Method, control device, battery device diagnostic device and computer program for determining a thermal runaway of a battery arrangement, and battery device and vehicle

Abstract

The present invention relates to a method, a control device (160), a battery device diagnostic device (170) and a computer program for determining a thermal runaway of a battery arrangement, and to a battery device (100) and a vehicle. The method according to the invention comprises receiving a thermal conductivity signal from a thermal conductivity sensor (140), receiving a presence signal from a pellistor (150), detecting a thermal runaway of the battery arrangement (120) if both the received thermal conductivity signal indicates a thermal conductivity of the gas mixture within the battery housing (110) which exceeds a predetermined thermal conductivity threshold value and the received presence signal indicates the presence of a combustible gas component in the gas mixture within the battery housing (110), and transmitting an error signal if a thermal runaway of the battery arrangement (120) has been determined, wherein the error signal is representative of a thermal runaway of the battery arrangement (120).

Description

[0001] Description

[0002] Method, control device, battery device diagnostic device and computer program for determining a thermal runaway of a battery assembly, as well as battery device and vehicle

[0003] The present invention relates to a method, a control device, a battery device diagnostic device and computer program for determining a thermal runaway of a battery assembly as well as a battery device and a vehicle.

[0004] New battery systems, for example with lithium-ion batteries or nickel-metal hydride batteries, are increasingly being used as rechargeable energy storage devices in both stationary applications such as wind turbines and mobile applications such as electric or hybrid vehicles. To ensure the safety and functionality of such battery systems, the battery cells must be operated within a specified temperature range. On the one hand, heat is generated during operation of the battery cells, which must be dissipated to prevent the battery cells from heating up above a critical operating temperature. On the other hand, it may be necessary to heat the battery cells to a minimum temperature at low temperatures. To maintain the specified temperature range, it is known that the battery system must be tempered, i.e. cooled or heated as needed.

[0005] For this purpose, it is known to temperature control the battery system as desired using a fluid, for example a liquid such as alcohol, for example propane-1,2,3-triol (glycerol, glycerin), oil or water or a liquid mixture, as a temperature control agent in a temperature control agent circuit. In the event of damage, such as a leak, to the temperature control agent circuit in the battery system, temperature control agent containing water can be released. If a housing of the battery system is not hermetically sealed, moisture in the form of water vapor can constantly penetrate the battery system, for example through vent valves. Since the temperature of the temperature control agent is significantly lower than the temperature in the housing when cooling the battery system, condensation can form inside the battery housing.

[0006] However, such battery systems, like all electrical, electronic or information technology devices in general, are very sensitive to the presence of liquids such as water, as these can cause or promote short circuits, corrosion, electrochemical migration, damage to insulation such as electrical insulation and other damage.

[0007] However, the formation or occurrence of liquids in the battery casing can have various origins, such as the ingress of water-containing air through leaky seals, as already described above. On the other hand, so-called thermal runaway or thermal failure of one of the battery cells in the battery casing can lead to the formation of liquids, such as water, within the battery casing due to reactions with hydrogen originating from the battery cells or due to a change in the composition of the gas mixture of the medium. Water can be formed, for example, during the oxidation of the organic electrolytes with atmospheric oxygen. In addition, hydrogen can also be formed during the thermal decomposition of the electrolytes, which can react to form water in the presence of atmospheric oxygen.

[0008] Examples of prior art include US 2023 / 0 349 978 A1 , US 2015 / 0 369 784 A1 , DE 102022 203 664 B3, WO 2022 / 060 845 A1 and CN 204 154 671 U.

[0009] The present invention is based, at least in part, on the object of detecting thermal runaway in a vehicle's battery assembly early and reliably. This object is achieved with a method according to independent claim 1, a control device according to claim 5, a battery device diagnostic device according to claim 7, a battery device according to claim 8, a vehicle according to claim 9, a computer program according to claim 10, and a computer-readable medium according to claim 11. Advantageous embodiments are specified in the subclaims.

