Rechargeable batteries and
battery chargers
Rechargeable batteries and battery chargers
030/3.0
Content Page
Summary 1
Introduction and history 1
Other means of control in the area 2
Legislation concerning batteries 2
Other ecolabelling systems 2
The market situation 3
Description of the product 3
Primary cells 3
Secondary cells 4
The impact of the product on the environment - RPS 5
Background to the requirements imposed 6
Metal content of batteries (4.1) 6
Requirements regarding plastic in chargers (4.2) 6
Packaging (Requirement 4.3) 6
Recovery systems for products and packaging (requirement 4.4) 6 Capacity requirement, rechargeable batteries (Requirement 5.1) 7 Energy consumption requirements – chargers for nickel metal hydride batteries
(Requirement 5.2) 8
Information for the consumer, batteries (Requirement 6.1.1) 9 Information for the consumer, chargers (Requirement 6.1.2) 9 Environmental and quality control (Requirement 6.3) 10 Analyses and inspection – Metal content in batteries (requirement 7.2.1) 10
Future criteria and the need for investigations 11
Summary
The greatest environmental problem with rechargeable batteries is the spread of metals. The main focus has been on the heavy metals arsenic, mercury, cadmium and lead. Batteries that require these metals for their operation cannot be ecolabelled. For other batteries, these metals occur only as impurities. By imposing requirements for a low content of these four metals, we reduce the spread of metals in our environment.
In this revision we have imposed requirements for the capacity of rechargeable batteries. The aim has been to highlight the batteries that achieve the stated capacity, and hopefully, this can be used in their marketing. Replacing primary (non-rechargeable) batteries with rechargeable batteries is beneficial for the environment and for the family budget. If ecolabelling can help so that more consumers chose rechargeable batteries, this would benefit the environment.
We also chose to extend the product group to include chargers for nickel metal hydride batteries. It has been shown that a great deal of energy can be saved by choosing chargers with a low energy consumption. We therefore chose to include this type of chargers where it is relevant to impose energy requirements.
The revision of the criteria for rechargeable batteries has been carried out by the Nordic secretariats. For the requirements regarding the capacity of the batteries and the energy consumption of the chargers we have been working together with a consultant.
This background document contains a brief description of the product and its environ-mental impact, an overview of other means of control in the area, a market overview and a background to the requirements that have been imposed.
Introduction and history
The Nordic Ecolabelling Board laid down the first criteria document for rechargeable batteries in 1996. The document has been revised and adjusted since then and is today published as version 3.0.
The metal levels were adjusted on 23/4 1999 in accordance with EU Directive 98/101/EG.
The greatest change in the new version of the criteria is the introduction of capacity requirements. The product group has also been extended to include chargers for nickel metal hydride batteries.
The definition of the product group given in Version 2 of the document is still relevant but chargers for nickel metal hydride batteries have been added.
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Other means of control in the area
Legislation concerning batteries
EU Commission Directive 98/101/EG (22 December 1998) prohibits the sale of batteries and accumulators that contain more than 5 ppm mercury from 2000-01-01. The exception is button cells, where the maximum permitted mercury content is 2 percent by weight. The prohibition also applies to batteries that are installed in products at the time of sale. This prohibition is also valid in Norway.
In Denmark, Finland and Sweden the batteries must be marked if the content of mercury exceed 5 ppm, cadmium 250 ppm or lead 4000 ppm. In Norway the batteries must be marked if the total content of mercury and cadmium exceed 250 ppm or the content of lead exceed 4000 ppm.
The EU Directive on batteries and accumulators is being processed within the EU. This directive, which has not yet been confirmed, focuses mainly on the phasing out of cadmium, battery recycling systems and battery marking.
Other ecolabelling systems
Der Blaue Engel1, the German ecolabelling system, has criteria for several different types of
batteries. Lithium batteries must not contain mercury or cadmium. For zinc-air batteries the mercury content must not exceed 60 mg per Ah. For RAM batteries (rechargeable alka-line manganese batteries), including chargers for these, they have requirements regarding metal content (max limit for mercury is 5 ppm and cadmium 10 ppm) and also that the battery must be capable of being recharged at least 25 times. At the 25th charge the battery must achieve at least 40% of its original capacity. In all of the above criteria, there are also requirements that the batteries do not contain substances listed in Annex 1 of EU
Directive 67/548/EEC.
