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Showing posts from July, 2023

Things to know

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The difference between alkaline and lithium cells

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 The Alkaline battery gets its name because it has an alkaline electrolyte of potassium hydroxide, instead of the acidic ammonium chloride or zinc chloride electrolyte of zinc-carbon batteries. Above, you see pictures of two types of cells that Panasonic makes. The ones on the top are AA type Alkaline cells. The ones on the bottom are AA type Zinc Carbon cells. Alkaline cell Zinc carbon cell Based on the tables above, the Zinc Carbon cell is lighter, but has a lower shelf life. They both are AA type and have a nominal voltage of 1.5V, but there is one point of comparison that is not listed in the table above. That is Capacity. The Capacity of a AA cell depends on the load connected to it. For example, if you discharge the AA cell at 1A, it might discharge for say 1 hour. Now what if you discharged it at 0.5A, will it discharge for 2 hours? The answer is no, the effective capacity at 0.5A will be slightly higher, so the cell will be able to supply for a little more than 2 hours. This is

Range estimation for an electric vehicle

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   Range estimation is an important parameter for putting an Electric Vehicle on the road. Certification tests require disclosure of estimated range at different conditions, and more importantly users of the vehicle make daily decisions about their driving based on the amount of range left as calculated by the vehicle itself. A lot of parameters can be considered to increase the accuracy of range estimation, but it is important to form a starting point In the default configuration above, using the formula we get a runtime of 0.6 hours for a 100kWh battery connected to a 100kW motor. Here are some things to note here. The first question may arise, 100kWh pack, connected to a 100kW motor; shouldn't that run for 1 hour? You need to take into account motor and transmission efficiency, which means that all the energy from your battery pack doesn't make it to the motor, some of it gets lost along the way, mostly as heat. Another thing to note is that the calculation for runtime is do

Understanding thermal runaway in lithium-ion battery

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 When you hear about Lithium-ion battery safety, Thermal runaway is a very commonly talked about term. The purpose of this article and the attached video is to explain Thermal runaway in an intuitive way, so that the fear around it is a little less and the understanding a little more. As the name suggests, thermal runaway is a negative cyclic reaction that leads to a high temperature and pressure environment inside a Lithium-ion cell. This in its most extreme case can cause a fire, although many times the thermal runaway cycle is broken much before that through safety features built inside the cell and in surrounding electronics like the Battery Management System. Thermal runaway takes place in multiple stages. It needs to start with a trigger, which can either be a rule violation caused by the product or improper use of the product or in some cases an internal cell failure as well. Once the first stage of thermal runaway in activated, the reactions that take place inside the cell are