Battery system for a vehicle

Abstract

A battery system (50, 80, 100, 200) for a vehicle comprises a first battery cell stack (51, 86, 103, 208), at least one second battery cell stack (52, 104), a housing (53, 82, 203) for at least partially accommodating the battery cell stacks (51, 86, 103, 208, 52, 104), a heat sink (81, 108, 207) for cooling the battery cell stacks, wherein the heat sink comprises an upper heat sink element (111) and a lower heat sink element (112), wherein the heat sink is arranged above the battery cell stacks on an upper side of the housing, wherein the heat sink comprises at least one functional region (87, 88, 89, 109, 201) which is designed to be deformed in a targeted manner in the event of a crash.

Description

Technical Field

[0001] The present invention relates to a battery system for a vehicle, a vehicle having such a battery system, and the use of a heat sink in such a battery system and / or such a vehicle. Background Technology

[0002] Battery systems for vehicles are largely known from existing technology. In electric vehicles, battery systems are mostly located in the lower region of the vehicle body. Typically, multiple battery cells are stacked within a casing. In traffic accidents, forces may arise that deform the casing of the battery system. Typically, in such accidents, efforts are made to ensure the defined movement of the battery cell stacks to avoid further danger to occupants and the environment. However, defined movement of the battery cell stacks in a side-impact collision scenario has not yet been achieved.

[0003] A battery housing with a connecting element is known from DE 10 2008 010 822 A1, which folds in a targeted manner upon deformation. A battery housing with a wall section having an unloading groove is known from DE 10 2009 006 991 A1. A battery housing with a housing cover having an integrated cooling channel is known from DE 10 2017 005 314 A1.

[0004] Against this backdrop, a need has been identified for providing a battery system for vehicles. In particular, there is a need for an improved battery system for vehicles. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome, or at least partially overcome, the aforementioned disadvantages in battery systems for vehicles. In particular, the technical problem to be solved by the present invention is to provide an improved battery system for vehicles.

[0006] The aforementioned technical problem is solved by various aspects of the present invention. In particular, the technical problem is solved by a battery system for a vehicle according to the present invention. Furthermore, the technical problem is solved by a vehicle according to the present invention and by its application according to the present invention. Here, the features described with respect to the battery system according to the present invention also apply to the vehicle according to the present invention and its application according to the present invention, and vice versa; therefore, the disclosures regarding various aspects of the invention are always mutually referenced or can be mutually referenced.

[0007] According to a first aspect of the invention, a battery system for a vehicle is provided, comprising a first battery cell stack, at least one second battery cell stack, a housing for at least partially housing the battery cell stack, and a heat sink for cooling the battery cell stack, wherein the heat sink includes an upper heat sink element and a lower heat sink element, wherein the heat sink is disposed above the battery cell stack on an upper side of the housing, and wherein the heat sink includes at least one functional region configured to deform in a targeted manner upon impact.

[0008] The term "vehicle" herein specifically refers to electric vehicles and / or hybrid vehicles. The vehicle preferably includes a battery system configured to supply energy to an electric motor drive unit for vehicle motion. The battery system is preferably located in the underside area of ​​the vehicle.

[0009] The term "cell stack" herein preferably refers to a plurality of cell stacks arranged close to each other. These cell stacks may include lithium-ion cell stacks. Each individual lithium-ion cell stack may include a housing. The housing may be made of, for example, plastic, metal, and / or composite material. The individual cell stacks may be connected to each other by tension bands. The cell stack may have end plates at its ends.

[0010] The term "housing" herein refers to a structural component configured to house and arrange the battery cell stack. The housing may be constructed as a single piece or in multiple pieces. The housing may comprise metal, plastic, and / or composite materials. The housing preferably has a frame and a bottom region. The housing preferably has a boundary defined by heat sinks on a side opposite the bottom region. The heat sinks are preferably arranged on the upper side of the housing. The heat sinks are preferably arranged on the upper side of the housing frame. The housing is preferably located in the bottom region of the vehicle body. The housing may be connected to the vehicle body, for example, by material bonding, form fitting, and / or friction fitting connection methods.

