98/03/20

Guideline for the design and production ofsafe Lithium batteries for camera application

2nd edition
March 1998

Battery Association of Japan

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Contents

Introduction ········································ ··························· 1
Chapter 1

Background and abstract ········· ··························· 4

Chapter 2

Basic design principles for ensuring safety ofLithium batteries ·················· ··························· 8General design principles ········ ··························· 8Important design principles for the prevention ofinternal short-circuiting ·········· ························· 23

2.1
2.2

Chapter 3

Quality control items in a production process ·········· 27

Chapter 4
4.1

Safety tests and criteria ·········· ························· 29
Safety tests and criteria of cylindrical
Lithium single cell battery ······· ························· 29
Safety tests and criteria of cylindrical
Lithium battery pack ············· ························· 37

4.2[Acknowledgements] ···························· ························· 442Introduction
In August 1991, which is about six(6) years ago from now, we have published"A guideline for the safety evaluation of Lithium batteries for camera application",for the purpose of preventing further accidents from occurring which were caused
by unsafe Lithium batteries used for camera application.
At that time, many fire accidents happened on the market by the cylindrical
Lithium batteries which were used in full automatic cameras due to improper
design of these Lithium batteries.
Consequently, it was a very important and urgent issue that battery i ndustry as
a whole should take necessary measures for the prevention of further accidents
from occurring by Lithium batteries and to remove any uneasy feeling on Lithium
batteries both by OEM customers and by general consumers.
So far each Lithium battery manufacturer had been separately working for thesafety measures, but at that time, we have decided to accumulate necessary
expertises on safety of Lithium battery from each manufacturer and to prepare a
guideline on the following safety issues.
(1) Design principles for ensuring safety of Lithium batteries.
(2) Quality control items to ensure safety during mass -production of
Lithium batteries.
(3) Safety tests and criteria of Lithium batteries.
After the publication of above guideline, number of safety accidents by Lithium
batteries for camera application have significantly decreased since necessary
expertises for the production of safe Lithium batteries were suitably shared by all
battery manufacturers.
From several years ago, fire accidents by unsafe Lithium batteries have
gradually increased in the market again.
These Lithium batteries seem to be mainly produced by new foreign Lithium
battery manufacturers and they do not apparently seem to properly adopt
necessary design principles of safe Lithium batteries which were disclosed in ourabove guideline.

1As a result, we have judged it very important to more widely and popularly
disclose necessary expertises on the design and production of safe Lithium
batteries more in detail at this time than before.
We have reviewed the contents of our above guideline (1 st edition) and comeup with 2 nd edition this time so that it can more widely and popularly be used than
before, by many battery manufacturers and by many camera manufacturers, as
well.
During the review of our guideline this time, we tried to harmonize the contents
with those of IEC 60086-4, Safety standards of Lithium batteries, as much as
possible.
Our basic principles of ensuring safety of Lithium batteries are based onfollowing four measures ((a), (b-1), (b-2), (b-3)), which are explained in detail in
Chapter 1-3.
(a)All batteries shipped from each manufacturer to the market should be safe andfree from any uncertainty on safety. It means that all batteries with uncertainty on
safety should be rejected at the final inspection before shipment by eachmanufacturer.
(b)When a Lithium battery used in camera becomes unsafe and comes to catch
fire, following measures should be taken to avoid any big accident.
(b-1) Fire is stopped inside of the battery.
(b-2) Battery is damaged but the camera is not damaged.
(b-3) Camera is also damaged but it does not lead to an accident of injury or of
big fire.
In chapter 4 Safety tests and criteria, we explained the criteria of discrimination
between safe batteries and unsafe batteries, based on various safety evaluation
tests.
As is the same for such safety evaluation tests, these tests can judge the safetylevel of each production lot but all production defects from all production lots("defects of ppm order") cannot be rejected by these tests.

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We reasonably assume that it is a task for each battery manufacturer tominimize the number of defects in each production lot ("variation of defects") by
its own production engineering technologies and expertises whic h cannot be
specified in detail in design principles or in quality control items.
i.e.
This guideline discloses important and basic principles which arenecessary to be observed to increase safety level of Lithium batteries but it does
not guarantee that all batteries from each manufacturer are safe if the contents ofthis guideline are observed.
It is reasonable to assume that the relevant battery manufacturers are fully
responsible for the defective batteries which were produced by them.

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Background and abstract
From around early years of 1980's, many cameras have come to be provided
with electronic features, such as automatic adjustment of light exposure, datememory, electronic shutter, automatic placement of a film roll, automatic windingof a film, and automatic rewinding of a film roll. Portable batteries are used as a
power source for the above applications.
Initially, zinc-carbon batteries and alkaline manganese batteries were used as a
power source. Later, both higher output power and higher capa city have come tobe required than before for advanced type cameras. Consequently majority ofpresent cameras use Lithium batteries. Japanese camera manufacturers haveproduced and shipped about 36 mln cameras in 1997 from their domestic andoverseas factories. These Lithium batteries which are used as a power source of
cameras employ spirally wound electrodes so that the battery can provide highoutput power. Since these batteries use electrodes of very large surface area,
battery case and/or camera body may be deformed or even molten when an
excessive current flows through these batteries. Since Lithium batteries use
metallic Lithium as anode material, which has a relatively low melting point of
about 180℃, metallic Lithium may be molten when the battery i s excessively
overheated and it may lead to fire accidents.
Main conditions in which Lithium batteries are overheated are as follows;(1.1) When a battery is internally short-circuited.
(1.2) When a battery is abnormally overheated.
(1.3) When an excessive current is provided from outside to flow through abattery or the external circuit is composed to provide an excessive current
to flow through a battery.
(1.4) When a charging current of exceeding a certain limit value flows
through a battery.
(1.5) When two(2) or more batteries, whose internal resistance or capacity issignificantly different from each other, are connected in series and one ofthese batteries is forcibly discharged.

