Method and device for determining and using a damage quantity of an energy storage device

Abstract

The present invention claims a method for determining damage to an energy storage device in a vehicle, as well as its use in a method for controlling safety measures based on the detected damage. Furthermore, devices and a vehicle that implement one of the methods are also claimed. To detect a critical and therefore dangerous change in the energy storage device, a damage variable is determined, which in particular represents the mechanical deformation of the energy storage device and / or the damage to its internal structure due to an impact of an object on the energy storage device and / or on the vehicle. To detect the impact, at least one acceleration variable is recorded, which represents the acceleration of at least part of the vehicle and / or the battery. The impact location of the object is then determined using the at least one acceleration variable. With the knowledge of the impact location, the recorded acceleration variable can be used to determine a damage variable. Based on the damage variable, it can be determined whether the energy storage device is still intact and can be operated without concerns.

Description

[0001] The invention relates to a method and a device for determining a damage quantity of an energy storage device in a vehicle and the use of the damage quantity in a corresponding device and a vehicle for initiating safety measures. State of the art

[0002] When using electrical energy storage devices in vehicles, it is important to ensure that the energy storage device itself does not become a hazard due to damage in the event of an accident. For example, a defective battery cell can cause flammable or combustible material to leak out, posing a safety risk to both passengers and emergency personnel.

[0003] For example, DE 10 2010 054 463 A1 discloses a vehicle battery that detects a dangerous condition of the battery based on a signal from an electronic sensor. In response to this detected condition, the terminals of the vehicle battery are de-energized.

[0004] The present invention is intended to describe a system which detects damage to the energy storage device even more accurately. Disclosure of the invention

[0005] The present invention claims a method for determining damage to an energy storage device in a vehicle, as well as its use in a method for controlling safety measures based on the detected damage. Furthermore, devices and a vehicle that implement one of the methods are also claimed.

[0006] To detect a critical and therefore dangerous change in the energy storage device, a damage variable is determined, which in particular represents the mechanical deformation of the energy storage device and / or the damage to its internal structure due to an impact of an object on the energy storage device and / or on the vehicle. To detect the impact, at least one acceleration variable is recorded, which represents the acceleration of at least part of the vehicle and / or the battery. The impact location of the object is then determined using the at least one acceleration variable. With the knowledge of the impact location, the recorded acceleration variable can be used to determine a damage variable. Based on the damage variable, it can be determined whether the energy storage device is still intact and can be operated without concerns.

[0007] When determining the extent of damage, the deformation stiffness of the vehicle and / or the energy storage device can also be taken into account to determine whether the impact of the object has caused damage to the energy storage device. For example, an object striking a reinforced part of the vehicle body, such as the A-, B-, or C-pillar, may have a lesser impact on the damage to the energy storage device than a central impact on a side door, despite the same impact energy acting on the vehicle body. An object striking the edge of the energy storage device also has a lesser impact on its structural integrity than an impact on its side surfaces.

[0008] The detected acceleration variable can be evaluated with regard to its maximum value, its duration, especially above a threshold value, or its shape to determine the damage magnitude. It can also be used as a measure of the impact energy. In an alternative embodiment, another (sensor) variable can also represent the impact energy in the method according to the invention and be used as a measure for determining the damage magnitude. In this embodiment, the acceleration variable could be used for plausibility checks.

[0009] In a further development of the invention, it is provided that at least two acceleration variables are recorded and used to derive the impact location and / or to determine the damage quantity. In this case, it can be provided that the two acceleration variables are sensor variables from different sensors at different locations on or in the vehicle or the energy storage device. However, it would also be possible for two acceleration variables from the same or different acceleration sensors to be recorded and taken into account at different times. Furthermore, it is conceivable that a first acceleration variable is used to determine the impact location and a second acceleration variable is used to determine the damage quantity. In this case, too, the sensor variables can be recorded separately from one another in time or space.Optionally, at least one piece of information from a crash detection system such as an airbag system can also be used, among other things, to verify and / or specify the findings in determining the extent of damage.

[0010] To detect damage or deformation of the energy storage device, at least one acceleration value is compared with at least one threshold value. Damage to the energy storage device can be assumed if the acceleration value exceeds this threshold value. Furthermore, the derivation of the damage can be specified based on the comparison with one or more threshold values and the consideration of other (sensor) variables and boundary conditions. It is conceivable, for example, that damage is only detected if acceleration peaks occur in certain driving situations or if the exceedance follows a specific pattern.