[0011] The term heat sink, as used herein, specifically refers to a fluid-cooled heat sink. The heat sink preferably comprises an upper heat sink element and a lower heat sink element, which are arranged at least partially spaced apart from each other to form a cavity through which cooling liquid or cooling gas can flow. The cavity may extend in a channel-like manner along the longitudinal and / or transverse axis of the heat sink. Preferably, the cavity may extend along the longitudinal axis of the heat sink. The heat sink may be connected to the upper side of the housing by material bonding, form fitting, and / or friction fitting methods. An adhesive or filler material may preferably be disposed between the heat sink and the battery cell stack for thermal bonding between the battery cell stack and the heat sink. The heat sink is used to cool the battery cell stack.

[0012] The term "functional region" herein refers to a structural region within a heat sink that possesses specific mechanical and geometric characteristics configured to deform under load, preferably lateral load, in such a manner that the heat sink can deform in a lateral direction. This deformation may include deformation along a preferred direction. The functional region may include an upper heat sink element and / or a lower heat sink element. The functional region may, for example, have a geometry such as a curved or arched region that compresses or further bulges or tears under lateral load, allowing the heat sink and the stack of battery cells connected to it to perform unimpeded lateral movement. This functional region is preferably distinct from the rest of the heat sink. The functional region may include cooling channels. The functional region preferably does not include cooling channels.

[0013] This invention is based on the understanding that battery cell stacks are fixedly connected to heat sinks using adhesives. The adhesives are primarily used for heat exchange or heat dissipation. However, in side-impact collisions, it has been observed that the heat sinks deform uncoordinatedly. Consequently, the battery cell stacks connected to the heat sinks also move uncoordinatedly. This introduces further danger, as the battery cell stacks may be torn or otherwise damaged. This could pose a hazard to vehicle occupants and the environment, as lithium-ion batteries contain heavy metals and other toxic substances. Furthermore, uncontrolled deformation of the battery cells can lead to short circuits and thermal runaway, potentially resulting in a fire or explosion.

[0014] To mitigate these hazards, this invention proposes equipping the heat sink with functional areas that enable targeted deformation of the heat sink in the event of a collision. This, in turn, allows for targeted movement of the battery cell stack in the event of a collision, thereby reducing harm to occupants and the environment. Furthermore, in addition to cooling, the functional areas for targeted deformation can be advantageously integrated into the heat sink.

[0015] High-voltage traction battery cell stacks must be protected in vehicle accidents due to their reactivity. For high-voltage traction batteries under the vehicle floor, a common approach in side impacts is to implement the door sill as a deformable element to absorb impact energy while keeping the battery casing virtually undeformed. In this way, the theoretically available deformation space inside the battery (e.g., intrusion gaps) is consumed only on the impact side, but largely unused on the inner side and the opposite side of the impact.

[0016] For example, individual battery cells are bonded as a longitudinally arranged stack (i.e., a battery cell stack) to a longitudinally arranged structure within the battery casing. The bonding of the stack can be performed on a Y-shaped soft suspension that allows kinematically defined movement without the adhesive or bonding agent between the battery cells and the battery casing failing. To cool the battery cells, heat sinks, through which water flows, are bonded to the battery using an adhesive (so-called gap filler). The failure time of this adhesive determines the kinematics of the individual battery cells or battery cell stack during a side impact.

[0017] This invention proposes a geometric optimization of the heat sink, thereby enabling deformation of the heat sink between battery cells. This geometric optimization or design allows functional performance in a collision to be decoupled from the relatively dispersed failure of the adhesive (i.e., gap filler), the prediction of which has significant uncertainty. Displacement of battery cells or battery cell stacks then functions normally even with arbitrarily strong adhesives used between the heat sink and the stack, thus the collision mechanism is not based on failure phenomena. Therefore, a robust design can be achieved. This also allows for lower vehicle weight due to the potential elimination of structural lateral load paths within the battery or above the vehicle body.

[0018] According to a preferred embodiment, the at least one functional region may include a localized weakening portion in the upper heat sink element and / or the lower heat sink element.

[0019] The term "localized weakening" herein refers to a reduction in material thickness at least partially relative to the other major material thicknesses of the upper and / or lower heatsink elements. Here, a weakening portion may include a smaller wall thickness. A weakening portion may also include a localized recess, such as a drilled hole or a pocket.

[0020] This method allows for targeted deformation of the heat sink in weakened areas. This, in turn, enables targeted movement of the battery cell stack, thereby reducing the risk of accidents.

[0021] According to a preferred embodiment, the at least one functional area may include a trigger groove in the upper heat sink element and / or the lower heat sink element, and in particular, the trigger groove includes a groove, a raised portion or a recessed portion.

