Using lithium-ion (Li-ion) and lithium-polymer (LiPo) batteries together can be done, but there are important considerations and potential issues to be aware of:

1. Voltage Matching:

• Voltage Compatibility: Both Li-ion and LiPo batteries typically have similar nominal voltages (e.g., 3.7V per cell) and fully charged voltages (e.g., 4.2V per cell). However, their exact voltage characteristics can vary slightly depending on the specific chemistry and design.
• Battery Packs: If you are combining cells in series or parallel, make sure that the voltage and capacity of the combined battery pack are properly managed. Mixing different types of cells in a single pack is generally not recommended due to potential mismatches in voltage and discharge characteristics.

2. Charging Requirements:

• Different Chargers: Li-ion and LiPo batteries may have different charging requirements and safety protocols. Li-ion batteries typically use a constant current/constant voltage (CC/CV) charging method, while LiPo batteries require careful balancing to ensure all cells charge equally.
• Dedicated Chargers: Use chargers specifically designed for the type of battery you are using. Using the wrong charger can lead to overcharging, overheating, or even fire hazards.

3. Battery Management:

• Battery Management System (BMS): Both types of batteries benefit from a BMS to monitor cell voltages, balance cells, and protect against overcharge, over-discharge, and overheating. Ensure that your system has a suitable BMS for the type of batteries you are using.
• Mixing Cells: When combining different types of cells, the BMS needs to be able to handle the specific characteristics of each type. Mixing cells with different discharge rates or capacities can lead to imbalanced charging and reduced battery life.

4. Safety Considerations:

• Thermal Management: Both Li-ion and LiPo batteries are sensitive to heat. Ensure adequate cooling and avoid conditions that could lead to overheating.
• Physical Damage: Avoid physical stress or damage to batteries. Both Li-ion and LiPo batteries can be hazardous if punctured or damaged, leading to swelling, fires, or explosions.

5. Practical Usage:

• Separate Systems: It’s generally better to use batteries of the same type and chemistry in a single system to avoid complications. If you need to mix types, carefully design the system to manage the differences and ensure compatibility.

Summary:

While Li-ion and LiPo batteries have similar characteristics, mixing them can be problematic due to differences in their charging requirements, voltage characteristics, and safety protocols. It’s best to use batteries of the same type in a single system and ensure that you use appropriate chargers and battery management systems for each type. If you do need to use both types, ensure that your system is designed to handle their specific needs and maintain safety at all times.