UN/SCETDG/33/INF.34
page 5
UN/SCETDG/35/INF.
COMMITTEE OF EXPERTS ON THE TRANSPORT OF
DANGEROUS GOODS AND ON THE GLOBALLY
HARMONIZED SYSTEM OF CLASSIFICATION
AND LABELLING OF CHEMICALS
Sub-Committee of Experts on the
Transport of Dangerous Goods
Thirty-fifth session
Geneva, June 2009
Item 4 of the provisional agenda
LISTING, CLASSIFICATION AND PACKING
Transport of Lithium Batteries
Definition and new test type in UN38.3
Transmitted by the experts from China
Background
As we know, UN38.3 has no significant changes in last few years, while the lithium battery technology and application has rapidly and widely developed. As a result, some definition may not so well applied on current lithium battery/cell.
1. Classification for new test type
a) The mass change for anode, cathode, and electrolyte is relative easy to acquire for manufacture. While for the other laboratories, the data is not so easy to get.
b) PRBA proposes to determine the new test type for rechargeable cells and batteries with a change in Watt-hours of more than 20% or an increase in voltage of more than 20%. It is generally agreed by experts. However, the “Watt-hours” is a unit but not a physical quantity. Comparing with the “voltage” used, a physical quantity using here may be more proper. Furthermore, the “voltage” of a battery could be various. Such as: charge voltage, nominal voltage and endpoint voltage. To make it clear, accurate description is necessary.
c) 38.3.2.1 (b): “a change that would materially affect the test results.” How to determine if the change would affect the test results? The conclusion may be drawn after comparing the test data from actual testing. However, we use this conclusion from test to determine whether the battery/cell needs to be re-tested currently. It could be confused.
d) Some changes may just for satisfying the physical requirements (such as size). Could it affect the test result or not? Maybe the designer can not make sure either.
2. Definition
a) Parts of the definition in current UN38.3 are not consistent with other International standards. It takes confusion on performing standards. Such as: battery, leakage etc.
b) Some definition may have various interpretations or the definition is not so precise. For example, in UN test requirements battery means one or more cells which are electrically connected together by permanent means, including case, terminals and markings. Under this definition, a rechargeable electrochemical unit which fulfils the requirements above but without protective devices can be named as a “battery”. While this electrochemical unit cannot pass the T.7 overcharge test that required for battery anyway.
c) The current definition of disassembly: “disassembly means a vent or rupture where solid matter from any part of a cell or battery penetrates a wire mesh screen (annealed aluminium wire with a diameter of 0.25 mm and grid density of 6 to 7 wires per cm) placed 25 cm away from the cell or battery.” In actual application, due to the multi-size of batteries and cells, the unified wire mesh screen is hard to meet the requirements for all the batteries/cells. At present, quite a few batteries/cells themselves are much larger than the length of 25 cm. It makes the distance of 25 cm not so suitable for being the test requirement. In addition, there are an amount of batteries/cells needed for the test. If each battery/cell needs one wire mesh screen in each test item, there will be large amount of wire mesh screen needed. It is not reasonable for applying tests.
d) As test requirements, some fundamental definitions are missing. For instance, anode, cathode, capacity, fire, etc. These definitions are directly related with the other definition and test procedure. It may result the inconsistent interpretation for the UN test requirements.
Concluded by above discussion, the definition of UN test requirements need to be consummated.
Proposal
1. We propose the following modification on PRBA proposal:
“38.3.2.1 Lithium metal and lithium ion cells and batteries shall be subjected to the tests, as required by special provisions 188 and 230 of Chapter 3.3 of the Model Regulations prior to the transport of a particular cell or battery type. Cells or batteries which differ from a tested type by:
(a) For primary cells and batteries, a change of more than 0.1 g or 20% by mass, whichever is greater, to the cathode, to the anode, or to the electrolyte;
(b) For rechargeable cells and batteries, an change in Watt-hours nominal energy of more than 20% or an increase change in nominal voltage of more than 20%; or
(c) A change that would materially affect the test results,
Including:
i. The material change of the anode, the cathode, the separator, or the electrolyte;
ii. The change of protective devices, including hardware and software;
iii. The change of safety design in cells, such as venting valve;
iv. The change of number and connecting mode of component cells in battery.
shall be considered a new type and shall be subjected to the required tests.
In the event that a cell or battery type does not meet one or more of the test requirements, steps shall be taken to correct the deficiency or deficiencies that caused the failure before such cell or battery type is retested.”