[0011] In a further development of the invention, a pressure variable can be recorded that represents the internal pressure in the energy storage device. This pressure variable can be used to detect damage to a cell of the energy storage device and the escape of gas or other materials. Alternatively or additionally, a humidity sensor in or on the energy storage device can detect the escape of material from individual cells or the energy storage device and indicate a hazard. The additional sensor variable, such as a pressure variable, a humidity variable, a rotation rate, or a speed, can also be used to check the plausibility of the recorded acceleration variables, for example, to avoid false-positive results of the method in borderline cases, during special impact events, or in certain driving situations.

[0012] Determining the extent of damage can also involve classifying the detected object impact and / or damage incident. In addition to a simple classification, the impact or damage incident can be divided into non-critical and problematic processes. For example, early stages of damage to the energy storage system or individual cells can be detected without yet requiring the energy storage system to be shut down and / or the vehicle to be taken out of service. Early detection of potential damage can alert the driver to change driving behavior. Furthermore, a recommendation to visit a workshop can be given. It is also conceivable that the classification could provide the workshop with information regarding repairs.

[0013] To determine the impact location, the at least one acceleration variable can be compared with at least one threshold value of the first type, while to determine the damage variable, the acceleration variable is compared with a threshold value of the second type. In particular, it can be provided that in the two comparisons, different properties or parameters of the at least one acceleration variable or of the associated acceleration signal are compared with the threshold values. Thus, it is conceivable to use the impact energy associated with the acceleration variable in the first comparison, while in the second comparison the maximum amplitude is used to determine the damage variable and detect damage. In general, any combination of different signal properties can be used.

[0014] If damage to the energy storage device or its internal structure is detected, a cascading of safety measures can be implemented, for example using the classification mentioned above. In addition to simply informing the driver when damage is detected based on the specific extent of the damage, direct influence can also be exerted on the vehicle, its driving behavior and / or individual components. This allows measures to be initiated that mitigate further damage to the vehicle or prevent damage to the driver. For example, individual consumers such as a heater can be switched off to reduce energy consumption. Furthermore, safety measures such as an extinguishing device for the energy storage device or the battery can be activated. Activation of a material that absorbs escaping gas, for example hydrogen when using a hydrogen drive, is also conceivable.In addition, based on the extent of the damage detected, passive measures are also conceivable, such as initiating an emergency call, issuing instructions to the driver, passenger or emergency services, and documenting the damage for the workshop for later repair.

[0015] As already stated at the beginning, a device is also claimed that carries out the aforementioned method for determining the damage magnitude. For this purpose, a processing unit is advantageously provided that records the necessary (sensor) variables, boundary conditions, and information and derives the damage magnitude from them. This device and the processing unit can also be used to control safety measures to protect the driver, passenger, and rescue personnel from injury and to prevent further damage to the vehicle.

[0016] Due to their space requirements, common electric vehicles have flat energy storage units in the floor area. To implement the claimed method, such vehicles are therefore equipped according to the invention with at least one acceleration sensor in the front area of the vehicle and / or in the front area of the energy storage unit. Alternatively or additionally, acceleration sensors can also be arranged in the area of the side doors, between the pillars. The arrangement of the acceleration sensors at these locations makes it possible to detect impact events occurring particularly at these locations, since these impact points are particularly susceptible to deformation or damage to the energy storage unit.

[0017] Further advantages emerge from the following description of embodiments and from the dependent patent claims. Short description of the drawings The Fig. 1a and Fig. 1b shows a vehicle in which a battery is mounted in the underbody. Fig. Figure 2 schematically shows an evaluation unit which carries out a method according to the invention, as is exemplified by the flow chart of Fig. 3 is shown. Embodiments of the invention

[0018] In the description of the invention according to the following description, it is assumed that the energy storage device 120 in the vehicle 100 is an electric battery or accumulator. However, it should be clarified that other types of energy storage devices, for example gas storage devices such as a hydrogen tank, can also be monitored for damage or deformation using the present invention. Furthermore, the present invention is described with reference to a passenger car (car). However, the invention can also be readily implemented in any other type of vehicle, for example, in trucks, electric bicycles, e-scooters, or other alternatively powered vehicles.The following essentially focuses on a crash or collision between the vehicle and other road users to detect the impact and / or deformation / damage to the energy storage device. However, the method can also be used for any impact or collision of an object with the vehicle that is capable of damaging the energy storage device. For example, driving into a bollard, a curb, or even the impact of (swirling) stones, particularly on the vehicle underbody, can lead to damage to the energy storage device. It should also be noted that damage to the energy storage device does not only mean external damage or deformation of the energy storage device, but also any form of damage to the (proper) functioning of the energy storage device, for example, the internal structure.

