DE102022204846A1 - High-voltage battery system - Google Patents

Abstract

The invention relates to a high-voltage battery system, in particular for a vehicle, with a battery housing (1) in which battery cells are arranged, which are spaced in a housing vertical direction (z) from a housing cover (9) of the battery housing via an intermediate space (23), wherein a flame retardant foam (45) is arranged inside the housing, which partially fills the gap (23) in order to provide a predefined gas guide path. According to the invention, the high-voltage battery system has at least one bulkhead element (21), which is constructed from a bag-shaped covering material (41) which surrounds the flame retardant foam (45), so that direct contact of the flame retardant foam (45) with the in the battery housing (1) arranged battery components is prevented.

Description

The invention relates to a high-voltage battery system according to the preamble of claim 1 or claim 10.

A generic high-voltage battery system has a battery housing in which battery cells are arranged. The battery cells are spaced from a housing cover in a vertical direction of the housing via a free space. The battery cells positioned in the battery housing can each be combined to form battery modules. Due to a cell defect in a lithium-ion battery cell installed in a battery module, a thermal event can occur, for example as a result of a short circuit between electrodes of the battery cell. During such a thermal event, hot fire gas can be generated, which escapes from the top of the damaged battery cell and collects in the gap.

In the generic high-voltage battery system, a thermally activated output component of a flame retardant foam is arranged inside the housing. In the prior art, the flame retardant foam starting component can be provided, for example, as a coating on the inside of the housing cover. During a thermal event, the flame retardant foam starting component is thermally activated, whereby the flame retardant foam formed is distributed over a large area and in an undefined manner inside the housing and adhesively bonds to surrounding components. Such contamination of the inside of the housing with flame retardant foam is, for example, a hindrance in customer service cases. In addition, adverse interactions can occur between the flame retardant foam and live parts in the battery housing.

From the DE 10 2010 030 881 A1 Thermal decoupling of battery cells in the event of a fault is known.

The object of the invention is to provide a high-voltage battery system and a method for producing such a high-voltage battery system, in which, in the event of a thermal event, components adjacent to a failing battery cell can be protected more effectively compared to the prior art.

The task is solved by the features of claim 1 or claim 10. Preferred developments of the invention are disclosed in the subclaims.

A first embodiment of the invention is described below: Accordingly, a high-voltage battery system is assumed, in the battery housing of which lithium-ion battery cells are arranged. These are spaced apart from a housing cover of the battery housing in a vertical direction of the housing via a free space. A thermally activated flame retardant foam starting component is also arranged inside the housing. In the event of a thermal event, this foams up, partially filling the gap. With the help of the foamed flame retardant foam, a predefined gas path can be provided, via which a fire gas emerging from the failing battery cell can be guided towards an emergency degassing opening in the battery housing. The flame retardant foam starting component or the foamed flame retardant foam is no longer in direct contact with components adjacent to the failing battery cell. Rather, the high-voltage battery system has a bulkhead element that is constructed from a bag-shaped shell material that surrounds the foamed flame retardant foam or its starting component. In this way, direct contact of the foam material with battery components arranged in the battery housing is prevented. The bag-shaped covering material is sufficiently stretchy so that it can expand together with the flame retardant foam starting component in the event of a thermal event. With the help of the bag-shaped covering material, any shape (before or after foaming) can be impressed on the flame retardant foam or its starting component. In this way, a targeted foaming process can take place, in which predefined gas paths are provided in order to remove the combustion gas from the failing battery cell.

In a technical implementation, the interior of the housing can be divided into partial chambers using partition walls. A battery module can be used in each of these sub-chambers. For manufacturing reasons, the battery modules used in the partial chambers are each spaced from the partition walls via an assembly gap. In the deactivated state, the bulkhead element can preferably be U-shaped in cross section, with two U-legs that are connected to one another via a base web. In the installed position, the base web of the bulkhead element can be arranged on an upper side of the partition wall facing the housing cover, while the two U-legs of the bulkhead element protrude into the respective assembly gap on both sides of the partition wall. In the activated state, i.e. when the bulkhead element is foamed, the U-profile-shaped bulkhead element has a dual function as follows: On the one hand, with the help of the The bulkhead element base web positioned on the top of the partition wall can be filled or blocked. On the other hand, the mounting gap can be sealed gas-tight by the foaming bulkhead element legs, whereby fire gas flow paths within the mounting gap are reduced or prevented.