2. We propose the following modification on subsection 38.3 of the 4th revised edition of Manual of Tests and Criteria:
(a) Battery means one or more cells electrically connected together by permanent means, including case, terminals, and markings fitted with devices necessary for use, for example case, terminals, marking and protective devices. ( IEC 60050-482)
(b) Disassembly means a vent or rupture where solid matter from any part of a cell or battery penetrates a wire mesh screen (annealed aluminium wire with a diameter of 0.25 mm and grid density of 6 to 7 wires per cm) placed 25 cm away from the cell or battery the failure that occurs when a cell container or battery case opens violently and major components are forcibly expelled. (IEC 62133 - explosion)
(c) First cycle means the initial cycle of a rechargeable cell or battery following completion of all manufacturing processes.
(d) Large cell means a cell in which the mass is more than 500g. (Comparing with large battery) lithium content or lithium equivalent content of the anode, when fully charged, is more than 12 g.
(e) Leakage means the escape of material from a cell or battery unplanned escape of electrolyte, gas or other material from a cell or battery. (IEC60050-482)
(f) Table 1: Mass loss limit
Mass M of cell or battery / Mass loss limitM≤1 g / 0.5%
1 g<M<5 g / 0.2%
M ≥ 5 g / 0.1%
Note: if there are evidence shows the mass loss does not rise up from cell and without influence on safety, the mass loss can be neglected.
(g) Primary cell or battery means a cell or battery which is not designed to be electrically charged or recharged.
(h) Rechargeable cell or battery means a cell or battery which is designed to be electrically recharged.
(i) Small cell means a cell in which the mass is not more than 500g. (Comparing with large battery) lithium content of the anode, when fully charged, is not more than 12 g.
3. We propose the following supplement on subsection 38.3 of the 4th revised edition of Manual of Tests and Criteria:
(a) Anode means that, by convention, the cell electrode at which an oxidation reaction occurs.
NOTE: The anode is the negative electrode during discharge and the positive electrode during charge. (IEC 60050-482)
(b) Battery assembly means the battery with multiple separate but electrically connected cell compartments each of which is designed to house an assembly of electrodes, electrolyte, terminals or interconnections and possible separators.
NOTE: The cells in a battery assembly can be connected in series or in parallel. (IEC 60050-482-monobloc battery )
(c) Capacity means the electric charge which a cell or battery can deliver under specified discharge conditions.
NOTE: The SI unit for electric charge, or quantity of electricity, is the coulomb (1 C = 1 A.s) but in practice, capacity is usually expressed in ampere hours (Ah). (IEC 60050-482)
(d) Cathode means that, by convention, the cell electrode at which a reduction reaction occurs.
NOTE: The cathode is the positive electrode during discharge and the negative electrode during charge. (IEC 60050-482)
(e) Closed circuit voltage means the voltage between the terminals of a cell or battery when being discharged. (IEC 60050-482-discharge voltage)
(f) Depth of discharge means the percentage of rated capacity discharged from a cell or battery. (IEC 60086)
(g) Electrolyte means the liquid or solid substance containing mobile ions which render it ionically conductive. (IEC 60050-482)
(h) Endpoint voltage means the specified closed circuit voltage at which a discharge of a cell or battery is terminated. (IEC 61960)
(i) Battery Energy means the electric energy which a cell or battery can deliver under specified discharge conditions.
NOTE: The SI unit for energy is joule (1 J = 1 W · s), but in practice, battery energy is usually expressed in watt hours (Wh) (1 Wh = 3 600 J). The formula for Wh is watts multiplied by hours used. (IEC 60050-482)
(j) A fire means that the flames are emitted from the test cell or battery during a test. (IEC 62281)
(k) Nominal voltage means the suitable approximate value of the voltage used to designate or identify a cell, a battery or an electrochemical system. (IEC 60050-482)
(l) Nominal energy means the energy value of a cell or battery determined under specified conditions and declared by the manufacturer. The nominal energy is calculated by multiplying nominal voltage by rated capacity.
(m) Open circuit voltage means the voltage across the terminals of a cell or battery when no external current is flowing, which is commonly abbreviated to OCV or Uoc. (IEC 60086)
(n) Terminal means the conductive part of a device, electric circuit or electric network, provided for connecting that device, electric circuit or electric network to one or more external conductors. (IEC 60050-482)
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