Battery assemblies for electric vehicles

Abstract

A battery assembly for an electric vehicle comprises: a battery (12) having a battery housing (16) and a plurality of battery cells (20), wherein the battery cells (20) are arranged in the battery housing (16); a protective plate (30) arranged on a side of the battery (12) facing a roadway (22); and a deformation recognition device (31) having at least one deformation sensor (40, 42), wherein the deformation sensor (40, 42) is arranged on the protective plate (30), the protective plate (30) being multi-layered and having at least a first layer (32) and a second layer (36) spaced apart from the first layer (32), and the deformation recognition device (31) having a first deformation sensor (40) and a second deformation sensor (42), the first deformation sensor (40) being arranged on the first layer (32) of the multi-layer protective plate (30), and the second deformation sensor (42) being arranged on the second layer (36) of the multi-layer protective plate (30).

Description

Technical Field

[0001] The present invention relates to a battery assembly for an electric vehicle, comprising: a battery having a battery housing and a plurality of battery cells, wherein the battery cells are arranged in the battery housing; a protective plate, which is arranged on a side of the battery facing the roadway; and a deformation recognition device, which has at least one deformation sensor, wherein the deformation sensor is arranged on the protective plate. Background Art

[0002] Such batteries are typically used in electric vehicles and serve to store electrical energy and supply the drive unit with electrical energy during driving. Batteries typically have a plurality of battery cells arranged in a battery housing and electrically connected to one another. Alternatively, the battery cells are divided into a plurality of battery modules, wherein the battery cells within the battery modules are electrically connected to one another, and the battery modules are in turn electrically connected to one another.

[0003] To provide the corresponding driving power for the relatively long driving range of electric vehicles, the battery, based on the multiple battery cells, requires a relatively large structural space. The batteries are typically located on the floor of the electric vehicle because this provides the required structural space. Floor-mounted batteries are typically protected by protective plates from objects thrown from the roadway. Despite the presence of the protective plates, such objects can still deform the battery housing or even penetrate it, potentially damaging the battery cells. In this case, the protective plates can be severely deformed or even penetrated by the objects. Damage to the battery cells can lead to deflation of the cells and even fire in the entire battery.

[0004] Battery failures are typically detected by the battery management system. However, the battery management system may not detect such deformations or punctures of the battery housing immediately, but rather too late, because the affected battery cells may not yet be significantly damaged. However, the battery cells may be damaged to the point where there is a fear of imminent failure or that they no longer meet safety requirements.

[0005] For example, DE 10 2017 206 663 A1 discloses an electric vehicle with a floor battery, wherein the floor battery is protected from objects thrown from the roadway by a protective plate arranged between the floor battery and the roadway. To improve safety, the protective plate has a deformation sensor that actively monitors the condition of the protective plate and, therefore, immediately identifies damage to the floor battery by detecting damage to the protective plate. The deformation sensor has a conductive coating applied to the protective plate, wherein an evaluation circuit detects changes in the resistance of the deformation sensor. A disadvantage is that the deformation sensor only detects whether the protective plate is damaged and in which area, and thus directly infers battery damage based on this. This design does not allow for the actual extent of battery damage and the degree of battery damage. Therefore, there is a risk that measures, in particular, switching the electric vehicle to emergency mode or completely shutting down the vehicle, may be taken even though the protective plate is only slightly damaged and the battery is not seriously damaged. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a battery assembly with which the degree of damage to the protective plate and the battery can be reliably detected, and measures can be taken based on this.

[0007] Because the protective panel is multi-layered and has at least a first layer and a second layer spaced apart from the first, and the deformation detection device includes a first deformation sensor and a second deformation sensor, with the first deformation sensor being located on the first layer and the second deformation sensor being located on the second layer of the multi-layer protective panel, the extent of an object's impact on the protective panel can be quantified and, based on this, appropriate measures can be taken or recommended. The impact can be so minor that only the second layer (i.e., the layer closest to the roadway) deforms. Despite the deformation of the protective panel, no immediate action is required and the panel can be replaced during the next visit to the repair shop. If an object impacts with significant force, the deformation sensors detect deformation in both layers. Based on the load caused by the object's impact, which is detected by the deformation, damage to the battery and, possibly, the extent of the damage can be inferred. Knowledge of the stiffness of each layer and the detected deformation of each layer allows the load caused by the object's impact to be determined and the load acting on the battery to be estimated. This allows an assessment of whether critical battery loads exist and whether appropriate measures are necessary.