The Environmental Choice Program2 in Canada has criteria for zinc-air batteries. The main
requirement is that the mercury content of the battery must not exceed 40 mg per Ah. They also have criteria for rechargeable batteries. These requirements are set to be specifically applicable to RAM batteries.
Ecolabelling of batteries also exists in Israel, Korea, New Zealand, Thailand and Taiwan. In 1996/97, The EU Flower scheme carried out a preliminary study for the development of environmental criteria for batteries but the product group is now resting.
1 www.blauer-engel.de 2 www.terrachoice.ca
Market overview
There is in Sweden only one manufacturer of nickel-cadmium batteries. Apart from this, foreign manufacturers with manufacturing all over the world have agents in Sweden. There are some companies in Sweden that manufacture battery packs designed for specific
products but the cells in the packs are then produced outside of Sweden. In Denmark there is one manufacturer of alkaline batteries.In Norway there is no manufacturer of batteries. Because of the increased use of electrical and electronic equipment, the use of rechargeable batteries is also increasing. It is very difficult to obtain sales data for rechargeable batteries, mainly because these batteries are sold as accessories to a product and are therefore not included in any import statistics. The European industry association states that about 19 % by weight of all batteries sold are accounted for by rechargeable batteries.3
Description of the product
A battery is an electrochemical current source which is either a primary cell (a primary battery), i.e. a cell that is exhausted after one discharge, or a secondary cell (a rechargeable battery or an accumulator) which can be recharged. This brief description will include both primary and secondary cells, even though this criteria document only applies to secondary cells.
All batteries have a negative and a positive electrode, electrolyte and a container (can). What separates the different types of batteries is the choice of electrode and electrolyte materials. The capacity of a battery depends on the materials chosen and the design of the battery.
Primary cells
Primary cells can be either cylindrical (rod) cells or button cells.
The most common cylindrical cells nowadays are alkaline cells and manganese dioxide cells. The only difference in the chemical design is in the electrolyte; see the table below.
Name Material, negative electrode Material, positive electrode Material, electrolyte
Alkaline Zinc Manganese
dioxide Alkaline Manganese dioxide Leclan-ché Zinc Manganese dioxide Ammonium chloride Zinc
chloride Zinc Manganesedioxide Zinc chlor-ide
Mercury used to be added to cells to influence the chemical reaction. Nowadays this is no longer done, so any remaining mercury content occurs as impurities in any of the raw materials.
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Swan labelled alkaline primary cells have an average mercury content of 0.02 ppm, 0.5 ppm cadmium and 7 ppm lead. The contents of these metals shall be below the limits laid down in current legislation. This means that the mercury content must be below 5 ppm, the cadmium content below 250 ppm and the lead content below 4000 ppm4.
Service time of alkaline batteries is about 2 – 5 times longer than for manganese oxide batteries.
As well as the metals needed for the chemistry of the battery, others are needed for its construction. The table below shows the average metal content of alkaline manganese dioxide batteries (percent by weight).5
Cd Cu Cr Fe Hg Mn Pb Zn Other
0,0074 0,5 0,004 28 0,0013 28 0,04 35 8,4
Intensive development work is being done on new chemical systems, and there are now other chemical systems with substances such as lithium, which have won market share for certain applications.
For button cells, there are several chemical systems depending on the field of application. The only variants that do not contain added mercury are lithium cells and certain zinc-air cells.
Secondary cells
The most common secondary cells currently on the consumer market (apart from the lead-acid accumulator) are nickel/cadmium, nickel metal hydride, ion and lithium-polymer accumulators. Intensive work is being done on developing various materials. Another type of rechargeable battery is a development of the alkaline battery that can be recharged. This type of battery is often referred to as a rechargeable alkaline manganese or RAM battery.
In the nickel-cadmium accumulator, cadmium is an electrode material and therefore accounts for a large proportion of the metal content, around 15 wt% in smaller batteries and around 6 wt% in industrial batteries. In the other accumulators listed above, the heavy metals mercury, cadmium, lead and arsenic only occur as impurities in the raw material. Swan labelled secondary cells have an average mercury content of 0.02 ppm, cadmium 2.2 ppm, lead 8.1 ppm and arsenic 4 ppm.
