Balance between Battery Life And Safety of Portable Ultrasound: NiMH Or Lithium Battery Is More Suitable?

Balance between battery life and safety of portable ultrasound: NiMH or lithium battery is more suitable?

As an important tool for modern medical diagnosis, the battery life and safety of portable ultrasound directly affect the reliability of clinical use. In terms of battery selection, nickel-metal hydride (Ni-MH) batteries and lithium-ion (Li-ion) batteries have their own advantages and disadvantages. How to weigh the performance of the two and find the best balance? This article will conduct an in-depth analysis from the aspects of battery life, safety, temperature adaptability, cycle life, etc., to provide scientific reference for medical equipment manufacturers and clinical users.

1. Battery life comparison: lithium batteries are significantly superior

The battery life of portable ultrasound directly affects the continuity of clinical operations, and the energy density of the battery is a key factor.

The energy density of lithium batteries (such as Li-ion, Li-Po) is usually 150-250Wh/kg, which can provide a longer single-use time and is suitable for scenarios that require long-term scanning (such as emergency departments and field rescue).

The energy density of nickel-hydrogen batteries is only 60-120Wh/kg. At the same volume, the battery life may be only half of that of lithium batteries, so it is more suitable for short-term examinations (such as outpatient ultrasound).

Conclusion: If the equipment needs to work uninterruptedly for a long time, lithium batteries are a better choice; if it is only needed for a short time, nickel-hydrogen batteries can also meet the needs.

2. Safety considerations: nickel-hydrogen is more stable, and lithium batteries need strict management

Medical equipment has extremely high safety requirements, and the chemical stability of the battery directly affects the risk of use.

Nickel-hydrogen batteries use aqueous electrolytes, which are not easy to burn or explode, and have high safety. They are suitable for high-reliability medical environments (such as operating rooms and ICUs).

Lithium batteries may experience thermal runaway (such as expansion and fire) under overcharge, short circuit or high temperature conditions, so they must be equipped with a battery management system (BMS) to ensure safe charging and discharging.

Conclusion: In high-risk medical environments (such as ultrasound equipment used in surgery), nickel-hydrogen batteries are more reliable; in ordinary clinical scenarios, lithium batteries can still be used safely under the protection of BMS.

3. Temperature adaptability: Lithium batteries are more suitable for extreme environments

Portable ultrasound devices may be used in different temperature environments (such as ambulances and field medical stations), and the low-temperature performance of the battery is crucial.

The capacity of nickel-hydrogen batteries will drop significantly (may be reduced by more than 50%) in **low temperature (<0°C)** environments, affecting the stability of the equipment.

Lithium batteries (especially lithium iron phosphate batteries) can still maintain high performance in the range of **-20°C to 60°C, and are more suitable for medical applications in extreme environments**.

Conclusion: If the equipment needs to be used in cold or high temperature environments (such as disaster relief, military medical treatment), lithium batteries are more reliable; if it is only used in a constant temperature indoor environment, nickel-hydrogen batteries can also do the job.

4. Cycle life: lithium batteries are more economical and long-lasting

Cycle life (the number of times it can be charged and discharged) directly affects the long-term use cost of the equipment.

The cycle life of nickel-hydrogen batteries is usually 500-1000 times, and there is a memory effect (if charged without being fully discharged, the capacity will decrease).

The cycle life of lithium batteries can reach 1000-2000 times, and there is no memory effect, which is more economical for long-term use.

Conclusion: If the device is used frequently every day (such as the hospital ultrasound department), lithium batteries have a longer life; if it is only used occasionally (such as grassroots clinics), nickel-metal hydride batteries are also acceptable.

5. Weight and portability: lithium batteries are lighter

Portable ultrasound devices emphasize lightweight, and the weight of the battery directly affects the user experience.

Due to their high energy density, lithium batteries are 30%-50% lighter than nickel-metal hydride batteries at the same capacity, making them more suitable for devices that require handheld or mobile scanning.

Nickel-metal hydride batteries are heavier and may affect the comfort of long-term operation.

Conclusion: If you pursue extreme portability (such as a handheld ultrasound device), lithium batteries are more suitable; if you are not sensitive to weight (such as a cart-type ultrasound), nickel-metal hydride batteries can also be used.

6. Recommendation

Operating room, ICU and other high-risk environments → NiMH batteries (high safety first)

Emergency department, field rescue → Lithium batteries (long battery life + low temperature resistance)

Primary clinics, outpatient ultrasound → Choose according to budget (NiMH has low cost, lithium battery has long life)

7. Conclusion: How to find the best balance?

The battery selection of portable ultrasound equipment needs to find the best balance between battery life, safety, environmental adaptability, life and weight.

If safety is paramount (such as intraoperative ultrasound), NiMH batteries are more reliable.

If long battery life + lightness is required (such as mobile medical care, emergency department), lithium batteries are a better solution.

For use in extreme environments (such as disaster relief), low temperature resistant lithium batteries are essential.

Ultimately, medical device manufacturers should choose the most appropriate power solution according to specific application scenarios, and clinical users should also pay attention to battery maintenance (such as avoiding overcharging and regular inspections) to ensure long-term stable operation of the equipment.