Lithium Batteries Explained: A 30-Minute Guide for Europe

Lithium batteries are now part of everyday life across Europe. They power smartphones, laptops, e-bikes, electric vehicles, campervans, marine electronics, home storage systems, solar battery banks, power tools, medical devices, and portable energy stations. As solar energy, off-grid living, electric mobility, and energy storage become more common, understanding lithium batteries is no longer just for engineers.

This guide is designed to help you build a practical knowledge framework in about 30 minutes. It explains the main battery families, key technical terms, lithium battery classifications, voltage and capacity basics, safety risks, and real-world applications. Whether you are choosing a LiFePO4 battery for a motorhome, comparing lithium storage for a balcony solar system, or simply trying to understand battery specifications, this article will help you speak the language of batteries with more confidence.

1. The Battery Family

Primary Batteries: Non-Rechargeable Cells

Primary batteries are designed for single-use applications. Once their stored chemical energy is depleted, they are normally recycled or disposed of through the correct battery collection channel. In Europe, these batteries are commonly found in remote controls, wall clocks, toys, sensors, and low-power household devices.

• Zinc-carbon batteries: These are basic dry cells used in low-drain devices. They are inexpensive, but their capacity and energy density are limited compared with modern alternatives.

• Alkaline batteries: Alkaline cells are more common than zinc-carbon batteries in many European homes. They offer better capacity and shelf life, making them suitable for everyday electronics.

• Primary lithium batteries: These are not the same as rechargeable lithium-ion batteries. They are often used where long shelf life, low weight, or strong cold-weather performance is required, such as sensors, cameras, and specialist equipment.

Secondary Batteries: Rechargeable Batteries

Secondary batteries can be charged and discharged many times. They are used wherever stored energy needs to be reused, from vehicle starter batteries to solar storage systems and electric mobility.

• Lead-acid batteries: Lead-acid batteries are one of the oldest rechargeable battery technologies. They are widely used for engine starting, backup power, golf carts, mobility scooters, and some off-grid systems. Their advantages are low upfront cost and mature recycling systems, but they are heavy and have lower energy density.

• Nickel-cadmium batteries: NiCd batteries were once common in older portable electronics and industrial tools. They are now far less common due to toxic cadmium content, memory effect, and environmental concerns.

• Nickel-metal hydride batteries: NiMH batteries are cleaner than NiCd batteries and are used in rechargeable AA/AAA cells, some hybrid vehicles, and certain medical or industrial devices. They are durable but do not match lithium-ion energy density.

• Lithium-ion batteries: Lithium-ion batteries are now the leading rechargeable technology for portable electronics, electric vehicles, e-bikes, home storage, marine systems, and modern solar battery banks. They offer high energy density, high efficiency, and long service life when properly managed.

Emerging and Large-Scale Battery Technologies

Beyond the everyday battery types, several advanced technologies are being developed or deployed for grid storage, renewable energy balancing, and industrial applications.

• Flow batteries: Flow batteries store energy in liquid electrolytes held in external tanks. They are promising for large stationary storage because capacity can be increased by using larger tanks. However, they are not normally used in mobile or compact battery applications.

• Sodium-based batteries: Sodium-ion and sodium-sulfur batteries are being studied and deployed in selected applications. Sodium is more abundant than lithium, which may help future supply chains.

• Solid-state batteries: Solid-state batteries replace liquid electrolytes with solid materials. They may improve safety and energy density in the future, but large-scale commercialisation is still developing.

The word “lithium battery” can be confusing. Historically, it could refer to lithium metal primary batteries. Today, in most consumer, solar, EV, and energy storage discussions, “lithium battery” usually means a rechargeable lithium-ion battery. Within that category, LiFePO4, NMC, NCA, LCO, and other chemistries each have different strengths.

