All technical contents of this standard are compulsory.
This standard is drafted according to the regulations given by GB/T 1.1-2009.
This standard was proposed by the Ministry of Industry and Information Technology of the People's Republic of China.
This national standard is under the jurisdiction of China Electronics Standardization Institute (CESI).
Drafting organizations of this standard: China Electronics Standardization Institute, Shenzhen BAK Battery, Co., Ltd., Tianjin Lishen Battery Co., Ltd., Amperex Technology Limited, Sunwoda Electronics Co., Ltd., Feimaotui (Fujian) Electronics Co., Ltd., Beijing Zhongxing Microelectronics Co., Ltd., Beijing Saixi Technology Development Co., Ltd.
Chief drafting staff of this standard: He Penglin, Hu Jingping, Cao Xuan, Su Jinran, Chen Zhikui, Wu Yuanming, Li Wuqi, Lin Nengqi and Feng Haiyu.
Introduction
This introduction aims at introducing the principles that requirements of this standard are based on. Understanding these principles is very necessary to design and produce safe lithium ion cells and batteries. It requires attention that this standard only considers the most basic safety requirements of lithium ion cells and batteries in order to provide safety protection of person and property, instead of involving performances and functional characteristics.
With the further development of technologies and techniques, a further revision to this standard is necessary.
The danger that lithium ion cells and batteries lead to in the scope of this standard refers to:
——Leakage, may directly do chemical corrosion to the human body, or lead to internal insulation fault in battery powered electronic equipment and indirectly cause danger such as electric shock and fire;
——Catching fire, directly burns the human body, or cause fire hazard to battery powered electronic equipment;
——Explosion, directly harms the human body or destroys equipment;
——Overheating, directly burns the human body, or result in insulation grade decline and safety component performance degradation, or ignite combustible liquid.
The leakage hazard is caused by the actions of internal stress or external stress and the enclosure damage. Fire and explosion hazards may be caused by thermal runaway within the cell. Thermal runaway is possibly caused by internal short circuit of the cell and strong oxidizing reaction of cell materials.
For the purpose of determining the design scheme for cells or batteries, the following priority shall be complied with:
——First, if possible, materials with high security shall be selected in priority. Materials which are liable to thermal runaway shall be avoided as much as possible;
——Secondly, if unable to achieve above principles, then protective devices shall be designed to minimize or eliminate the possible generation of hazards, such as increasing protective devices;
——Finally, if above schemes and others measures are incapable of preventing hazards, then measures of labeling and explanations to residual hazards shall be taken.
Above principles may not replace the detail requirements of this standard, only to let the designer learn about the principles that these requirements are based on.
The safety of lithium ion cells and batteries are relevant to its material selection, design, production technology, transportation and service conditions. Its service conditions include normal operating condition, foreseeable misuse condition and foreseeable fault condition, and include factors which affect its safety environmental conditions such as temperature and altitude.
Safety requirements on lithium ion cells and batteries cover hazards of all above factors to the staff. Staff refers to maintainers and users.
Maintainers refer to maintainers of electronic equipment and the cells. They can apply the professional skills they have grasped to prevent possible harms to themselves or others in obvious danger. However, the following methods may be carried out to protect maintainers against accidental danger, for example, remind maintainers of residual hazards by means of labels or caution explanations.
Users refer to all the staff other than maintainers. Safety protection requirements are raised assuming users have not received trainings of identifying hazards, but will not create hazard conditions deliberately.
Production process links such as material selection, design and technology of lithium ion cells and batteries are vital to their safety. See Appendix A for the quality control example of the production process; for design and manufacturing process, Appendix B may be referred to.
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
中華人民共和國國家標準
GB 31241-2014
Lithium Ion Cells and Batteries Used in Portable Electronic Equipments -
Safety Requirements
便攜式電子產品用鋰離子電池和電池組
安全要求
1 Scope
This standard specifies the safety requirements of lithium ion cells and batteries used in portable electronic equipment.