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These Lithium batteries which are now shipped to the market are generally
designed to prevent from being overheated at the above conditions ((1.1) (1.5)). Detail measures against overheating of these batteries are summarized
in Fig.1 and brief explanations are as follows;(2.1) Design(a) Following measures are taken so that the battery temperature does notincrease in above conditions ((1.1) - (1.5)).
(a-1) PTC device is incorporated in the battery.
(a-2) Other measures are taken to prevent internal short-circuiting.
(b) When the battery temperature still increases, inside construction of thebattery is destructed by "shut-down" of the separator and the current isceased to flow.
(c) Battery case is destructed by the operation of safety ven t and internalpressure of the battery is decreased to prevent overheating of the battery.
The above three(3) measures and others are explained in detail in Chapter2.
(2.2) Pilot production
Small amount of batteries which are designed as per (2.1) are pr oduced ina pilot production line. These batteries are examined if they meet necessary
design qualities as per (2.1). It should also actually be demonstrated andconfirmed with these batteries that all measures as per (2.1) properly workand overheating (accidents) of a battery is prevented.
Details are explained in Chapter 3.
(2.3) Mass production
High amount of batteries which are designed as per (2.1) and whose design
qualities are proved to meet as per (2.2) are produced in a mass production
line, with suitable production equipment and production engineering
technologies to reproduce design qualities as per (2.1).
Number of production defects in a mass production line should be
minimized by the proper quality control during production and also these5defects should properly be rejected by inspections at various stages before
shipment.
It is necessary that each battery manufacturer should elaborate its own
expertises to minimize and to reject such defects.
Details are explained in Chapter 3.
(2.4) Final inspection before shipment
These batteries which are mass-produced as per (2.3) are inspected at the
final inspection to check if they meet necessary design qualities and thenshipped. Each defective battery, as well as defective lots, should also
properly be rejected at this inspection. It is necessary that each battery
manufacturer should elaborate its own expertises to achieve the above.
Details are explained in Chapter 4.

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Fig.1

Flow chart for the design and production of safe Lithium batteries[example]①

Measures to prevent battery
temperature from increasing at
abnormal conditions.

Incorporation in a battery of a
PTC device which triggers in 218sec at a current of 4A at 20 ˚C
Other measures to prevent
internal short-circuiting②

Inside construction of a battery
is destructed when the battery
temperature increases and thus
the current is ceased to flow.

Use of separator which “shuts
down“ between 30˚C-155˚C③

A part of battery case is destructedwhen the battery temperature further
increases and thus overheating of thebattery is prevented.

Mounting of a safety vent which
operates at the following
conditions;about 10-40kg/cm 2 at 20˚C
about 5-20kg/cm 2 at 80˚C

Examination if necessary design
qualities are met by these batteries frompilot production. Confirmation thatabove
measures ① ,② ,③ .
properly work and thus overheatingof a battery is prevented.

Establishment of necessary
conditions for batteries to besafely used.

DesignPilot production

Mass production

Mass production of batteries withsafety designs as per ① ,② ,③ .

Request for equipment
manufactures toobserve above necessary
conditions for the safeuse of batteries.
Inform users to observe abovenecessary conditions for the safeuse of batteries.

To minimize and to reject production defects
Final inspection

Confirmation that batteries meetnecessary design qualities.
Proper rejection of production defects.

7Basic design principles for ensuring safety of Lithium
batteries
When cylindrical Lithium batteries for camera application are improperly
designed, they may cause accidents due to overheating and others. In this chapter,
necessary basic design principles for ensuring safety on both single cell Lithium
battery and Lithium battery pack are explained. General design principles are
explained in (2.1) and these especially related to the prevention of internal short circuiting are explained in (2.2).
2.1 General design principles
Basic design principles
Lithium battery for camera application should, in principle, be designed assuch that it should not overheat and/or explode, its safety vent should not, inprinciple, operate (*) and significant electrolyte leakage should not occur
except when its safety vent operates, at following situations.
When fresh batteries before use are stored.
When a battery is being incorporated in a camera.
When a camera with the battery is actually used to take photos.
When a camera with the battery is exposed to various environmental
conditions.
When a battery is being removed from the camera.
When used batteries are removed from cameras and stored before disposal.
* Safety vent should not, in principle, operate. However, when the battery isin abnormal condition and it may overheat and/or explode, the safety vent should
be sure to operate and prevent accidents.
Followings are necessary measures which Lithium batter ies for camera
application should be provided to ensure safety based on the above basic designprinciples.
Safety design principle of single cell Lithium battery
Safety issues, measures in design for each issue and their explanations are
summarized in the following.

82.1.2.1 Internal short-circuitinga) Measures in design
Material and thickness of a separator should properly be selected
so that short-circuiting between positive electrode and negativeelectrode through the separator should be prevented.
Width of positive electrode should be designed to be bigger thanthat of negative electrode. Starting positions of winding of thetwo(2) electrodes should be displaced between each other so thatthe edge of positive electrode should not get in touch with negativeelectrode.
Insulators should be placed both at the top and bottom of two(2)electrodes so that wound electrodes are tightly fixed in the battery
can and internal short-circuiting due to shock by vibration or dropshould be prevented.
Lower part of both positive lead and negative lead should becovered with insulation tapes so that internal short -circuiting
between the two(2) leads is prevented.
Small holes in a separator should be choked ("shut down") when
the battery temperature is elevated and thus the internal resistanceshould be increased. In this way, further current flow should
properly be controlled and the battery temperature should notexceed 150℃.
Safety vent should properly operate, as follows.
① It should operate at lower pressure at high temperatures t han at room
temperature.
② When it operates, it should instantaneously open to enough size andeject excessive gases from inside of the battery.
b) Explanations
When a "soft" internal short-circuiting occurs, the self-discharge of abattery increases but it does not lead to unsafe phenomena of a battery.
However, when "hard" internal short-circuiting occurs, significant amount of9

heat generates in a battery in some cases, and thus the battery may overheat
and the safety vent may operate.
One of the reasons why internal short-circuiting occurs is because thepositive electrode and the negative electrode get directly in touch with eachother through separator. To avoid this, material and thickness of a separator
should be selected as described in [Measure A].
When a separator is too thin, internal short-circuiting can easily occur.
However, when it is too thick, discharge performance of the battery generally
decreases
Other reason is that the edge of positive electrode gets in touch withnegative electrode. To avoid this, width of positive electrode should bedesigned to be bigger than that of negative electrode and starting positions ofwinding of the two(2) electrodes should be displaced between each other.
([Measure B])
Other reason is that a lead plate of either positive electrode or negativeelectrode in wound electrodes penetrates through separator and gets in direct
touch with the other electrode. It sometimes causes "hard" internal short circuiting. To avoid this, the following measures have to be taken.
① Wound electrodes should be tightly fixed with the insulators both at the
top and bottom of two(2) electrodes so that internal short -circuiting due
to shock by vibration or drop is prevented. ([Measure C])② Lower part of both positive lead and negative lead should be covered
with insulation tapes so that internal short-circuiting between the two(2)leads is prevented. It is also effective that the vertical edge of positiveelectrode is covered with insulation tape. ([Measure D])
When internal short-circuiting actually occurs, it is effective to melt the
separator by the generated heat and to choke ("shut down") small holes in theseparator. In this way, internal resistance increases and further current flow iscontrolled. Material of the separator should properly be selected and the10