Comparison of Major Energy Storage Battery Types

Battery Type	Typical Energy Density	Cycle Life	Efficiency	Safety Profile	Main Advantages	Main Limitations
Lithium-ion	High	High, depending on chemistry and use	High	Good with proper BMS protection	Lightweight, efficient, high usable capacity, long life	Higher upfront cost, requires proper charging and protection
Lead-acid	Low to moderate	Lower than lithium under deep cycling	Moderate	Mature technology, but acid and gas risks exist	Low initial cost, widely available, recyclable	Heavy, limited depth of discharge, regular maintenance for flooded types
Flow battery	Low to moderate	Potentially long	Moderate	Generally suitable for stationary systems	Scalable for large storage, long-duration potential	Large footprint, not suitable for compact mobile use
Sodium-based battery	Moderate, depending on design	Application-dependent	Moderate to high	Depends on chemistry and system design	Uses abundant materials, promising for future storage	Less mature than lithium-ion in many consumer applications

2. Battery Terminology Explained

To understand lithium batteries properly, you need to know a few common terms. These terms appear in battery manuals, solar charge controller settings, electric vehicle discussions, and battery management system data.

SOX: State of X

SOX is a general term that refers to different “states” of a battery. The letter X can represent charge, health, power, energy, or capacity. It is similar to describing a vehicle by fuel level, engine health, output power, and remaining range.

• SOC: State of Charge

• SOH: State of Health

• SOP: State of Power

• SOE: State of Energy

• SOCap: State of Capacity, sometimes used in technical contexts

SOC: State of Charge

State of Charge describes how full the battery is. A fully charged battery may be described as 100% SOC, while a completely discharged battery may be described as 0% SOC. In practical use, lithium batteries should usually operate within the limits recommended by the manufacturer and the battery management system.

For example, if a 100Ah battery has 60Ah available, its SOC is approximately 60%.

DOD: Depth of Discharge

Depth of Discharge describes how much of the battery has been used. If a battery is fully charged, its DOD is 0%. If half of its usable capacity has been discharged, its DOD is 50%.

The relationship is simple:

SOC + DOD = 100%

For example, if a battery is at 70% SOC, it has been discharged by about 30%, so its DOD is 30%.

SOH: State of Health

State of Health describes how much usable capacity or performance remains compared with the battery’s original condition. As a battery ages, its capacity gradually decreases and its internal resistance may increase.

A common capacity-based formula is:

SOH = Current Capacity ÷ Rated Capacity × 100%

For example, if a battery was originally rated at 100Ah but now only delivers 85Ah under standard test conditions, its SOH is approximately 85%.

Internal Resistance

Internal resistance is the resistance inside the battery. As internal resistance rises, the battery produces more heat under load, voltage sag becomes more noticeable, and usable performance declines. This is why an old battery may still show reasonable voltage when resting but perform poorly when powering an inverter, e-bike motor, or trolling motor.

C-Rate

C-rate describes how quickly a battery is charged or discharged relative to its capacity. For a 100Ah battery, a 1C discharge rate equals 100A. A 0.5C rate equals 50A. Understanding C-rate helps determine whether a battery can safely support a specific load or charger.

3. Lithium Battery Classification

Lithium batteries can be classified in several ways: by use, shape, electrolyte, cathode material, and anode material. These classifications matter because a battery designed for a smartphone is very different from one designed for a motorhome, electric vehicle, solar battery bank, or marine system.

By Application: Power Type vs Energy Type

• Power batteries: These are designed to deliver high current quickly. They are used in electric vehicles, e-bikes, power tools, drones, and applications requiring strong acceleration or high discharge power.

• Energy batteries: These are designed for longer-duration storage. They are common in solar storage, home battery systems, campervan power systems, marine house banks, and off-grid applications.

By Physical Form

• Cylindrical cells: These cells look like small metal cylinders. They are common in power tools, older laptop packs, e-bikes, and some electric vehicles.

• Prismatic cells: These rectangular cells are usually housed in aluminium or steel cases. They are widely used in LiFePO4 batteries for RV, marine, solar, and energy storage systems.

• Pouch cells: These cells use flexible laminated packaging. They can achieve high packing efficiency and are often used in phones, tablets, drones, and some EV battery packs.

By Electrolyte Type

• Liquid lithium-ion batteries: These use liquid electrolyte and are common in many traditional lithium-ion applications.

• Polymer lithium-ion batteries: These use gel-like or polymer-based electrolyte systems. They are often associated with thin, lightweight pouch-style cells.

• Solid-state batteries: These use solid electrolytes. They are considered a future direction for improved safety and energy density, though widespread adoption is still developing.

By Cathode Material

• Lithium Iron Phosphate (LiFePO4 or LFP): Known for strong thermal stability, long cycle life, and high safety. It is widely used in solar storage, motorhomes, marine batteries, and off-grid systems.