[0022] The term "trigger groove" preferably refers herein to a structural weakening or targeted deformation portion in a heat sink, which is configured to induce controlled deformation under load or accident conditions. A trigger groove may include, for example, a groove, a raised portion, or a recess.

[0023] In this way, the heat sink can deform in a targeted manner during a collision or accident, allowing the stack of battery cells connected to the heat sink to move in a targeted manner as well. This can reduce the danger during an accident.

[0024] According to a preferred embodiment, the at least one functional area may include at least one longitudinal continuous recess and / or perforation in the upper heat sink element and / or the lower heat sink element.

[0025] The elongated recesses may include elongated holes. The perforations may include multiple individual drilled holes. The elongated recesses and / or perforations can enable targeted deformation of the heat sink in the event of a collision and / or accident. This allows for targeted movement of the battery cell stack, thereby reducing potential hazards.

[0026] According to a preferred embodiment, the at least one functional area may be arranged between the first battery cell stack and the at least one second battery cell stack.

[0027] The first and second battery cell stacks are preferably arranged spaced apart from each other. Preferably, the functional area is arranged between the two battery cell stacks in this area. This advantageously allows for targeted movement of the battery cell stacks, which are preferably connected to the heat sink. This minimizes potential hazards.

[0028] According to a preferred embodiment, the at least one functional region may extend parallel to the longitudinal direction of the first battery cell stack and / or the at least one second battery cell stack.

[0029] By arranging functional regions along the longitudinal direction of the battery cell stack, targeted deformation can be achieved along the entire length of the battery cell stack. This can minimize potential hazards.

[0030] According to a preferred embodiment, a battery system may be provided, which may further include at least one separating element, wherein the at least one separating element may be arranged between the first battery cell stack and the at least one second battery cell stack, and wherein the at least one functional area may be arranged above the at least one separating element.

[0031] The term "separating element" herein refers to a structural element that divides the housing into different regions. Within these regions, individual battery cell stacks can be arranged spatially separate from each other. The separating element can be made of the same material as the housing or a different material. The separating element can be a wall or a spacer. The separating element can have receptacles for accommodating the battery cell stacks or be a laterally overhanging structural element. The separating element can be connected to the bottom and / or frame of the housing. Preferably, the separating element can be connected only to the frame of the housing. Preferably, the receptacles for accommodating the battery cell stacks can be designed so that these receptacles can undergo targeted deformation in the event of a collision. Preferably, the housing can have corresponding receptacles for accommodating the battery cell stacks, which are correspondingly designed to be flexible so that they can undergo targeted deformation in the event of a collision. In this way, targeted movement of the battery cell stacks during a collision can be achieved in coordination with the functional areas without damaging the battery cell stacks.

[0032] According to a preferred embodiment, the first battery cell stack and the at least one second battery cell stack can be connected to the heat sink and / or to the housing and / or to the at least one partition element by an adhesive.

[0033] The adhesive described herein can achieve thermal bonding. That is, the adhesive facilitates thermal conduction from the battery cell stack to the heat sink. Preferably, the adhesive between the battery cell stack and the heat sink has a thermal conductivity set to facilitate heat dissipation. The adhesive described herein can also achieve structural bonding, that is, the adhesive can achieve material bonding between the battery cell stack and the separator element and / or between the battery cell stack and the heat sink and / or between the battery cell stack and the housing. Structural bonding refers to a bonding with a strength that provides retention for the battery cell stack. The adhesive preferably achieves both thermal and structural bonding. Preferably, the adhesive between the battery cell stack and the heat sink can achieve thermal bonding and / or structural and thermal bonding. Preferably, the adhesive between the battery cell stack and the separator element and / or between the battery cell stack and the housing achieves structural bonding. The adhesive is preferably disposed in the housing portion of the housing and / or the housing portion of the separator element. Through functional areas, the adhesive between the battery cell stack and the heat sink element can have any bonding strength, as the heat sink preferably deforms in a defined lateral direction upon lateral impact. Furthermore, the housing portion for the battery cell stack preferably deforms in the lateral direction. Therefore, regardless of whether the adhesive between the battery cell stack and the heat sink is maintained, the battery cell stack will deform laterally. In the absence of functional areas, if the battery cell stack is inextricably linked to the heat sink, it will result in uncoordinated movement of the battery cell stack, as the heat sink will also deform uncoordinatedly.