battery should properly be designed so that the separator "shuts down" atappropriate temperature and the battery temperature should not exceed 165 ℃.
([Measure E])
When internal short-circuiting actually occurs and the battery temperature
further increases, the safety vent should operate. ([Measure F])
It should operate at lower pressure at high temperatures than at room
temperature, since it is more dangerous at high temperatures. It should also
instantaneously open to eject excessive gases from inside of the battery.
2.1.2.2 External short-circuitinga) Measures in design
Terminal construction should be as such that external shortcircuiting is difficult to occur.
Protective device against excessive current (for example; PTC
device) should be incorporated inside the battery to prevent heatgeneration by an excessive current.
Small holes in a separator should be choked ("shut down") when
the battery temperature is elevated and thus the internal resistanceshould be increased. In this way, further current flow should
properly be controlled and the battery temperature should notexceed 150℃.
Safety vent should properly operate.
b) Explanations
When external short-circuiting occurs, similar phenomena as in the case ofinternal short-circuiting occur. To avoid this, it is necessary that terminal
construction should be as such that external short-circuiting is difficult tooccur. For example, terminal should be recessed from external case. ([MeasureA])
When external short-circuiting occurs in a battery, it is possible to prevent
excessive current from flowing, by incorporating protective device against
excessive current (for example; PTC device) inside of the battery. (PTC device11

is connected in series with the battery). When excessive current flows througha battery, resistance of PTC significantly increases and thus further flow ofexcessive current is prevented to avoid overheating of the battery.
[Remarks] It is not possible to prevent excessive current from flowing in caseof internal short-circuiting. This is the difference between internal
short-circuiting and external short-circuiting.
When a protective device against excessive current inside of the battery
operates properly, the battery remains safe even when external short-circuiting
occurs. However, when a protective device is defective (or short -circuited),
the battery becomes unsafe.
Measures for such cases are the same as those for the case of internal short circuiting. i.e. Small holes in a separator should be choked ("shut down")([Measure C]) or safety vent should properly operate. ([Measure D])
2.1.2.3 Dischargea) Measures in design
Protective device against excessive current (for example; PTC
device) should be incorporated inside of the battery to prevent heatgeneration by an excessive current.
Small holes in a separator should be choked ("shut down") when
the battery temperature is elevated and thus the internal resistanceshould be increased.
In this way, further current flow should properly be controlled andthe battery temperature should not exceed 150℃.
Safety vent should properly operate.
b) Explanations
When a battery is discharged during normal camera operations(taking photo, placing or rewinding a film roll, rewinding and others),
the maximum battery temperature does not exceed about 60℃ and the battery
remains safe. However, when a camera becomes defective, it is possible thatthe battery is overdischarged with abnormal high current. In this case, the12battery is subjected to a similar condition as that at external short -circuiting.
Consequently, the same measures as in case of external short -circuiting arerequested in design as follows;[Measure.A]: Incorporation of protective device against excessive current.
[Measure.B]: Choking ("shut down") of small holes in a separator.
[Measure.C]: Operation of a safety vent.
As is the same in the case of external short-circuiting, when a battery isoverheated by abnormal discharge, protective device operates and the battery
remains safe. However, when a protective device is defective (or short circuited), [Measure B] and [Measure C] become effective.
2.1.2.4 Drop, vibration and shocka) Measures in design
Insulators should be placed both at the top and bottom of two(2)electrodes so that wound electrodes are tightly fixed in the battery
can and internal short-circuiting due to shock by vibration or dropshould be prevented.
Lower part of both positive lead and negative lead should becovered with insulation tapes so that internal short -circuiting
between the two(2) leads is prevented.
b) Explanations
Such physical phenomenon as drop, vibration or shock does not leadchemical substances in a battery into unsafe conditions. However, it is possiblethat internal short-circuiting may occur due to drop, vibration or shock and thebattery becomes unsafe.
Consequently, the same measures as in case of internal short -circuiting arerequested as follows;[Measure.A]: Insulators should be placed both at the top and bottom of two(2)electrodes.
[Measure.B]: Lower part of both positive lead and negative lead should be13

covered with insulation tapes.
2.1.2.5 Overheatinga) Measures in design
Safety vent should be provided to prevent explosion due to theincrease of internal pressure when a battery is overheated. Safety
vent should be designed in such a way that it should not operate
within five(5) hours at 100℃ but it should operate below 165℃.
b) Explanations
Safety vent should be provided to prevent explosion due to the increase ofinternal pressure when a battery is overheated. When a battery is overheated at
100℃ within five(5) hours, the battery generally remains safe.
Consequently, it is not necessary that the safety vent operates at this condition.
However, since a battery generally becomes unsafe after five(5) hours at 100℃,
the safety vent should operate.
As the temperature becomes higher, a battery cannot remain safe for long time.
Consequently, the safety vent should operate when the battery temperaturereaches at 165℃.
2.1.2.6 Charging by reverse connectiona) Measures in design
Battery should be designed so that two(2) negative terminals
should not directly contact each other or electric circuit should not
be formed when a battery is inserted in a reversed orientation.
Safety vent should operate.
b) Explanations
When more than four(4) batteries are connected in series in a circuit and
if one(l)(1) of them is reversely connected, the said one(l)(1) battery is charged
by the rest of batteries.
To avoid this, battery should be designed so that two(2) batteries should notelectrically contact each other when one(l)(1) battery is inserted in a reversedorientation. ([Measure A])

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However, if one(l)(1) battery is charged by the rest of batteries and internalpressure of the said one(l)(1) battery increases abnormally, it is necessary thatthe safety vent should operate [Measure B].
When two(2) batteries are connected in series in a circuit and if one (l)(1)of them is reversely connected, one(l)(1) battery, whose voltage is lower thanthe other, is charged by the other battery with higher voltage. However, sincevoltage difference between the two(2) batteries is relatively small, the said
one(l)(1) battery generally remains safe.
2.1.2.7 Charging by the current of below 10mAa) Measures in design
Materials of both separator and electrolyte should properly be
selected so that electrolytic deposition through a separator during
charging should be prevented.
Safety vent should operate.
b) Explanations
Battery for camera application may possibly be charged by the reverse motive
force of a motor. The battery, generally, does not seem to become unsafe by theabove charging. Still, it is necessary to take [Measure A]. It is also necessary totake [Measure B] when internal pressure increases abnormally due to above
charging.
2.1.2.8 Reversed polarity (No. 1)
When internal resistance* of one(l)(1) battery in series connection issignificantly higher than that of the rest, the said one(l)(1) battery may be
overdischarged into reversed polarity.
* measured at 20℃ by alternative current method (1kHz, 10mA)a) Measures in design
Battery should be designed so that its internal resistance does notexceed about 5 ohm until the battery is discharged to about 75%
DOD.
Battery should be designed so that little amount of metallic