This standard is applicable to lithium ion cells and batteries used in portable electronic equipment (hereinafter referred as cells and batteries); examples of portable electronic equipment which belong to this standard are as follows:
a) Portable office products: laptop, PDA, etc.
b) Mobile communication products: cellphone, cordless telephone, Bluetooth earphone, interphone, etc.
c) Portable audio/video products: portable television, portable DVD player, MP3/MP4 player, camera, video camera, recording pen, etc.
d) Other portable products: electronic navigator, digital photo frame, game console, eBook, etc.
Above listed portable electronic equipment do not cover all products; therefore non-listed products are possibly in the scope of this standard.
For lithium ion cells or batteries used for portable electronic equipment at specific occasions such as on the vehicle, ship and plane, and in special fields such as medical treatment, mining and seabed operation, there are possibly additional requirements.
2 Normative References
The following documents are indispensable for the application of this standard. For dated references, only the dated edition is applicable to this document. For undated references, the latest editions of the normative documents (including all the amendments) are applicable to this document.
GB 4943.1 Information Technology Equipment - Safety - Part 1: General Requirements
GB/T 5169.5-2008 Fire Hazard Testing for Electric and Electronic Products - Part 5: Test Flames - Needle Test Method-Apparatus Confirmatory Arrangement and Guidance
GB/T 5330-2003 Industrial Woven Metal Wire Cloth (Square Opening Series)
GB/T 6005-2008 Test Sieves - Metal Wire Cloth, Perforated Metal Plate and Electroformed Sheet - Nominal Sizes of Opening
GB 8898 Audio, Video and Similar Electronic Apparatus-Safety Requirements
GB/T 17626.2 Electromagnetic Compatibility - Testing and Measurement Techniques - Electrostatic Discharge Immunity Test
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Lithium ion cell
A device which contains lithium ion and is capable of directly transforming chemical energy into electric energy. The device includes electrode, diaphragm, electrolyte, container, terminal, etc., and is designed as rechargeable.
3.2
Lithium ion battery
An assembly consists of arbitrary amount of lithium ion cells and is ready for use. The assembly includes proper encapsulating materials, connectors and possibly contains electronic control devices.
3.3
Portable electronic equipment
A movable electronic equipment not exceeding 18kg and may be frequently carried by users.
3.4
Hand-held electronic equipment
A portable electronic equipment which requires hand holding in normal use.
Note: for example, cellphone, palmtop computer, palmtop game console, portable video player, etc.
3.5
User replaceable battery
A lithium ion battery which is applied to portable electronic equipment and allows users to replace directly.
3.6
Non-user replaceable cell/battery
A lithium ion cell or lithium ion battery which is built in the portable electronic equipment and does not allow users to replace directly.
3.7
Rated capacity
C
Cell or battery capacity labeled by the manufacturer.
Note: the unit is amperehour (Ah) or milliamp hour (mAh).
3.8
Limited charging voltage
Ucl
The rated maximum charging voltage of the cells or batteries specified by the manufacturer.
Note: for example, the limited charging voltage of a single lithium cobaltate/graphite system cell is 4.20V generally.
3.9
Upper limited charging voltage
Uup
The highest safety charging voltage of the cells or batteries specified by the manufacturer.
Note: for example, the upper limited charging voltage of a single lithium cobaltate/graphite system cell is 4.25V generally.
3.10
Over voltage for charge protection
Ucp
The action voltage of protection circuit specified by the manufacturer during large voltage charging.
3.11
Discharge cut-off voltage
Udo
The load voltage of cells or batteries at discharge off specified by the manufacturer.
3.12
Low voltage for discharge protection
Udp
The action voltage of protection circuit specified by the manufacturer during low voltage discharge.
3.13
Recommendation charging current
Icr
The constant current charging current recommended by the manufacturer.
3.14
Maximum charging current
Icm
The maximum constant current charging current specified by the manufacturer.
3.15
Over current for charge protection
Icp
The action current of protection circuit specified by the manufacturer during large voltage charging.
3.16
Recommendation discharging current
Idr
The continuous discharging current recommended by the manufacturer.