[0034] Another aspect of the invention relates to a vehicle having the above-described battery system.

[0035] Another aspect relates to the use of heat sinks in the aforementioned battery systems and / or the aforementioned vehicles.

[0036] All disclosures and embodiments described herein relate to the use of the aforementioned battery systems, vehicles, and heat sinks, and vice versa. Advantageously, the advantages provided by one aspect or one of the described embodiments and examples also apply to all other aspects or embodiments and examples, and vice versa. Attached Figure Description

[0037] The following figures illustrate:

[0038] Figure 1 The image shows a stack of individual battery cells;

[0039] Figure 2 A top view of a battery system without a heat sink is shown.

[0040] Figure 3 A cross-sectional view of the battery system according to the present invention is shown;

[0041] Figure 4 A detailed view showing a cross-sectional view of the battery system according to the present invention; and

[0042] Figure 5 A cross-sectional view of the battery system according to the invention in a deformed state is shown. Detailed Implementation

[0043] Figure 1 A battery cell stack 10 is shown. This battery cell stack 10 includes a plurality of individual battery cells 11. These battery cells 11 are pressed together by tension bands 13. The battery cell stack 10 has end plates 12 at its ends. First and second battery cell stacks correspond to the battery cell stack 10 shown here.

[0044] Figure 2 A top view of a battery system 50 for a vehicle without heat sinks is shown. The battery system 50 has a housing 53. The battery system 50 is arranged in the bottom region of the vehicle and connected to the vehicle body (not shown). The battery system 50 includes a first battery cell stack 51, a second battery cell stack 52, and additional battery cell stacks 55 and 56. The housing 53 includes a frame structure that at least partially houses the battery cell stacks 51, 52, 55, and 56. The battery cell stacks 51 and 52 are separated from each other by a partition wall 54. The partition wall 54 extends along the longitudinal direction of the battery cell stacks 51 and 52.

[0045] Figure 3A cross-sectional view of a battery system 80 according to the present invention is shown. A housing 82 has a bottom region 83. The housing 82 is enclosed by a heat sink 81. The heat sink 81 is a water-cooled heat sink 81 used to cool a stack of battery cells 86. The stack of battery cells 86 is supported on a receiving portion 85 arranged on the housing 82 and a receiving portion 84 arranged on a partition wall 90. The heat sink 81 has functional regions 87, 88, and 89 in the region of the partition wall 90, respectively, which are configured for targeted deformation upon impact. Functional regions 87, 88, and 89 are designed as trigger recesses. The heat sink 81 has an upper heat sink element and a lower heat sink element. Trigger recesses 87, 88, and 89 are arranged in the upper and lower heat sink elements. Trigger recesses 87, 88, and 89 each include a recess, here an upward-pointing triangular recess. The receiving portions 84 and 85 are designed to deform laterally upon a side impact, thereby enabling the stack of battery cells 86 to move laterally.

[0046] Figure 4 A detailed cross-sectional view of a battery system 100 according to the present invention is shown. Battery cell stacks 103 and 104 are supported on receiving portions 105 and 106 of a partition wall 113, respectively. Adhesive layers 101 and 102 are provided between the receiving portions 105 and 106 and the battery cell stacks 103 and 104 for fixation. A heat sink 108 has a lower heat sink element 112 and an upper heat sink element 111. The battery cell stacks 103 and 104 are indirectly connected to the heat sink 108 via adhesive layers 107 and 110, respectively. The adhesive layers serve for connection between the battery cell stacks and the heat sink, as well as for heat conduction. The heat sink 108 has a trigger groove 109 above the partition wall 113.

[0047] Figure 5 This is a cross-sectional view of the battery system 200 after the housing 203 collides with the pillar 202 and deforms. The trigger groove 201 is specifically deformed here due to the lateral impact with the pillar 202. Furthermore, the receiving portions 205 and 204 for the battery cell stack 208 are also specifically deformed, here shifting to the left. The adhesive layers 210 and 211 that connect the battery cell stack to the receiving portions 205 and 204 do not detach. Furthermore, the battery cell stack 208 does not detach from the cooling plate 207 or the adhesive layer 209. Therefore, the targeted deformation of the cooling plate 207, particularly through the trigger groove 201, combined with the targeted deformation of the receiving portions 204 and 205, allows the battery cell stack 208 to move in a targeted manner along the deformation direction 206. This can generally have a positive impact on vehicle safety.

