Charge At High and Low Temperatures

The operating environment of the battery allows a wide range of temperatures, but its charging capacity is not so arbitrary. The requirements are many.

The charging process needs to be very careful and delicate. Still, the discharging operation can be very rough, and the battery charging temperature must be moderate, too low, or too high.

The newly invented battery has a larger charging capacity.

Old batteries such as lead-acid batteries, nickel-cadmium batteries, and new batteries like lithium-ion batteries. So the new battery’s minimum temperature tolerance can be below freezing. Nick is more robust than NIMH when charged at low temperatures.

Lead-acid is also very tolerant, but lithium ions are not so forgiving and need special attention.

Table 1 summarizes the allowable charge and discharge temperatures of commonly used rechargeable batteries.

Lead acid –20°C to 50°C
(–4°F to 122°F)
–20°C to 50°C
(–4°F to 122°F)
Charging can be done at a temperature lower than 0.3 ° c or below, and the v threshold can be lowered by 3mv/° c at a high temperature.
NiCd, NiMH 0°C to 45°C
(32°F to 113°F)
–20°C to 65°C
(–4°F to 149°F)
0.1 ° C * 18 ° C * 0 ° C charge 0.3 ° C * 5 ° C charge 45 ° C reception rate is 70%.

The charge for 60 ° C is 45%.

Li-ion 0°C to 45°C
(32°F to 113°F)
–20°C to 60°C
(–4°F to 140°F)
The charging capacity is meager, short life, only allowed to charge and discharge at high temperature, low temperature is not allowed to criticize.

Table 1: Various batteries can be charged at the allowable temperature limit, but set at a limited temperature requires attention.

For best results, the battery needs to be charged between 10 ° C and 30 ° C (50 ° F and 86 ° F).

Lower the charging current if the temperature is too low.

Low-temperature Charge

Nickel-based: Most batteries are limited to charging temperatures of 5 ° C to 45 ° C (41 ° F to 113 ° F). Charging works best when you reduce the temperature range to between 10 ° C and 30 ° C (50 ° F and 86 ° F), which reduces the ability of oxygen and hydrogen to recombine within the battery.

The pressure building up in the battery, causing it to deflate, is the result of charging too quickly.

Conversely, suppose the temperature of the rechargeable battery is below zero. In that case, the lithium ion battery must reduce the charge current of all nickel-based batteries to 0.1c to protect the battery from damage.

However, sometimes emergency electricity needs to be charged quickly. To quickly charge the battery at all temperatures, some industries add a thermal blanket that can heat the battery to the appropriate temperature.

Others can adjust the charging rate of the charger to the appropriate temperature.

But consumer chargers are not as powerful as industrial chargers, so users who want to save the battery can only solve this problem by charging it at room temperature.

Lead acid: Lead acid batteries can be controlled at extreme temperatures.

This performance is due to its slow movement.

The recommended charging temperature is 0.3 ° C at low temperature and 2.415 V /cell at 20 ° C (68 ° F) at a comfortable temperature when the battery starts to deflate.

Lead acid batteries are charged at a constant current to 2.40 V/cell at an average temperature.

But temperature is the main factor controlling this voltage, and the voltage needs to be set high when it is cold and the opposite when it is warm.

Figure 2 illustrates the recommended voltage for most lead-acid batteries.

And I was floating charge voltage, which means the voltage the charger recovers when the battery is fully charged.

If the lead acid is charged at a variable temperature, the charger’s voltage needs to be adjusted to reduce stress and damage to the battery and keep it running for as long as possible.

(See BU-403: Lead filled acid)

Figure 2: Charging and floating battery voltage (at different temperatures) [1] The voltage needs to be adjusted for charging at different temperatures.

Lead-acid batteries can be permanently damaged if frozen at too low a temperature.

To avoid this, ensure the battery is fully charged because the electrolyte freezes earlier in a discharge than in a full charge.

According to the INTERNATIONAL Battery Council (BCI), when discharged, the specific gravity of the battery is 1.15, and the freezing point temperature is -15 ° C (5 ° F).

It is 1.265 degrees Celsius (-67 degrees Fahrenheit) lighter than when the battery is fully charged.

In the discharge state, the lead-acid battery is more likely to be damaged when it is full of electrolytes, the temperature is low, freezing will lead to leakage, and then the lead-acid battery pack will fail, so the lead-acid battery can only be charged for a few cycles and then it needs to be replaced after it fades.

Lithium-ion: Lithium-ion batteries can be quickly charged at temperatures between 5 ° C and 45 ° C (41 to 113 ° F).

Below 5 ° C, battery current needs to be reduced, and low freezing temperatures do not allow charging.