[0019] The electric batteries in electric vehicles have a large volume due to the energy required for propulsion. There are various approaches to accommodating this volume in the vehicle. One possibility is to move the battery to the trunk. Fig. 1a and Fig. 1b, in contrast, shows an embodiment in the form of a flat battery 120 in the area of the underbody of the vehicle 100. Such a large-area design has the advantage that, despite its large volume, the battery is not very bulky, is located in an area that is of limited use to the driver anyway, and has a large surface area for cooling. In contrast to accommodating the battery in the trunk and / or compactly centrally in the vehicle, this type of arrangement poses a greater risk that the battery could be deformed and thus damaged in a side-on collision. In the event of a side-on collision, it is also necessary to distinguish where an actual impact occurs in order to detect possible damage or deformation of the energy storage device 120.

[0020] Typical passenger vehicles have an A-pillar 130 between the engine compartment and the passenger cell, a B-pillar 140 between the front and rear rows of seats, and a C-pillar 150 between the passenger cell and the trunk. These A-, B-, and C-pillars reinforce the structure of the body and protect the passenger cell from being crushed, for example, in the event of a rollover and thus endangering the occupants. However, the front and rear doors 135 and 145, respectively, have no special reinforcement, as their flat design is intended to facilitate entry and exit and thus has no special bracing with the rest of the body. Accordingly, a side impact by another road user on one of these pillars would be less problematic for the energy storage unit 120 than a direct impact on doors 135 or 145.The present invention therefore provides a method with which such impact locations can be specifically detected in order to then determine whether the impact could have caused damage or deformation to the energy storage device. Furthermore, it is of course also possible to detect a rear-end collision or impact from the front 160 or rear 170 of the vehicle.

[0021] To implement the invention and to increase the significance of the determined damage magnitude, provision can be made for accommodating at least one acceleration sensor in the front region 180 of the energy storage device 120. This has the advantage that a side impact results in a more pronounced and stronger acceleration signal than an impact from the front 160 or the rear 170. Generally, acceleration sensors that detect movement at least in the x- and y-directions, i.e., in the plane of movement of the vehicle, are suitable. However, it is also possible to use three-axis acceleration sensors.

[0022] In the Fig. Figure 2 schematically describes a possible device that implements the inventive concept. A processing unit 200 is provided, for example, as part of a higher-level device, in particular an airbag system, or even a vehicle, which records the necessary parameters for determining a damage parameter with respect to an energy storage device. This processing unit 200 can also be provided to control or initiate appropriate safety measures in the event of a detected deformation or damage to the energy storage device 120 that results in a hazard.

[0023] The processing unit 200 detects at least one acceleration variable from an acceleration sensor 220, which represents the acceleration of at least one part or component of the monitored vehicle. This can be an acceleration of the vehicle, (a part of) the body, and / or the battery. Optionally, multiple acceleration variables can also be detected in order to be able to track the separate movement of the various parts or components, for example, in the event of a side impact on the front door 135. Alternatively or additionally, the different acceleration variables can also have a time offset, so that the behavior of the vehicle, the battery, and / or individual components of the vehicle can be detected. Based on the acceleration variables or accelerations thus detected, the processing unit 200 determines the impact location.The impact location can be used to determine whether the detected acceleration could have caused damage to the energy storage device. This potential damage is determined in the form of a damage variable and made available for further processing. To derive the possible damage, the processing unit 200 can access structural data of the vehicle, in particular its stability, and / or the energy storage device, which are stored, for example, in an internal memory 210 or can be retrieved externally. The damage variable can be used to warn the driver, for example via a corresponding display 260. Optionally, it is also possible to control or initiate measures that prevent or reduce further endangerment of the vehicle and / or the vehicle occupants. For this purpose, safety components 270 can be controlled, such as an extinguishing device.Furthermore, it is possible for the processing unit to transmit information about possible damage to the energy storage device to third parties 280, for example, a database. It is conceivable that this damage value could be stored on a central server for later workshop visits. Furthermore, this information could also be made available to emergency services. If the vehicle is part of a fleet, the fleet operator, aware of the damage value, can also dispatch assistance if there is a risk that the vehicle will no longer be able to move independently. In general, the damage value can also be used to assess the quality and residual value of the energy storage device.

