Method for checking the credibility of electronic circuits for time measurement in electrochemical energy storage systems

Abstract

The invention relates to a method for plausibility checking of an electronic circuit for time determination of an electrochemical energy storage system by means of the cooling properties of at least one electrochemical energy storage device during non-use of the electrochemical energy storage device.

Description

Technical Field

[0001] The invention is based on a method for plausibility checking of an electronic circuit for measuring the time of an electrochemical energy storage system, an electrochemical energy storage system and a use of an electrochemical energy storage system according to the preambles of the independent claims. Background Art

[0002] Publication US 5 955 869 discloses a method for monitoring the remaining capacity of a battery pack. In this method, two different methods are used to estimate the remaining capacity. In the first method, data generated on the battery pack is used to estimate the remaining battery capacity, and in the second method, data transmitted to the battery pack by a host device is used to estimate the remaining battery capacity. The battery pack switches between these two methods under defined conditions, and in a preferred embodiment described in detail in the present specification, the battery pack switches from the first method to the second method when the battery current is below a threshold value.

[0003] Publication US 2018 / 183252 discloses a method and device for detecting the battery status of an electronic device. The electronic device includes a battery; a charging circuit for charging the battery; a measuring circuit for checking the status of the battery; and a processor configured to charge the battery using the charging circuit so as to determine whether the charging process meets a preset condition.

[0004] The object of the present invention is to further improve the prior art. This object is achieved by the features of the independent claims. Summary of the invention

[0005] Advantages of the present invention

[0006] In contrast, the method according to the invention having the characterizing features of the independent claim has the advantage that during non-use of at least one electrochemical energy store a plausibility check is carried out using the cooling behavior of the electrochemical energy store, the method comprising the following steps:

[0007] a) Detect the ambient temperature of the electrochemical energy storage device ;

[0008] b) detecting the temperature of the electrochemical energy storage device when the electrochemical energy storage device is not used for a period of time ;

[0009] c) detecting the temperature of the electrochemical energy storage device when starting to restart the electrochemical energy storage device ;

[0010] d) According to the formula To calculate the time the electrochemical accumulator is not used , where τ is a system constant, which is calculated according to The material properties of the electrochemical energy storage device are as follows: m is the mass of the electrochemical energy storage device, A is the contact area of ​​the electrochemical energy storage device, α is the thermal conductivity of the electrochemical energy storage device and c p is the specific heat capacity of the electrochemical accumulator;

[0011] e) According to the formula To determine the length of time that the electrochemical energy store is not used The total error of the calculation is

[0012] Errors in the temperature measurement when restarting the electrochemical energy store,

[0013] The temperature measurement error when the electrochemical accumulator is not used at the beginning, and

[0014] Temperature measurement error of the ambient temperature;

[0015] f) by measuring the length of time that the electrochemical energy storage device has not been used, which is measured by the electronic circuit for measuring the time The calculated period of non-use of the electrochemical energy store Performing comparison to check the credibility of the electronic circuit used for time measurement;

[0016] g) If , an error in the electronic circuit used for time determination is detected.

[0017] Further advantageous embodiments are the subject matter of the dependent claims.

[0018] The method for performing a plausibility check on an electronic circuit for time measurement further comprises the following steps:

[0019] h) generating an electrical, optical, acoustic and / or tactile signal if an error in the electronic circuit for measuring time is detected.

[0020] Thus, for example, when an error in the electronic circuit for time determination is detected, a user of the electrochemical energy storage system can be warned and / or the error can be stored for service purposes.

[0021] Advantageously, the electrochemical energy storage system comprises: at least one electrochemical energy storage device; at least one sensor for detecting the temperature of the electrochemical energy storage device and / or the temperature of the surrounding environment of the electrochemical energy storage device; an electronic circuit for time measurement; and at least one device, in particular an electronic battery management control device, which is configured to perform the steps of the method according to the present invention.

[0022] Advantageously, a computer program comprises instructions which, when the computer program is executed by an electronic battery management and control device, cause the electronic battery management and control device to carry out the method according to the invention.

[0023] Advantageously, the computer program is stored on a machine-readable storage medium.

