EP1902326A1

EP1902326A1 - Method for identifying preset values of an electric accumulator

Info

Publication number: EP1902326A1
Application number: EP06755142A
Authority: EP
Inventors: Eberhard Schoch
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2005-07-05
Filing date: 2006-05-11
Publication date: 2008-03-26
Also published as: WO2007003460A1; JP2009510390A; KR101077765B1; KR20080033237A; DE102005031254A1; JP5495560B2

Abstract

The invention relates to a method for identifying preset values of an electric accumulator, for example of a battery in a vehicle, according to which method various parameters are determined. These parameters are rapidly adaptable parameters that can be adapted within seconds or minutes and slowly adaptable parameters that are adapted within hours or days. One of these slowly adaptable parameters is the battery capacity. Since the rapidly adaptable parameters correlate with the slowly adaptable parameters, the latter, especially the battery capacity, is inferred from the rapidly adaptable parameters while taking into consideration settable rating routines and incorrect ratings. The determined parameters are compared with stored parameters, thereby allowing to identify the inserted battery type.

Description

Method for detecting predefinable sizes of an electrical memory

The invention relates to a method for detecting predeterminable sizes of an electrical memory with the features of claim 1. In particular, quantities of an electrical energy or charge storage are determined for a motor vehicle, with predeterminable sizes include the performance, the storage capability or the type of electrical storage.

State of the art

To monitor the performance and / or storage capacity of the electrical

Energy storage in the motor vehicle electrical system, for example in the context of electrical energy management, usually methods are used, which use to a certain extent a priori knowledge about the energy storage used. Such methods are described for example in DE 199 59 019. Such knowledge about the energy storage used use e.g. the rated capacity or the cold start current to the desired sizes Leistungs- u. Storage capacity to be determined.

If different battery sizes come into question for a vehicle type, for example, depending on its motorization or the built-in consumers, the a priori data of the battery state detection must be communicated when installing or replacing the energy store. This can be done in the workshop by appropriate coding, but is not practical when changing the battery by the end user. In addition, errors in the coding can not be excluded. Another possibility is provided by adaptive model-based methods for battery state detection, which autonomously determine, for example, the parameters relevant to the power or storage capability continuous measurement of current, voltage u. Adapt the temperature of the energy storage. These methods are dependent on a sufficient on-board network dynamics and cyclization of the energy storage for a quick adaptation of the desired parameters, since an active intervention in the electrical system is not approved by the vehicle manufacturer or too expensive and therefore too expensive.

However, adequate on-board network dynamics are not always present, for example when driving on a motorway, and over-cycling is undesirable since it reduces battery life. As a result, it may take a few days to weeks for the battery condition detection to change the parameters of the battery

Battery has adapted. This applies in particular to the battery capacity, for the adaptation of which current charging / discharging strokes of> 20-30% nominal capacity are required. Another aspect is that in general not all relevant parameters for power and storage capability can be adapted, otherwise the procedure would be too costly, the measured quantities current, voltage, temperature would not be sufficient or the energy storage would have to be operated at operating points. that does not normally occur in the vehicle, for example, overcharging or low state of charge.

Advantages of the invention

The inventive method for detecting predeterminable sizes of an electrical memory with the features of claim 1 has the advantage of enabling rapid detection of the memory type and the parameters of the memory type and to carry out the adaptation of relevant for the determination of power and / or storage capacity parameters. It is particularly suitable to be used for an electrical storage in a vehicle electrical system, such as a lead acid battery and to get along from the continuous measurement of current, voltage and temperature without conditioning the storage or battery type or active stimulation of the electrical system.

It is particularly advantageous that the type and the parameters of the electrical energy store can also be determined much faster compared to the known model-based methods. As a result, the method according to the invention allows a reliable statement about the performance and storage capacity of the exchanged within a few minutes of the first operating phase Energy storage. This is particularly important for safety-critical applications such as x-by-wire applications, so that it is recognized as quickly as possible whether the exchanged energy storage or the exchanged energy is approved for this application and the subsidized performance or storage capability can basically.

