Why battery’s internal resistance decreases with temperature?

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Discussion Overview

The discussion centers around the behavior of a battery's internal resistance in relation to temperature changes, exploring the apparent contradiction between the general resistance-temperature rule for metals and the behavior observed in batteries. The scope includes theoretical explanations and conceptual clarifications regarding electrochemical reactions and resistance in galvanic cells.

Discussion Character

  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Bob questions whether battery internal resistance follows the general resistance-temperature rule, noting that for metals, resistance typically increases with temperature.
  • Some participants propose that the internal resistance of batteries decreases with temperature due to increased electron mobility, which facilitates faster electrochemical reactions.
  • One participant mentions the Arrhenius equation, suggesting that the rate of chemical reactions increases with temperature, leading to better current transport and lower effective resistance.
  • Bob expresses gratitude for the clarification after reviewing the relevant literature.

Areas of Agreement / Disagreement

Participants generally agree on the idea that increased temperature leads to decreased internal resistance in batteries due to enhanced electron mobility and reaction rates, although the initial question about the contradiction remains open for further exploration.

Contextual Notes

The discussion does not resolve the broader implications of the temperature-resistance relationship in different materials, nor does it clarify the specific conditions under which these behaviors occur in batteries compared to metals.

bobfei
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Hi,

Does battery internal resistance obey the general resistance-temperature rule?

For metal, resistance usually increases with temperature (see wikipedia).

For batteries however, its internal resistance decreases with temperature (also see wikipedia).

Could anyone explain the contradiction?


Bob
 
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The resistance of any galvanic cell such as a battery decreases as temperature increases due to increased electron mobility at higher temps.

The increased electron mobility means that the electrochemical reactions inside the cell can happen faster or easier (not sure which one it is, someone else might know) which means the internal resistance is effectively reduced.
 
Last edited:
trollcast said:
The resistance of any galvanic cell such as a battery decreases as temperature increases due to increased electron mobility at higher temps.

The increased electron mobility means that the electrochemical reactions inside the cell can happen faster or easier (not sure which one it is, someone else might know vague) which means the internal resistance is effectively reduced.

Then they are consistent. Thank you!

Bob
 
Batteries are chemical devices that rely on chemical reactions to produce their 'electricity'.

Chemical reactions mostly obey the Arrhenius equation which says that the rate of reaction increases with temperature.

http://en.wikipedia.org/wiki/Arrhenius_equation

So the faster the reactions the better the current transport and the lower the effective resistance.

Note that the cell voltage is only weakly dependent on temperature.
 
Last edited:
Studiot,

I just read the wiki article and got a better understanding. Thanks!

Bob
 

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