Introducing the Poweroad Infinity Lithium battery and why you shouldn’t charge your Lithium batteries below 0°C?
If you have a Lithium (LiFePO4) battery, there are some crucial things to consider when charging at temperatures below
Lithium battery manufacturers often state an operational temperature range of -20°C to +55°C (this varies depending on brand and model). One of the main misconceptions with this is that it is often misconstrued as a safe temperature range for both charging and discharging, however this is not the case, as the operational temperature range is referring purely to discharging the battery only.
Charging a Lithium battery in temperatures below 0°C must be avoided unless your battery is equipped to do so ( a compensating charger), as it may potentially damage the battery and reduce its lifespan.
When attempting to charge a Lithium battery below 0°C / 32°F a chemical reaction called “Lithium Plating” occurs which is caused by the charge current forcing the lithium ions to move at a faster reaction rate than usual and accumulate on the surface of the anode.
When this chemical reaction occurs the internal resistance of the battery increases, which can have big consequences when linked in series or parallel connections. As well as this, another side effect to the chemical reaction is it reduces the rate of the chemical metabolism and causes a permanent reduction of the battery’s capacity. This will continue to reduce further each time this reaction occurs.
The Poweroad Infinity PRLC-100 LINC has a battery management system that can monitor your battery’s temperature – an invaluable tool in marine, leisure, vehicle conversions & cold weather applications. With the touch of a button you can see what the standing temperature of your battery is and therefore whether it is safe to charge.
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How does the hi-tech heating function work on the Infinity PRLC-100-LT ‘Sub Zero’?
The process of heating and charging is automatically controlled by the BMS and the heating element embedded within the battery and takes roughly 40 minutes to change the temperature from -20°C to +5°C. Once the battery temperature reaches +5°C the charging starts immediately and once the temperature rises to +10°C the heating element stops and continues with the charging.
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To explain the chemistry behind lithium plating requires a quick summary of how lithium-ion batteries work.
They have an anode and cathode and electrolyte just like any other battery, but there is a twist: lithium ions actually move from the cathode to anode during charging and intercalate into it.
The gist of intercalation is that molecules or ions (lithium ions in this case) are crammed in between the molecular gaps of some of the material’s lattice.
During discharging the lithium ions leave the anode and return to the cathode and likewise intercalate into the cathode, effectively resulting in both the cathode and anode acting as sort of a ‘sponge’ for lithium ions. Once most of the lithium ions are intercalated into the cathode (meaning the battery is in a fairly discharged state), the cathode material will expand slightly due to volumetric strain (because of all the extra atoms wedged in between its lattice), but generally most of this is intercalation force is converted to internal stresses (analogous to tempered glass), so the volumetric strain is slight.
During charging, the lithium ions leave the cathode and intercalate into the graphite anode. Graphite is basically a carbon biscuit, made of a bunch of graphene layers to form an aggregate biscuit structure. This greatly reduces the graphite anode’s ability to convert the force from the intercalation into internal stresses, so the anode undergoes significantly more volumetric strain – so much so that it will actually increase in volume by 10-20%.
This must be allowed for when designing a lithium-ion cell otherwise the anode can slowly weaken or even ultimately puncture the internal membrane that separates the anode from the cathode, causing a dead short inside the cell but only once a bunch of joules have been shoved into the cell (thus expanding the anode).
Ok, but what does any of this have to do with cold temperatures?
When you charge a lithium ion cell in below freezing temperatures, most of the lithium ions fail to intercalate into the graphite anode. Instead, they plate the anode with metallic lithium, just like electroplating an anode coin with a cathode precious metal. So charging will electroplate the anode with lithium rather than recharging it. Some of the ions do intercalate into the anode, and some of the atoms in the metal plating will intercalate later over 20+ hours if the cell is allowed to rest, but most will not. That is the source of the capacity reduction, increased internal resistance, and also the danger.
This lithium plating of the anode isn’t nice and smooth and even – it forms in dendrites, little sharp tendrils of lithium metal growing on the anode.
As with the other failure mechanisms, which likewise are due to metallic lithium plating of the anode, these dendrites can put unexpected pressure on the separating membrane as the anode expands and forces the membrane to one day fail unexpectedly – ie a short circuit / dead cell.
Additional features about the PRLC-100 INFINITY LINC
*The POWEROAD Bluetooth LINC Battery Monitor App is free to download on Android & IOS phones and allow you to connect with your battery via Bluetooth to easily check the State of Charge (SoC), Battery status, State of Health (SoH) & individual cell voltages. You can also, through the setting menu, name each individual battery, which is extremely helpful when using multiple batteries within your machinery or power bank.
You can check any battery alerts for things such as the battery temperature, the number of cycles performed and the event record, cell over/under voltage protection, over/under charge protection, over/under temperature charging protection, over-temperature discharging, overcurrent protection, short circuit protection and can also be disconnected and reconnected all through the app.
** Other Benefits of the PRLC-100 INFINITY LINC
- Can be charged at temperature down to -20°C for cold weather use (sub Zero version)
- Can be linked in series to achieve 12V, 24v, 36v & 48V arrays
- 150Amp high output current for driving high-powered devices
- 350Amp Peak Discharge for current surges, such as Inverters, electric motors, winches, etc
- Detachable upper cover and replaceable BMS, designed specifically to reduce the cost of maintenance
- Embedded BMS which can prolong the battery life and guarantee batteries safety
- Sleep mode for reducing energy consumption and prolonging the shelf life
- Dual terminal design for easier installation and better heat dissipation
- IP54 protection level for ensuring battery remains unaffected by water under specified conditions
- Compact size ensures easy installation even in limited space
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DC Battery Technologies Ltd, DC Power House, 25 Earlstrees Road, Corby, NN17 4AZ
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