In a specific embodiment variant, the partition walls are designed as longitudinal and cross members. Of these, a longitudinal support runs in the longitudinal direction of the housing centrally within the battery housing. Cross beams protrude from the longitudinal beam on both sides in the transverse direction of the housing. In the event of a side crash, the impact force can be transmitted to the side of the vehicle facing away from the crash via a transverse load path in which the cross members are integrated.

In the battery structure outlined above, a cross-sectionally large clearance that extends continuously in the longitudinal direction of the housing can be formed between the top side of the longitudinal support and the housing cover. Battery components can be arranged in the longitudinal clearance, for example HV and LV cables/conductors. In addition, during a thermal event, the longitudinal clearance acts as a main fire gas path, along which the fire gas flows to the emergency degassing opening of the battery housing and exits there to the outside of the housing.

With regard to effective heat protection of the battery components positioned in the longitudinal clearance, it is preferred if the longitudinal clearance is divided in the vertical direction of the housing by means of a heat protection element, namely into a lower line channel in which the battery components are laid in a heat-protected manner on the top side of the longitudinal support , and in an upper gas guide channel that provides the main fire gas path.

In the specific battery construction specified above, it is preferred if a bulkhead element is positioned on each of the cross members. In the thermally activated state, the bulkhead elements can at least partially prevent fire gas from flowing from the space above the damaged battery module towards neighboring components. In addition, the activated bulkhead elements can provide a predefined flow path along which the fire gas emerging from the failing battery module is guided towards the main fire gas path. With the help of the U-legs of the respective bulkhead element, the inflow of combustion gas from the gap into the assembly gap can also be effectively prevented. In this way, the duct on the top of the longitudinal member is effectively protected from fire gas access via the assembly gap.

A second embodiment of the invention is described below, which is essentially identical to the above first embodiment. In this respect, reference is made to the previous description. In contrast to the first exemplary embodiment, in the second exemplary embodiment the starting component of the flame retardant foam cannot be activated thermally, but rather can be activated mechanically and/or chemically, namely to form the flame retardant foam.

The activation of the initial component of the flame retardant foam takes place during the production of the high-voltage battery system. Accordingly, the initial component of the flame retardant foam is activated at a point in the process before the housing cover is assembled. In particular, activation takes place before or during an insertion process in which the bulkhead element (i.e. the casing material with the foaming starting component contained therein) is inserted into the battery housing equipped with the battery cells.

In the second embodiment, the foaming process of the starting component takes place at least partially with the housing cover still removed. In order to avoid an undirected foaming process, an auxiliary tool can be provided which acts as a foaming template during the foaming process. The auxiliary tool can be positioned on the top of the battery housing instead of the housing cover, thereby controlling the shaping of the flame retardant foam that takes place during the foaming process.

After the foaming process has ended, the auxiliary tool is removed and the housing cover assembly is carried out.

The chemical activation of the starting component can take place by bringing the starting component into contact with an initialization component in the manner of a two-component adhesive technology during the filling process of the bag-shaped wrapping material. In this way the frothing process starts. Alternatively, the chemical activation of the starting component can take place by bringing the starting component into contact with air-oxygen, for example.

In a further embodiment variant, the output component can be activated mechanically. In this case, the bag-shaped wrapping material with the starting component inside activated by mechanical force, for example by kneading. The force can be applied manually before and/or during the insertion process with the help of a worker.

• 1 In einer perspektivischen Darstellung ein zusammengebautes Hochvolt-Batteriesystem;
• 2 in einer vergrößerten perspektivischen Teilansicht das Hochvolt-Batteriesystem mit entferntem Gehäusedeckel;
• 3 und 4 jeweils Schnittdarstellungen entlang der Schnittebene A-A und B-B aus der 2; und
• 5 eine Ansicht entsprechend der 3 bei einem thermisch aktivierten Schottelement;
• 6 bis 11 eine Prozessabfolge zum Zusammenbau des Hochvoltbatterie gemäß einem zweiten Ausführungsbeispiel; und
• 12 eine Ansicht, anhand der eine weitere Ausführungsvariante beschrieben ist.

