Lion Engineering GmbH

Braunschweig, Germany

Lion Engineering GmbH

Braunschweig, Germany

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Westphal B.G.,TU Braunschweig | Westphal B.G.,Lion Engineering GmbH | Mainusch N.,Hochschule fur angewandte Wissenschaft und Kunst Gottingen | Meyer C.,TU Braunschweig | And 8 more authors.
Journal of Energy Storage | Year: 2017

In order to achieve a profound understanding of the production process of electrodes for lithium-ion batteries, methods to determine the (intermediate) product quality are a necessity. Therefore, a new, fast and easy to use two point method to determine the relative resistivity of dry electrodes has been established. The method is used to determine process-induced changes in the electrode's structure. A materials testing machine is used to ensure a homogeneous and constant mechanical stress during the analysis. By applying a direct current and measuring the voltage drop the electron transport characteristic along the whole electrode cross-section, taking all battery relevant resistances into account, can be determined. The result is an easy to compare relative resistivity value including coating resistance, contact resistance between coating and adhering current collector as well as the contact resistances between sample and probe. Process-induced changes are clearly visible in the results. The influence of the main testing parameters – contact stress and applied current – is determined. To cross-check the results, an established ‘powder probe’ method is used to confirm the relative resistivity changes caused by calendering. Slight calendering of LiNiMnCoO2 cathodes leads to an increase in electrode resistivity as conductive pathways are broken by the applied shear forces. However, increasing the cathode density to 2.95 g/cm3 decreases resistivity by one third compared to uncalendered electrodes by re-establishing and shortening electrical pathways. Furthermore, a relative resistivity of anodes produced with a high energy powder mixing step is measured and shows that applying too much stress to the carbon black leads to a loss in long range conductivity, resulting in electrodes with an increased resistivity of up to 50%. © 2017 Elsevier Ltd


Hanisch C.,TU Braunschweig | Hanisch C.,Battery LabFactory Braunschweig | Hanisch C.,Lion Engineering GmbH | Schunemann J.-H.,TU Braunschweig | And 14 more authors.
ECS Transactions | Year: 2015

Having a closer look at the details, recycling of scraps from the production of lithium-ion batteries is different from recycling of spent batteries. On the one hand it is less dangerous on the other hand pristine electrodes retain the original non-aged quality and thus the separation process is more difficult. Two different separation mechanisms, one mechanical and one based on the solvent N-methyl-2-pyrrolidone, are examined in this work. The resulting separated coatings are directly re-applied on new electrodes and electrochemically characterized in full cells. © 2015 The Electrochemical Society.


Westphal B.G.,TU Braunschweig | Westphal B.G.,Lion Engineering GmbH | Bockholt H.,TU Braunschweig | Gunther T.,TU Braunschweig | And 4 more authors.
ECS Transactions | Year: 2015

In the present work two of the various drying process parameters, air temperature and nozzle speed, are studied and their influence on the electrode's physical properties is examined by different mechanical and electrical analyzes. It was found that elasticity, electrical volume resistivity and adhesion strength of the coating to the substrate, can be dependent on process parameters used for manufacturing. These properties are also influenced by the electrode's mass loading and its recipe, as the total solvent content and therefore the drying time plays an important role. Assuming binder demixing during drying allows explaining the results, since evaporating solvent induces a temperature dependent compensational flow of solvent and solved binder. If immobilization occurs faster than compensational flow can cause significant demixing, no binder gradient emerges. The driving force counteracts the drying time, but increases demixing, so that optimum drying conditions exist for each mass loading and solid content. © 2015 The Electrochemical Society.


Hanisch C.,TU Braunschweig | Hanisch C.,Lion Engineering GmbH | Loellhoeffel T.,TU Braunschweig | Diekmann J.,TU Braunschweig | And 7 more authors.
Journal of Cleaner Production | Year: 2015

Lithium-ion batteries will play a crucial role in the development of mobile consumer devices, stationary energy storage systems, and electric mobility. The growth in these fields will bring about a surge in the lithium-ion battery market. This leads experts to agree that more effective recycling processes are needed in conjunction with the recycling of lithium. This calls for an entirely revolutionary recycling process which we here have attempted to develop. Our approach uses thermal decomposition of the polyvinylidene fluoride binder to lessen the cohesion of coated active material particles and weaken the adhesion between coating and foil. Then, an air-jet-separator is able to detach the coating powder from the current collector foils while stressing remaining particulate agglomerates. This separation process named ANVIIL (Adhesion Neutralization via Incineration and Impact Liberation) was tested on a laboratory scale with electrode rejects. We compared this to the widely used mechanical recycling process that utilizes a cutting mill to separate the current collector and coating. Intermediates and products were characterized using thermogravimetric analysis, tape adhesion tests, atomic absorption spectroscopy, particle size analysis, and gravimetric sieve analysis. We found that 97.1% w/w of the electrode coating can be regained with aluminum impurities of only 0.1% w/w, 30 times purer than the comparative process. This demonstrates a more effective recycling process than is currently available that also enables the recapture of lithium from the electrode coating. © 2015 Elsevier Ltd. All rights reserved.


Haselrieder W.,TU Braunschweig | Haselrieder W.,Lion Engineering GmbH | Westphal B.,TU Braunschweig | Westphal B.,Lion Engineering GmbH | And 5 more authors.
International Journal of Adhesion and Adhesives | Year: 2015

Abstract The coating adhesion strength of lithium-ion battery electrodes is a very important mechanical property, affecting the electrochemical life time of battery cells and the electrochemical handling during cell manufacturing. Hence the establishment of a standardized pull-off test with high reproducibility was long time overdue. The measurement setup is realized in a material testing machine. Machine and process parameters have been investigated to propose a reliable measurement procedure with a clearly specified parameter setup. Data acquisition rate (f), contact stress (σc), dwell time (td) and pull-off velocity (vpo) were identified to affect the adhesion strength measurement significantly. Finally electrodes with material and process parameter variations were manufactured to assess the applicability of the presented method. The impact of the amount of binder and its molecular weight as well as the influence of the dry mixing and the dispersing process on adhesion strength was verified and the differences can be clearly distinguished by the developed test method. © 2015 Elsevier Ltd. All rights reserved.


Diekmann J.,TU Braunschweig | Hanisch C.,Lion Engineering GmbH | Loellhoeffel T.,TU Braunschweig | Schalicke G.,TU Braunschweig | Kwade A.,TU Braunschweig
ECS Transactions | Year: 2016

Nowadays recycling processes for lithium-ion batteries focus on the recovery of nickel and cobalt. These processes are mainly pyro-metallurgical and as such energy and cost intensive. The project LithoRec, sponsored by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB), aims at a realization of a new ecological recycling process tracing mechanical process-steps and considering recycling of lithium. This work presents the main challenges of the recycling of battery systems of electric and hybrid electric vehicles and the developed process chain, as well as the influence of a second crushing step on the yield and purity of the separated black mass containing the aged active materials. © The Electrochemical Society.

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