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Lithium remains at the end of discharge.
Electrolyte should be as "mild" as possible so that it does not easily
catch fire when the battery polarity is reversed.
Safety vent should operate when internal pressure of the bat teryincreases abnormally.
b) Explanations
When internal resistance of one(l)(1) battery in series connection of lessthan four(4) batteries is significantly higher than that of the rest of batteries,
the said one(l)(1) battery may forcibly be discharged to reversed polarity by
the rest of batteries with lower internal resistance and it may overheat.
Example in the case of two(2) batteries in series connection is as follows;
Internal resistance of a normal battery is below 1.0 ohm. If the internal
resistance of one of the two(2) batteries increases into 10-50 ohms and thesetwo(2) batteries are continued to be discharged by the current of over 100mA,
the battery with higher internal resistance may forcibly be discharged toreversed polarity by the other battery with lower internal resistance and thesaid battery may generate high amount of heat. However, when the internal
resistance significantly increases, the current ceases to flow and thus thebattery remains safe. When the internal resistance increases at th e end ofdischarge, the battery also remains safe since remaining capacity is very small.
To avoid this, the internal resistance of a battery should be kept as low as
possible by minimizing the contamination with impurities such as water.
([Measure A])
Battery should be designed so that little amount of metallic Lithium remains
at the end of discharge. ([Measure B])
Solute in the electrolyte should be as "mild" as possible to keep the battery
safe even at reversed polarity. ([Measure C])
Safety vent should operate when internal pressure of the battery increases
abnormally due to reversed polarity. ([Measure D])
2.1.2.9 Reversed polarity (No.2)
When discharge capacity of one(l)(1) battery in series connection issignificantly smaller then that of the rest, the said one(l)(1) battery may be

16

overdischarged into reversed polarity.
a) Measures in design
Electrolyte should be as "mild" as possible, so that it does noteasily catch fire when the battery polarity is reversed.
Battery should be designed so that little amount of metallic
Lithium remains at the end of discharge.
Safety vent should operate when internal pressure of the battery
increases abnormally.
b) Explanations
When more than two(2) batteries but less than four(4) batteries areconnected in series, discharge capacity of one(l)(1) battery may besignificantly smaller than that of the rest in following cases;① Fresh battery and old battery are mixed.
② Batteries from different manufacturers are mixed.
③ Fresh battery and used battery are mixed.
In such cases, the said one(l)(1) battery with small discharge capacity may
forcibly be discharged to reversed polarity by the rest of batteries with large
discharge capacity.
To avoid this, it is very important to use "mild" electrolyte such as Lithium
tri-fluoro methane sulfonate (LiCF 3 SO 3 ). ([Measure A])
Battery should be designed so that little amount of metallic Lithium remains
at the end of discharge. ([Measure B])
Safety vent should operate when internal pressure of the battery increases
abnormally due to reversed polarity.
2.1.2.10 Low pressurea) Measures in design[Measure.A]: Sealing construction should be as such that battery weight17

should not decrease under low pressure.
b) Explanation
When a camera is used at low pressure, for example at the top of high mountains,chemical materials in a battery does not become dangerous. However, when
sealing construction is improper (for example, ununiform sealing, broken gasket),battery weight may decrease and/or electrolyte leakage may occur and thus unsafe
phenomena may generate. To avoid this, uniform sealing construction should beensured with proper die shape, gasket material and gasket shape.
Safety design principles of battery pack made of cylindrical Lithium
single cells.
Safety issues, measures in design for each issue and their explanations are
summarized in the following.
a) Measures in design
Internal short-circuitingsame as [Measure A] of 2.1.2.1 a)same as [Measure B] of 2.1.2.1 a)same as [Measure C] of 2.1.2.1 a)same as [Measure D] of 2.1.2.1 a)same as [Measure E] of 2.1.2.1 a)same as [Measure F] of 2.1.2.1 a)External short-circuitingsame as [Measure A] of 2.1.2.2 a)Protective device against excessive current (for example; PTC
device) should be incorporated inside of a battery pack or of asingle cell to prevent heat generation by an excessive current.
same as [Measure C] of 2.1.2.2 a)same as [Measure D] of 2.1.2.2 a)
Discharge
Protective device against excessive current (for example; PTC

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device) should be incorporated inside of a battery pack or of asingle cell to prevent heat generation by an excessive current.
same as [Measure B] of 2.1.2.3 a)same as [Measure C] of 2.1.2.3 a)Drop, vibration and shock
same as [Measure A] of 2.1.2.4 a)same as [Measure B] of 2.1.2.4 a)Overheatingsame as [Measure A] of 2.1.2.5 a)Charging by the current of below 10mA
same as [Measure A] of 2.1.2.7 a)same as [Measure B] of 2.1.2.7 a)Reversed polarity (No. 1)
When internal resistance of one(l)(1) single cell in series connection in the packis significantly higher than that of the rest, the said single cell may be
overdischarged into reversed polarity.
same as [Measure A] of 2.1.2.8 a)same as [Measure B] of 2.1.2.8 a)same as [Measure C] of 2.1.2.8 a)same as [Measure D] of 2.1.2.8 a)
Reversed polarity (No.2)
When discharge capacity of one(l)(1) single cell in series connection in thepack is significantly smaller than that of the rest, the said single cell may be
overdischarged into reversed polarity.
same as [Measure A] of 2.1.2.9 a)same as [Measure B] of 2.1.2.9 a)same as [Measure C] of 2.1.2.9 a)
Low pressure