Two exemplary embodiments of the invention are described below with reference to the attached figures. Show it:

• 1 In a perspective view of an assembled high-voltage battery system;
• 2 an enlarged partial perspective view of the high-voltage battery system with the housing cover removed;
• 3 and 4 each sectional view along the section plane AA and BB from the 2 ; and
• 5 a view corresponding to that 3 with a thermally activated bulkhead element;
• 6 until 11 a process sequence for assembling the high-voltage battery according to a second exemplary embodiment; and
• 12 a view on the basis of which a further embodiment variant is described.

In the 1 A high-voltage battery system is shown which has a battery housing 1 with a lower housing part 2. The lower housing part 2 is made of a housing base 3 ( 2 until 5 ) and a frame-like housing side wall 5 raised from it. A circumferential housing flange 7 protrudes from the housing side wall 5, via which the high-voltage battery system can be installed on a vehicle body floor. The lower housing part 1 is in the 1 closed towards the top of the housing by means of a housing cover 9.

In the 2 the battery housing 1 is shown without the housing cover 9. Accordingly, a longitudinal support 11 extends centrally in a housing longitudinal direction x between the two housing side walls 5 (of which in the 2 only one is shown). Cross members 13 project from the longitudinal member 11 in the transverse direction of the housing. The cross members 13 are both on the housing side walls 5 (in the 2 not shown) as well as connected to the longitudinal beam 11 in a force-transmitting manner. During normal driving, the longitudinal beams 11 and the cross beams 13 cause component stiffening of the battery housing 1, whereby the crash performance of the battery housing 1 is increased. In addition, the longitudinal and cross members 11, 13 divide the interior of the housing into partial chambers, in each of which a battery module 15 made up of several battery cells is inserted.

The battery modules 15 are according to 3 for manufacturing and assembly reasons, spaced from the respective cross members 13 via mounting gaps 17. A U-leg 19 of a bulkhead element 21 described later is inserted into each of these mounting gaps 17.

Like from the 3 As can be seen further, the housing cover 9 is spaced from the top of the battery module by a gap 23. The top 25 of the longitudinal beam 11 is in the 3 by a height offset Δz ( 4 ) set back downwards relative to the top of the battery module. In this way, a cross-sectionally large longitudinal clearance 27 is created between the top side of the longitudinal support 25 and the housing cover 9. This extends continuously through the interior of the housing in the longitudinal direction x of the housing.

Like from the 4 Further shows, the longitudinal clearance 27 in the vertical direction of the housing z is divided into a lower line channel 31 and an upper gas guide channel 33 by means of a heat protection element 29. In the lower line channel 31 are in the 4 Battery components 28, for example HV and LV cables, are laid, while the upper gas guide channel 33 provides a main fire gas path in the event of a thermal event, through which a fire gas emerging from a failing battery cell flows towards an emergency degassing opening 35 ( 2 ) is conducted, which is formed in the housing side wall 5.

Like from the 2 until 5 As can be seen, a bulkhead element 21 is positioned on each of the cross members 13. The bulkhead element 21 is U-shaped in cross section with two U-legs 19, which are connected to one another via a base web 37. In the, in the 3 In the installation position shown, the base web 37 of the bulkhead element 21 is arranged on a cross member top 39 facing the housing cover 9. The two U-legs 19 of the bulkhead element 21 protrude into the respective assembly gap 17 on both sides of the respective cross member 13 (viewed in the longitudinal direction x of the housing).

In an assembly process sequence, the lower housing part 2 is first provided together with the cross and longitudinal beams 11, 13 positioned therein. A module setting process then takes place, in which the battery modules 15 are inserted into the respective sub-chambers from above and mounted therein. In a following process step, the bulkhead elements 21 are placed on the respective cross members 13, so that the U-legs 19 of the bulkhead elements 21 at least partially fill the assembly gap 17.