• Lithium Cobalt Oxide (LCO): Common in smartphones and small electronics because of its high energy density, but it is less suitable for heavy cycling and high-power storage.

• Lithium Manganese Oxide (LMO): Offers good power capability and improved stability compared with some earlier lithium chemistries.

• NMC: Lithium nickel manganese cobalt oxide is widely used in EVs and energy storage where a balance of energy density, power, and cost is required.

• NCA: Lithium nickel cobalt aluminium oxide offers high energy density and is used in some electric vehicle applications.

By Anode Material

• Graphite: The most common anode material in lithium-ion batteries.

• Lithium titanate: Known for very fast charging and long cycle life, but with lower energy density.

• Silicon-enhanced anodes: These are being developed to increase capacity, although expansion during cycling must be managed.

• Graphene-related materials: Graphene may improve conductivity and performance, but commercial use depends on design and cost.

18650 Battery

The 18650 battery is one of the best-known cylindrical lithium-ion cell formats. The name describes its approximate dimensions: 18mm in diameter and 65mm in length. The final “0” indicates a cylindrical form.

18650 cells became widely used because they were standardised, mature, and relatively easy to manufacture at scale. They appeared in laptop battery packs, power tools, e-bikes, portable equipment, and some early electric vehicle battery systems.

Common 18650 lithium-ion cells often have a nominal voltage around 3.6V to 3.7V, while LiFePO4 cylindrical cells typically have a nominal voltage around 3.2V. Capacity depends on the chemistry, manufacturer, and cell design.

Advantages of 18650 Cells

• Standard format: The size is widely recognised, making pack design and replacement easier.

• Mature manufacturing: Production quality has improved significantly over time.

• Good consistency: Quality cells can be grouped into battery packs with predictable performance.

• Mechanical strength: Steel-cased cylindrical cells provide better impact resistance than some pouch-style cells.

However, 18650 cells are not the only option. Larger cylindrical formats, prismatic cells, and pouch cells may be better suited for certain applications. For example, many modern LiFePO4 solar and leisure batteries use prismatic cells because they are easier to package into large-capacity battery packs.

Lithium Iron Phosphate Battery (LiFePO4 or LFP)

LiFePO4 batteries use lithium iron phosphate as the cathode material. They are especially valued for safety, long cycle life, stable discharge voltage, and strong thermal stability. In Europe, LiFePO4 is widely used in motorhome leisure batteries, marine house batteries, off-grid solar systems, home storage, and portable power systems.

LiFePO4 cells usually have a nominal voltage of about 3.2V. Four cells connected in series create a 12.8V nominal battery, which is commonly marketed as a 12V lithium battery. This makes LiFePO4 a practical replacement for many lead-acid systems, provided the charger, BMS, and system design are compatible.

• Long cycle life: LiFePO4 batteries can often handle thousands of cycles when used correctly.

• High safety: LFP chemistry is more thermally stable than many high-energy lithium chemistries.

• Good usable capacity: More of the rated capacity can be used compared with typical lead-acid batteries.

• No routine maintenance: No watering, acid checks, or equalisation charging is required.

• Suitable for solar: Efficient charging and deep cycling make LFP ideal for renewable energy storage.

4. Lithium-Ion Battery Voltage and Capacity

Battery voltage is not fixed throughout discharge. It changes depending on chemistry, state of charge, discharge current, temperature, and cell design. This is why the same battery may show different voltages under load, at rest, in summer, or during winter use.

The discharge curve above shows how voltage changes as capacity is used. A typical lithium-ion cell may start near 4.2V when fully charged, then gradually decline through its working range before dropping more sharply near the end of discharge. The average working voltage is often used as the nominal voltage.

For many lithium-ion cells, nominal voltage is around 3.6V to 3.7V. For LiFePO4 cells, nominal voltage is around 3.2V. This difference is important when designing battery packs, choosing chargers, or comparing battery energy.

Battery Type	Typical Charge Cut-Off Voltage	Nominal Voltage	Typical Discharge Cut-Off Voltage
Common Lithium-Ion Cell	4.2V	3.6V-3.7V	About 2.7V-3.0V, depending on design
LiFePO4 Cell	3.6V-3.65V	3.2V	About 2.0V-2.5V, depending on BMS and manufacturer limits

Battery Capacity: Rated Capacity and Actual Capacity

Battery capacity is usually measured in amp-hours (Ah) or milliamp-hours (mAh). Small cells, such as phone or 18650 cells, often use mAh. Larger batteries for solar, motorhomes, boats, and energy storage usually use Ah.