19

[Measure.A]: same as [Measure A] of 2.1.2.10 a)b) Explanations
As per described in above 2.1.3 a), measures in design are, in principle, thesame as these for single cell batteries.
Differences from these for single cell batteries are as follows;① For 2.1.3 a) (2) External short-circuiting and 2.1.3 a) (2) Discharge,
protective device against excessive current (example; PTC device)
should be incorporated in each single cell battery. On the other hand, ina battery pack with more than two(2) single cell batteries, protective
device against excessive current (example; PTC device) should beincorporated in each single cell battery or connected to the wiring
among these single cell batteries. It means that, two(2) protective
devices against excessive current (example; PTC devices) are necessary
when two(2) single cell batteries are in series connection, but one (l)(1)protective device against excessive current (example; PTC device) may
be enough when two(2) single cell batteries are incorporated in abattery pack.
② When more than two(2) single cell batteries are connected in series,
one(l)(1) of them may be reversely connected and thus it may becharged by the rest. In case of battery pack, single cells are alreadyconnected and incorporated in the pack and thus the above problem
does not occur.
Additional explanationsa) All battery manufacturers design, produce and inspect their Lithium batteries
very carefully to avoid any accidents from occurring based on their fullexpertises, and thus all these batteries can, in principle, be regarded as safe
batteries. However, electrolyte leakage and overheating may sometimes occur
when design, production and/or inspection are improperly performed asfollows;
Electrolyte leakage;

20

Electrolyte in a battery comes out from improper sealing of the battery or whensafety vent operates in abnormal conditions. Leakage of electrolyte itself does
not cause any unsafe phenomena but organic electrolyte which leaked out of
the battery may catch fire when fire source is present nearby.
Overheating;Battery may generate large amount of heat and may overheat under theconditions of 1.1-1.5 of Chapter 1. Usually, when a battery temperaturereaches a certain limit value, various safety devices in a battery operate andthus further heat generation and overheating is prevented. However, when
design, production and/or inspection are improperly performed, these safety
devices may not properly operate and thus battery case and/or camera bodymay be deformed or molten due to overheating of a battery and fire may occur
in extreme cases.
b) Followings are possible causes of overheating.
Single cell battery① "Hard" internal short-circuiting② External short-circuiting when protective device against excessive
current (example; PTC device) is defective③ Discharge with very high current* when protective device against
excessive current (example; PTC device) is defective*
Value of "very high current" is specified by manufacturers.
If not specified, short-circuit current value is applied.
④ Overheating⑤ Charging (including charging by reverse connection)⑥ Deformation by pressing⑦ Drilling⑧ Operation of safety vent near fire source.
Battery consisting of less than four(4) single cells.
① Same as 2.1.4 b) (1) ①② Same as 2.1.4 b) (1) ②③ Same as 2.1.4 b) (1) ③21

④ Same as 2.1.4 b) (1) ④⑤ Same as 2.1.4 b) (1) ⑤⑥ Same as 2.1.4 b) (1) ⑥⑦ Same as 2.1.4 b) (1) ⑦⑧ Same as 2.1.4 b) (1) ⑧⑨ Forced discharge due to significant difference of internal resistanceamong single cells.
⑩ Forced discharge due to significant difference of discharge capacity
among single cells.
Battery pack
① Same as 2.1.4 b) (1)② Same as 2.1.4 b) (1)③ Same as 2.1.4 b) (1)④ Same as 2.1.4 b) (1)⑤ Same as 2.1.4 b) (1)⑥ Same as 2.1.4 b) (1)⑦ Same as 2.1.4 b) (1)⑧ Same as 2.1.4 b) (1)⑨ Same as 2.1.4 b) (1)⑩ Same as 2.1.4 b) (1)

①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩

c) Overheating of a battery due to above (b) can be prevented by "measures indesign" as per 2.1.2 and 2.1.3.
d) "Deformation by pressing", "Drilling" and "Operation of safety vent near firesource", as per above (b) are not related to these batteries in a camera.
Consequently, those items except these three(3) were explained in detail in
2.1.2 and 2.1.3.

22

2.2 Important design principles for the prevention of internal short circuiting.
Followings are important design principles of Lithium batteries for camera
application to prevent them from internal short-circuiting and thus to ensure safety.
These items which are marked as ◎ should, in principle, be employed.
However, these items which are marked as ● may not always be necessary or
effective to employ, depending on the basic design of Lithium ba tteries of eachmanufacturer. Consequently, it should carefully be studied based on basic designprinciples of each manufacturer, if these items which are marked as ● should be
employed.
Materials and components of a battery.
2.2.1.1 Requirements on separator material.
a) It should have sufficient mechanical strength.
◎
It should not break or tear during winding with electrodes.
◎
It should not break or produce pin-holes when strange
particle is mingled and winding is blocked.
b) Short-circuiting should not occur by the penetration of particles throughseparator.
◎
Small particles of positive mix should not penetrate throughseparator.
c) Heat resistivity of a separator.
◎
When discharge current of a battery abnormally increases
or internal short-circuiting occurs, the separator should "shutdown" to cut-off the current and prevent abnormal increase of
temperature.
◎
Separator should not shrink and thus should not lose film
characteristics due to abnormal overheating of current collector
lead during discharge with very high current or internal short circuiting.
[Remarks] Normally, current collector lead is covered with insulation tape to
avoid abnormal overheating.

23d) Separator should be thick enough to prevent short -circuiting.
However, suitable thickness should be selected to ensure acceptable discharge
performances of a battery.
e) Evaluation criteria of "shut-down" performance of a separator.
Various methods are proposed for the evaluation of "shut-down"
performance of a separator but standard method is not defined yet. Some ofthem are as follows;① Measurement of the change of internal resistance when a battery isheated up at a constant rate.
② Measurement of the battery temperature when a battery is shortcircuited and a current is decreased to a certain level.
Shut down temperature is normally designed to be 130 -155℃ withpresently available batteries.
2.2.1.2 Safety evaluation criteria of a safety vent.
a) Safety vent operates when internal pressure of a battery abnormally increases
during internal short-circuiting and others and ejects gases and/or electrolyte
from inside of a battery. In this way, it prevents explosion and other accidents
from occurring.
b) It is generally designed to operate at the following conditions in presently
available batteries.
10 - 40kg/cm 2 at 20℃
5 - 20kg/cm 2 at 80℃
2.2.1.3 Protective device against excessive currenta) When a very high current flows through a battery and the battery temperature
increases, its resistance value increases significantly and thus further current isceased to flow. It is a reversible component.
b) PTC is a typical protective device against excessive current and it is generally
designed to trigger in 2-180sec with a current of 4A at 20℃ in presently

24available batteries. In future, other devices than PTC may also be used for thesame purpose.
2.2.1.4 Electrolytea) It is preferred to use electrolyte of weak oxidation power for the prevention of
possible overheating of a battery at reversed polarity. Lithium trifluoro methane
sulfonate (LiCF 3 S0 3 ) is a typical solute to be used for electrolyte of weakoxidation power.
b) It is also necessary that electrolyte of environmentally friendly nature should
be used.
Production process
2.2.2.1 Production process of positive electrode◎
Width of positive electrode should be bigger than that of negativeelectrode (metallic Lithium)
Lead position of positive electrode and negative electrode should●
be displaced between each other.
Both width and length of positive lead should properly be●
adjusted.
◎
Burr at the cut-off surface of electrodes should be kept underproper tolerance limit.
Welding position of positive lead should properly be adjusted.
●●●

Vertical edge of positive electrode should be covered with aninsulation tape.
Positive electrode should be put into a separator bag.