Each of the bulkhead elements 21 is according to 3 made up of a bag-shaped shell material 41 which surrounds a thermally activated flame retardant foam starting component 43. In the event of a thermal event, the flame retardant foam starting component 43 is activated and thereby becomes a larger volume molded foam 45 ( 5 ) foamed. The bag-shaped covering material 41 is sufficiently elastic so that it expands with the expanded flame retardant foam 45 without tearing. In this way, direct contact of the flame retardant foam 45 or its output component 43 with components arranged in the battery housing 1 is prevented.

In the 4 The thermally activated bulkhead element 21' is indicated by a dotted line. Accordingly, the space 23 above the cross member 13 is blocked with the foamed base web 37. A transfer (in the longitudinal direction of the housing x) of the fire gas collecting in the space 23 above the failing battery module 15 towards neighboring components is therefore at least partially prevented, as also shown in FIG 5 is shown. At the same time, the activated bulkhead elements 21' provide a flow path along which the fire gas emerging from the failing battery module 15 in the direction of the main fire gas path (ie the gas guide channel 33 according to 4 ) is directed. In addition, the foamed U-legs 19 ( 5 ) an inflow of fire gas from the gap 23 into the assembly gap 17 is prevented. The lower conduit 31 running in the longitudinal clearance 27 is therefore effectively protected from fire gas access via the assembly gap 17.

The following is based on the 6 until 11 a second exemplary embodiment is described, which is essentially identical to the first exemplary embodiment according to the 1 until 5 is. In contrast to the first exemplary embodiment, in the second exemplary embodiment the output component 43 cannot be thermally activated until a thermal event occurs. Rather, in the second exemplary embodiment, the starting component 43 of the flame retardant foam 45 can already be chemically activated during the manufacturing process.

The following is based on the 6 until 11 a process sequence for assembling the high-voltage battery system is described. Accordingly, it takes place in the 6 a filling process in which the starting component 43 is brought into contact together with an initialization component 44 in a mixer unit 46. The mixture created in the mixer unit 46 is filled into the bag-shaped covering material 41. The foaming process starts by mixing the starting component 43 with the initialization component 44.

After the filling process, the filling opening 48 of the bag-shaped wrapping material 41 is sealed ( 7 ). This is followed by an insertion process in which a worker inserts the bag-shaped covering material 41 into the battery housing 1 equipped with the battery modules 15 ( 8th ). As the foaming process progresses, the volume of the bag-shaped covering material 41 increases. During the foaming process, in the 9 a foaming template is provided as an auxiliary tool 50. The auxiliary tool 50 is according to 9 positioned on the top of the battery housing 1 in order to specifically control the shaping of the flame retardant foam 45 that takes place during the foaming process.

In the 10 the state after the end of the foaming process is shown, with the auxiliary tool 50 being removed from the top of the battery housing 1. The housing cover assembly can then be carried out, in which the housing cover 9 is mounted on the battery housing 1 ( 11 ).

In a further embodiment variant, the output component 43 can also be activated mechanically. In this case, before and/or during the insertion process, a mechanical force is applied (for example by kneading) to the bag-shaped wrapping material 41 with the starting component 43 located therein, as described in FIG 12 is indicated by double arrows. After mechanical activation of the output component 43, the worker places the bag-shaped covering material 41 into the battery housing 1 equipped with the battery modules 15. In order to control the foaming process in a targeted manner, the auxiliary tool 50 can also be provided again. After the foaming process has been completed, the auxiliary tool 50 is removed and then the housing cover 9 is mounted on the battery housing 1.

Reference symbol list

1

Battery case

2

Housing base

3

Case back

5

Housing side walls

7

Housing flange

9

Housing cover

11

Longitudinal beam

13

Cross beam

15

Battery modules

17

Module column

19

U-thigh

21

Bulkhead elements in deactivated state

21'

Bulkhead elements in activated state

23

space

25

Longitudinal beam top

27

Longitudinal clearance

28

Battery components

29

Heat protection elements

31

lower duct

33

upper gas guide channel

35

Emergency degassing opening

37

Base bridge

39

Cross member top

41

Cover material

43

Output component

44

Initialization component

45

Flame retardant foam

46

Mixer unit

48

Filling opening

50

Auxiliary tool

Δz

Height offset

QUOTES INCLUDED IN THE DESCRIPTION

This list of 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.