These advantages are achieved by using a method for identifying predeterminable variables of an electrical storage, for example a battery in a vehicle, in which various parameters are determined. These parameters are fast-adaptable parameters that can be adapted within seconds or minutes, and slowly adaptable parameters that can be adjusted within hours or minutes

Days are adapted. One such slow adaptable parameter is the battery capacity. Since the rapidly adaptable parameters correlate with the slowly adaptable parameters, the latter, in particular the battery capacity, is deduced from the rapidly adaptable parameters, taking account of predefinable estimation routines and estimation errors. By comparing the determined parameters with stored parameters, the type of battery used can be detected.

Further advantages of the invention are achieved by the measures specified in the dependent claims. It is particularly advantageous that the method according to the invention can also detect whether an exchange of the energy storage has taken place at all or whether the possibly aged battery is only used for other purposes, e.g. for recharging in a charger was disconnected from the electrical system.

As quickly adaptable parameters are advantageously selected time constants of RC elements with small time constants, which consist of specifiable resistors and

Assemble capacities of the electrical storage or the ohmic internal resistance of the electrical storage. As a slowly adaptable parameter, for example, the equivalent capacity of the electrical memory is selected.

From the comparison of the fast-adaptable parameters and the slowly adaptable

Parameters with stored parameters can be reliably concluded on the performance and / or the storage capability or whether it is the energy storage is an approved energy storage whether an exchange of memory has occurred. It is particularly advantageous that a distance measure is formed from the adapted and the non-adapted parameters, which is compared with the stored parameters for the recognition of the predeterminable variables and that from the comparison result on the predeterminable size, in particular the memory type is concluded. The distance measure can be formed depending on the error square or on absolute values of predefinable parameters. Relative error squares of predeterminable parameters or parameter sets can be determined, depending on the current accuracy of the estimated parameter and its significance for a particular memory type, taking into account the significance by means of weighting factors. The advantage here is that quickly adaptable parameters contribute more to the distance measure than slow ones whose

Error variance stays high for a long time. Advantageously, parameters are weighted with respect to their significance for distinguishing the different memory types, and the parameter with the greatest relative variance is most heavily weighted with respect to the memory type, in particular the battery type, and vice versa.

drawing

An embodiment of the invention is illustrated in the drawings and will be explained in more detail in the description. FIG. 1 essentially describes the equivalent circuit diagram of a lead-acid battery and FIG. 2 shows essential to the invention

Components of a device for detecting predeterminable sizes of an electrical memory. FIG. 3 shows a flowchart with essential method steps.

description

The basic idea behind the invention is that certain parameters (seconds to minutes) of an electrical energy store, for example a lead-acid battery, correlate with parameters that are rather slowly adaptable (hours to days) such as the battery capacity, so that after the transient of the battery quickly adaptable parameters can be concluded on the slowly adaptable parameters.

Essential parameters or sizes of an electrical storage device, for example a lead-acid battery or a lead-acid battery, are given in FIG. The equivalent circuit of a lead-acid battery shows the following relationships:

Operating variables:

Eat _att ⁼ battery current (<0 for unloading) Ußatt ⁼ battery voltage T.sub.Batt ⁼ battery temperature state variables:

Uco = open-circuit voltage U _k = concentration polarization U _Dp = penetration polarization of the positive electrode U _Dn = penetration polarization of the negative electrode

Parameter:

R ₁ = resistive internal resistance (lead grid + acid) C ₀ = replacement capacity of the battery

R _k5 C _k = resistance and capacity of acid diffusion

R _DP , C _DP = resistance and capacity of the positive electrode double layer

R _Dn5 C _Dn = resistance and capacitance of the negative electrode double layer

The replacement capacity C _{0 of} the battery is typically in starter batteries in the

Order of magnitude of 150000F-350000F. In other words, in order to be able to determine the capacitance C ₀ from a voltage change that can be measured at the battery terminals, large charge withdrawals or charge increases of 20-30% of the nominal capacity are required, which in the vehicle electrical system, if at all, only over a period of several hours or more. Days occur. The capacitances C _{k of} the acid diffusion and C _Dp or C _{Dn of} the electric double layer between the electrodes u. The electrolyte can be scaled approximately at least for new batteries with the equivalent capacitance C ₀ . Together with the respective parallel resistor R _k and R _Dp , Ru _n they form RC elements with time constants on the order of <seconds to minutes, so that C _k u. C _Dp , C _Dn at sufficiently high charge / discharge currents significantly faster than the

Replacement capacity C ₀ can be adapted. Furthermore, the ohmic internal resistance R _1, at least in the case of a new battery and based on the fixed state of charge and temperature, also provides an indication of the replacement capacity since this decreases as the battery capacity increases.