3.17
Maximum discharging current
Idm
The maximum continuous discharging current specified by the manufacturer.
3.18
Over current for discharge protection
Idp
The action current of protection circuit specified by the manufacturer during high-current discharge.
3.19
Upper limited charging temperature
Tcm
The highest environment temperature specified by the manufacturer during cell or battery charging.
Note: the temperature is the environment temperature instead of the surface temperature of cells or batteries.
3.20
Upper limited discharging temperature
Tdm
The highest environment temperature specified by the manufacturer during cell or battery discharging.
Note: the temperature is the environment temperature instead of the surface temperature of cells or batteries.
3.21
Leakage
Leakage of visible liquid electrolyte.
[GB/T 28164-2011, definition 1.3.9]
3.22
Venting
When the internal pressure in cells or batteries increases, the gas is released through predesigned explosion-proof device.
3.23
Rupture
Mechanical damage to cellpacking or battery enclosure caused by internal or external factors, resulting in internal substance exposure or overflow but not jetting out.
[GB/T 28164-2011, definition 1.3.11]
3.24
Fire
Cells or batteries give out flame.
[GB/T 28164-2011, definition 1.3.12]
3.25
Explosion
Fierce rupture of the enclosure of cells or batteries results in main components jetting out.
[GB/T 28164-2011, definition 1.3.13]
3.26
Fire enclosure
Parts used to reduce the spreading of burning or flame to the minimum.
3.27
Type test
The test carried out to representative samples. The purpose is to determine whether the design and manufacturing meets the requirements of this standard.
[GB 4943.1-2011, definition 1.2.13.1]
3.28
Routine test
The test carried out during the manufacturing period or after the manufacturing to each independent product in order to inspect whether it meets relevant criteria.
[GB 4943.1-2011, definition 1.2.13.3]
4 Test Conditions
4.1 Applicability of the Test
The test specified in this standard shall be carried out only when safety is concerned.
The test may not be carried out, if it is not applicable to such cell or battery products that are determined inapplicable in the standard due to restrictions of design, structures or functions. In case restricted by the product design, structure or function and unable to carry out the test to cells or batteries, while the test must be implemented, the electronic equipment, the accessorial chargers of the electronic equipment or partial spare parts which constitute the electronic equipment of the cells or batteries may be subjected to relevant test together with the cells or batteries.
Note: portable electronic equipment and their accessorial chargers or partial spare parts which constitute the electronic equipment are produced by the manufacturer of the cells or batteries or the manufacturer of electronic equipment, and the manufacturer shall provide the operation instructions.
Unless otherwise specified, the samples after the test are not required to be of normal use.
4.2 Environmental Conditions of the Test
Unless otherwise specified, the test is carried out in the following conditions generally:
a) Temperature: 20℃±5℃;
b) Relative humidity: not larger than 75%;
c) Atmospheric pressure: 86 kPa~106 kPa.
4.3 Parameter Measurement Tolerance
Relative to specified values or actual values, the accuracy of all the control values or measured values shall be within the undermentioned tolerance range:
a) Voltage: ±1%;
b) Current: ±1%;
c) Temperature: ±2℃;
d) Time: ±0.1%;
e) Capacity: ±1%.
The above tolerances include the accuracy of measuring instruments used, errors of the adopted testing method and all the other errors introduced in the testing process. See GB/T 7676 for the selection of analog instruments; see IEC 60485 for the selection of digital instruments. In every copy of report which records the results, the details of test equipment used shall be provided.
4.4 Temperature Measurement Method
Adopt thermocouple method to measure the surface temperature of cells or batteries. The temperature testing points shall be located on the surface of geometrical center of cells or batteries or side contact point and other positions, and select the temperature peak point as the judgment reference of the test.
4.5 Charge/Discharge Procedure Used for the Testing
4.5.1 Charging procedure used for the testing
Cells or batteries shall be subjected to charging according to the method specified by the manufacturer.
Note: before charging, the cells or batteries shall discharge according to the method specified by the manufacturer to discharge cut-off voltage.