These batteries differ in their capacity. One way of measuring the capacity is to charge the battery to a given nominal capacity, discharge with a given load and then recharge. A measure of the capacity is the number of times the battery can be recharged to the given nominal capacity.The number of times RAM batteries can be recharged is less than with the other rechargeable types. Compared with primary batteries these batteries are
interesting from an environmental point of view since they can be recharged and thus contribute to reducing the waste of resources. For a major consumer of primary batteries there is also a financial gain.6
4 Ordinance on batteries (1997:645), SFS 1997:645
5 Quantifying the environmental benefit of ecolabelling systems - changes in the mercury content of alkaline
manganese dioxide batteries, Carl Johan Rydh, Universtityof Kalmar, Report SIS Ecolabelling 1999-04-01
A study carried out at The University of Stockholm7 shows that there are nickel metal
hydride batteries and lithium-ion batteries suitable for most applications nowadays and that nickel-cadmium batteries can therefore be phased out. Exceptions are reserve power sources for industry, hospitals, airports, etc., where nickel-cadmium batteries are still needed.
The impact of the product on the environment - RPS
The main principle in our prioritisation of the ecolabelling requirements is that we take the unique environmental profile of the product group as a starting point. The requirements focus primarily on those activities and processes that have the greatest relevance, potential and steerability (RPS) with regard to the life cycle of the product.
The relevance is assessed on the basis of what environmental problem the group contri-butes to and the magnitude of the problem. For batteries the main environmental problem is the spread of metals to the environment. This is caused both by the production of batteries and by the handling of used batteries. For the chargers of batteries, the main environmental problem is the energy consumption and in particular, the energy
consumption when the batteries are fully charged and when there are no batteries in the charger.
The potential is assessed in terms of possible environmental gain within the specific
product group, e.g. the difference between existing products or technical innovation, which is considered realistic in the near future. The development of portable electric and
electronic products increases. If you choose rechargeable batteries instead of primary batteries you get an environmental gain.
There is a big difference in capacity between rechargeable batteries on the market. The better capacity, the more times can you charge/recharge the battery and the higher becomes the environmental gain. For charger of batteries, there are differences in energy consumption both when the battery is fully charged respective when the charger is empty but still connected to the electricity supply system. The aim is that the charger should shut down completely when the battery is fully charged and when there are no batteries in the charger.
Steerability is a measure of how the activity, the problem or the requirement can be influenced by the ecolabelling. There is an economical gain for the consumer to choose rechargeable batteries with high capacity and chargers with low energy consumption.
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Background to the requirements imposed
Metal content of batteries (4.1)
The requirement regarding metal content in version 2 of the criteria document was set so that the mercury, cadmium and arsenic contents were each below 5 ppm. The lead content had to be less than 15 ppm.
In those batteries that you can ecolabel the metals arsenic, lead, cadmium and mercury do not perform any function today. If there are measurable amounts of these metals it is due to impurities in the raw material. The requirement can therefore be set so that only low levels of these metals are permitted in the battery.
We have chosen to make the mercury content requirements stricter, so that the content in the battery must not exceed 0.1 ppm. Taken together, the other three metals must not exceed 20 ppm.
The question whether contents of the heavy metals cobalt and chromium should be included has also been discussed. These two metals are added for the operation of the battery. At present we do not know whether it is possible to limit this use. We shall monitor the use of these heavy metals for a future revision.
Requirements regarding plastic in chargers (4.2)
The requirement is in principle identical to the requirement that applies to personal computers, decided on by NMN on 2002-03-14, with the difference that the requirement has no lower weight limit, i.e. all plastic parts are included.
Flame retardants and other additives in plastics have been discussed and then mainly the documentation requirements. The problem when dealing with chemicals is that a big part of the chemicals on the market are not tested. We have therefore imposed a requirement stating that “No data available” is not acceptable on a product information sheet. In other words, the chemicals used must have been tested.
To facilitate recycling of plastics, plastic casings must be marked in accordance with accepted standards.