[0024] In an extension of the method according to the invention, which can be used in the processing unit 200 to determine the damage magnitude, additional variables can be recorded that can specify both the impact location and the damage itself. For example, a pressure variable that detects the internal pressure of the energy storage device can be recorded using a pressure sensor 230. Information from an airbag system 240 can also be used to specify and / or verify the plausibility of the damage magnitude. By recording the driving state of the vehicle and / or the operating variables via corresponding systems 250, the damage magnitude can be further specified.Using the acceleration variables and, in particular, the further recording of (sensor) variables and information about the vehicle, especially its operation, a classification of the extent of damage can be achieved, which can lead to the derivation of suitable safety measures. For example, if the acceleration variables recorded are essentially the same for a stationary and a moving vehicle, different damage situations for the energy storage system can be inferred.

[0025] With the flow chart of the Fig. 3 describes a method which implements the inventive idea and is implemented in a processing unit according to Fig.2 can proceed. After the start of the method, at least one acceleration variable is recorded in a step 310, which describes the acceleration of the vehicle as a whole or only of a part, for example the battery. Optionally, it can be provided here that further acceleration variables are recorded, for example of further components or parts of the vehicle, in order to be able to map, for example, the deformation of the vehicle body during the impact, crash or accident. Additionally or alternatively, it can also be provided that the one or more acceleration variables are recorded in a chronological sequence of one another. In the next step 320, a check is carried out to determine whether the recorded acceleration variable exceeds a threshold value of the first type. If several acceleration variables were recorded in step 310, these can also be compared with further threshold values of the first type.The comparison in step 320 checks whether the severity of the impact could actually cause damage to the energy storage device. If this is not the case, the method can be terminated or restarted. However, if a minimum vibration that could cause damage was detected in step 320, the impact location is determined in the next step 330, before the damage magnitude itself is determined in the subsequent step 340. To determine the damage magnitude, in addition to the impact location, at least the first acceleration magnitude is used again to evaluate whether the strength of the acceleration at the detected impact location could actually have an effect on the energy storage device. For example, an impact on the A-pillar 130 and an impact on the front side door 135 can lead to a similar (lateral) acceleration value of the vehicle, but have different consequences for the assessment of damage to the energy storage device.For this reason, a second-type threshold value can be used in step 340, which is selected depending on the impact location to detect damage to the energy storage device. For example, if a side impact or an impact of an object from below onto the underbody is detected, different second-type threshold values can be used. When using multiple acceleration variables, different second-type threshold values can also be used for the acceleration variable or the acceleration sensors. If the comparison in step 340 determines that the damage variable does not indicate critical damage to the energy storage device, the method can be terminated or restarted. However, if damage to the energy storage device cannot be ruled out, a warning can be issued to the driver in the next step 350.Alternatively or additionally, a safety measure can also be initiated in step 350, for example, deactivating the battery's electrical supply. It is also conceivable to forward information about damage to the energy storage device to third parties, such as emergency services or a repair shop.

[0026] In a further embodiment of the method, the driving situation and / or the driving state of the vehicle can be recorded at the beginning in a further step 300. Alternatively or additionally, operating variables and / or driving dynamics variables can also be recorded. The information recorded in this way can be used in step 320 to assess whether the recorded acceleration exceeds the first type of threshold, in determining the impact location in step 330, and in determining the damage magnitude or comparing it with the second type of threshold in step 340 to specify the knowledge of damage to the energy storage device. If necessary, the knowledge of the driving state can also be used in step 350 to trigger a suitable measure to reduce the expected damage due to damage to the energy storage device.Optionally, the recording of the driving situation and / or driving condition can also be used to start the procedure.

[0027] To detect the internal integrity of the energy storage device, it can additionally be provided with at least one additional sensor. This battery sensor can be used, for example, to detect gas or liquid escaping from the individual cells in order to detect a battery fire in a timely manner. For example, in step 310, the sensor variable of a battery sensor can be detected, for example, a pressure variable, which, if increased, implies a damaged battery cell. Using this additional sensor variable, further information can be used in step 340 to determine the extent of damage and assess the damage.

[0028] In step 340, additional information from other systems or sensors in the vehicle can also be used to verify and / or validate the damage to the energy storage device. For this purpose, for example, information and sensor variables already available in the vehicle as part of an airbag deployment system can be recorded and taken into account.

[0029] Determining the damage magnitude in step 340 based on the impact location and acceleration magnitude can also be used to classify the impact and damage. All recorded variables and information can be used to differentiate between different damage cases and situations. By identifying or determining the various damage possibilities, each damage can be responded to with a specific, targeted measure in step 350. Furthermore, saving the identified damage situation in memory 210 can provide suitable information for repair during a subsequent workshop visit.

