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October 18 Information
In a li-ion battery, does the chip distribute the tear and wear?
In common mainstream li-ion batteries, does the controller distribute the use across all cells all the time? Or could it be that one cell gets weared out sooner than the others? That is, could a used battery have some cells that are still good, even if the battery has lost 30-40% of its capacity? --
Llaanngg (
talk) 17:56, 18 October 2016 (UTC)reply
They have a lot of great resources to help you understand modern
battery management systems - the engineered devices around the electrochemical cell that make sure the cells are operating correctly.
It would be irresponsible to categorize all lithium-ion battery systems into the same bucket - there are immensely variable configurations in modern systems. Some battery management and power-supply systems certainly perform
load balancing.
One of the easiest, simplest, most straightforward ways to do load-balancing is to
connect the cells in series.
There is a good reason, based on solid fundamental science, to explain why this works so surprisingly well - but it has alarming shortcomings and serious impact to total system performance.
The OP's question is a concern common to the thousands of owners of the ageing but popular
Toyota Prius hybrid electric cars. Individual cells of the series-connected
Li-Ion traction battery do indeed wear out (lose capacity) prematurely. The on-board diagnostic program gives an error code when it detects imbalance. There are video guides
[1][2][3] on line about how to rejeuvenate the battery by replacing individual cells but it must be warned that this requires working in a high voltage circuit that is dangerous for an amateur without full knowledge and precautions. The manufacturer's battery warranty will not cover an unauthorized repair.
AllBestFaith (
talk) 12:59, 19 October 2016 (UTC)reply
What are "common mainstream li-ion batteries" these days? It's a fast-moving field, it's hard to know.
Many battery packs, even single cells, incorporate a protection board whose main function is to avoid over-discharging the cell, either too quickly (too much current, risk of letting the smoke out) or for too long (damaging the cell). This doesn't have a balancing function though. Larger capacity multi-cell packs (radio control models are a leading example) have a separate connector with the inter-cell connections, used to balance the cells during charging. The balancing is done by a smart charger, not an on-board controller or protection circuit.
Where developments seem to be going now though are to avoid the traditional series-connected battery, in favour of single cells and a
DC-DC boost converter to produce the voltages needed. For Li-ion (unlike lead-acid) it's also possible to make a battery pack by parallel connection of cells, giving the energy capacity needed, and avoiding balance problems, and letting the DC-DC converter deal with voltage.
Andy Dingley (
talk) 10:21, 20 October 2016 (UTC)reply
Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the
current reference desk pages.
October 18 Information
In a li-ion battery, does the chip distribute the tear and wear?
In common mainstream li-ion batteries, does the controller distribute the use across all cells all the time? Or could it be that one cell gets weared out sooner than the others? That is, could a used battery have some cells that are still good, even if the battery has lost 30-40% of its capacity? --
Llaanngg (
talk) 17:56, 18 October 2016 (UTC)reply
They have a lot of great resources to help you understand modern
battery management systems - the engineered devices around the electrochemical cell that make sure the cells are operating correctly.
It would be irresponsible to categorize all lithium-ion battery systems into the same bucket - there are immensely variable configurations in modern systems. Some battery management and power-supply systems certainly perform
load balancing.
One of the easiest, simplest, most straightforward ways to do load-balancing is to
connect the cells in series.
There is a good reason, based on solid fundamental science, to explain why this works so surprisingly well - but it has alarming shortcomings and serious impact to total system performance.
The OP's question is a concern common to the thousands of owners of the ageing but popular
Toyota Prius hybrid electric cars. Individual cells of the series-connected
Li-Ion traction battery do indeed wear out (lose capacity) prematurely. The on-board diagnostic program gives an error code when it detects imbalance. There are video guides
[1][2][3] on line about how to rejeuvenate the battery by replacing individual cells but it must be warned that this requires working in a high voltage circuit that is dangerous for an amateur without full knowledge and precautions. The manufacturer's battery warranty will not cover an unauthorized repair.
AllBestFaith (
talk) 12:59, 19 October 2016 (UTC)reply
What are "common mainstream li-ion batteries" these days? It's a fast-moving field, it's hard to know.
Many battery packs, even single cells, incorporate a protection board whose main function is to avoid over-discharging the cell, either too quickly (too much current, risk of letting the smoke out) or for too long (damaging the cell). This doesn't have a balancing function though. Larger capacity multi-cell packs (radio control models are a leading example) have a separate connector with the inter-cell connections, used to balance the cells during charging. The balancing is done by a smart charger, not an on-board controller or protection circuit.
Where developments seem to be going now though are to avoid the traditional series-connected battery, in favour of single cells and a
DC-DC boost converter to produce the voltages needed. For Li-ion (unlike lead-acid) it's also possible to make a battery pack by parallel connection of cells, giving the energy capacity needed, and avoiding balance problems, and letting the DC-DC converter deal with voltage.
Andy Dingley (
talk) 10:21, 20 October 2016 (UTC)reply