When chargers were included in the product group, the aim was to be able to impose general requirement on chargers both in terms of energy consumption and plastics content. Since we did not find it possible to formulate a general requirement regarding energy con-sumption, we chose not to include all types of chargers in the criteria document. (see also requirements regarding the energy consumption of chargers, 5.2).
Packaging (4.3)
The requirement is new and is included in all criteria documents where it is relevant. It is a standard requirement in our criteria.
Recovery systems for products and packaging (4.4)
The requirement is new and is included in all criteria documents where it is relevant. It is a standard requirement in our criteria.
Capacity requirement, rechargeable batteries (5.1)
The basic idea was to formulate requirements that can be verified with the aid of a simple general method that can be applied to all rechargeable batteries.8
Such a common denominator is the nominal capacity9 of the batteries, which is stated by the manufacturers. The nominal capacity is also one of the few parameters available to the consumer when comparing and choosing products in the purchasing situation. The idea is to impose a requirement that the correct nominal capacity of the battery is stated and then use that value as a basis for the currents used when testing the battery before ecolabelling. If the stated nominal capacity is too high, the battery will not meet the requirements. To prevent manufacturers from under-rating their products in order to gain ecolabelling more easily, a supplementary deviation requirement should be imposed.
The IEC and ANSI standards applicable to these types of battery focus on definitions and safety issues. Few of the tests relate to quality and lifetime. In general, the requirements for battery life tests are vague or low: 60% after 500 cycles with C/4 discharging. The reason for this is that the interests of the battery manufacturers have controlled the level of the requirements. The following standards have been studied: IEC 61951-2 Ed 1 (2001), IEC 61436 Ed 1 FDIS (1997), IEC 285 Ed 3 (1993), ANSI C18.2M Part 1-2001.
Instead of using the standards above, we propose a verification method based on principles that are used by OEM10 manufacturers for the selection of batteries for their products. The
test method is simple and decisive as regards quality and performance. There are three stages in the testing of the batteries:
• initial cycling,
• life cycling
• final inspection
The capacity measured at final inspection is compared with the capacity measured initially to determine what proportion of the capacity remains after life cycling.
Testing of Li-ion, Li-polymer, RAM and NiMH batteries is done on four to eight batteries, and all the batteries must meet the final requirement: 80% of the nominal capacity is reached after 400 1C cycles. This is an accepted requirement level for several sectors (telecommunication, electric car and power industry) and one which battery manufacturers regard as high.
We have chosen not to include application requirements in the test method11. This is partly
because it could easily lead to unreasonably long testing times (6 months or more) and partly because it is not perceived as relevant for Li-ion, Li-polymer and NiMH batteries. These batteries must be designed to handle 1C discharges from the stated nominal capacity, which means that they can be used in most applications. Performance testing at lower currents would not reveal anything significant about the quality of the products.
8 Catella Generics
9Definition of the concept capacity and C:
Traditionally, manufacturers and users of rechargeable batteries have expressed the
charging/discharging current as a multiple of capacity. Example: A current of 20 A to charge a battery with a nominal capacity of 100 Ah is stated as C/5 or 0.2 C A. Briefly, the reference current (I) is stated as:
I(A)=C(Ah)/1(h).
C is the nominal capacity stated by the manufacturer in Ah.
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The question of an overcharging requirement has been raised in view of the safety risk associated with attempts to recharge with the wrong type of charger. After careful consi-deration we have chosen not to recommend overcharging requirements for NiMH, Li-ion and Li-polymer batteries. This is because criteria for Swan labelling should not be based on incorrect use of batteries. This should rather be regarded as a charger requirement.
Storage testing of batteries has also been excluded, since it is difficult to manage and requires a lengthy period of storage (of the order of a year) to give a correct result.11
There was a suggestion of lower capacity requirements for RAM-batteries in the proposal. This was strongly criticised in several comments to the proposal. One reasons for this was that consumers who choose a Swan labelled battery should expect equivalent capacity regardless of type of battery. After the proposal, we decided to impose the same require-ments on RAM-batteries as on other rechargeable batteries.
Energy consumption requirements – chargers for nickel metal hydride batteries (5.2)
Battery chargers are a new product group for Swan ecolabelling. It has been desirable to be able to impose the following requirements on the charger:
• The charger must not draw current, i.e. it must switch off, when the battery is fully charged.
