1. What are the main components of a Nickel-Metal Hydride (NiMH) battery?
The main components of a Nickel-Metal Hydride (NiMH) battery are:
Positive Electrode (Cathode): Typically made of nickel hydroxide (Ni(OH)₂) as the active material.Negative Electrode (Anode): Typically made of a hydrogen-absorbing alloy (such as a lanthanum-nickel alloy, LaNi₅) which can absorb and release hydrogen ions.
Electrolyte: Usually a potassium hydroxide (KOH) or sodium hydroxide (NaOH) aqueous solution that facilitates ionic conduction.
Separator: A microporous plastic film, often made of polypropylene or polyester, which separates the positive and negative electrodes to prevent short-circuiting while allowing ionic flow.
Battery Case: Typically made of metal or plastic, it provides structural support and protection for the internal components.
Connectors: Including electrode terminals and welding connections, used for electrical connections and assembling the battery pack.
These components work together to store and release energy through electrochemical reactions, providing electrical power to devices.
The main components of a Lithium-Ion battery are:
Battery Covers (Top and Bottom): Protect the internal structure and provide connection interfaces.Positive Electrode (Cathode): Typically made of lithium cobalt oxide (LiCoO₂) or other compounds like lithium iron phosphate (LiFePO₄) or lithium manganese oxide (LiMn₂O₄).
Separator: A special composite membrane that prevents direct contact between the positive and negative electrodes while allowing lithium ions to pass through.
Negative Electrode (Anode): Typically made of carbon, such as graphite, as the active material.
Organic Electrolyte: A solution that facilitates the movement of lithium ions between the electrodes, usually composed of a lithium salt dissolved in an organic solvent.
Battery Case: Available in steel or aluminum, it provides structural support and protection.
3. What is battery internal resistance?
Battery internal resistance refers to the resistance encountered by the current as it flows through the battery. It consists of two main parts:
Ohmic Resistance: The resistance of the battery's internal materials (electrodes, electrolyte, separator, etc.).Polarization Resistance: The resistance due to electrochemical reactions, including both charge transfer resistance and mass transport (concentration) resistance.
High internal resistance leads to a reduction in discharge voltage and shortened discharge time. The internal resistance is influenced by the battery materials, manufacturing processes, and battery structure. It is an important parameter for evaluating battery performance. Internal resistance is typically measured using specialized instruments, not with a multimeter's ohm setting.
4. What is nominal voltage?
Nominal voltage is the voltage value assigned to a battery or electronic device by the manufacturer, based on its design and expected performance. It represents the typical operating voltage, although the actual voltage can vary within a certain range during use.
5. What is open-circuit voltage?
Open-circuit voltage (OCV) is the voltage measured across the terminals of a battery when it is not connected to any load (i.e., no current is flowing). It reflects the electrochemical potential of the battery and can be used to assess the state of charge and overall health of the battery.
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