Space engineering,
product assurance
Li ion battery
This document is ….
END OF ….. is:
DISCLAIMER (for drafts)
This document is an ECSS Draft Handbook. It is subject to change without
any notice and may not be referred to as an ECSS document until published
as such.
ECSS Secretariat
ESA-ESTEC
Requirements & Standards Division
Noordwijk, The Netherlands
Foreword
This Handbook is one document of the series of ECSS Documents intended to be used as supporting
material for ECSS Standards in space projects and applications. ECSS is a cooperative effort of the
European Space Agency, national space agencies and European industry associations for the purpose of
developing and maintaining common standards.
The material in this Handbook is defined in terms of description and recommendation how to organize
and perform the work of lithium ion battery testing.
This handbook has been prepared by the ECSS-E-HB-20-02A Working Group, reviewed by the ECSS
Executive Secretariat and approved by the ECSS Technical Authority.
Disclaimer
ECSS does not provide any warranty whatsoever, whether expressed, implied, or statutory, including,
but not limited to, any warranty of merchantability or fitness for a particular purpose or any warranty
that the contents of the item are error-free. In no respect shall ECSS incur any liability for any damages,
including, but not limited to, direct, indirect, special, or consequential damages arising out of, resulting
from, or in any way connected to the use of this document, whether or not based upon warranty,
business agreement, tort, or otherwise; whether or not injury was sustained by persons or property or
otherwise; and whether or not loss was sustained from, or arose out of, the results of, the item, or any
services that may be provided by ECSS.
Published by:
Copyright:
ESA Requirements and Standards Division
ESTEC, P.O. Box 299,
2200 AG Noordwijk
The Netherlands
2009 © by the European Space Agency for the members of ECSS
Table of contents
1 Scope .......................................................................................................................5
2 References ..............................................................................................................6
3 Terms, definitions and abbreviated terms ............................................................7
3.1
Terms from other documents ................................................................................... 7
3.2
Terms specific to the present document ................................................................... 8
3.3
Abbreviated terms .................................................................................................. 13
4 Tests ......................................................................................................................14
4.1
Electrical tests........................................................................................................ 15
4.2
Environmental tests ............................................................................................... 17
4.3
Life tests ................................................................................................................ 19
4.4
Safety tests ............................................................................................................ 23
4.5
Storage, Handling, Transport, AIT .......................................................................... 25
5 Test Applicability Matrix ......................................................................................26
Figures
Figure 1: Internal cell resistance Measurement by pulse method ......................................... 16
Tables
Table 1: Thermal vacuum tests conditions ........................................................................... 18
Table 2: GEO eclipse cycles with maximum DoD of 80% .................................................... 21
Introduction
Energy Storage is required aboard almost all spacecraft. Batteries are the most common energy storage
device. Batteries provide electrical power when power from solar arrays is temporarily unavailable or
insufficient due to eclipses, payload peak loads, before solar panels are deployed or in case of
emergencies or special manoeuvres. Batteries are tested in order to assess their performances and their
suitability with the mission requirements.
In order for a new cell or battery system to be accepted for a spacecraft mission, it is essential not only to
have hardware which is qualified for a good beginning of life performance but also to have hardware
whose performance changes with cycle life are well understood and predictable by appropriate models.
For this reason the availability of comprehensive test data is very important.
The present handbook aims at providing practical and helpful information for Li ion cell and battery
testing (testing conditions, required information, reporting) in the development of space equipment and
systems. Its purpose is to support the use of ECSS-E-ST-20C.
It gathers battery testing experience, know-how and lessons-learnt from the European Space Community.
1
Scope
This Handbook establishes guidelines to ensure testing of Li ion battery and associated
documentation.
This Handbook is dedicated to all parties involved at all levels in the realization of space segment
hardware for which ECSS‐E‐ST‐20C is applicable.
This handbook sets out to:

summarize most relevant characterisation tests

provide guidelines for Li ion battery testing

provide guidelines for documentation associated with Li ion
battery/cell testing

give an overview of appropriate test methods

provide best practices
Applicability is mainly focused on lithium ion battery.
2
References
ECSS‐S‐ST‐00‐01C
ECSS System – Glossary of terms
ECSS‐E‐ST‐10‐03C
Space engineering ‐ Testing
ECSS‐E‐ST‐10‐02C
Space engineering ‐ Verification
ECSS‐E‐ST‐10‐04C
Space engineering ‐ Space environment
ECSS‐E‐ST‐20C
Space engineering ‐ Electrical and electronic
ECSS‐Q‐70‐71A
Space product assurance ‐ Data for selection of
space materials and processes
IEC 62281
Safety of primary and secondary lithium cells
and batteries during transport
ST/SG/AC.10/11/rev5
United Nations Transport of Dangerous Goods
UN manual of Tests and Criteria, Part III,
subsection 38.3
3
Terms, definitions and abbreviated terms
3.1
Terms from other documents
For the purpose of this document, the terms and definitions from ECSS-S-ST-00-01 apply, in particular for
the following terms:
acceptance
lot
review
applicable
document
model
safety
non conformance
specification
outgassing
standard
procedure
supplier
process
traceability
product assurance
validation
project
verification
assembly
bake-out
calibration
catastrophic
cots
environment
failure
qualification
quality
handbook
quality assurance
hazard
quality control
inspection
reliability
requirement
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3.2
3.2.1
Terms specific to the present document
A cce lerated test
Test designed to shorten cycle life test to estimate the average cell/battery lifetime at normal operating
conditions.
Note: Temperature, SoC, cycle profile are sources of test acceleration.
3.2.2
Activation
Introduction of electrolyte in an assembled cell at the manufacturing facility during production.
NOTE
3.2.3
this is used to define the start of the cell shelf-life.
Aging
Permanent change due to repeated use and/or the passage of time.
NOTE
3.2.4
Permanent changes include loss of capacity/energy, increase in
resistance.
Battery
One or more cells (or modules) electrically connected in a serial/parallel arrangement to provide the
required operating voltage, current and energy storage levels.
Note: usually the number of S is defined versus the battery bus voltage and number of P gives the
capacity.
3.2.5
Battery management system
Electronics circuitry managing battery operation to prevent overvoltage, overcurrent,
overtemperature, cell-to-cell unbalance.
3.2.6
Calendar loss
Permanent degradation of electrical performance due to time after activation.
Note: reversible effects such as self-discharge are not included in the calendar loss.
3.2.7
Capacity
Amount of charge available expressed in ampere-hours (Ah).
Note: It is the integral of the discharge current, between start of discharge and cut-off voltage or
other specified voltage or specified duration. The capacity of a cell/battery is determined by a
number of factors, including the cut-off voltage, discharge rate, temperature, method of charge (i.e
current, end of charge voltage) and the age and life history of the cell/battery.
Cell/Battery (Ah) =  Id.dt
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3.2.8
Capacity fade
See aging definition.
3.2.9
Capacity retention
Fraction of the rated capacity available from a cell/battery under specified conditions of discharge
after it has been stored for a certain time period at a specified temperature and state of charge in