• The charger must not draw current, i.e. it must switch off, if there are no batteries in the charger.
Chargers currently on the market do not have this function.
The chemistry of the battery determines the charging method that should be used. NiMH batteries are charged at constant current. Li-ion, Li-polymer and RAM-batteries are charged at constant voltage. The charging methods are characterised by different parameters and therefore call for different types of requirement criteria.
There are many different types of chargers on the market. The simplest types charge one kind of battery with the same current or voltage until the battery is removed. “Intelligent” chargers can charge different sizes of batteries and also batteries with different chemical systems. Some chargers have an indicator which senses when the battery is fully charged and reduces the charging rate to a lower level which only compensates for the self-discharging of the battery. As a consequence, there is an energy saving to be made if you choose a charger that does not charge “at full output” regardless of the status of the battery.
Closer studies of chargers show that it is difficult to impose relevant energy requirements on chargers to Li-ion and Li-polymer batteries and to RAM batteries. It would be possible to impose requirements only on the plastics content of these chargers, but instead we chose not to include them in the product group. There may be a risk that it appears as if Nordic Swan is promoting nickel metal hydride battery chargers over other kinds of charger.
The following requirements are imposed on chargers for nickel metal hydride batteries. An explanation follows to each requirement.
Requirement: The charger must have a built-in interruption criterion that interrupts the charging when the battery is fully charged. Independent of how the interruption technology works, the charger must interrupt in accordance to a reference charger that has an interruption criterion -∆∆∆∆V of 10 mV. In the proposal, the requirement stated that the charger must have an interruption criterion -∆V. The responses to the proposal pointed out that there were other technical solutions for charging interruption which were equivalent to -∆V. We decided, after the proposal, to change the requirement, as written above, in order to open up for other solutions.
Requirement: Minimum charging current: C/5. This is so that the maximum of the voltage curve is clear enough for the charger to be able to detect the right time for completed charging. At lower currents the voltage curve is smoothed out. One conse-quence of this requirement is that the applicant must state the maximum nominal capacity of batteries that the charger is suitable for.
Requirement: Maximum float charge current: 10% of C/5-current, i.e. C/50. The aim is that the charger should draw a minimum of electrical energy when the charging function is complete. High float charge currents also cause the batteries to degenerate owing to corrosion in the cell. The C/50 level is acceptable since it is low enough not to harm the battery.
Requirement: Maximum no-load current: 10% of C/5-current, i.e. C/50. There is not sufficient information to formulate separate requirements for the no-load current. The aim is that the charger should draw zero current at no load.12
Information to the consumer, batteries (6.1.1)
It is difficult for consumers to see the difference between primary batteries and
rechargeable batteries that also differ from each other in their chemical systems. We have discussed how the batteries must be marked to make them easier to handle, this is mostly for two reasons. No accidents must happen if the wrong type of battery is charged in the charger, and when consumers purchase a battery they must be informed of the capacity of the battery. The limitation is that the product is small and there is only space for a very limited amount of text/graphics. We have chosen to formulate the requirement so that the chemical system and nominal capacity must be stated on the battery.
Information to the consumer, chargers (6.1.2)
It is important, for reasons of safety, that the type of batteries for which the charger is intended should be clearly shown. In order to be able to check the energy requirements the maximum nominal capacity of batteries that the charger is suitable to charge must also be stated.
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Environmental and quality control (6.3)
This requirement is formulated in accordance with the template for the criteria document with an added requirement as follows:
The manufacturer of ecolabelled products must himself, or through an agent/importer, have documented routines and instructions for ensuring:
• the traceability of the batteries,
• that consumers can see which batteries are ecolabelled.
The documentation requirement as it is formulated in the criteria does not follow the template. Batteries of a single make may be manufactured in a large number of places all over the world. Each size is made where there is free capacity at the particular time. An explanation to why the documentation requirements from the template have been adjusted follows below:
a) Organisation, quality manager, contact and other responsible parties, along with their areas of responsibility. There must be someone to act as a contact between battery
manufacturing and the ecolabelling organisation. The contact is stated on the application form. It is not relevant to request details of other persons responsible at each manufacturing unit.
b) Internal routines for documenting and reporting unexpected deviations related to the ecolabelling requirements. A written statement explaining how the manufacturing units can guarantee that they meet the ecolabelling requirements must be provided.
c) Internal routines for documentation and reporting of planned production changes in the ecolabelled product. A written statement explaining how the manufacturing units can guarantee that they meet the ecolabelling requirements must be provided.
d) The contact’s routines for reporting on points b) and c)/ In this case this requirement is not relevant.
e) Routines for documentation, reporting and handling of complaints about the ecolabelled products.