Starting from this problem, the method according to the invention, the most essential steps of which are shown in FIG. 3, is described below Approach: The method initially assumes that the parameter sets of all n relevant for a particular vehicle, in particular new batteries are stored in a non-volatile memory (p_B _a tti, Eβate, J_ ₃ attn) - The adaptation of the parameters is in step Sl symbolizes. In addition, to detect whether a battery replacement has taken place, or the battery was only disconnected, the last adapted

Battery parameters non-volatile stored (p_ _Batt o) - It is also assumed that the parameters refer to fixed values of temperature and state of charge of the energy storage (eg Tban = 25 ° C, SOC = 100%), so that this with a new battery only depend on the battery type. The parameters are subdivided into adapted and unadapted parameters: p_B _att ^τ = [ρ_Batt, ad ^T l> Batt, noad ^T ] -

For the detection of the battery type or which of the stored sets of parameters p_ _Batt o, living _at e, £ _Battn the parameter set p_ _Batt the currently built-in battery is closest to the following "distance measure" is used for the adapted parameters:

D on ⁼ - pi, BattO n, ad) / pi, BattO n, ad] 1 = 1 m

As an alternative to the error square, the absolute value can also be used, for example. The rel. Error squares of the individual parameters are determined by the factor _m individually weighted for each of the m parameters of a parameter set as a function of the current accuracy of the estimated parameter and its significance for a particular battery type. If, for example, the parameters estimated with a Kalman filter, this provides for each parameter and its error variance P _p i _{m; Batt,} so that the weighting factors for the following approach offers:

m = min (1.0, threshold, lm / Pplm, Batt)

That with decreasing estimation error variance or increasing accuracy of a parameter, the weighting of the associated error increases until it reaches a given value

Variance threshold Ps _C hweiie, limited to the maximum value of 1.

This ensures that quickly adaptable parameters contribute more to the distance measure than slowly adaptable ones whose error variance remains at a high level for a long time. In addition, the parameters regarding their significance for the distinction of the weighted across different battery types, ie the parameter with the largest relative variance is most heavily weighted with respect to the battery type, and vice versa:

= min (1.0 U, l / (n + 1) * Σ [(p ₁ 3 _at tj, ad-pi, Batt, ad, middle) / pi, Batt, ad, middle] ² ) j = O..n with: pi, Batt, ad, medium = l / (n + l) *

In summary, the "distance measure" results as:

- pi, BattO n, ad) / pi, BattO n, ad] With :

PRO _A, i = min (1.0, P _S chwelle, i / Pp, i, Batt) = min (1.0, l / (n + l) * Σ [(p ₁ 3atto, ad-pi, Batt, ad, medium ) / pi, Batt, ad, middle]) j = O..n

Pi, Batt, ad, middle ⁼ l / (n + 1) * Σpi, Battj, ad j = O..n

After the rapidly adaptable parameters have settled and this is detected in step S2, in step S3, by minimizing the distance measures closest to the estimated parameter set, and replacing the slow or unadaptable parameters with those of the selected parameter set. In addition, it can be decided whether a battery replacement ever existed and whether, if the stored parameter sets were too large, a battery that was not intended for the intended purpose was exchanged:

k = index (min (D ² o _n )) Case 1: In step S4, the condition is checked if min (D ² ₀ .. _n ) <D ² ^

If this is not the case, then min (D ² o. _N )> D ² ^

^■ => unintended battery, ie it is detected in step S5 that an unintended

Battery was used.

Case 2;

If YES in step S4, it is checked in step S6 if k> 0.

If this is not the case: k = 0 and min (D ² ₀ .. _n ) <D ² _max => battery was not replaced (step S7)

Case 3:

If steps S4 and S6 are decided with yes, then k = 1..n and min (D ² ₀ .. _n ) <D ² ^ => battery type uniquely recognized (step S8)

If no suitable parameter set is determined as in case 1, predictors of the power and / or storage capability of the energy store such as e.g. in DE 103 01 823 A or DE 103 28 721 A specified based on the rapidly adapted parameters a basic statement about the usability for the particular application are made.