open circuit.
3.2.10
Cell building block/brick
Sub-assembly unit, which consists of identical electrically connected cells.
NOTE
3.2.11
Building blocks (or bricks) are connected together to form a
module.
Cell/battery cycle life
Number of cycles under specified conditions, that a cell/battery can undergo before failing to meet its
specified capacity or efficiency performance criteria.
3.2.12
Cell electromotive force (EMF)
Difference of potentials which exists between the two electrodes of opposite polarity in an
electrochemical cell under open circuit steady state conditions.
3.2.13
Charge/discharge rate
Amount of current applied to a cell/battery during the charge/discharge.
NOTE
3.2.14
: This rate is commonly expressed as a fraction of the nameplate
capacity of the battery. For example, C/2 or C/5.
Cycle loss
Gradual and irreversible loss of capacity of a secondary cell/battery due to cycling.
3.2.15
Depth of discharge (DoD)
Ampere–hour removed from a battery expressed as a percentage of the nameplate capacity.
3.2.16
Depth of discharged Energy (DoDE)
Watt-hours removed from a cell or battery, expressed as a percentage of rated energy, whatever the
initial state of charge of the cell.
3.2.17
Energy
Watt-hours available when the battery is discharged.
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NOTE
: It is the integral of the product of discharge current and voltage.
The limits of integration are the start of discharge and the cut-off
voltage or other specified voltage.
Cell/Battery (Wh) =  IdVd.dt
3.2.18
Energy reserve
Energy available in a cell/battery, discharged to the maximum allowed DoD under nominal
operation.
3.2.19
Internal resistance
Opposition to the flow of electric current within a cell/battery expressed as the sum of the ionic and
ohmic resistances of the cell components.
3.2.20
Maximum Charge Current
Maximum continuous DC charge current allowed by the cell manufacturer under specified
conditions.
3.2.21
Maximum Discharge Current
Maximum continuous DC discharge current allowed by the cell manufacturer under specified
conditions.
3.2.22
Maximum End of Charge Voltage (EOCV)
Voltage determined by the cell/battery manufacturer which expresses the highest voltage limit up to
which the cell can be safely charged.
3.2.23
Maximum End of Discharge Voltage (EODV)
Voltage determined by the cell/battery manufacturer which expresses the lowest voltage limit down
to which a cell can be safely discharged.
3.2.24
Module
Set of any number of identical cells, electrically connected.
NOTE
3.2.25
: Modules are connected appropriately to form the battery. A
module is a deliverable mechanically distinct item, as opposed to
cell brick.
Nameplate or Nominal Capacity
Amount of charge available expressed in ampere-hours (Ah) in conditions defined by the cell
manufacturer.
NOTE
: These conditions include:
- nominal charge current, method, ambient temperature and duration
- nominal cut-off voltage
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- nominal discharge current and ambient temperature
3.2.26
Nominal End of Charge Voltage
Characteristic End of Charge Voltage defined by the cell/battery manufacturer
3.2.27
Nominal End of Discharge Voltage
Characteristic End of Discharge Voltage defined by the cell/battery manufacturer.
3.2.28
Nominal operating voltage range
Characteristic operating voltage range of a cell/battery defined by the manufacturer.
3.2.29
Open-Circuit Voltage (OCV)
Cell/battery measured voltage under 0A condition.