In this case this requirement is not relevant.
f) Routines for traceability of the ecolabelled products in production. In this case this requirement is not relevant since it is not a specificproduction for ecolabelled products. Instead it is important that there is traceability of the product to a specific production location.
Analysis and inspection – Metal content in batteries (7.2.1)
In the proposal it was stated that the metal content of the batteries should be analysed using the method known as “A method for the determination of cadmium and mercury in dry batteries – a Nordic collaborative study”, National Environmental Research Institute, Söborg, Denmark, Nordic Council of Ministers report No. 0 - 0850.
It transpired that, if the method is followed completely, it is not possible to get down to the detection levels required for our requirements. For the analysis of cadmium, arsenic and lead (7.5.1) using the above method, we therefore allow the use of ICP-MS (Inductively Coupled Plasma Mass Spectrometry). When analysing mercury with the analysis method stated above, it is permissible to analyse the mercury content with AFS (Atomic Fluor-escence Spectrometry).
Some answers to the proposal recommend a method of analysis that has been developed by the manufacturers of batteries, “Battery Standard Analytical Method. For the
determination of Mercury, Cadmium and Lead in Alkaline Manganese Cells using AAS, ICP-AES and Cold Vapour”, European Portable Battery Association (EPBA), Battery Association of Japan (BAJ), National Electrical Manufacturers Association (NEMA;USA), April 1998.
The Swedish Institute for Metal Research in Stockholm has made a comparison between the Danish method and the method above. The Institute does not recommend one specific method but they point out that the method developed by the producers has, among other things, a matrix matched standard which is missing in the Danish method..
After the proposal, we decided to change the recommended analytical method for analysis of metal content to the method developed by the battery manufacturers.
Future criteria and the need for investigations
Future criteria should focus on:
• The handling of metals in the manufacture of batteries. More knowledge is needed for ecolabelling in this area. This also includes being able to impose requirements on the use of recycled metal in the manufacture of new batteries.
• Monitoring the use of the heavy metals cobalt and chromium in secondary cells.
• Monitoring the development of fuel cells in order to, if possible, extend the product group to include fuel cells.
• Following the development of chargers in order to, if possible, be able to impose requirements that the charger does not draw current when the battery is fully charged and when the charger is empty.
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Bibliography
Environmental Label German “Blue Engel” (2002) http://www.blauer-engel.de
Environmental Choice Program Canada (2002) http://www.terrachoice.ca
EU Commission Directive 98/101/EG (22 December 1998) http://www.europa.eu.int
European Portable Battery Association, EPBA (2002)
http://www.epba-europe.org
Ordinance on batteries 1997:645, SFS 1997:645
Noreus, D., Substitution of rechargeable NiCd batteries, Report Prof Dag Noreus. University of Stockholm, August 2000
Rydh, C-J. (1999) Kvantifiering av miljönyttan av märkningssystem – förändringar av kvicksilverinnehållet i brunstensbatterier (Quantifying the environmental benefit of ecolabelling systems – changes in the mercury content of alkaline manganese dioxide batteries), Report C-J Rydh, University of Kalmar, to SIS Ecolabelling 1999-04-01 Råd & Rön (Swedish Consumer Agency), Lönsamt med laddningsbart (Profitable with rechargeable), No 5, 2000.
Tidblad, A., Jonsson, J., Rosenlund, S., Catella generics, Review of requirements for Swan ecolabelling of batteries and chargers, Report to SIS Ecolabelling 2002-02-14
Swedish Institute for Metals Research, Utvärdering av två kemiska analysmetoder avseende bestämning av kvicksilver, kadmium, arsenik och bly i batterier (Evaluation of two
chemical analytical methods regarding mercury, cadmium, arsenic and lead in batteries), 1990-04-27.
