Challenges in handling lithium batteries

For the development, production and transportation of lithium ion batteries, many rules and regulations from global, European and national legislations have to be complied with. Jauch Quartz offers comprehensive advice and support throughout the entire project phase. The recent addition of curved and ultra thin batteries has enriched the standard product range of lithium polymer batteries.

The strong demand for lithium based batteries is driving the future development and growth: more and more producers of battery-operated products are focusing on energy sources with lithium ion technology. But what challenges do producers of battery operated products and battery assemblers face at design-in stage and during the production and transportation of lithium ion batteries?

Lithium technology
The advantages speak for themselves: Lithium has a much higher energy density and voltage than any material used up to now. Thus, it can be used for a much longer time or at a higher power. The batteries are considerably smaller than others with comparable performance data. The higher number of charge cycles as well as the extreme durability of the batteries argue in favour of the use of this technology.
However, due to their higher power density, the use of lithium ion batteries also carries a higher risk. This affects the battery production as well as the transportation of the battery as well as the finished product respectively, including the battery and its use.

Cell production
Intrinsic safety is an issue even at the cell production stage:  This begins with the choice of suitable anode and cathode material for the application. Multi-layered separators with shut-down function are partially used. These melt at about 130° C and interrupt the ion flow, or the cells are already produced with a PTC. In addition, predetermined breaking points are located in the housing. In a case of gas formation, these enable a controlled leakage of gas before an explosion occurs.

Furthermore, an integrated protection unit safeguards the lithium ion batteries against deep discharge, external short circuits and especially against overcharging. Additional functions of the integrated protection unit turn something simple into a smart battery: Cell balancing and communication via SMBus and I²C can be integrated into the battery management systems.

Assembling
We shouldn´t forget the mechanical stability: The layout of the individual lithium ion cells and correct assembling are responsible to provide the highest possible level of safety of the battery pack.

Quality management system
Every battery producer worldwide should work towards a quality management system for process safety reasons, to guarantee a consistently high quality in the production of single samples and complete series of batteries. In the meantime, the globally applicable UN38.3 transportation test has made this management system mandatory. This affects not only the cell producers but also the assemblers.

Tests and Certification
Even at the design-in stage of the finished product, it is important to collaborate closely with a battery assembler who understands the opportunities and risks involved  and can keep a sharp eye on the producer´s project from the battery prospect. This means not only advising the producer on safety and battery performance but also offering guidance on statutory requirements, the transportation of the finished product and also the specific particularities of individual sectors where the product will be used. Apart from the UN38.3 transportation test, there are further, in part obligatory tests but also optional ones which are not uniformly in force worldwide. Regulating this presents the producer with another very responsible undertaking, which can only be met together with an experienced battery assembler.

Transportation tests
The UN 38.3 transportation test is the mandatory transportation test of the United Nations. The successful testing is a worldwide requirement to allow a product to be carried by road, rail, sea or air. This test checks any underlying potential hazards associated with the battery:  The battery e.g. is dropped from a certain height, checked for vibrations or thermic changes and its reaction to overcharging and undercharging.

Sector-specific tests
The use of the product in special industry sectors requires additional testing. For example, medical technology demands various certifications to ensure that the product in use on or in the human body fulfils all additional safety requirements. The IEC 62133 is a certification procedure of the International Electrotechnical Commission (IEC), a standardisation body for electrical engineering. As with UL 1642, here, additional detailed testing beyond the requirements of the UN testing is conducted on the battery in order to guarantee its safety.

Tests for special requirements
If a product is intended for use in potentially explosive atmospheres, the complete device including battery must hold an ATEX certification. For that, the battery must comply with certain specific requirements.

Statutory requirements
Compliance with statutory requirements, such as battery law, the rules of CE conformity or the statutory requirements of RoHS and REACH directives should form a working basis for every battery assembler. 

Jauch Quartz UK Ltd,

7 Priory court,

Tuscam Way,

Camberley,

Surrey,

GU15 3YX

www.jauch.co.uk

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