[0010] The present invention is essentially based on the idea of ​​reliably detecting thermal runaway in a battery assembly for a vehicle in a redundant manner using two different measuring methods. The present invention utilizes, on the one hand, the thermal conductivity of the gas mixture within the battery assembly to detect the presence of hydrogen, and, on the other hand, the presence of a combustible gas component in the gas mixture, such as hydrogen, in order to determine the risk of an impending or already initiated thermal runaway. The thermal conductivity is determined using a thermal conductivity sensor, whereas the presence of the combustible gas component in the gas mixture is detected using a pellistor. Preferably, the pellistor can be operated significantly less frequently in order to reduce aging and drift of the pellistor as much as possible.It has been found that pellistors drift or become poisoned over their service life. High temperatures can even exacerbate this effect.

[0011] Accordingly, according to a first aspect of the present invention, a method for detecting thermal runaway of a battery assembly of a vehicle is disclosed. The battery assembly is located within a battery housing. A thermal conductivity sensor is provided, which is configured to generate a thermal conductivity signal representative of the thermal conductivity of the gas mixture within the battery housing. A pellistor is also provided, which is configured to generate a presence signal representative of the presence of a combustible gas component in the gas mixture within the battery housing.The method according to the invention comprises receiving a thermal conductivity signal from the thermal conductivity sensor, receiving a presence signal from the pellistor, detecting a thermal runaway of the battery assembly if both the received thermal conductivity signal indicates a thermal conductivity of the gas mixture within the battery housing that exceeds a predetermined thermal conductivity threshold and the received presence signal indicates the presence of a combustible gas component in the gas mixture within the battery housing, and transmitting an error signal if a thermal runaway of the battery assembly has been detected. The error signal is representative of a thermal runaway of the battery assembly.

[0012] Preferably, the thermal conductivity signal is received from the thermal conductivity sensor at first periodic intervals, and the presence signal is received from the pellistor at second periodic intervals that are greater than the first periodic intervals. It may further be preferred that the first periodic intervals be in a range of approximately 100 ms to approximately 10 seconds, and the second periodic intervals be in a range of approximately 60 seconds to 5 minutes.

[0013] In such a preferred embodiment, the pellistor can be operated significantly less frequently or less frequently than a thermal conductivity sensor. This can lead to the aging or drift of the pellistor being kept to a minimum. Accordingly, "pulsed" operation at lower temperatures, i.e., operation that is not continuous and occurs at longer intervals, is better for the pellistor.

[0014] In a further advantageous embodiment of the method according to the invention, the thermal conductivity sensor comprises a heating device designed to heat the gas mixture and a temperature sensing device designed to generate a temperature signal representative of the temperature of the heating device and / or the gas mixture surrounding the heating device. Generating the thermal conductivity signal comprises sending a heating signal to the heating device, receiving a temperature signal from the temperature sensing device, and generating the thermal conductivity signal based on the temperature signal. The heating signal sent to the heating device causes the heating device to operate at a predetermined electrical power.

[0015] According to a further aspect of the present invention, a control device is disclosed which is designed to carry out the steps of the method according to the invention for detecting a thermal runaway of a battery assembly of a vehicle.

[0016] Preferably, the control device according to the invention comprises a first control device section for carrying out the step of receiving a thermal conductivity signal from the thermal conductivity sensor, a second control device section for carrying out the step of receiving a presence signal from the pellistor, a third control device section for carrying out the step of detecting a thermal runaway of the battery assembly, and a fourth control device section for carrying out the step of transmitting the error signal.

[0017] According to yet another aspect of the present invention, a battery device diagnostic device for a vehicle is disclosed. The battery device diagnostic device according to the invention comprises a thermal conductivity sensor configured to be mounted in a battery housing of a battery device for a vehicle, said battery housing accommodating a battery assembly, a pellistor configured to be mounted in a battery housing of a battery device for a vehicle, said battery assembly accommodating a battery assembly, and a control device according to the invention. The thermal conductivity sensor is configured to generate a thermal conductivity signal representative of the thermal conductivity of the gas mixture within the battery housing. The pellistor is configured to generate a presence signal representative of the presence of a combustible gas component in the gas mixture within the battery housing.

[0018] According to yet another aspect of the present invention, a battery device for a vehicle is disclosed, comprising a battery housing, a battery assembly disposed in the battery housing, and a battery device diagnostic device according to the invention.

[0019] According to yet another aspect of the present invention, a vehicle having a battery device according to the invention is disclosed.

