How to choose a 3.7V lithium battery charging management chip?

wangerxian

How to choose a 3.7V lithium battery charging management chip? [Copy link]

 

I have a new project recently, which requires a built-in 3.7V lithium battery. The battery type has not been selected yet, but I plan to choose between 18650 and lithium polymer batteries.

Lithium polymer battery

18650 Lithium-ion Battery

Question 1: How should I choose the charging management chip for these two types of batteries? Are they compatible or different?

Question 2: If 18650 lithium-ion batteries are selected, since the battery capacity is not determined, we don’t know how many 18650 batteries to connect in parallel, but the maximum number should be 3 18650 lithium batteries. So can the charging management chip be suitable for lithium batteries with different numbers of batteries?

EricCheng

They are all lithium batteries, universal. It depends on the voltage required to fully charge, and the number of battery cells.

dcexpert

Parallel connection increases capacity. If you need to charge quickly, you have to choose a high-power model, but you also need to pay attention to temperature management.

wangerxian

EricCheng posted on 2022-4-2 13:47 They are all lithium batteries, universal. It depends on how much voltage is required for a full charge, and the number of battery cells

If two lithium batteries are connected in parallel, the voltage is still 3.7V. Is this considered a single lithium battery?

wangerxian

dcexpert posted on 2022-4-2 13:57 Parallel connection increases capacity. If you need to charge quickly, you have to choose a high-power model, but you also have to pay attention to temperature management.

I see. Is the heating mainly caused by the battery or the charging device?

dcexpert

wangerxian posted on 2022-4-2 14:08 I see. Is the heating mainly caused by the battery or the charging device?

Generally, charging chips have temperature management functions, which will reduce the current or stop charging when the temperature is too high.

In addition to the dedicated charging chip, a mobile power chip can also be used, and the peripheral circuit is relatively simple.

wangerxian

dcexpert posted on 2022-4-2 14:28 will heat up. Generally, charging chips have temperature management functions. When the temperature is too high, the current will be reduced or charging will be stopped. In addition to dedicated charging...

I chose two models, ME4057 and ME4069 , and will try them out when the time comes.

EricCheng

wangerxian posted on 2022-4-2 14:07 If two lithium batteries are connected in parallel, the voltage is still 3.7V. Does this count as a single lithium battery?

Yes, it just has a larger capacity. It depends on how much voltage is required to fully charge it.

EricCheng

Linear charging is simple, a few hundred mA of charging current is enough. If you want a larger charging current, you have to choose a switch charger.

wangerxian

EricCheng posted on 2022-4-2 15:04 Linear is simple, a few hundred mA of charging current is enough. If you want a large charging current, you have to choose a switch charger

What does linear mean?

Fred_1977

There are many charging management ICs now, with a wide range of choices and many brands.

wangerxian

Fred_1977 posted on 2022-4-3 08:54 There are many charging management ICs now, with a wide range of choices and many brands.

Any recommendations for manufacturers?

qwqwqw2088

You should consider the battery capacity first, then choose the battery management IC

Series boost and parallel capacity expansion

Now the domestic lithium battery management chips are also doing well

qwqwqw2088

Syschip lithium battery protection IC, this company seems to have less than 3 strings

There are many types of IC management of Wenxianwei multi-section, you can check them out on their official website

wangerxian

qwqwqw2088 posted on 2022-4-3 18:19 You should consider the battery capacity first, and then choose the battery management IC. Series boost and parallel capacity increase. Domestic lithium battery management chips are also doing well.

The current battery capacity is set at around 3000mA.

wangerxian

qwqwqw2088 posted on 2022-4-3 18:27 Saixinwei lithium battery protection IC, this company seems to have many models of Wenxianwei multi-section IC management with less than 3 strings, you can go to their official website to check it out ...

I'll take a look at the stable ones first.

chipsimi003

Three batteries in parallel are still 4.2V batteries, but the capacity is larger. CSM4056SG can be used with a charging current of 1A.