3.2.30
Overcharge
Cell/battery charged beyond the maximum end of charge voltage.
3.2.31
Overdischarge
Cell/battery discharged below the minimum end of discharge voltage.
3.2.32
Protective devices
Devices such as fuses, diodes, by-passes and current limiters which interrupts the current flow to
prevent catastrophic failure.
3.2.33
Rated capacity
Minimum capacity guaranteed by the battery manufacturer on delivery.
Note: The conditions specified by the battery manufacturer may be different to those specified by the
cell manufacturer.
3.2.34
Rated energy
Minimum energy guaranteed by the battery manufacturer on delivery.
3.2.35
Self-discharge
Reversible capacity decrease while no current is flowing to an outside circuit, due to internal
chemical reactions.
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3.2.36
Shelf-life
Duration of storage from the date of activation, under specified conditions, at the end of which a
cell/battery still retains the ability to give a specified performance.
3.2.37
short-circuit current
Initial value of the current obtained from a cell/battery under impedance specified by the
manufacturer.
3.2.38
Specific energy (or gravimetric energy)
Energy available by mass unit
NOTE
3.2.39
: Expressed in Wh/kg
State of Charge (SoC)
Value defined by the Open Circuit Voltage of the cell/battery , following determination of the cell
characteristic EMF vs SoC curve.
NOTE
3.2.40
: Available capacity of the cell/battery, expressed as a percentage
of its capacity at that time, where the capacity is measured at a low
current such that the terminal voltage approximates the EMF
Taper Charge
Charge method consisting in reducing progressively the charging current as the cell/battery SoC is
high.
3.2.41
Terminal Voltage
Voltage of the cell/battery when current is flowing.
3.2.42
Venting
Release of excessive internal pressure from a cell or battery in a manner intended by design to
preclude rupture or disassembly.
3.2.43
Volumetric Energy
Energy available by volume unit
NOTE
3.2.44
: expressed in Wh/l
Working voltage
Typical voltage range of a battery.
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3.3
Abbreviated terms
For the purpose of this document, the abbreviated terms from ECSS-S-ST-00-01 and the following
apply:
Abbreviation
Meaning
A
Analysis
AC
alternating current
AR
acceptance review
BOL
beginning–of–life
CC
constant current
CDR
critical design review
CV
Constant voltage
DC
direct current
DoD
depth of discharge
DoDE
depth of discharge energy
DRB
Delivery review board
EGSE
electrical ground support equipment
EOCV
end of charge voltage
EODV
end of discharge voltage
EOL
end of life
EPS
electrical power system
ESA
European space agency
FMECA
failure mode effect and criticality analysis
Li ion
Lithium ion
MRB
manufacturing review board
PCB
printed circuit board
PDR
preliminary design review
PTR
Post test review
ROD
review of design
SoC
State of Charge
SRR
system requirement review
T
test
TRB
test review board
TRR
test readiness review
TM&TC
telemetry/telecommand
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4
Battery Testing
Each cell or battery used in space application undertakes different tests i.e. acceptance, qualification
These are detailed with a supporting test plan with an associated procedure, test criteria, method and
report.
The test plan should contain a description the following:
Battery/cell characteristics under test:
 nominal capacity,
 nominal EOCV,
 nominal EODV,
 temperature range,
 nominal voltage range,

