100) according to claim 1, wherein the sealing means (40) is in contact with an inner surface of the housing (10) in a region surrounding the passage opening (13) and encloses the bus bar (30) in the housing (10) at least in sections.

3. Battery storage device (100) according to claim 1 or 2, wherein the sealing means (40) fills a circumference of the passage opening (13) and encloses the bus bar (30) in the passage opening (13).

4. Battery storage device (100) according to one of the preceding claims, wherein the bus bar (30) is arranged in a housing section (14) between the plurality of battery cells (20) arranged in the interior (12) of the housing (10) and a housing wall.

5. Battery storage device (100) according to claim 4, wherein the sealing means (40) substantially fills the housing portion (14) and substantially encloses the bus bar (30) and seals the interior (12) of the housing (10) in a gas-tight manner with respect to the outside (17).

6. Battery storage device (100) according to one of the preceding claims, wherein the housing (10) is composed of at least two housing elements (10, 11) at a component boundary (G), and the sealing means (40) is in contact with an inner surface of the housing (10) in a region surrounding the component boundary (G), for gas-tight sealing of the housing (10) to an inner side of the component boundary (G) between the housing elements (10, 11).

7. Battery storage device (100) according to one of the preceding claims, wherein the housing (10) is composed of at least two housing elements (10, 11) at a component boundary (G), and the sealing means (40) is arranged between opposite boundary surfaces (10g, 11g) of the housing elements (10, 11) for gas-tight sealing of the interior of the housing (10) at the component boundary (G) between the housing elements (10, 11).

8. Battery storage device (100) according to one of the preceding claims, wherein the sealing agent (40) comprises an inorganic, in particular mineral, filler.

9. Battery storage device (100) according to one of the preceding claims, wherein the sealing agent (40) comprises a silicon oxide-based ceramic composite.

10. Battery storage device (100) according to one of the preceding claims, wherein the sealing agent (40) comprises a high-temperature-resistant binder.

11. Battery storage device (100) according to one of the preceding claims, wherein the sealing agent (40) has an adhesive property or is an adhesive.

12. Battery storage device (100) according to one of the preceding claims, wherein the sealing means (40) has an electrically insulating property.

Images