1. Rated capacity: The capacity stated by the manufacturer under specific test conditions.

2. Actual capacity: The capacity the battery can deliver in real use, affected by temperature, current, age, and state of health.

For example, a 1300mAh cell could theoretically provide 130mA for 10 hours:

1300mAh ÷ 130mA = 10 hours

In real applications, the result may differ because loads are not always constant and battery voltage changes during discharge.

Battery Capacity Formula

The basic charge capacity formula is:

Q = I × t

Where:

• Q is electric charge capacity

• I is current

• t is time

Battery Energy Calculation Method

Capacity alone does not tell the full story because voltage also matters. Energy is usually measured in watt-hours (Wh):

W = U × I × t

This can also be written as:

Energy (Wh) = Voltage (V) × Capacity (Ah)

For example, a 12.8V 100Ah LiFePO4 battery stores approximately:

12.8V × 100Ah = 1280Wh

This is why two batteries with the same Ah rating may store different amounts of energy if their voltages are different.

Series and Parallel Connections

Battery packs are built by connecting cells in series and parallel. This is essential for understanding laptop batteries, e-bike batteries, solar batteries, and EV battery packs.

• Parallel connection: Voltage stays the same, but capacity increases.

• Series connection: Voltage increases, but capacity stays the same.

For example, if two 3.7V 3000mAh cells are connected in parallel, the pack remains 3.7V but becomes 6000mAh. If the same two cells are connected in series, the pack becomes 7.4V but remains 3000mAh.

This is why energy in watt-hours is often more useful than capacity in amp-hours when comparing battery packs. A laptop battery, e-bike battery, or solar battery bank may use multiple cells in series and parallel, so voltage and capacity must both be considered.

A laptop battery label may show both capacity and energy, such as mAh and Wh. This is because the pack contains multiple cells, not one single cell. To compare real runtime, Wh is usually more meaningful than mAh.

5. Why Choose Lithium-Ion Batteries?

High Energy Density and Lower Weight

Lithium-ion batteries store more energy per kilogram than lead-acid or nickel-based batteries. This is one of the main reasons they are used in electric vehicles, campervans, e-bikes, marine power systems, and portable devices.

For European motorhome and boat users, weight matters. A LiFePO4 leisure battery can often provide more usable energy while weighing much less than a comparable lead-acid battery bank. This helps with payload limits, fuel efficiency, handling, and available storage space.

Fast and Efficient Charging

Lithium batteries generally charge more efficiently than lead-acid batteries. They can accept higher charging currents when paired with a suitable charger or solar controller. This makes them ideal for solar systems, where limited sunlight hours need to be used effectively.

For European users with rooftop solar on a campervan, balcony PV storage, or an off-grid cabin, charging efficiency can make a noticeable difference, especially in winter or cloudy regions.

No Memory Effect

Older nickel-based batteries could suffer from memory effect, where repeated shallow cycling reduced usable capacity. Lithium-ion batteries do not have the same issue. They do not need full discharge cycles for normal use and generally prefer controlled cycling within safe voltage limits.

Higher Usable Capacity

Lead-acid batteries are often limited to about 50% depth of discharge if long service life is desired. LiFePO4 batteries can usually provide much deeper usable capacity while maintaining long cycle life. This means a 100Ah LiFePO4 battery can often deliver significantly more practical energy than a 100Ah lead-acid battery.

Lower Maintenance

Lithium batteries do not require watering, equalisation charging, or acid checks. This makes them especially attractive for motorhomes, boats, cabins, backup systems, and hard-to-access installations.

Better Fit for Renewable Energy

Lithium batteries are well suited to renewable energy systems because they charge efficiently, cycle deeply, and maintain stable voltage. In Europe, they are widely used in solar storage, home energy systems, mobile power, and off-grid installations.

6. Safety Issues with Lithium Batteries

Lithium batteries offer many advantages, but safety must be taken seriously. A quality lithium battery needs proper cell design, correct charging, suitable installation, and an effective battery management system. Poor-quality cells, incorrect chargers, mechanical damage, overheating, and electrical abuse can create serious risks.