[0020] According to yet another aspect of the present invention, a computer program is disclosed comprising instructions that, when executed by a computing unit, cause the computing unit to perform a method according to the invention for detecting a thermal runaway of a battery assembly of a vehicle.

[0021] According to yet another aspect of the present invention, a computer-readable medium is disclosed on which the computer program according to the invention is stored.

[0022] Further advantages and features of the present invention will become apparent to those skilled in the art by practicing the teachings described herein and viewing the accompanying single drawings in which:

[0023] Fig. 1 shows a schematic representation of a battery device according to the invention for a vehicle, and

[0024] Fig. 2 shows an exemplary flowchart of a method according to the invention for detecting thermal runaway of a battery assembly of the battery device of Fig. 1. In the context of the present disclosure, the term "pellistor" describes a gas sensor in the form of a resistance heater that is thermally decoupled from the environment. This heats a catalytically active layer thermally connected to the heater. Pellistors are preferably designed as a wound platinum coil embedded in a ceramic bead or as a micromechanical semiconductor membrane with a deposited heater and catalytic layer.

[0025] In the context of this disclosure, the term "signal" describes raw data that is converted for data transmission into a form that can be sent over the selected transport medium. This can be done analogically or digitally, with the data first being sampled and converted into discrete (often binary-coded) values, which are then sent over the medium as current pulses or voltages of varying magnitudes. Furthermore, in the context of this disclosure, the signals can be sent and received continuously. For example, digital signals are sent and received at intervals of a few milliseconds.

[0026] Fig. 1 shows a battery device 100 according to the invention, which has a battery housing 110 configured to accommodate a battery assembly 120. As is known in the art, the battery assembly 120 may include at least one battery cell. In Fig. 1, the battery assembly 120 is schematically illustrated as a block, although it is self-evident to those skilled in the art that the battery assembly 120 and the battery cells may be arranged and interconnected as is known in the art.

[0027] At this point, it should be noted that the "interior of the battery housing 110" comprises the free area surrounding the battery assembly 120. In particular, this is the fluid-filled, preferably air-filled, area around the battery assembly 120 located within the battery housing 110.

[0028] The battery device 100 further comprises a

[0029] Battery device diagnostic device 170, which in the embodiment shown in Fig. 1 comprises a thermal conductivity sensor 140, a pellistor 150 and a control device 160.

[0030] The thermal conductivity sensor 140 is configured to generate a thermal conductivity signal representative of the thermal conductivity of the gas mixture within the battery housing 110. The thermal conductivity sensor 140 can be a prior art thermal conductivity sensor based on the thermal conductivity measurement principle. The thermal conductivity of the entire gas mixture is determined, from which the concentration of a gas component of the gas mixture can be derived. In particular, for example, the hydrogen concentration in the gas mixture can be derived, since the thermal conductivity of hydrogen is significantly greater than the thermal conductivity of many other gas components.

[0031] The measuring operation of such a known thermal conductivity sensor 140 is essentially based on the constant operation of a heating device. A predetermined heat output is supplied to the gas mixture by supplying a predetermined electrical power to the heating device. Based on the heat dissipated from the gas mixture, the concentration of the gas component to be determined, such as hydrogen, can then be determined. A predetermined electrical power is supplied to the heating device, which, for a known gas mixture without the component to be measured, would lead to an expected temperature of the gas mixture.However, if the actual temperature of the gas mixture containing the gas component to be measured does not correspond to the expected temperature of the gas mixture without the gas component, the concentration of the gas component in the gas mixture can be determined based on the change in the thermal conductivity of the gas mixture caused by the gas component. In particular, the temperature difference between the heater and the temperature sensor can be determined. Alternatively, the measuring principle of the thermal conductivity sensor 140 is based on the gas mixture being heated to a predetermined temperature by means of the heating device, whereby the electrical heating power required for this can be used as a measure of the thermal conductivity of the gas mixture within the battery housing 110.

[0032] The pellistor 150 is preferably also a pellistor known from the prior art and is configured to generate a presence signal indicating the presence of a combustible gas component, such as hydrogen, in the gas mixture within the battery housing 110. The presence signal can either be a binary signal and / or qualitatively indicate the approximate concentration of the combustible gas component in the gas mixture within the battery housing 110.