4.5.2 Discharging procedure used for the testing
Cells or batteries shall be subjected to constant current discharge according to the current specified by the manufacturer to discharge cut-off voltage.
4.6 Simulated Faults or Abnormal Operating Conditions
If applying simulated faults or abnormal operating conditions is required, then the application shall be carried out in turn, simulate one fault at a time. The fault directly caused by simulated faults or abnormal operating conditions is regarded as part of simulated faults or abnormal operating conditions.
When a certain single fault is set, this single fault includes the fault of any component.
The circuit board, circuit diagram and component specifications shall be inspected to determine possible fault condition which may be reasonably predicted. For example:
——Short circuit and open circuit of semiconductor devices;
——Short circuit and open circuit of capacitors;
——Short circuit and open circuit of current-limiting devices;
——Short circuit and open circuit of voltage limiting devices;
——Internal fault which makes the integrated circuit form excessive power consumption.
4.7 Type Test
Unless otherwise stated, the tests specified in this standard are type tests.
4.7.1 Requirements on samples
Unless otherwise specified, the tested sample shall be representative samples of the products that the client is about to accept, including small batch of pilot production samples or products which are ready to be delivered to the client.
In case the test requires lead wire for testing or connection, the total resistance generated by lead wire testing or connection shall be less than 20mΩ.
Foreword i
Introduction ii
1 Scope
2 Normative References
3 Terms and Definitions
4 Test Conditions
4.1 Applicability of the Test
4.2 Environmental Conditions of the Test
4.3 Parameter Measurement Tolerance
4.4 Temperature Measurement Method
4.5 Charge/Discharge Procedure Used for the Testing
4.6 Simulated Faults or Abnormal Operating Conditions
4.7 Type Test
5 General Safety Requirements
5.1 General Safety Consideration
5.2 Safe Operation Parameters
5.3 Label and Caution Explanations
5.4 Safety Critical Components
6 Electric Safety Test for Cells
6.1 External Short Circuit at Normal Temperature
6.2 External Short Circuit at High Temperature
6.3 Overcharge
6.4 Forced Discharge
7 Cell Safe Environment Test
7.1 Low Atmospheric Pressure
7.2 Temperature Cycle
7.3 Vibration
7.4 Acceleration Impact
7.5 Fall
7.6 Extrusion
7.7 Impact with Heavy Objects
7.8 Heat Misuse
7.9 Burning and Jetting
8 Battery Environment Safety Test
8.1 Low Atmospheric Pressure
8.2 Temperature Cycle
8.3 Vibration
8.4 Acceleration Impact
8.5 Fall
8.6 Stress Relief
8.7 High Temperature Service
8.8 Washing
8.9 Inflaming Retarding Requirements
9 Electric Safety Test for Batteries
9.1 General
9.2 Over Voltage Charge
9.3 Over Current Charge
9.4 Low Voltage Discharge
9.5 Over Load
9.6 External Short Circuit
9.7 Reverse Charge
9.8 Electrostatic Discharge
10 Safety Requirements of Protection Circuit for Batteries
10.1 General
10.2 Over Voltage Charge Protection
10.3 Over Current Charge Protection
10.4 Low Voltage Discharge Protection
10.5 Over Load Protection
10.6 Short Circuit Protection
10.7 High Voltage Proof
11 Safety Requirements of System Protection Circuit
11.1 General
11.2 Charging Voltage Control
11.3 Charging Current Control
11.4 Discharging Voltage Control
11.5 Discharging Current Control
11.6 Temperature Control for Charge/Discharge
12 Requirements for Consistency
12.1 General requirements
12.2 Test Requirements
Appendix A (Informative) Example for Requirements of Quality Control Procedure
Appendix B (Informative) Design and Manufacturing Process
Appendix C (Normative) Test Sequence
Appendix D (Informative) Example for Operating Range of Lithium Cobaltate-Graphite System Cells
Appendix E (Normative) Test Equipment and Measuring Instrument
Appendix F (Normative) Washing Test
Appendix G (Normative) Method of Flame Retardance Test for Lead Wires
Bibliography