[0008] Furthermore, a cooling plate with a predefined stiffness may be arranged between the battery and the protective plate, with the coolant flow through the cooling plate monitored, for example, by a pressure sensor. Furthermore, monitoring the coolant flow can detect battery damage, where damage to the cooling plate and the resulting coolant leakage can be used to infer possible battery damage. Furthermore, detecting cooling plate damage can be used to estimate the extent of the load acting on the battery.

[0009] Such a design of the deformation detection device can significantly improve the availability of the electric vehicle, because the electric vehicle can still be used for daily driving even if the fender is slightly damaged, and only needs to be disconnected or taken to a repair workshop immediately if the fender and battery are severely damaged.

[0010] In a preferred embodiment, the first deformation sensor and / or the second deformation sensor are divided into different sections, so that the deformation position of the protective plate can be located and corresponding measures can be taken only in the detected severely deformed sections, in particular disconnecting individual battery modules of the battery.

[0011] The deformation sensor is preferably embodied as a strain gauge, a resistance sensor, a piezoelectric strain sensor or a Bragg sensor.

[0012] Preferably, the first deformation sensor is arranged on the side of the first layer facing the second layer, and the second deformation sensor is arranged on the side of the second layer facing the first layer. Alternatively, the first deformation sensor is embedded in the first layer, and / or the second deformation sensor is embedded in the second layer. In both cases, the deformation sensors are protected from environmental influences and their reliable operation is ensured. This improves the safety and availability of electric vehicles, as failure of the deformation sensors can be reliably prevented.

[0013] In a preferred design, the protective plate is arranged to be spaced apart from the battery housing. Thus, damage or deformation of the protective plate will not directly cause a load on the battery, so a certain degree of damage or deformation can be allowed without having to take safety measures due to damaged batteries.

[0014] Preferably, a third layer is disposed between the first and second layers, wherein the third layer is made of a deformable material. In a preferred design, the third layer is made of structural foam. The third layer has a predefined stiffness and strength. By knowing the deformation of the first and second layers, the impact strength of an object on the protective plate can be determined based on the sensor signal of the deformation sensor and the stiffness of the first, second, and third layers, thereby detecting battery damage. Furthermore, the third layer serves to cushion impacts on the protective plate, with structural foam having a relatively high cushioning effect.

[0015] In a preferred design, the first layer and the second layer are made of fiber reinforced plastic. Thus, the first layer and the second layer have relatively high strength, so that the protective plate can provide relatively high protection to prevent the battery from being damaged.

[0016] Preferably, the deformation recognition device has an evaluation unit that is operatively connected to the at least one deformation sensor. The evaluation unit is configured to evaluate signals from the deformation sensor, wherein the evaluation unit may, for example, generate a warning signal to the driver and / or other road users, issue an emergency call to firefighters, and / or initiate predefined safety measures on the electric vehicle.

[0017] This embodiment makes it possible to reliably detect severe damage to the protective plate in a simple manner and to take measures that restrict or completely prevent further driving of the electric vehicle only in the event of actual severe damage to the battery.

[0018] In general, the present invention discloses the following technical solution 1, and the following 2-10 are preferred technical solutions of the present invention:

[0019] 1. A battery assembly for an electric vehicle, comprising:

[0020] A battery (12) having a battery housing (16) and a plurality of battery cells (20), wherein the battery cells (20) are arranged in the battery housing (16);

[0021] a protective plate (30) arranged on a side of the battery (12) facing the roadway (22); and

[0022] A deformation recognition device (31) having at least one deformation sensor (40, 42), wherein the deformation sensor (40, 42) is arranged on the protection plate (30),

[0023] It is characterized in that

[0024] The protective plate (30) is implemented as a multi-layer and has at least a first layer (32) and a second layer (36) spaced apart from the first layer (32), wherein the deformation recognition device (31) has a first deformation sensor (40) and a second deformation sensor (42), wherein the first deformation sensor (40) is arranged at the first layer (32) of the multi-layer protective plate (30), and the second deformation sensor (42) is arranged at the second layer (36) of the multi-layer protective plate (30).

[0025] 2. The battery pack according to 1 above,

[0026] It is characterized in that

[0027] The first deformation sensor (40) and / or the second deformation sensor (42) are divided into different sections.

[0028] 3. The battery pack according to 1 or 2 above,

[0029] It is characterized in that

[0030] The deformation sensors (40, 42) are implemented as strain gauges, resistance sensors, piezoelectric strain sensors or Bragg sensors.

