ISO/TR 20891:2020
(Main)Space systems — Space batteries — Guidelines for in-flight health assessment of lithium-ion batteries
Space systems — Space batteries — Guidelines for in-flight health assessment of lithium-ion batteries
This document provides detailed information on the various methods of assessing the health status of lithium-ion space batteries in flight and makes recommendations to battery suppliers, spacecraft manufacturers and operators to ease this assessment.
Systèmes spatiaux - Batteries spatiales - lignes directrices pour l'évaluation en vol de la santé des batteries lithium-ion
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TECHNICAL ISO/TR
REPORT 20891
First edition
2020-10
Space systems — Space batteries
— Guidelines for in-flight health
assessment of lithium-ion batteries
Systèmes spatiaux - Batteries spatiales - lignes directrices pour
l'évaluation en vol de la santé des batteries lithium-ion
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Term and definitions . 1
3.2 Abbreviated terms . 1
4 Overview . 2
4.1 General . 2
4.2 Battery capacity . 4
4.3 Battery impedance . . 4
4.3.1 General. 4
4.3.2 Electrochemical impedance spectroscopy (EIS) . 5
4.4 Battery internal resistance . 8
5 Specificities of spacecraft telemetry and resulting limitations .11
5.1 General .11
5.2 Signal digitization .11
5.3 Temperature .12
5.4 Voltage .12
5.5 Current .12
5.6 Sampling frequency .13
5.7 Synchronisation .13
5.8 On-board memory .13
6 Main methods for the evaluation of battery ageing parameters .14
6.1 Global method: fitting of a numerical model to in-flight data .14
6.1.1 General.14
6.1.2 Model structure .14
6.1.3 Data fitting .16
6.2 Evaluation of battery capacity .25
6.2.1 Direct method .25
6.2.2 Indirect method .30
6.3 Measurement of battery internal resistance .32
6.3.1 Direct internal resistance measurement .32
6.3.2 Indirect measurement of battery resistance .34
6.3.3 Correlation of internal resistance to capacity .46
6.4 Measurement of battery spectral impedance .47
6.4.1 General.47
6.4.2 Time domain identification of a dynamic model .48
6.4.3 Derivation of impedance from frequency domain processing of transients .49
6.4.4 Derivation of impedance from frequency domain processing of disturbances .50
7 Recommendations for easing battery in-flight health assessment .51
7.1 General recommendations.51
7.2 Recommendations related to battery characterization prior to flight.52
7.3 Recommendations related to spacecraft telemetry performance .52
7.4 Recommendations related to spacecraft operations.52
7.5 Recommendations related to data formatting .52
7.6 Recommendations related to data processing .53
Bibliography .54
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,
Subcommittee SC 14, Space systems and operations.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
Introduction
The charge and discharge cycle of a battery is not 100 % efficient, with each cycle side reactions can
occur that eventually accumulate and cause degradation of the battery's performance. Understanding
how the battery’s performance changes throughout the mission is a subject of importance; and accurate
determination of the battery’s current SoH is essential in a large number of situations, for example:
— the routine assessment of battery performance to allow early detection of anomalies (by comparing
its actual versus predicted performance);
— the setting of alarm thresholds to ensure adequate energy;
— detection of battery anomalies that can put at risk the spacecraft passivation and/or de-orbiting
strategy;
— decisions regarding mission extension beyond initial target life;
— evaluating the remaining capability of a spacecraft upon occurrence of an anomaly;
— feedback to the battery manufacturer to improve the performance predictions.
However, it is often difficult to properly assess the in-flight status, due to various factors:
— Flight electrical load profiles differ significantly to load profiles used to characterize battery
performance models and the battery’s SoH; for example, the total available battery capacity, which is
the most important parameter, is not directly accessible during flight since its simple measurement
by full discharge of the battery goes against the spacecraft operational safety.
— The quality of the accessible data from telemetry is sometimes poor: insufficient telemetry
resolution and/or accuracy, lack of synchronization between related parameters like current and
voltage, possibly large load consumption fluctuations introducing a high level of noise, delivery of
data under a form not easy to process, etc.
— The battery is operating in flight in a way that is generally very different from the test conditions
at qualification or acceptance. As a consequence, if no in-flight assessment has been made at the
beginning of life, the direct comparison between current in-flight status and available ground
testing data can be difficult and in any case more difficult than a comparison with the initial in-
flight behaviour.
— The battery is operated under time variant conditions in a large bandwidth of different time
scales, e.g. switching heater circuits vs. variations of the charge profile and eclipse length for a LEO
satellite with drifting orbit. Low frequency variations introduced by drifting orbits or seasons are
considered for the computation of trends and averaging over several orbits.