specific and volumetric energy,

shelf-life,
 mass,
 dimension,
 protective devices.
Test criteria:
 Test duration,
 frequency,
 sinusoidal vibration amplitude input,
 random vibration acceleration power spectral density (g2/Hz) .
 measurement accuracy of the voltage, current, temperature and time required
Test Conditions:
 temperature,
 charge/discharge rate,
 EOCV,
 EODV,
 constant current or constant power profile
 connectivity,
 thermal control (chamber or base plate),
 Test equipment to be used (e.g. accelerometers, measuring tool (including calibration )
The test specification/procedures then group all the different steps for the execution of the tests to
measure and validate the batteries/cell characteristics.
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4.1
Electrical tests
The objectives of the initial cell/battery electrical characterization tests are to
- establish the appropriate test parameters consistent with accepted technology limitations and
requirements for the target application,
- verify the initial capabilities of the life test cells
4.1.1
Standard Capacity and Energy measurements
The capacity and energy measurements test, at a given temperature, will consist of a residual
discharge followed by a recharge using the manufacturer’s recommended procedure, and a constant
current discharge at a specified rate to the manufacturer’s recommended cut-off voltage.
The following information are required prior to the measurements:
- Charging protocol, e.g Constant Current – Constant Voltage, Taper
- Charge current
- End Of Charge Voltage (EOCV)
- Taper charge conditions
- Discharge protocol (constant current, constant power)
- Discharge current
- End Of Discharge Voltage (EODV)
- Temperature
Current, Voltage, Temperature will be measured versus time and capacity and energy will be
calculated.
4.1.2
Internal resistance measurement
The impact of ionic and electronic resistance can be evaluated by applying pulses during discharge
(e.g capacity check) or current interruption.
Using Ohm’s law, the total cell internal resistance can be calculated by dividing the change in voltage
by the change in current.
The measurement conditions should be specified with the test results i.e.: SoC, temperature, discharge
current, pulse current, pulse duration, measurement time (or current interruption duration).
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Figure 1: Internal cell resistance Measurement by pulse method
4.1.3
AC Impedance Measurement
The AC impedance measurement gives a range of impedance value as a function of frequency (i.e.
0.01 to 100 kHz).
The impedance is measured at a specified SOC for the operational temperature range.
4.1.4
Self-discharge Test
The self-discharge rate of cell is evaluated by stopping charge/discharge cycles at specific SoC,
temperature, monitoring the cell open-circuit voltage for a long period (e.g. 30 days).
4.1.5
Cell rate capability
Cell/battery rate capability is evaluated by performing capacity measurements at different
charge/discharge currents and different temperatures.
After stabilising the cell at a specified temperature, a residual discharge is performed. The cell is
charged and discharged at a given rate, to cut-off voltages specified by the cell manufacturer. The
same test, is repeated at different currents and temperatures. The maximum charge and discharge
current indicated by the cell manufacturer should be verified.
4.1.6
Cell EMF measurement
The cell EMF measurement should be obtained by a slow charge/discharge cycle at 20°C.
After stabilising the temperature at 20°C, a residual discharge is performed Then the cell is charged at
C/50 to maximum EOCV indicated by manufacturer, immediately followed by a discharge at C/50 to
minimum EODV indicated by the manufacturer.
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4.1.7
Battery magnetic moment measurement
There are two components in the battery magnetic moment.
-
Static moment, which is inherent due to the presence of magnetic materials
-
Dynamic moment due to the field induced by drawing power from the battery.
As a magnetic moment is a vector, the worst case magnetic moment occurs when both components act
in the same direction and are superimposed.
The battery magnetic moment should be measured before deperm, when battery is unpowered Then
after applying a demagnetising filed on each axis for a given time, the unpowered battery magnetic
field should be measured again.
Then the battery is discharged through a resistor and the powered battery magnetic field should be
measured.
4.1.8
Battery Corona testing
For high voltage battery (>xxV), a corona test is carried out.
The battery is placed in a vacuum chamber at 20°C. A power supply is connected between the battery
negative power connection and the ground reference point. The power supply is switched on and the