Thermal Runaway

Thermal runaway is one of the most important lithium battery safety concepts. It occurs when heat generation inside a battery becomes faster than heat dissipation. As temperature rises, internal reactions can accelerate, creating even more heat. This positive feedback loop can lead to swelling, venting, fire, or explosion in severe cases.

Thermal runaway can be triggered by three broad types of abuse:

• Mechanical abuse: Crushing, puncturing, dropping, collision damage, or severe vibration.

• Electrical abuse: Overcharging, over-discharging, short circuits, incorrect wiring, or using the wrong charger.

• Thermal abuse: Exposure to excessive heat, poor ventilation, or charging outside the allowed temperature range.

These triggers can be connected. For example, mechanical damage can cause an internal short circuit, which creates electrical abuse. That electrical abuse generates heat, which can then become thermal abuse. If the heat continues to build, thermal runaway may occur.

How Thermal Runaway Develops

1. Initial heating: Internal temperature rises due to overcharge, short circuit, external heat, or physical damage.

2. Protective layer breakdown: The SEI layer on the anode may begin to decompose at high temperature, producing more heat.

3. Electrolyte and electrode reactions: Internal materials react more aggressively as temperature rises.

4. Gas generation: The cell may swell or vent as gases build inside.

5. Fire or explosion risk: If heat and pressure are not controlled, ignition or rupture may occur.

Overcharging and Lithium Dendrites

Overcharging can cause lithium metal to deposit on the anode in branch-like structures called dendrites. If dendrites grow far enough, they can puncture the separator between the anode and cathode, creating an internal short circuit.

This is one reason proper charging control is essential. Lithium batteries should be charged with compatible chargers and protected by a BMS. Overcharging is not only bad for lifespan; it can also become a safety issue.

Battery Ageing

All rechargeable batteries age. In lithium-ion batteries, ageing usually appears as reduced capacity, increased internal resistance, more heat under load, and shorter runtime. Internal causes include loss of active lithium, electrode degradation, electrolyte ageing, and growth of internal resistance.

Aged batteries may also become less tolerant of overcharge, high current, and extreme temperatures. This is why old or damaged lithium batteries should not be pushed beyond their rated limits.

Battery Management System: The Practical Safety Solution

A battery management system, or BMS, is one of the most important safety features in a lithium battery pack. It monitors and controls the battery to help prevent unsafe operating conditions.

A good BMS may provide protection against:

• Overcharge: Prevents cell voltage from rising too high.

• Over-discharge: Stops the battery from being drained too deeply.

• Over-current: Protects against loads that exceed the battery’s rating.

• Short circuits: Helps shut down dangerous fault conditions.

• High temperature: Prevents use when the battery becomes too hot.

• Low-temperature charging: Blocks charging below the safe temperature range, especially important for LiFePO4 in winter.

• Cell balancing: Keeps cells in a battery pack operating evenly.

For European solar, motorhome, marine, and off-grid users, a BMS is not optional. It is a core part of safe lithium battery operation.

Safety Tips for European Users

• Use the correct charger: Match the charger profile to the battery chemistry.

• Do not charge frozen LiFePO4 batteries: Standard LiFePO4 batteries should not be charged below 0°C unless they include low-temperature protection or heating.

• Install proper fuses and breakers: DC battery systems can deliver very high current.

• Protect batteries from impact: Avoid crushing, puncturing, dropping, or poorly securing battery packs.

• Keep batteries away from excessive heat: Do not install them near heaters, exhausts, or direct high-temperature zones.

• Recycle responsibly: Used lithium batteries should be returned through approved battery recycling or collection channels.

7. Applications of Lithium Batteries

Lithium batteries are used across many industries because they combine high energy density, efficient charging, long cycle life, and flexible packaging. In Europe, they are especially important for electric mobility, renewable energy storage, portable electronics, and low-carbon energy systems.

Electric Vehicles and E-Mobility

Electric vehicles are one of the largest applications for lithium batteries. Lithium-ion battery packs provide the energy density and power required for long driving range, acceleration, regenerative braking, and fast charging. E-bikes, scooters, and light electric vehicles also rely heavily on lithium battery technology.

Renewable Energy Storage

Solar and wind energy are variable. Lithium batteries help store excess energy when generation is high and release it when demand increases or production drops. This is why lithium batteries are used in home storage systems, balcony solar storage, off-grid homes, farm energy systems, and backup power applications.