2.2.2.2 Production process of negative electrode◎
Negative lead should be covered with an insulation tape.
◎
Both width and length of negative lead should properly be
adjusted.

25

2.2.2.3 Winding process◎
Starting position of winding of positive electrode should be inadvance of that of both negative electrode and separator.
◎
External diameter of wound electrodes should properly be
adjusted.
When polarity of battery case and electrode at the external●
circumference is different, the electrode should fully be covered
with separator to avoid direct contact with the battery case.
Positions of positive lead and negative lead should be displaced●
between each other.
◎
Displacement of wound electrodes should be kept under proper
tolerance limit.
2.2.2.4 Assembly process◎
Insulation plate at the bottom should properly be designed.
◎
Upper insulation ring should properly be designed.

26

Quality control items in a production process
It is most important to prevent internal short-circuiting in production processesof cylindrical Lithium batteries for camera application. Typical quality control
items in each production process are summarized in the following.
Several of them may not be necessary depending on construction and/or
production method of batteries in each manufacturer.
a) Production process of positive electrode
Scatter of the thickness of mix sheet.
Drop and adhesion of mix powder during cut-off and transportation of mix
sheet.
Dimension of burr of positive lead.
Welding position of positive lead.
Presence and position of insulation tape which is used to cover positive
lead.
Presence and position of insulation tape which is used to cover ver ticaledge of positive electrode.
b) Production process of negative electrode
Dimension of burr of negative lead.
Presence and position of insulation tape which is used to cover lead sectionof negative lead.
c) Winding process
Starting position of winding of positive electrode and negative electrode,
respectively.
Pressure during winding.
Prevention of blocking of winding by strange particles.
Prevention of displacement of positive electrode, negative electrode and/or
separator during winding. (Prevention of bamboo shoot like winding and/or
exposure of metallic Lithium.)
External diameter of wound electrodes. (Prevention of loose winding or
forcible insertion of wound electrodes in the battery case.)
Prevention of the separator from being excessively folded durin g winding.

27

Measurement of the insulation resistance of all wound electrodes after
winding and rejection of defects due to internal short -circuiting.
d) Assembly process
Presence of insulation plate at the bottom.
Degree of bending of positive lead and negative lead, respectively.
Presence of upper insulation ring.
Measurement of the insulation resistance of all assembled batteries andrejection of defects due to internal short-circuiting.
e) Finishing process and inspection process before shipment.
Inspection of battery temperature.
Inspection of OCV (open circuit voltage).
Inspection of CCV (closed circuit voltage).
Rejection of defects due to internal short-circuiting by subjecting batteries
to vibration, drop or aging.
Inspection of internal construction of batteries (random sample) withtransmission X ray.

28

Safety tests and criteria
4.1 Safety tests and criteria of cylindrical Lithium single cell battery.
Internal short-circuiting, Crush
4.1.1.1 Internal short-circuitinga) Test procedure
A test battery* is to be placed on a flat wooden plate. A nail, whose diameteris 2.5 mm and length is 40-70 mm, is to be drilled and penetrated through centerof the battery, perpendicular through center of the battery, perpendicular to its
longitudinal axis.
* Fresh (undischarged) battery and 50% D.O.D. battery, respectively.
(i.e. Two(2) tests should be conducted)b) Requirements
No explosion and no fire.
c) Explanation
The aim of this test is to determine the behavior of battery at "hardest" internal
short-circuiting. Nail penetration through the battery was adopted to simulate"hardest" internal short-circuiting.
4.1.1.2 Crusha) Test procedure
A test battery is to be crushed between two(2) flat surfaces. It is to be crushedwith its longitudinal axis parallel to the flat surfaces of the crushing apparatus.
The force for the crushing is to be approximately 3,000 pounds (13 KN). The
force is to be applied by a vise or by a hydraulic ram.
b) Requirements
No explosion and no fire.
c) Explanation

29

The aim of this test is to determine the behavior of a battery when it is crushed
in a waste compactor.
External short-circuiting
4.1.2.1 Test Aa) Test procedure
A test battery is to be externally short-circuited at the following conditions.
-20℃ 24 hrs+20℃ 24 hrs+80℃ 5 hrsb) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 130℃.
4.1.2.2 Test Ba) Test procedure
A test battery is to be externally short-circuited in a battery case of camera, for
24 hrs at 20℃.
b) Requirements
No venting, no fuming, no explosion, and no fire.
Battery temperature should not exceed 130℃
4.1.2.3 Explanations of Test A and Test Ba) Test periods at -20℃ and +20℃ are specified to be 24 hrs so that to be enoughfor battery temperature to reduce to original ambient temperature. Normally, ittakes 3-4 hrs for battery temperature to reduce to original ambient temperature.
b) Test condition 4.1.2.1 a) (3) +80℃ 5 hrs, is severer than that of 4.1.2.1 a) (1)and 4.1.2.1 a) (2).
c) Any safety problem does not seem to occur when a test battery remains ove r30

above time periods, at respective temperatures.
Dischargea) Test procedure
A test battery is to be discharged at 2 ohm for 24 hrs at 20℃ and 60℃,
respectively.
b) Requirements
No electrolyte leakage, no venting, no fuming, no explosion and no fire. Battery
temperature should not exceed 100℃c) Explanation
The aim of this test is to confirm that a battery can properly operate when it isused in a camera.
A pulse discharge of about 1A is assumed to be a typical specification for
normal use of camera, and continuous discharge at about 1A is assumed to bea typical specification when a motor continues to operate during blocking of afilm.
Consequently, continuous discharge at 2 ohm (corresponding to about
1A) was adopted to simulate above conditions.
Drop, Vibration, Shock, Impact
4.1.4.1 Dropa) Test procedure
A test battery is to be dropped randomly ten(10) times from 1.9 m (6 feet) onto
a concrete floor.
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 45℃.
4.1.4.2 Vibrationa) Test procedure31

A test battery is to be subjected to a simple harmonic motion with an amplitudeof 0.8 mm (0.03 inch) (1.6 mm total maximum excursion). The frequency ofthe harmonic motion is to be increased and decreased at a rate of 1 Hz/min
between limits of 10 Hz and 55 Hz.
It has to be tested in three(3) mutually perpendicular directions for 90 -100 min,respectively.
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 45℃
4.1.4.3 Shocka) Test procedure
A test battery is to be secured to the testing machine. It is to be subjected a totalof three(3) shocks of equal magnitude, which are applied in each of three(3)mutually perpendicular directions. For each shock, the battery is to beaccelerated so that in the initial 3 ms, the minimum acceleration is 75 gn, andthe peak acceleration is between 125-175 gn (gn : local acceleration due togravity).
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 45℃.
4.1.4.4 Impacta) Test procedure
A test battery is to be placed on a flat surface. A 7.9 mm (5/16 inch) diameterbar is to be placed across the center of the battery. A 9.1 kg (20 pound) weightis dropped from a height of 61 cm (2 feet) on to it.
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 45℃.