— The processing of data to derive the health status is not straightforward and is usually performed
by identifying the ageing parameters of a model. Therefore, the representativeness of this model is
a key is
...
TECHNICAL ISO/TR
REPORT 20891
First edition
2020-10
Space systems — Space batteries
— Guidelines for in-flight health
assessment of lithium-ion batteries
Systèmes spatiaux - Batteries spatiales - lignes directrices pour
l'évaluation en vol de la santé des batteries lithium-ion
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Term and definitions . 1
3.2 Abbreviated terms . 1
4 Overview . 2
4.1 General . 2
4.2 Battery capacity . 4
4.3 Battery impedance . . 4
4.3.1 General. 4
4.3.2 Electrochemical impedance spectroscopy (EIS) . 5
4.4 Battery internal resistance . 8
5 Specificities of spacecraft telemetry and resulting limitations .11
5.1 General .11
5.2 Signal digitization .11
5.3 Temperature .12
5.4 Voltage .12
5.5 Current .12
5.6 Sampling frequency .13
5.7 Synchronisation .13
5.8 On-board memory .13
6 Main methods for the evaluation of battery ageing parameters .14
6.1 Global method: fitting of a numerical model to in-flight data .14
6.1.1 General.14
6.1.2 Model structure .14
6.1.3 Data fitting .16
6.2 Evaluation of battery capacity .25
6.2.1 Direct method .25
6.2.2 Indirect method .30
6.3 Measurement of battery internal resistance .32
6.3.1 Direct internal resistance measurement .32
6.3.2 Indirect measurement of battery resistance .34
6.3.3 Correlation of internal resistance to capacity .46
6.4 Measurement of battery spectral impedance .47
6.4.1 General.47
6.4.2 Time domain identification of a dynamic model .48
6.4.3 Derivation of impedance from frequency domain processing of transients .49
6.4.4 Derivation of impedance from frequency domain processing of disturbances .50
7 Recommendations for easing battery in-flight health assessment .51
7.1 General recommendations.51
7.2 Recommendations related to battery characterization prior to flight.52
7.3 Recommendations related to spacecraft telemetry performance .52
7.4 Recommendations related to spacecraft operations.52
7.5 Recommendations related to data formatting .52
7.6 Recommendations related to data processing .53
Bibliography .54
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,
Subcommittee SC 14, Space systems and operations.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
Introduction
The charge and discharge cycle of a battery is not 100 % efficient, with each cycle side reactions can
occur that eventually accumulate and cause degradation of the battery's performance. Understanding
how the battery’s performance changes throughout the mission is a subject of importance; and accurate
determination of the battery’s current SoH is essential in a large number of situations, for example:
— the routine assessment of battery performance to allow early detection of anomalies (by comparing
its actual versus predicted performance);
— the setting of alarm thresholds to ensure adequate energy;
— detection of battery anomalies that can put at risk the spacecraft passivation and/or de-orbiting
strategy;
— decisions regarding mission extension beyond initial target life;
— evaluating the remaining capability of a spacecraft upon occurrence of an anomaly;
— feedback to the battery manufacturer to improve the performance predictions.
However, it is often difficult to properly assess the in-flight status, due to various factors:
— Flight electrical load profiles differ significantly to load profiles used to characterize battery
performance models and the battery’s SoH; for example, the total available battery capacity, which is
the most important parameter, is not directly accessible during flight since its simple measurement
by full discharge of the battery goes against the spacecraft operational safety.
— The quality of the accessible data from telemetry is sometimes poor: insufficient telemetry
resolution and/or accuracy, lack of synchronization between related parameters like current and
voltage, possibly large load consumption fluctuations introducing a high level of noise, delivery of
data under a form not easy to process, etc.
— The battery is operating in flight in a way that is generally very different from the test conditions
at qualification or acceptance. As a consequence, if no in-flight assessment has been made at the
beginning of life, the direct comparison between current in-flight status and available ground
testing data can be difficult and in any case more difficult than a comparison with the initial in-
flight behaviour.
— The battery is operated under time variant conditions in a large bandwidth of different time
scales, e.g. switching heater circuits vs. variations of the charge profile and eclipse length for a LEO
satellite with drifting orbit. Low frequency variations introduced by drifting orbits or seasons are
considered for the computation of trends and averaging over several orbits.
— The processing of data to derive the health status is not straightforward and is usually performed
by identifying the ageing parameters of a model. Therefore, the representativeness of this model is
a key is
...
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