[0030] When detecting the acceleration quantity in step 310, all properties of the sensor quantity or the corresponding sensor signal can be detected, i.e., the (maximum) amplitude, the amplitude curve, the signal shape, and / or the (impact) energy associated with the acceleration. The properties of the quantity or the associated signal thus detected can be used individually or in combination to determine the damage quantity in step 340. It should also be noted that in the comparisons in steps 320 and 340, different properties of the acceleration quantity or the corresponding acceleration signals are compared with the threshold values of the first and second type.It is conceivable that in step 320, the impact energy based on the acceleration magnitude is compared with a first-type threshold, while in step 340, the duration of the acceleration signal is compared with the second-type threshold. Thus, a check is first made to determine whether the impact energy during the impact was even large enough to cause damage. If so, a check is made to determine whether the impact occurred within a short or long period of time, so that it can be determined whether the introduced energy could have been dissipated elsewhere, for example, laterally into the body. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] DE 10 2010 054 463 A1

[0003]

Claims

[1] Method for determining a damage quantity which represents the damage to an energy storage device (120) in a vehicle (100) due to the impact of an object on the vehicle (100), the method comprising at least • detects (310) an acceleration quantity that represents the acceleration of at least a part of the vehicle, and • determines an impact location depending on the at least one acceleration variable (320, 330), and • the damage magnitude is determined as a function of the acceleration magnitude and the impact location (340). [2] Method according to claim 1, characterized by that the method for determining the damage magnitude takes into account different deformation stiffnesses of the vehicle (100) and / or the energy storage device (120). [3] Method according to claim 1 or 2, characterized bythat the method for determining the impact location takes into account at least two acceleration variables (320), wherein it is provided in particular that the method detects the acceleration variables from different acceleration sensors and / or in a temporal sequence. [4] Method according to one of the preceding claims, characterized by that the method for determining the damage variable compares the at least one acceleration variable with at least one threshold value (320), wherein it is provided in particular that damage or deformation of the energy store (120) is inferred if at least one acceleration variable exceeds a threshold value. [5] Method according to one of the preceding claims, characterized by that the procedure - detects (310) at least one pressure variable representing the internal pressure of the energy storage device (120), and - the damage quantity is additionally determined (340) as a function of the at least one pressure quantity, wherein it is provided in particular that the damage quantity is determined as a function of the temporal course of the pressure quantity. [6] Method according to one of the preceding claims, characterized by that the procedure - at least one driving state variable is recorded (300) which represents the driving state of the vehicle (100), and - the damage quantity is additionally determined as a function of the at least one driving state quantity (340). [7] Method according to one of the preceding claims, characterized by that the procedure • to determine the impact location, compares at least one acceleration value with a threshold value of the first type (320, 330), and • to determine the damage quantity, the acceleration quantity is compared with a threshold value of the second type (340), wherein it is provided in particular that to determine the impact location and the damage quantity, different properties of the acceleration quantity or of an associated acceleration signal are compared with the threshold values. [8] Method according to one of the preceding claims, characterized by that the method classifies the damage depending on the extent of the damage (340), wherein it is provided in particular that the method links the classification to at least two different security measures. [9] Method for initiating safety measures upon detection of damage to an energy storage device of a vehicle as a function of the determined damage magnitude according to one of the methods in claims 1 to 8, wherein the method carries out at least one vehicle damage mitigation measure and / or one vehicle occupant safety measure as a function of the damage magnitude (350). [10] Method according to claim 9, characterized by that as a security measure - a shutdown of the energy storage system, and / or - switching off consumers in the vehicle, and / or - initiation of an emergency call, and / or - an instruction to the vehicle occupants, and / or - documentation of the damage is created. [11] Processing unit for determining a damage quantity, which carries out a method according to one of claims 1 to 8, wherein the processing unit (200) at least • detects an acceleration value that represents the acceleration of at least part of the vehicle, and • determines an impact location depending on the at least one acceleration variable, and • the damage magnitude is determined depending on the acceleration magnitude and the impact location. [12] Device with a processing unit according to claim 11 for initiating safety measures upon detection of damage to an energy storage device of a vehicle as a function of the deformation, wherein the device carries out a method according to one of claims 9 or 10 and carries out at least one vehicle damage mitigation measure and / or a vehicle occupant safety measure as a function of the deformation. [13] Vehicle with a processing unit according to claim 11 and / or a device according to claim 12. [14] Vehicle according to claim 13, characterized bythat the vehicle has an energy storage device in the floor area, wherein at least one acceleration variable of an acceleration sensor in the front area of the vehicle and / or in the front area of the energy storage device is used to determine the deformation.

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