The inventive method according to the main claim including the advantageous developments are carried out with the aid of an evaluation, in particular a computational insight or a control device, such as a battery control unit or a

On-board control unit represents and in addition to suitable processors also includes storage means. The variables required for carrying out the method are measured by suitable means, for example sensors and fed to the evaluation and processed by this optionally after a treatment. In Figure 2 are essential to the invention Means of the evaluation device shown. These are a processor P, in which the methods according to the invention run, one or more memories SP, into which initial values are stored, which can be accessed by the processor P. Measurements can also be taken continuously in the memories SP. The measured values, for example I _Batt = battery current (<0 for discharging), U _Ba tt = battery voltage and T _Ba tt = battery temperature are measured by suitable means, in particular sensors Sen and supplied to the processor P. A display A may indicate the determined state of charge or the battery type and so on.

Claims

claims

1. A method for detecting predeterminable sizes of an electrical memory, characterized in that fast-adaptable parameters of the electrical memory and slowly adaptable parameters of the electrical memory are determined, the slowly adaptable parameters are determined from the rapidly adaptable parameters and compared the determined parameters with stored parameters become.

2. The method according to claim 1, characterized in that the determination of the parameters takes place at normal or usual load of the electrical storage.

3. The method of claim 1 or 2, characterized in that the fast-adaptable parameters are parameters that are adapted within seconds to minutes and the slowly adaptable parameters are parameters whose adaptation takes hours to days.

4. The method of claim 1, 2 or 3, characterized in that is closed after a transient of the fast-adaptable parameter from these to the slowly adaptable parameters.

5. The method according to any one of the preceding claims, characterized in that parameter sets are stored in a non-volatile memory.

6. The method according to any one of the preceding claims, characterized in that a battery is provided in a vehicle as an electrical memory and the Parameter sets of all eligible for a particular vehicle in question batteries are stored in a non-volatile memory.

7. The method according to any one of the preceding claims, characterized in that are selected as fast adaptable parameters at least RC elements with small time constants, which are composed of predetermined resistances and capacitances of the electrical memory or the ohmic internal resistance of the electrical memory.

8. The method according to any one of the preceding claims, characterized in that at least the replacement capacity of the electrical memory is selected as a slowly adaptable parameter.

9. The method according to any one of the preceding claims, characterized in that from the comparison of the fast-adaptable parameters and the slowly adaptable

Parameter with stored parameters on the performance and / or storage capacity is closed.

10. The method according to any one of the preceding claims, characterized in that from the comparison of the fast-adaptable parameters and the slowly adaptable

Parameter with stored parameters on whether it is the energy storage is an approved energy storage.

11. The method according to any one of the preceding claims, characterized in that from the comparison of the fast-adaptable parameters and the slowly adaptable

Parameter with stored parameters it is concluded whether an exchange of the memory has occurred.

12. The method according to any one of the preceding claims, characterized in that from the adapted and the non-adapted parameters, a distance measure is formed, which is compared for detecting the predetermined sizes with the stored parameters and that from the comparison result to the predetermined size, in particular the Storage type is closed.

13. The method according to claim 12, characterized in that the distance measure is formed depending on the error square or absolute values of predeterminable parameters.

14. The method according to claim 12 or 13, characterized in that relative

Error squares of predefinable parameters or parameter sets can be determined, depending on the current accuracy of the estimated parameter and its significance for a particular memory type

15. The method according to claim 14, characterized in that the significance by means of

Weighting factors is taken into account.

16. The method according to any one of the preceding claims 12 to 15, characterized in that quickly adaptable parameters contribute more to the distance measure than slow, the error variance remains at a high level for a long time

17. The method according to any one of the preceding claims 12 to 16, characterized in that the parameters are weighted in terms of their significance for the different types of storage types and the parameter with the largest relative variance with respect to the memory type, in particular the battery type is most heavily weighted and vice versa.

18. Device for carrying out at least one method according to one of the preceding claims, characterized in that the device comprises computing means and storage means and in particular part of a

Control unit is.