[0048] List of reference numerals

[0049] 10 battery cell stacks

[0050] 11, 86, 103, 104, 208 battery cells

[0051] 12 end plates

[0052] 13 Tight Bands

[0053] 51, 86, 103, 208 First battery cell stack

[0054] 52, 104 Second battery cell stack

[0055] 53, 82, 203 Casing

[0056] 54, 90 dividing elements

[0057] 50, 80, 100, 200 battery systems

[0058] 81, 108, 207 Cooling plates / heat sinks

[0059] 83. Lower / Bottom Area of ​​the Housing

[0060] 84, 85, 105, 106, 204, 205 Battery cell housing

[0061] 87, 88, 89, 109, 201 Trigger grooves and functional areas

[0062] 101, 102, 209 Heatsink bonding layer

[0063] 107, 110, 210, 211 Adhesive layers for receiving parts

[0064] 111 Heat sink component

[0065] 112 Lower heat sink component

[0066] 202 pillars

[0067] 206 Deformation direction

Claims

1. A battery system (50, 80, 100, 200) for a vehicle, comprising: First battery cell stack (51, 86, 103, 208); At least one second battery cell stack (52, 104). Housings (53, 82, 203) for at least partially accommodating the battery cell stacks (51, 86, 103, 208, 52, 104). Heat sinks (81, 108, 207) are used to cool the battery cell stacks (51, 86, 103, 208, 52, 104). The heat sink (81, 108, 207) includes an upper heat sink element (111) and a lower heat sink element (112). The heat sinks (81, 108, 207) are arranged on the upper side of the housing (53, 82, 203) above the battery cell stack (51, 86, 103, 208, 52, 104); The heat sink (81, 108, 207) includes at least one functional area (87, 88, 89, 109, 201) which is configured to deform in a targeted manner upon impact.

2. The battery system (50, 80, 100, 200) according to claim 1, wherein, The at least one functional region (87, 88, 89, 109, 201) includes a localized weakened portion in the upper heat sink element (111) and / or the lower heat sink element (112).

3. The battery system (50, 80, 100, 200) according to claim 1 or 2, wherein, The at least one functional area (87, 88, 89, 109, 201) includes a trigger groove (87, 88, 89, 109, 201) in the upper heat sink element (111) and / or the lower heat sink element (112), and in particular, the trigger groove (87, 88, 89, 109, 201) includes a groove, a raised portion or a recessed portion.

4. The battery system (50, 80, 100, 200) according to any one of the preceding claims, wherein, The at least one functional area (87, 88, 89, 109, 201) includes at least one longitudinal continuous recess and / or perforation in the upper heat sink element (111) and / or the lower heat sink element (112).

5. The battery system (50, 80, 100, 200) according to any one of the preceding claims. in, The at least one functional area (87, 88, 89, 109, 201) is arranged between the first battery cell stack (51, 86, 103, 208) and the at least one second battery cell stack (52, 104).

6. The battery system (50, 80, 100, 200) according to any one of the preceding claims. in, The at least one functional region (87, 88, 89, 109, 201) extends parallel to the longitudinal direction of the first battery cell stack (51, 86, 103, 208) and / or the at least one second battery cell stack (52, 104).

7. The battery system (50, 80, 100, 200) according to any one of the preceding claims. It also includes at least one separating element (54, 90). in, The at least one separating element (54, 90) is arranged between the first battery cell stack (51, 86, 103, 208) and the at least one second battery cell stack (52, 104); and wherein the at least one functional region (87, 88, 89, 109, 201) is arranged above the at least one separating element (54, 90).

8. The battery system (50, 80, 100, 200) according to any one of the preceding claims. in, The first battery cell stack (51, 86, 103, 208) and the at least one second battery cell stack (52, 104) are connected to the heat sink (81, 108, 207) and / or to the housing (53, 82, 203) and / or to the at least one separator element (54, 90) by adhesives (101, 102, 107, 110, 209, 210, 211).

9. A vehicle having a battery system (50, 80, 100, 200) according to any one of claims 1 to 8.

10. Use of a heat sink (81, 108, 207) in a battery system (50, 80, 100, 200) according to any one of claims 1 to 8 and / or in a vehicle according to claim 9.

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