[0024] Advantageously, the electrochemical energy storage system according to the invention is used in electric vehicles, hybrid vehicles, aircraft, plug-in hybrid vehicles, power-assisted bicycles or electric bicycles, portable devices for long-distance communication or data processing, electric hand tools or kitchen machines and in stationary energy storage devices for storing electrical energy, in particular obtained in a regenerative manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

[0026] in:

[0027] Figure 1 A schematic diagram showing the temperature change of an electrochemical energy storage device during non-use; and

[0028] Figure 2 A diagram showing the temperature-dependent length of time for which an electrochemical energy store is not used is shown. DETAILED DESCRIPTION

[0029] In all the figures, the same reference numerals denote the same equipment parts. DETAILED DESCRIPTION

[0031] Figure 1 A schematic diagram of the temperature profile of an electrochemical energy store during non-use is shown. The heat release of an electrochemical energy store, in particular a high-pressure or low-pressure system, can be described with the aid of the following differential equation:

[0032] .

[0033] When using the electrochemical energy store, for example during a charging or discharging process of the electrochemical energy store, power losses occur due to the internal resistance of the electrochemical energy store. , and the electrochemical accumulator has a higher Slightly higher temperature. During non-use, power consumption is essentially zero, while the temperature course depends on the heat exchange with the surroundings of the electrochemical energy store and on the mechanical construction of the electrochemical energy store, which has certain material properties, such as the mass m, contact area A, thermal conductivity α and specific heat capacity c of the electrochemical energy store.p .

[0034] The length of time during which the electrochemical energy store is not in use can be calculated using the cooling behavior of the electrochemical energy store during non-use.

[0035] Figure 1 The temperature profile of an electrochemical energy storage device, for example a 48-volt battery, is shown. At an ambient temperature of 20° C. The electrochemical energy storage device is heated to a temperature of 50° C. due to use, for example, due to a discharge process. The electrochemical energy store is not in use starting at time t0. The temperature profile shown corresponds to the cooling curve during the period of non-use of the electrochemical energy store until time t1, at which the electrochemical energy store is put into operation again. The electrochemical energy store is cooled to a temperature of 30° C. at time t1. .

[0036] The length of time the electrochemical energy store is not in use According to the formula

[0037] is calculated, where τ is a system constant, which is calculated according to The system constant τ can be determined analytically or experimentally, for example. Thus, if determined experimentally, the electrochemical energy storage device can be used at a given ambient temperature. By means of observation and measurement of the temperature profile at multiple points in time when the electrochemical energy store is not in use, the system constant can be determined using standard methods, such as the least square method. Ideally, the experimental parameter determination is carried out after the electrochemical energy store has been installed, for example in a vehicle. This allows measurement inaccuracies and model inaccuracies to be minimized.

[0038] Determined duration of non-use The accuracy of can be determined with the help of the error propagation method. The first part of the error The second error is caused by an error in the temperature measurement when the electrochemical energy storage device is restarted. The third error is caused by the temperature measurement error when the electrochemical accumulator is not used at the beginning. Caused by temperature measurement errors of the ambient temperature of the electrochemical energy store. Calculation of the period of non-use of the electrochemical energy store The total error According to the sum of all partial errors Come get.

[0039] Each input parameter , , The inaccuracy can be determined experimentally, for example in a vehicle, since the measurement accuracy of the temperature of the electrochemical energy store increases if no power loss occurs in the electrochemical energy store over a short period of time, typically a few minutes, and a uniform temperature distribution can be assumed in the electrochemical energy store.

[0040] In one advantageous embodiment, during non-use of at least one electrochemical energy store, a plausibility check of an electronic circuit for measuring the time of the electrochemical energy storage system is carried out using the cooling behavior of the electrochemical energy store, using the length of non-use of the electrochemical energy store measured by the electronic circuit. The calculated period of non-use of the electrochemical energy store This is achieved by comparison.

[0041] The measured duration The calculated duration The difference must be in the total error Otherwise, the electronic circuit used to measure the time will have errors.

[0042] - The electronic circuit for measuring time has no errors:

[0043]

[0044] - The electronic circuit used for time measurement has an error:

[0045] .