Cited patent literature

• DE 102010030881 A1 [0004]

Claims (10)

High-voltage battery system, in particular for a vehicle, with a battery housing (1) in which battery cells are arranged, which are spaced in a housing vertical direction (z) from a housing cover (9) of the battery housing via an intermediate space (23), with a Flame retardant foam (45) is arranged, which partially fills the gap (23) in order to provide a predefined gas guide path, characterized in that the high-voltage battery system has at least one bulkhead element (21), which is constructed from a bag-shaped enveloping material (41), which surrounds the flame retardant foam (45), so that direct contact of the flame retardant foam (45) with the battery components arranged in the battery housing (1) is prevented. High-voltage battery system Claim 1 , characterized in that a starting component (43) of the flame retardant foam (45) can be activated mechanically and/or chemically, specifically to form the flame retardant foam (45). High-voltage battery system Claim 1 or 2 , characterized in that the activation of the output component (43) of the flame retardant foam (45) takes place at a time in the process before the housing cover is assembled, in particular before or during an insertion process in which the bulkhead element (21) is inserted into the battery housing equipped with the battery cells (1) is inserted. High-voltage battery system Claim 2 or 3 , characterized in that the foaming process of the starting component (43) takes place at least partially with the housing cover (9) still dismantled, and/or that a foaming template can be provided as an auxiliary tool (50), in particular during the foaming process, and that in particular the auxiliary tool (50 ) can be positioned on the top of the battery housing (1) instead of the housing cover (9) in order to control the shaping of the flame retardant foam (45) that takes place during the foaming process. High-voltage battery system Claim 4 , characterized in that after the end of the foaming process, the auxiliary tool (50) is removed and the housing cover assembly is carried out. High-voltage battery system according to one of the Claims 2 until 5 , characterized in that the starting component (43) can be chemically activated, and / or that during a filling process of the bag-shaped wrapping material (41), the starting component (43) is brought into contact with an initialization component (44), whereby the foaming process starts. High-voltage battery system according to one of the Claims 2 until 6 , characterized in that the starting component (43) can be activated mechanically, and/or that the bag-shaped covering material (41) with the starting component (43) located therein is activated by mechanical force, for example by kneading, in particular before and/or during of the insertion process. High-voltage battery system according to one of the preceding claims, characterized in that the interior of the housing is divided into partial chambers by means of partitions (11, 13), in each of which a battery module (15) is inserted, and that the battery modules (15) each have a mounting gap ( 17) are spaced from the partition walls (11, 13), and in particular the bulkhead element (21) in the deactivated state is U-shaped in cross section with two U-legs (19) which are connected to one another via a base web (37), and that in an installed position, the base web (37) of the bulkhead element (21) is arranged on a partition wall top (39) facing the housing cover (9), and the two U-legs (19) of the bulkhead element (21) on both sides of the partition ( 11, 13) into the respective assembly gap (17). High-voltage battery system Claim 8 , characterized in that the partitions (11, 13) are designed as longitudinal and cross members, of which one longitudinal member (11) runs centrally in a longitudinal direction (x) of the housing, and that of the longitudinal member (11) on both sides in the transverse direction (y) of the housing Project cross member (13). Method for assembling a high-voltage battery system, in particular according to one of the preceding claims, with a battery housing (1) in which battery cells are arranged, which in the assembled state are spaced from a housing cover (9) in a housing vertical direction (z) via an intermediate space (23). are, wherein before a housing cover assembly, a flame retardant foam (45) is inserted into the battery housing (1) equipped with the battery cells, which at least partially fills the gap (23) in the assembled state, characterized in that the high-voltage battery system has at least one bulkhead element ( 21), which is made up of a bag-shaped shell material (41) that surrounds the flame retardant foam (45).

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