Motorhomes, Campervans, and Caravans

LiFePO4 batteries are increasingly popular in European leisure vehicles. They provide more usable capacity, lower weight, faster charging, and better cycle life than traditional lead-acid leisure batteries. They are ideal for users running compressor fridges, diesel heater controls, lights, water pumps, inverters, laptops, and solar charging systems.

Marine and Boating

Boat owners use lithium batteries for trolling motors, house banks, navigation equipment, lighting, communication systems, and electric propulsion. Their low weight and stable voltage are useful on sailing boats, fishing boats, narrowboats, and coastal leisure craft.

Consumer Electronics

Smartphones, laptops, tablets, cameras, headphones, and power banks rely on lithium batteries because they need compact, lightweight energy storage. High energy density is essential for modern portable electronics.

Medical Devices

Portable medical equipment, diagnostic devices, hearing aids, mobility aids, and certain implantable devices use lithium batteries because reliability and long runtime are important.

Aerospace, Industrial, and Professional Equipment

Lithium batteries are also used in drones, satellites, robotics, industrial sensors, emergency power packs, and professional tools. In these applications, energy-to-weight ratio and reliability are often critical.

8. Advancements in Lithium Battery Technology

Solid-State Batteries

Solid-state batteries are one of the most discussed future technologies. By replacing liquid electrolyte with solid material, they may improve safety and energy density. If commercial production becomes cost-effective, solid-state batteries could influence electric vehicles, consumer electronics, and high-performance storage systems.

Lithium-Sulfur Batteries

Lithium-sulfur batteries have the potential for higher energy density than conventional lithium-ion batteries. However, challenges such as cycle life and material stability still need to be solved before they become mainstream.

Improved Recycling Technologies

As lithium battery use grows, recycling becomes more important. Better recycling helps recover valuable materials, reduce environmental impact, and support a more circular battery economy in Europe. Recycling technology continues to improve, especially for lithium, nickel, cobalt, copper, aluminium, and other battery materials.

Better Anode Materials

Silicon-enhanced anodes are being developed to increase energy storage capacity. Silicon can store more lithium than graphite, but it expands during charging. Battery engineers are working on ways to manage this expansion while maintaining cycle life.

Smarter Battery Management

Battery management systems are becoming more advanced. Modern BMS designs can support Bluetooth monitoring, CAN communication, temperature control, active balancing, fault recording, and system integration with inverters and solar controllers.

9. Future Prospects for Lithium Batteries

Greater Use in Grid and Home Storage

As renewable energy adoption increases, lithium batteries are expected to play a larger role in grid balancing, residential energy storage, and commercial backup systems. They help store solar energy during the day and release it during evening demand peaks.

Improved Safety Design

Future lithium batteries will continue to improve through safer cell chemistry, stronger separators, better thermal design, smarter BMS protection, and more robust installation standards.

More Sustainable Supply Chains

Battery supply chains are under pressure to become more transparent, responsible, and sustainable. Europe is placing increasing emphasis on battery recycling, responsible sourcing, traceability, and lower environmental impact.

More Specialised Batteries

There will not be one battery chemistry for every use. High-energy cells may dominate long-range EVs, while LiFePO4 may remain preferred for solar storage, motorhomes, marine systems, and long-cycle applications. Sodium-ion, solid-state, and other chemistries may fill additional niches.

Conclusion: Becoming a Semi-Expert in Lithium Batteries

After understanding the battery family, core terms, lithium classifications, voltage, capacity, safety, and applications, you already have a strong foundation for evaluating battery products. You now know why LiFePO4 batteries are widely used in solar storage, why watt-hours are often more useful than amp-hours, why a BMS is essential, and why battery chemistry matters for safety and performance.

For European users, lithium batteries are especially relevant in motorhomes, campervans, boats, home energy storage, balcony solar systems, off-grid cabins, and electric mobility. The best choice depends on the application, required energy, charge method, temperature conditions, available space, and safety requirements.

If you remember only a few key points, remember these: capacity tells you how much charge a battery can deliver, watt-hours tell you how much energy it stores, chemistry determines performance and safety, and the BMS protects the battery from dangerous operating conditions. With these basics, you are no longer a beginner—you are well on your way to becoming a semi-expert in lithium batteries.