32

High temperature storage, Thermal shock, Thermal exposure
4.1.5.1 High temperature storagea) Test procedure
A test battery is to be exposed to following conditions.
5 hrs at 100℃, then 8 hrs at 20℃.
30 hrs at 60℃, then 8 hrs at 20℃.
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 130℃.
4.1.5.2 Thermal shocka) Test procedure
A test battery is stored for 1 hr in -20℃, moved to a temperature of 60℃ within
5 min and stored for 1 h, then it is moved again to a temperature of -20℃. This
cycle is repeated for nine(9) times.
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 100℃.
4.1.5.3 Thermal exposurea) Test procedure
A test battery is to be placed in an oven. The oven temperature is to be increased
at a rate of 5/min until the oven reaches 150℃. The oven is to be maintained at
150℃ for 10 min.
b) Requirements
No explosion and no fire.
4.1.5.4 Explanations of 4.1.5.1-4.1.5.3
The aim of these tests is to determine the thermal stability of a battery atelevated temperatures.

33

These tests should be conducted by properly adjusting ambient temperatures.
Charging by reverse connectiona) Test procedure
Four(4) batteries are to be connected in series with one(l)(1) battery (testbattery) reversed for 24 hrs at 20℃.
b) Requirements
No overheating, no fuming, no explosion and no fire.
c) Explanation
One(l)(1) battery may be reversely connected, by mistake, in series connectionof more than two(2) batteries. The aim of this test is to determine the behaviorof a battery when it is reversely connected in series connection of four(4)batteries, which is used very often in actual applications.
Charging by the current of below 10 mAa) Test procedure
A test battery is to be charged for 1 hr with a current of 10 mA at 20℃.
b) Requirements
No venting, no fuming, no explosion and no fire.
Battery temperature should not exceed 100℃.
c) Explanation
When a battery is used as a main power source of camera, it may be charged
with a charging current due to reverse electromotive force which generates ina motor.
Normally, a prevention circuit of reverse electromotive force is provided andthus the battery is not charged.
The aim of this test is to evaluate the ability of a battery to withstand a small
charging current when it is charged by any possibility.
Reversed polarity (No. 1)
When internal resistance of one(l)(1) battery in series connection of more34

than two(2) batteries is significantly higher than that of the rest, the said (one)battery may be overdischarged into reversed polarity.
a) Test procedure
A test battery* is to be stored for ten(10) days at 60℃ and to be connected inseries with other three(3) batteries* (total of four(4) batteries) and with aresistance of 8.2 ohm. The circuit is to be closed and the four(4) batteries areto be discharged for 24 hrs at 20℃.
* batteries of 25%, 50% and 75% D.O.D., respectively
i.e. Three(3) tests should be conducted.
b) Requirements
No overheating, no fuming, no explosion and no fire.
c) Explanation
When a battery is improperly designed and/or produced, its int ernal resistanceis easy to increase if it is discharged to a certain extent and then stored for acertain period at an elevated temperature.
The aim of this test is to determine the behavior of a test battery which is
subjected to the above condition.
8.2 ohm resistance was selected by assuming about 2 ohm resistance for eachbattery. (See 4.1.3)
Reversed polarity (No.2)
When discharge capacity of one(l)(1) battery in series connection of morethan two(2) batteries is significantly smaller than that of the rest, the said
one(l)(1) battery may be overdischarged into reversed polarity.
a) Test procedure
A test battery* is to be connected in series with three(3) fresh (undischarged)
batteries (total of four(4) batteries) and a resistance of 8.2 ohm. The circuit i s
to be closed and the four(4) batteries are to be discharged for 24 hrs at 20℃.
* battery of 25%, 50% and 75% D.O.D., respectively
i.e. Three(3) tests should be conducted.
b) Requirements35

No overheating, no fuming, no explosion and no fire.
c) Explanation
This test assumes a popular case in which four(4) batteries are connected inseries. 8.2 ohm resistance was selected by assuming about 2 ohm resistance foreach battery. (See 4.1.3)
Low pressurea) Test procedure
A test battery is to be placed in a vacuum chamber which has a pressure equal
to or less than 11.6 kPa for six(6) hrs at an ambient temperature of 20℃.
b) Requirements
No deformation, no electrolyte leakage, no fuming, no explosion and no fire.
c) Explanation
The aim of this test to evaluate the ability of a battery to withstand low ambientpressures. This test simulates an altitude of 15,240 m.
Remarks
Overheating means that the temperature of external surface of a single cell
Lithium battery exceeds 150℃.
Fuming means that a smoke emits by partial thermal decom position of theplastic resin of battery case and/or of camera body.
Unless otherwise stated, an ambient test temperature should be 20±15℃.
Unless otherwise stated, a test battery should be a fresh (undischarged)
battery.
For external short-circuiting, the resistance of wiring should be below 0.05
ohm.
Number of test batteries and criteria
The aim of above tests (4.1.1-4.1.10) is to evaluate safety level of Lithium
single cell batteries for camera application.
Number of test batteries and test criteria are specified as follows;
Number of test batteries36n = 5 for each test item
[Remarks]
When two(2) or more test conditions (for example : different test
temperatures or different D.O.D. of test batteries) are specified for each test,
test with n=5 should be conducted at each test condition.
Test criteria
The relevant test lot is to be rejected if one(l)(1) battery fails the test.
4.2 Safety tests and criteria of cylindrical Lithium battery packInternal short-circuiting, Crush
4.2.1.1 Internal short-circuitinga) Test procedure
Same as 4.1.1.1 a)b) Requirements
No explosion and no fire
4.2.1.2 Crusha) Test procedure
Same as 4.1.1.2 a)b) Requirements
No explosion and no fireExternal short-circuiting
4.2.2.1 Test Aa) Test procedure
A test battery pack is to be externally short-circuited at the following conditions.
(1) -20℃, 24 hrs+20℃, 24 hrs+80℃, 5 hrs

37b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 130℃.
4.2.2.2 Test Ba) Test procedure
A test battery pack is to be externally short-circuited in a battery case of camera
for 24 hrs at 20℃.
b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 130℃.
4.2.2.3 Test Ca) Test procedure
A single cell battery for a test battery pack is to be externally short-circuited at
the following conditions.
-20℃, 24 hrs+20℃, 24 hrs+60℃, 5 hrsb) Requirements
No explosion and no fire.
Dischargea) Test procedure
A test battery pack is to be discharged at 4.3 ohm for 24 hrs at 20℃ and 60℃,
respectively.
b) Requirements
No electrolyte leakage, no venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 100℃.