[0031] 4. The battery assembly according to any one of 1 to 3 above,

[0032] It is characterized in that

[0033] The first deformation sensor (40) is arranged on a side of the first layer (32) facing the second layer (36), and the second deformation sensor (42) is arranged on a side of the second layer (36) facing the first layer (32).

[0034] 5. The battery assembly according to any one of 1 to 4 above,

[0035] It is characterized in that

[0036] The first deformation sensor (40) is embedded in the first layer (32), and / or the second deformation sensor (42) is embedded in the second layer (36).

[0037] 6. The battery assembly according to any one of 1 to 5 above,

[0038] It is characterized in that

[0039] The protection plate (30) is arranged to be spaced apart from the battery case (16).

[0040] 7. The battery assembly according to any one of 1 to 6 above,

[0041] It is characterized in that

[0042] A third layer (34) is arranged between the first layer (32) and the second layer (36), wherein the third layer (34) is made of a deformable material.

[0043] 8. The battery assembly according to any one of 1 to 7 above,

[0044] It is characterized in that

[0045] The third layer (34) is made of structural foam.

[0046] 9. The battery assembly according to any one of 1 to 8 above,

[0047] It is characterized by:

[0048] The first layer (32) and the second layer (36) are made of fiber reinforced plastic.

[0049] 10. The battery assembly according to any one of 1 to 9 above,

[0050] It is characterized by:

[0051] The deformation recognition device (31) has an evaluation unit (50) which is operatively connected to the at least one deformation sensor (40, 42). BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Exemplary embodiments of the invention are explained in more detail with reference to the drawings.

[0053] Figure 1 A schematically illustrated electric vehicle is shown, and

[0054] Figure 2 An embodiment of a battery assembly is shown. DETAILED DESCRIPTION

[0055] Figure 1 The diagram shows a schematic diagram of an electric vehicle 10 having a battery 12 and a drive unit 14. The battery 12 serves to store electrical energy and supplies the drive unit 14 with electrical energy during driving operation of the electric vehicle 10.

[0056] The battery 12 has a battery housing 16 and is arranged on a floor 18 of the electric vehicle 10. A plurality of battery cells 20 are arranged in the battery housing 16 and are separated from the external environment in a fluid-tight manner by the battery housing 16 and are therefore protected from environmental influences by the battery housing 16. A protective plate 30 is arranged below the battery 12 (i.e., between the battery 12 and the roadway 22). The protective plate 30 is fastened to the vehicle body and, as viewed from the roadway 22, completely covers the battery 12.

[0057] The purpose of the protective plate 30 is to prevent objects on the roadway and thrown upward from striking the protective plate 30 during driving of the electric vehicle 10. The battery 12 or the battery housing 16 is thus protected by the protective plate 30 from the impact of the thrown objects, thereby reducing the risk of damage to the battery 12.

[0058] Despite the presence of the protective plate 30 , the battery 12 and in particular the battery cells 20 can be damaged by objects passing by or being located on the roadway 22 and thrown upwards, such that the protective plate 30 is severely deformed or punctured.

[0059] In the event of damage to a battery cell 20 , the driver of the electric vehicle 10 must be informed of this as quickly as possible and / or appropriate measures must be taken to prevent a fire in particular of the battery 12 or even of the entire electric vehicle 10 .

[0060] Possible damage to the battery 12 is detected by means of the deformation detection device 31 . Figure 2 Such a deformation recognition device 31 arranged at the protective plate 30 is shown. The protective plate 30 is implemented as a multi-layer and includes three layers 32, 34, and 36. The first layer 32 is arranged closest to the battery when the protective plate 30 is assembled. The protective plate 30 is arranged on the body of the electric vehicle 10 by means of the first layer 32 (i.e., by means of the lateral section). The second layer 36 is arranged on the side of the protective plate 30 facing the roadway 22. Thus, the second layer 36 is the layer that deforms as the first layer when an object hits. The third layer 34 is arranged between the first layer 32 and the second layer 36 and completely fills the cavity between the two layers 32 and 36. The first and second layers 32 and 36 are made of fiber-reinforced plastic and therefore have relatively high strength. The third layer 34 is made of structural foam, wherein the raw material of the structural foam is filled into the cavity between the two layers 32 and 36 and is subsequently foamed.

