【Featured Q&A】Battery protection and fuel gauge design

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【Featured Q&A】Battery protection and fuel gauge design [Copy link]

In battery pack design, battery safety, battery life, battery life, fast charging, etc. are important design considerations. Currently, the battery pack design solutions provided by TI can be applied to:

• Laptop Battery Pack Design 查看详情
• 1-9 battery pack design for Bluetooth speakers, EPOS , E-bike and other applications 查看详情

Selected Q&A:

1. Battery protection: In addition to the battery’s own protection board, what other backup protections are needed to enhance battery safety?

A: The battery protection board will start protection only when the battery is in danger. If it often enters the protection mode, it is easy to damage the battery itself. Therefore, in addition to the battery protection board itself, it is also hoped that the related charging circuit should control the charging voltage and current as much as possible, and the discharge circuit itself should also control the normal discharge current at a level that the battery can accept. Some batteries have communication functions, such as CAN communication, so they also need isolation and overvoltage and ESD protection.

2. What are TI ’s advantages in battery electrical testing?

A: TI's solution has high accuracy and stability, as well as a wide range of battery parameter models. Users can find the corresponding matching battery model in TI's battery library according to their specific needs. At the same time, TI also provides customers with very complete tools and instructions for setting debugging parameters. In addition, our solution has also been recognized by battery panel solution companies in the industry, and production test equipment can also support the solution for related testing.

3. What are the main aspects of battery protection provided by TI ?

Answer: The battery protection functions are basically standardized in the industry, including charging and discharging overcurrent and overvoltage, undervoltage, overtemperature, undertemperature, short circuit, imbalance, etc. Currently, some customers have also begun to use protection against micro-short circuits inside the battery cells to provide early warning of dangers inside the battery cells.

4. What battery materials do TI fuel gauge products support?

A: The impedance tracking algorithm usually supports cobalt, manganese, and ternary batteries. Because the discharge curve of lithium iron phosphate batteries is relatively flat, the accuracy of the impedance tracking algorithm will be reduced to a certain extent. TI also has CEDV algorithm solutions, such as BQ4050 , which can support lithium iron phosphate batteries.

5. We understand that fast charging will damage the active materials of the battery, shortening its lifespan. Long-life batteries often have poor energy density. How can we balance the performance between the two?

A: This usually requires choosing different batteries according to the application conditions. For example, for mobile phone applications, capacity density is the first priority, while for solar energy storage batteries, cycle life is more important. Fast charging is what everyone wants to achieve, which can be solved by using batteries that are more expensive and support high-rate charging and discharging.

6. Battery life is important to users. How does TI improve the efficiency of battery life?

A: Taking BQ40Z50 as an example, the advanced charging algorithms it provides help extend battery life, such as Rate of change in charge voltage/currentCell Swelling Control (via Charging Voltage Degradation)Option to set charging current in C-Rate Cell Balancing at restCell Balancing at charge.

7. Does TI have a DC/DC solution that supports lithium battery applications ?

A: TI can provide more DC/DC solutions. Usually, battery applications need to take into account the long transportation and storage time of batteries, so the static power consumption requirements are higher. The LM5164 and LM5165 launched by TI are suitable for DC-DC of 10~16S batteries.

8.Can the amount of electricity be accurately measured at low temperatures?

A: Under low temperature conditions, it is necessary to specifically test the low temperature discharge characteristics of the battery cell and adjust the low temperature parameters of the fuel gauge to provide higher accuracy. However, this requires that the discharge characteristics of the battery cell maintain a high consistency at low temperatures, otherwise it will cause a large error.

9. How to accurately display the power of different parallel combinations ?

Answer: After parallel connection, the characteristics of the battery pack will still be slightly different from those of a single battery cell. If high accuracy is required, you can first measure the charge and discharge curves of the battery pack for matching.

10. Does TI 's solution support simultaneous voltage and current sampling?

A: TI's fuel gauge solutions usually integrate independent voltage and current ADCs, so they can support Eastern sampling of voltage and current.

11. What special parameters should be paid attention to when selecting the control MOS tube of the battery protection board?

A: Generally, the following aspects need to be considered, including: withstand voltage, current capability, and impedance should be as low as possible. Another key point is that because the short-circuit current of the battery is large, MOS is usually connected in parallel to meet the current requirements. At this time, the switching speed of the MOS tube must be very consistent, otherwise it is easy to burn the MOS. When using, the layout and wiring of the MOS tube also need to be carefully considered.

Recommended reference designs:

name	illustrate	Design Guide	Schematic	BOM
TIDA-010030	Accurate Monitoring and 50μA Standby Current, 13S, 48V Li-Ion Battery Pack Reference Design	查看详情	查看详情	查看详情
TIDA-00449	10-cell battery pack monitoring, balancing and protection	查看详情	查看详情	查看详情
TIDA-00895	1- to 2-Cell I2C Li-Ion Battery Pack Manager Reference Design	查看详情	查看详情	查看详情

alan000345

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