pressure is decreased down to 10-3 mbar at a rate specified by the manufacturer and agreed by the
custommer. specified rate.
The absence of arc is shown by the absence of fluctuation of the power supply voltage throughout the
all test.
4.2
Environmental tests
The objectives of the environmental tests are to
- establish the technology limitations and verify requirements for the target
application/mission,
- verify the initial capabilities of the life test cells
In the environmental tests report, the test conditions (as mentioned in Section 4) together with specific
details on the test set-up i.e.(connection, thermal control, equipment used, accelerometers type and
location ), the test data and the test data analysis are provided.
4.2.1
Mechanical tests: vibration (low level sine, random, sine),
shocks
Mechanical environment tests should be performed in accordance with the mission environmental
profile.
The test item, i.e cell, cell bricks/building block, battery module or battery will be fully described in
the test specification.
The cell/battery is tested in the 3 orthogonal axis at a specified SoC under load and for a specified
duration.
Low level Sine will be performed before and after random vibration and shock tests.
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The sequence of the tests can be: low level sine  Sine  low level sine  random vibration  low
level sine  shock  low level sine.
The test conditions: battery SoC, discharge or OCV, temperature, accelerometers place are to be
provided. The raw test data should be provided.
The following is an example of a common set of vibration and shock level, these can vary depending
on the specifics of the launch vehicle or mission of the space example (a spacecraft in space, a rover
that has to survive landing on a lunar surface)
Example of vibration and shock levels?
4.2.2
Thermal vacuum test
The battery is submitted to a thermal vacuum test according to the mission thermal environment.
In the test plan, the different temperatures are specified, the temperature increase/decrease rate, the
dwell time between the temperatures and the number of cycles required.
Operational Temperatures
Minimum
Maximum
Non-operational
Temperatures
Minimum
Number of
cycles
Dwell
Time
Maximum
Acceptance
Qualification
Tolerance
Table 1: Thermal vacuum tests conditions
The cell/battery charge/discharge cycling conditions will be specified in accordance with the mission
profile.
Bake-out of cells or batteries should not be carried out.
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4.2.3
Leak test
Each Cell and complete Battery is placed in a vacuum chamber and exposed to a specified vacuum
level in order to let it outgass (for outgassing see Q70-02C) before starting the leak test. After this first
step that will eliminate gases coming from outgassing of housing, the vacuum is lowered to 10-6 mbar
(~ 10-6 torr). The vacuum chamber can be equipped with a mass spectrometer to detect any chemical
release from the cell/battery due to leak. If no mass spectrometer is used, then the cells can be wiped
with a pH paper to detect the leak of electrolyte.
4.2.4
Hermeticity test (Helium test)
The hermeticity of the cell can is evaluated by a helium test.
Helium is injected into the cell can and the leak rate is measured. The leak rate should be less than 10-6
Pa.m3/s
4.2.5
Radiation test
The radiation tests should be performed using the representative radiation dose for the mission.
NOTE
ECSS-E-ST-10-04 has further information on space environment
The radiation test can be performed prior life tests or during life tests.
4.3
Life tests
The objectives of the life tests are to
- establish the technology limitations and verify requirements for the target application,
A life test should be performed on the individual cell type and battery that have been submitted to
acceptance tests (including visual inspection, mass & dimension measurement, OCV, cycle test,
vibration, thermal cycling))
In the life tests plan, the test items (i.e. cells, module or battery) description, the test conditions
(temperature, charge/discharge rate, EOCV, EODV, constant current or constant power profile)
together with description of the test set-up (connection, thermal control, equipment used) should be
detailed. And in the test report, the test data and the test data analysis will be provided.
4.3.1
Calendar tests (survivability test)
In order to evaluate the irreversible capacity loss due to calendar effect, i.e calendar loss, some
calendar tests should be performed.
The cells should be stored at different temperature and different SoC. Regular capacity checks should
be performed and results plotted to present the capacity loss trend.
4.3.2
Cycling tests
In order to evaluate the capacity loss due to cycling effect, i.e cycle loss, cycling tests in different