[0061] The deformation detection device 31 includes two deformation sensors 40 and 42 and an evaluation unit 50. The evaluation unit 50 is signal-connected to the deformation sensors 40 and 42. The evaluation unit 50 receives and evaluates the signals from the deformation sensors 40 and 42 and takes appropriate measures, such as shutting down the battery 12 or notifying the driver that the battery 12 is damaged. The first deformation sensor 40 is arranged on the first layer 32, on the side of the first layer 32 facing the second layer 36, that is, between the first layer and the third layer 32 and 34, thereby protecting the first deformation sensor 40 from environmental influences. The second deformation sensor 42 is arranged on the side of the second layer 36 facing the first layer 32, that is, between the second layer 36 and the third layer 34. The two deformation sensors 40 and 42 extend over the entire surface of the protective plate 30, with the deformation sensors 40 and 42 being divided into multiple sections, thereby enabling the location of deformation.

[0062] When an object strikes the protective plate 30, the resulting deformation of the protective plate 30 is detected by deformation sensors 40 and 42. Depending on the impact force of the object, either only the second layer 36 and possibly the third layer 34 deform, or all layers 32, 34, and 36 deform. The impact of the object can be so small that only the second layer 36 deforms, and only the second deformation sensor 42 detects the deformation. Despite the deformation of the protective plate 30, no immediate action is required, as no damage to the battery 12 or the battery housing 16 is expected. In the event of a greater impact force, all layers 32, 34, and 36 deform. Knowledge of the stiffness of each layer 32, 34, and 36 and the detected deformations of each layer 32 and 36 allow an estimate of the load acting on the battery 12. Based on this information, it is possible to determine whether the battery 12 is critically loaded and whether appropriate measures are necessary.

[0063] Such a design of the deformation detection device 31 can significantly improve the usability of the electric vehicle 10, because the electric vehicle 10 can still be used for daily driving even if the protective plate 30 is slightly damaged, and only needs to be disconnected or immediately taken to a repair workshop if the protective plate 30 and the battery 12 are seriously damaged.

[0064] Architectural embodiments differing from the described embodiment are also possible, these falling within the scope of protection of the main claim.

Claims

1. A battery assembly for an electric vehicle, comprising: A battery (12) having a battery housing (16) and a plurality of battery cells (20), wherein the battery cells (20) are arranged in the battery housing (16); a protective plate (30) arranged on a side of the battery (12) facing the roadway (22); as well as A deformation recognition device (31) having at least one deformation sensor (40, 42), wherein the deformation sensor (40, 42) is arranged on the protection plate (30), It is characterized by: The protective plate (30) is implemented as a multi-layer and has at least a first layer (32) and a second layer (36) spaced apart from the first layer (32), wherein the deformation recognition device (31) has a first deformation sensor (40) and a second deformation sensor (42), wherein the first deformation sensor (40) is arranged at the first layer (32) of the multi-layer protective plate (30), wherein the second deformation sensor (42) is arranged at the second layer (36) of the multi-layer protective plate (30), and the second deformation sensor (42) extends over the entire surface of the protective plate (30) and is divided into a plurality of sections.

2. The battery assembly according to claim 1, It is characterized by: The first deformation sensor (40) is divided into different sections.

3. The battery assembly according to claim 1 or 2, It is characterized by: The deformation sensors (40, 42) are implemented as strain gauges, resistance sensors, piezoelectric strain sensors or Bragg sensors.

4. The battery assembly according to claim 1 or 2, It is characterized by: The first deformation sensor (40) is arranged on a side of the first layer (32) facing the second layer (36), and the second deformation sensor (42) is arranged on a side of the second layer (36) facing the first layer (32).

5. The battery assembly according to claim 1 or 2, It is characterized by: The first deformation sensor (40) is embedded in the first layer (32), and / or the second deformation sensor (42) is embedded in the second layer (36).

6. The battery assembly according to claim 1 or 2, It is characterized by: The protection plate (30) is arranged to be spaced apart from the battery case (16).

7. The battery assembly according to claim 1 or 2, It is characterized by: A third layer (34) is arranged between the first layer (32) and the second layer (36), wherein the third layer (34) is made of a deformable material.

8. The battery assembly according to claim 7, It is characterized by: The third layer (34) is made of structural foam.

9. The battery assembly according to claim 1 or 2, It is characterized by: The first layer (32) and the second layer (36) are made of fiber reinforced plastic.

10. The battery assembly according to claim 1 or 2, It is characterized by: The deformation recognition device (31) has an evaluation unit (50) which is operatively connected to the at least one deformation sensor (40, 42).

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