[0033] It is expressly noted at this point that the arrangement of the thermal conductivity sensor 140 and the pellistor 150 can be arbitrarily chosen and is thus not limited to the specific arrangement shown in Fig. 1. For example, it may be preferable for the thermal conductivity sensor 140 and the pellistor 150 to be arranged on opposite sides relative to the battery assembly 120 within the battery housing 110.

[0034] The battery device diagnostic device 170 may further include a metal oxide semiconductor gas sensor (= MOx sensor) configured to detect the concentration of a gas component, such as hydrogen.

[0035] The battery device diagnostic device 170 further includes a controller 160. The controller 160 may include a processor and a memory. Alternatively, the controller 160 may be the processor coupled to the memory. The processor may be a central processing unit (CPU). The processor may further be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor or the like.

[0036] Memory includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or portable read-only memory (e.g., CD-ROM). The memory is configured to store associated program instructions and associated data.

[0037] In the exemplary embodiment of FIG. 1, the control device 160 has a first control device section 162, a second control device section 164, a third control device section 166, a fourth control device section 168, a fifth control device section 167, and a sixth control device section 169, which will be discussed in more detail below with reference to FIG. 2. At this point, however, it should only be noted that the fifth control device section 167 and the sixth control device section 169 are optional.

[0038] Fig. 2 shows an exemplary flowchart of a method according to the invention for detecting a thermal runaway of a battery assembly 120 of the battery device 100 of Fig. 1.

[0039] The method of Fig. 2 starts at step 200 and then proceeds to step 210, at which the control device 160, in particular the first control device section 162, can receive a thermal conductivity signal from the thermal conductivity sensor 140. Preferably, the thermal conductivity sensor 140 is configured to generate and transmit a thermal conductivity signal at first periodic intervals ranging between approximately 100 ms and 10 seconds.

[0040] In a subsequent step 220, it is checked whether the thermal conductivity signal received in step 210 indicates a thermal conductivity of the gas mixture within the battery housing 110 that exceeds a predetermined thermal conductivity threshold. If it is determined in step 220 that the thermal conductivity signal received in step 210 indicates a thermal conductivity of the gas mixture within the battery housing 110 that does not exceed the predetermined thermal conductivity threshold, the method proceeds to step 270 and is terminated.

[0041] However, if it is determined in step 220 that the thermal conductivity signal received in step 210 indicates a thermal conductivity of the gas mixture within the battery housing 110 that exceeds the predetermined thermal conductivity threshold, the method proceeds to step 230, at which the control device 160, in particular the second control device section 164, receives a presence signal from the pellistor 150. Preferably, the pellistor 150 is configured to generate and transmit a presence signal at second periodic intervals that are greater than the first periodic intervals. For example, the second periodic intervals are in a range of approximately 60 seconds to 10 hours.

[0042] Alternatively, the first controller portion 162 and the second controller portion 164 may be integrally formed as a single controller portion configured to receive both the thermal conductivity signal from the thermal conductivity sensor 140 and the presence signal from the pellistor 150.

[0043] In a subsequent step 240, it is checked whether the presence signal received in step 230 indicates the presence of a combustible gas component in the gas mixture within the battery housing 110. If it is determined in step 240 that the presence signal received in step 230 does not indicate the presence of a combustible gas component in the gas mixture within the battery housing 110, the method proceeds to step 270 and is terminated.

[0044] However, if it is determined in step 240 that the presence signal received in step 230 indicates the presence of a combustible gas component in the gas mixture within the battery housing 110, the method proceeds to step 250, at which the control device 160, in particular the third control device section 166, determines a thermal runaway of the battery assembly 120. In a subsequent step 260, the control device 160, in particular the fourth control device section 168, sends an error signal representative of a thermal runaway of the battery assembly 120.

[0045] In a further exemplary embodiment of the method according to the invention, a diagnostic signal can be transmitted if the received thermal conductivity signal indicates a thermal conductivity of the gas mixture within the battery housing 110 that exceeds the predetermined thermal conductivity threshold, but the received presence signal does not indicate the presence of a combustible gas component in the gas mixture within the battery housing 110. Alternatively or additionally, the diagnostic signal can also be transmitted if the received thermal conductivity signal indicates a thermal conductivity of the gas mixture within the battery housing 110 that does not exceed the predetermined thermal conductivity threshold, but the received presence signal indicates the presence of a combustible gas component in the gas mixture within the battery housing 110.The diagnostic signal may then indicate a fault in the thermal conductivity sensor 140 and / or the pellistor 150.