conditions (temperature, discharge/charge rate, DoD) should be performed.
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4.3.2.1
Constant DoD
For constant DoD cycling test, the cell/battery is cycled at a specified temperature, to a given DoD
-
Charge at a specified current for a specified duration to an EOCV defined by the battery
supplier
-
Discharge at a specified current, to the desired DoD.
-
Standard Capacity check performed before starting the test and every 500 cycles
4.3.2.2
Mission profile, including micro-cycling (ripple)
For each mission profile, the following parameters should be defined:
-
Temperature and thermal environment (base plate, thermal chamber…)
-
Charge method and duration
-
Discharge method and duration
-
Regular standard capacity checks to assess the aging (capacity fade) trend
4.3.2.2.1
GEO profile
GEO profile can be simulated using period of 45 eclipses, and period of solstice. (The Geo test can be
accelerated by shortening this solstice period)
-
It is recommended to select a temperature representative of the thermal environment expected
during the mission
-
Charge: constant current or constant power- constant voltage, with a charge current < C/5, to
a specified EOCV, and a given duration
-
Discharge: Constant current or constant power, for different duration (seeTable 2)
-
Plasma Propulsion Simulation cycle can be added to the GEO profile
-
Specified days in solstice with a constant voltage given by the battery supplier
-
The GEO life test can be performed with the battery management system
Standard capacity measurements will be performed prior starting the cycling and regularly during the
test e.g. every two seasons.
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Cycle Number
Duration (minutes)
DOD
1
21
23.3%
2
29.37
32.6%
3
35.55
39.5%
4
40.58
45.1%
5
44.82
49.8%
6
48.5
53.9%
7
51.72
57.5%
8
54.58
60.6%
9
57.13
63.5%
10
59.4
66.0%
11
61.42
68.2%
12
63.23
70.3%
13
64.84
72.0%
14
66.26
73.6%
15
67.5
75.0%
16
68.58
76.2%
17
69.51
77.2%
18
70.28
78.1%
19
70.9
78.8%
20
71.38
79.3%
21
71.73
79.7%
22
71.93
79.9%
23
72
80.0%
24
71.93
79.9%
25
71.73
79.7%
26
71.38
79.3%
27
70.9
78.8%
28
70.28
78.1%
29
69.51
77.2%
30
68.58
76.2%
31
67.5
75.0%
32
66.26
73.6%
33
64.84
72.0%
34
63.23
70.3%
35
61.42
68.2%
36
59.4
66.0%
37
57.13
63.5%
38
54.58
60.6%
39
51.72
57.5%
40
48.5
53.9%
41
44.82
49.8%
42
40.58
45.1%
43
35.55
39.5%
44
29.37
32.6%
45
21
23.3%
Table 2: GEO eclipse cycles with maximum DoD of 80%
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4.3.2.2.2
LEO profile
A LEO profile can be very different depending on the mission. Nevertheless, a generic real time LEO
profile will consist of repeating 90 minutes cycles as follow: 60 minutes charge and 30 minutes
discharge.
-
It is recommended to select a temperature representative of the thermal environment expected
during the mission. The thermal control of the test sample should be well detailed in the test
plan.
-
Charge: CC-CV at a specified current, for one hour to a specified EOCV
-
Dicharge: CC at a specified current for 30 minutes
Standard capacity measurements will be performed prior starting the cycling and regularly
during the test e.g. every 500 cycles or more.
4.3.2.3
Real time tests
The life tests is performed without any acceleration.
Charge and discharge profiles are fully representative of the mission requirements.
Such approach has the advantage to assess the capacity loss due to cycling and the capacity loss due to
the calendar effect.
4.3.2.4
Accelerated tests
Mission duration can be long, 25 years for a GEO mission, up to 12 years for a LEO mission. Real time
tests can be too long to qualify a technology. Thus it can be required to perform accelerate tests and to
extrapolate the capacity loss using models.
Tests can be accelerated by different methods: shortening solstice period, increasing charge/discharge
rate, increasing the temperature.
The acceleration of the tests and its effect on the cell aging need to be fully assessed in order to avoid
over-testing the cells.
4.3.2.5
Wear-out tests
The wear-out tests are short-duration life tests performed to verify the performances of cells lots and
get confidence in the ability of the cell to fulfil the mission requirements, and to identify early on any
issue due to materials or process change impacting performances.
Accelerated conditions are applied for such tests. The battery supplier should propose a wear-out test
to demonstrate the performance of the cells to be used for space battery manufacturing, and should
provide a trend analysis with all results from the different lots used.
Such wear-out tests are part of the Lot Acceptance Test (see applicability matrix in Annex A).
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4.4
Safety tests
The potential hazards of li ion cell/battery are:

Venting

Fire

Burst/explosion

Electrolyte leakage
Detailed descriptions of the hazards associated with different battery chemistry are given in reference
document: Crew vehicle battery safety requirements, JSC‐20793 Rev B April 06.
The objectives of the cell/battery safety tests are to
- establish the technology limitations,
- verify the safety features at cell and/or battery level
4.4.1
Overcharge
The cell/battery overcharge test should be performed at ambient temperature (e.g 20°C). The cell
should be charged to a EOCV greater than the EOCV recommended by the manufacturer, at a
specified current and the charging condition should be maintained till triggering of cell/battery safety
protection.
Battery overcharge test depends on the battery design and detailed test procedure should be provided
by the manufacturer.
4.4.2
Overdischarge
The cell overdischarge test should be performed at ambient temperature (e.g 20°C). The cell should be
discharged to a EODV lower than the EODV recommended by the manufacturer, at a specified
current and the discharging condition should be maintained till triggering of cell/battery safety
protection..
The cell can be forced to reversal to assess the cell behaviour in such conditions.
4.4.3
Short-circuit test
4.4.3.1
External short-circuit
The cell/battery should be tested for external short-circuit by applying a resistor across the positive
and the negative terminals till the safety protection(s) trigger and recording the temperature, the
voltage and the current
There should not be any fire or explosion.
4.4.3.2
Internal short-circuit
This test is performed at cell level. A crush test may be used for simulating an internal short. [Other
method to suggest?]
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4.4.4
Vent and burst test
4.4.4.1
Vent Test
An empty cell can, equipped with its safety can, is pressurised with inert gas till the safety vent
operates. This test gives the vent pressure of the can.
4.4.4.2
Burst Test
The burst test is performed on empty cell cans. The test is performed up to can burst and give the
value of the can burst pressure.
The cell can is slowly pressurised by an inert gas up to the can burst. Cell can may be equipped with
distortion gages to record the distortion at different location.
4.4.5
Drop test
The drop test is usually performed at battery level.
The battery is dropped from a height of 1.2 m onto a concrete surface in such a manner that any of its
corners first touches the ground. [IEC62281]
The SoC of the battery before the drop test should be specified.
Cell voltages, isolation and bonding should be compared before and after the drop test.
4.4.6
Protective devices
The protective devices included at cell or battery level should be characterised by tests:

Electrical fuse

Current Interrupt Device / Circuit breaker

Positive thermal coefficient (PTC) device

Vent

Shutdown separator

Thermal fuse

Bypass

Mosfet
The protective devices are to be characterised in details as they are part of the reliability of the cells
and ultimately of the battery.
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4.5
4.5.1
Storage, Handling, Transport, AIT
Storage and maintenance
The cell/battery storage and maintenance conditions will be detailed in the User Manual. The
conditions should minimise the irreversible capacity loss due to storage. The shelf-life of the
cell/battery should be indicated in the User Manual.
4.5.2
Handling
the battery handling methods are detailed in the User Manual to minimise safety hazards to
personnel and facilities, to minimize on battery shelf-life.
4.5.3
Transport
Mandatory safety tests for transport as specified in “United Nations Transport of Dangerous
Goods UN manual of Tests and Criteria, Part III, subsection 38.3” regulation will be
performed prior transportation.
UN38.3 tests such as vibration and shocks may be already covered by the acceptance test
environmental tests.
4.5.4
Assembly Integration Test (AIT)
During the AIT program, the use of the flight battery should be minimised as specified in
ECSS-E-ST-20C, paragraph 5.6.4.
Prior to any AIT activity with the battery, a standard capacity check should be performed.
And a standard capacity check should be performed at the end of the AIT campaign in order
to compare the capacity measured before and after the satellite test campaign.
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5
Test Applicability Matrix
The table below summarises the tests applicabe to different phase of a programme: lot acceptance
tests, accepance and qualifications test.
Lot Acceptance Test (LAT)
Acceptance
Qualification
Standard capacity and energy measurements
x
x
x
Internal Resistance Measurement
x
x
x
AC impedance measurement
x
x
Self-discharge test
x
x
Cell rate capability
x
x
Cell EMF measurement
x
x
Battery Magnetic Moment measurement
x
Battery Corona Tests
x
Low level sine vibration test
x
x
high level sine vibration test
x
x
random vibration test
x
x
x
shock test
x
x
x
Thermal vacuum test
x
x
x
Leak test
x
x
Hermeticity test
x
x
Radiation test
x
Calendar Tests
x
Real Time cycling tests
x
Accelerated cycling tests
x
Wear-out cycling tests
x
x
Overcharge test
x
x
Overdischarge test
x
x
Short-circuit test
x
x
Vent test
x
x
Burst test
x
x
Drop test
x
x
Protective devices test
x
x
Balancing system test
x
x
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Table 3: Test matrix
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