[0046] Figure 2 A diagrammatic representation of the temperature-dependent duration of non-use of an electrochemical energy store is shown. The temperature of the electrochemical energy store at the beginning of the restart of the electrochemical energy store is plotted on the abscissa. The ambient temperature of the electrochemical accumulator difference The temperature of the electrochemical energy store at the beginning of non-use of the electrochemical energy store is plotted on the ordinate. The ambient temperature of the electrochemical accumulator difference In order to present the duration of non-use calculated according to the invention, for example, 4 hours is assumed as the value of the system constant τ and 3 Kelvin, 6 Kelvin, 1.5 Kelvin is a value used as the accuracy of temperature measurement.

[0047] In a first example, at a point in time when the electrochemical energy storage device is not used, the temperature difference is 40 Kelvin. During restart, the temperature difference The temperature-dependent period 201 during which the electrochemical energy store is not used is approximately 5 hours.

[0048] In the second example, at a point in time when the electrochemical energy storage device is not used, the temperature difference is 30 Kelvin. When restarting, the temperature difference The temperature-dependent period 202 during which the electrochemical energy store is not used is approximately 3 hours.

Claims

1. A method for carrying out a plausibility check of an electronic circuit for measuring the time of an electrochemical energy storage system by means of a cooling property of at least one electrochemical energy storage device during non-use of the electrochemical energy storage device, the method comprising the following steps: a) detecting the ambient temperature T of the electrochemical energy storage device Env ; b) detecting the temperature T of the electrochemical energy store when the electrochemical energy store is initially not in use t0 ; c) detecting the temperature T of the electrochemical energy store at the beginning of the restart of the electrochemical energy store t1 ; d) According to the formula To calculate the time t during which the electrochemical energy storage device is not used off , where τ is a system constant, according to The system constants include the material properties of the electrochemical energy store, where m is the mass of the electrochemical energy store, A is the contact area of ​​the electrochemical energy store, α is the thermal conductivity of the electrochemical energy store and c p is the specific heat capacity of the electrochemical accumulator; e) According to the formula To determine the time t for which the electrochemical energy store is not used off The total error of the calculation is Δt1 is the temperature measurement error when restarting the electrochemical energy store, Δt2 is the temperature measurement error when the electrochemical energy storage device is not used at the beginning, and Δt3 is the temperature measurement error of the ambient temperature; f) by measuring the length of time during which the electrochemical energy storage device has not been used, which is measured by the electronic circuit for measuring time and the calculated period t of non-use of the electrochemical energy storage device off Performing comparison and checking the credibility of the electronic circuit for time measurement; g) If A fault in the electronic circuit for determining the time is then detected.

2. The method according to claim 1, further comprising the steps of: h) if an error of the electronic circuit for measuring time is detected, generating at least one of an electrical signal, a light signal, an acoustic signal and a tactile signal.

3. An electrochemical energy storage system comprising: at least one electrochemical energy accumulator; at least one sensor for detecting the temperature of the electrochemical energy storage device and the temperature of the surrounding environment of the electrochemical energy storage device; Electronic circuits for measuring time; and at least one device configured to carry out the steps of the method according to claim 1 .

4. The electrochemical energy storage system according to claim 3, wherein the device is an electronic battery management control device.

5. Computer program product comprising a computer program, wherein the computer program comprises instructions which, when executed by an electronic battery management control device, cause the electronic battery management control device to carry out the method according to any one of claims 1 or 2.

6. A machine-readable storage medium having a computer program stored thereon, wherein the computer program comprises instructions which, when executed by an electronic battery management control device, cause the electronic battery management control device to implement the method according to any one of claims 1 or 2.

7. The electrochemical energy storage system according to claim 3 or 4 is used for the following applications: electric vehicles, hybrid vehicles, aircraft, power-assisted bicycles, portable devices for long-distance communication or data processing, electric hand tools or kitchen machines, and stationary energy storage devices for storing electrical energy.

8. The use of claim 7, wherein the electric vehicle comprises an electric bicycle and the hybrid vehicle comprises a plug-in hybrid vehicle.

9. Use according to claim 7, wherein the electrical energy comprises energy obtained in a renewable manner.

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