[0046] According to the invention, a redundant system for reliably detecting thermal runaway of the battery assembly 120 can thus be created, wherein the measuring principles of the two sensors are based on different physics and, preferably, the respective sensor signals are transmitted at different periodic intervals. This can, for example, reduce sensor aging and / or drift.

Claims

Patent claims 1. A method for detecting a thermal runaway of a battery assembly (120) of a vehicle, wherein the battery assembly (100) is arranged within a battery housing (110), wherein a thermal conductivity sensor (140) is provided, which is designed to generate a thermal conductivity signal that is representative of the thermal conductivity of the gas mixture within the battery housing (110), wherein a pellistor (150) is further provided, which is designed to generate a presence signal that is representative of the presence of a combustible gas component in the gas mixture within the battery housing (110), the method comprising: Receiving a thermal conductivity signal from the thermal conductivity sensor (140), Receiving a presence signal from the pellistor (150), Detecting a thermal runaway of the battery assembly (120) when both the received thermal conductivity signal indicates a thermal conductivity of the gas mixture within the battery housing (110) that exceeds a predetermined thermal conductivity threshold and the received presence signal indicates the presence of a combustible gas component in the gas mixture within the battery housing (110), and Sending an error signal when a thermal runaway of the battery assembly (120) has been detected, the error signal being representative of a thermal runaway of the battery assembly (120).

2. The method according to claim 1, wherein receiving the thermal conductivity signal from the thermal conductivity sensor (140) occurs at first periodic intervals, wherein receiving the presence signal from the pellistor (150) occurs at second periodic intervals that are greater than the first periodic intervals.

3. The method of claim 2, wherein the first periodic intervals are in a range of approximately 100 ms to approximately 10 seconds, wherein the second periodic intervals are in a range of approximately 60 seconds and 5 minutes.

4. The method according to any one of the preceding claims, wherein the thermal conductivity sensor (140) comprises a heating device configured to heat the gas mixture and a temperature sensing device configured to generate a temperature signal representative of the temperature of the heating device and / or the gas mixture surrounding the heating device, wherein generating the thermal conductivity signal comprises: Sending a heating signal to the heating device, the heating signal causing the heating device to be operated with a predetermined electrical power, Receiving a temperature signal from the temperature sensing device, and Generating the thermal conductivity signal based on the temperature signal.

5. Control device (160) designed to carry out the steps of the method according to one of the preceding claims.

6. The control device (160) of claim 5, comprising: a first control device portion (162) for performing the step of receiving a thermal conductivity signal from the thermal conductivity sensor (140), a second control device portion (164) for performing the step of receiving a presence signal from the pellistor (150), a third control device portion (166) for performing the step of detecting a thermal runaway of the battery assembly (120), and a fourth controller portion (168) for performing the step of transmitting the error signal.

7. A battery device diagnostic device (170) for a vehicle, comprising: a thermal conductivity sensor (140) configured to be mounted in a battery housing (110) of a battery device (100) for a vehicle, said battery housing accommodating a battery assembly (120), wherein the thermal conductivity sensor (140) is configured to generate a thermal conductivity signal representative of the thermal conductivity of the gas mixture within the battery housing (110); a pellistor (150) configured to be mounted in a battery housing (110) of a battery device (100) for a vehicle, said battery assembly accommodating a battery assembly, said pellistor being configured to generate a presence signal representative of the presence of a combustible gas component in the gas mixture within the battery housing (110); and a control device (160) according to one of claims 5 and 6.

8. A battery device (100) for a vehicle, comprising a battery housing (110), a battery assembly (120) arranged in the battery housing (110), and a battery device diagnostic device (170) according to claim 7.

9. A vehicle having a battery device (100) according to claim 8.

10. A computer program comprising instructions which, when executed by a computing unit, cause the computing unit to carry out a method according to any one of claims 1 to 4. 11 . A computer-readable medium on which the computer program according to claim 10 is stored.

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