Which is better,Nickel hydrogen battery and lithium battery
NiMH battery and lithium battery are environment-friendly and pollution-free batteries, which are widely used in the market and are important fields of new energy battery development. So which is better, nickel metal hydride battery or lithium battery? Now let's learn about their respective advantages and disadvantages.
What is NiMH battery?
NiMH battery is a kind of battery with good performance. Nickel metal hydride battery is divided into high-voltage nickel metal hydride battery and low-voltage nickel metal hydride battery. The positive active substance of nickel hydrogen battery is Ni (OH) 2 (called NiO electrode), the negative active substance is metal hydride, also called hydrogen storage alloy (called hydrogen storage electrode), and the electrolyte is 6mol/L potassium hydroxide solution.
What is a lithium battery?
Lithium battery is a kind of battery with lithium metal or lithium alloy as positive/negative electrode material and non-aqueous electrolyte solution. Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium ion batteries. Lithium ion batteries do not contain metallic lithium and can be recharged.
Advantages and disadvantages of nickel hydrogen battery and lithium battery:
The design of NiMH battery charger and lithium battery charger is based on voltage in principle, and the charging scheme designed for memory effect or not is also different. The advantages and disadvantages of the two products are as follows:
1. Advantages and disadvantages of nickel hydrogen battery
Advantages: low price, strong versatility, large current, environmental stability.
Disadvantages: large weight, short battery life.
With the same volume, the capacity is relatively high. Take the common No. 5 battery as an example, the nominal capacity of nickel metal hydride battery can reach 2900mAh (milliampere hour), while that of nickel cadmium battery is only 1100mAh (milliampere hour). NiMH battery has higher output current than carbon zinc battery or alkaline battery, and is more suitable for high power consumption products.
Long cycle life, it can be recycled for more than 500 times under correct conditions. Poor high temperature resistance, try not to make the temperature of the battery higher than 45 ℃. Otherwise, the service life will decrease quickly and the internal resistance of the battery will increase. Overcharging has a great impact on the battery life and is dangerous. Therefore, when the battery is fully charged, it is necessary to stop charging.
The working voltage of NiMH and NiCd batteries is 1.2V, but the volume specific energy of NiMH is higher than that of NiCd batteries. Due to the excellent large rate discharge performance of nickel cadmium battery, nickel hydrogen battery can not replace nickel cadmium battery in many electric tools. Therefore, nickel cadmium battery is temporarily allowed to be used in the field of electric tools in ROSH standard.
2. Advantages and disadvantages of lithium battery
Advantages: no memory effect, light weight.
Disadvantages: high cost, small current, and not resistant to overcharge (compared with nickel hydrogen).
The lithium battery has a primary lithium battery (not rechargeable) and a secondary lithium battery (rechargeable). The secondary lithium battery is divided into Li ion battery and Li Polymer lithium polymer battery.
Compared with Ni MH battery, it is light in weight, but its volume energy density ratio is 48% higher. Because of this, the production and sales volume of lithium ion secondary batteries are gradually surpassing that of nickel metal hydride batteries. The battery has small self discharge, no memory effect and can be charged and discharged more than 600 times.
Lithium batteries are not resistant to overcharge. If they are used carelessly, they may explode. Therefore, a control IC needs to be built in to prevent overcharge. However, the cost is much higher. Since the specifications of lithium batteries are not unified, there will be cases where batteries cannot be purchased after the model is discontinued. However, many improvements have been made.