During the charging process, the battery’s temperature will rise slightly so that it does not get too cold.

But many users do not know that ordinary lithium-ion batteries cannot be charged below 0 ° C (32 ° F).

Because temperatures too low or even below freezing can permanently degrade the battery’s performance and safety, even though the pack usually appears to be charging, a lithium metal coating can be deposited at the anode in the process. And if the battery is kept vibrating or under other pressure conditions, it will damage the lithium-plated battery.

A premium charger (Cadex) is needed because it will prevent charging at temperatures below freezing. Most lithium-ion batteries can only be set at shallow currents, which is inconvenient. So chargers that can charge at low temperatures are being worked on.

According to the study document, the allowable charging rate at -30 ° C (-22 ° F) is 0.02 ° C, and the charging time can reach more than 50 hours in this case. As a result, some lithium-ion manufacturers have invented cold-rechargeable batteries.

But using it requires a special charger and the need to reduce the battery charge to a low voltage peak, such as 4.00 V /cell.

That would keep the lithium-ion battery at about 80 percent of its power.

Lithium ion batteries can also extend Lithium-ion batteries to last 12 hours or more by charging below 0 ° C (32 ° F). A specially designed charger is required.

This, of course, is very expensive.

Similar requirements apply to batteries that are themselves safe (see BU-304: Why are Circuits Protected?).

Some manufacturers suggest charging lithium ions at low temperatures, but most worry about the risks and do not want to be responsible.

Yes, charging lithium-ion batteries at low temperatures requires research LABS to dissect these batteries to study the results.

High-temperature Charge

The most significant danger of batteries, including lead-acid ones, is heat.

Adding temperature to lead acid chargers to reduce temperature changes can increase life expectancy. If set to 2.30 V/battery floating voltage, then at 25 ° C (77 ° F), the voltage should be 2.27 V/battery.At 15 ° C (59 ° F), the voltage should be 2.33 V/battery.

When the temperature is adjusted by 10 ° c, the voltage changes by 30mv.

Table 3 shows the maximum lead acid battery voltage charging at different temperatures.

Also included are floating-point voltages suggested when the battery is not in use.

BATTERY STATUS -40°C (-40°F) -20°C (-4°F) 0°C (32°F) 25°C (77°F) 40°C (104°F)
Voltage limit
on recharge
2.85V/cell 2.70V/cell 2.55V/cell 2.45V/cell 2.35V/cell
Float voltage
at full charge
or lower
or lower
or lower
or lower
or lower

Table 3: Recommended voltage limits for floating charge and maintenance of lead-acid batteries.

Voltage compensation extends battery life when operating at extreme temperatures.

Charging nickel-based batteries at high temperatures can reduce oxygen production and thus reduce charge adjustability.

Heat can sometimes trick chargers into thinking the battery is fully charged when it’s not.

FIG. 4 shows that the charge efficiency drops substantially below the “100% efficiency line” at temperatures above 30 ° C (86 ° F).

The battery only has a 70% charge capacity at 45 ° C (113 ° F) and drops to 45% at 60 ° C (140 ° F).

Temperature sensing is essential because NDVS used for complete power detection are unreliable at high temperatures.

FIG. 4: Acceptability of NICD charge with temperature [2]

High temperatures reduce charge acceptance to the point where it deviates from the “100% efficiency line” dotted line, with commercial NIMH batteries charging at 55 ° C at 35-40% efficiency and new industrial NIMH batteries at 75-80% efficiency.

Lithium-ion batteries perform well at high temperatures, but that can degrade their life over time. Battery charging and discharging at high temperatures tend to generate gases, which may cause the battery to deflate or expand.

Many chargers have a charging limit of 50 degrees Celsius (122 degrees Fahrenheit).

The charged state of a battery is related to capacity loss at high temperatures.

Figure 5 illustrates the role of li-Cobalt (licOO2), which is cycled at room temperature (RT), then heated for 90 minutes to 130 ° C (266 ° F), and then cycled at 20%, 50%, and 100% soc.

It can be seen that there is no significant capacity loss at room temperature. At 130 ° C, with a soc of 20%, there is a slight capacity loss after ten cycles. This loss is up to 50% of soc.

Figure 5: Capacity loss of surgical power tool batteries at room temperature (RT) and 130 ° C for 90 minutes [3]. Lithium ion batteries can only perform sterilization activities of surgical power tool batteries at low temperatures.

Test: Licoo2 / graphite cell exposed for 90 min at 130 ° C.

Warning: the battery should be flushed with water immediately if the electrolyte leaks or comes into contact with the electrolyte after breaking.

If the eyes contact the electrolyte, flush with water for 15 minutes and consult your doctor immediately to check and ask for solutions.

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