38

Drop, Vibration, Shock, Impact
4.2.4.1 Dropa) Test procedure
Same as 4.1.4.1 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 45℃.
4.2.4.2 Vibrationa) Test procedure
Same as 4.1.4.2 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 45℃
4.2.4.3 Shocka) Test procedure
Same as 4.1.4.3 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 45℃.
4.2.4.4 Impacta) Test procedure
Same as 4.1.4.4 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 45℃.

39

High temperature storage, Thermal Shock, Thermal exposure
4.2.5.1 High temperature storagea) Test procedure
Same as 4.1.5.1 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 130℃.
4.2.5.2 Thermal shocka) Test procedure
Same as 4.1.5.2 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 100℃.
4.2.5.3 Thermal exposurea) Test procedure
Same as 4.1.5.3 a)b) Requirements
No explosion and no fire.
Charging by the current of below 10 mAa) Test procedure
Same as 4.1.7 a)b) Requirements
No venting, no fuming, no explosion and no fire.
Temperature of a battery pack should not exceed 100℃.

40

Reversed polarity (No. 1)
When internal resistance of one(l)(1) battery in series connection of morethan two(2) batteries is significantly higher than that of the rest, the said
one(l)(1) battery may be overdischarged into reversed polarity.
a) Test procedure
A test battery (*) is to be stored for ten(10) days at 60℃ a nd to be connected
in series with another battery (*) (total of two(2) batteries) with a protective
device against excessive current (example; PTC device) in a battery pack.
These two(2) batteries in the battery pack are to be discharged with a resistanceof 4.3 ohm for 24 hrs at 20℃.
*: batteries of 25%, 50% and 75% D.O.D., respectively
i.e. Three(3) tests should be conducted.
b) Requirements
No overheating, no fuming, no explosion and no fire.
Reversed polarity (No.2)
When discharge capacity of one(l)(1) battery in series connection of morethan two(2) batteries is significantly smaller than that of the rest, the said
one(l)(1) battery may be overdischarged into reversed polarity.
a) Test procedure
A test battery (*) is to be connected in series with a fresh (undischarged) battery(total of two(2) batteries) with a protective device against excessive current(example; PTC device) in a battery pack. These two(2) batteries in the battery
pack are to be discharged with a resistance of 4.3 ohm for 24 hrs at 20℃.
*:
battery of 25%, 50% and 75% D.O.D., respectively
i.e. Three(3) tests should be conducted.
b) Requirements
No overheating, no fuming, no explosion and no fire.
Low pressurea) Test procedure

41

Same as 4.1.10 a)b) Requirements
No deformation, no electrolyte leakage, no fuming, no explosion and no fire.
Remarks
Overheating means that the temperature of external surface of a single cell
Lithium battery exceeds 150℃.
Fuming means that a smoke emits by partial thermal decomposition of theplastic resin of battery case and/or of camera body.
Number of battery packs for test and criteria
The aim of above tests 4.2.1-4.2.9 is to evaluate safety level of Lithium
battery packs for camera application.
Number of battery packs for test and test criteria are specifi ed as follows;
Number of battery packs for testn = 5 for each test item
[Remarks]
When two(2) or more test conditions (for example, different test
temperatures and different D.O.D of test batteries) are specified for eachtest, test with n = 5 should be conducted at each test condition.
Test criteria
The relevant test lot is to be rejected if one(l)(1) battery pack fails the test.
Explanations
4.2.12.1 4.2.8 Reversed polarity (No.2);
When single cell batteries are used for camera application, fresh battery
and old battery or batteries from different manufacturers may sometimes bemixed together in series connection by end users. In such cases, discharge
capacity of each battery may significantly be different among each other andthus it is necessary that a battery of 25%, 50% and 75% D.O.D., respectively,
should be tested.
On the contrary, in case of a battery pack, single cell batteries with similarlevel of discharge capacity are generally selected by pack manufacturers andincorporated in a pack, and thus discharge capacity of each battery in a pack42

does not significantly differ, unless it is internally short -circuited in the pack
and its capacity has decreased.
Such failure can be prevented by each battery manufacturer with a suitablebattery design and proper quality control to reject production defects.
Consequently, each battery manufacturer can judge if this test should be
conducted based on its own level of quality control. Normally, it isrecommended that the test with 25% D.O.D. battery should be conducted andeach manufacturer should decide if the other two(2) tests (with 50% D.O.D.
battery and 75% D.O.D. battery) should be conducted.
4.2.12.2 External battery case
These battery packs which passed the above safety tests 4.2.1-4.2.9 do not,in general, catch fire. However, when it is heated to 200℃ or a single cellbattery in the pack is subjected to "hard" internal short-circuiting, it may catch
fire. Consequently, it is recommended to use non-combustible plastic resin for
external battery case.
Necessary characteristics which are required for battery case, other thansafety, are as follows.
① Heat resistivity② (Thermal deformation temperature should sufficiently be high.)③ Resistance against electrolyte solution④ Shock resistivity⑤ Environmentally friendly nature

43

[Acknowledgements]
We express our sincere appreciation to the following organizations / companies
for the preparation of this guideline
Lithium battery subcommittee of Battery Association of Japan
Lithium battery technical committee of Japanese Camera Industry
Association
Sanyo Electric Co.
Sony Energy Tec. Co.
Toshiba Battery Co.
Toyo Takasago Dry Battery Co.
Hitachi Maxell Co.
Fuji Electrochemical Co.
Matsushita Battery Ind. Co.
Duracell Inc. (U.S.A)
Energizer Inc. (U.S.A)

All rights reserved

44