Gel Battery Lifespan Vs Lithium Battery: Showdown
Gel Battery Lifespan Vs Lithium Battery: Showdown
Gel Battery Lifespan Vs Lithium Battery: Showdown
Choosing between gel and lithium batteries for your energy storage needs can feel like a complex puzzle. Did you know that lithium batteries generally offer a longer cycle life than their gel counterparts? This article breaks down the performance battle between these two battery technologies, providing clear insights into the lifespan, efficiency, maintenance, safety, and cost.
Keep reading to discover which battery type will supercharge your projects.
Key Takeaways
- Gel batteries are spill-proof and good for tilting or bouncy environments, but they're sensitive to heat and have shorter cycle lives.
- Lithium batteries provide more power, handle high temperatures well, and last longer with a lifespan of 8-12 years compared to gel's 3-5 years.
- Lithium options have faster charge rates and can discharge at higher rates without affecting their lifespan as much as gel batteries.
- Safety is a key issue; lithium requires careful management to avoid risks like thermal runaway, while damaged gel batteries can leak harmful lead-acid substances.
- When looking at environmental impact, lithium batteries are less wasteful over time due to their long life and energy efficiency.
What are Gel Batteries?
Gel batteries feature a unique gel electrolyte, formulated by combining silica with sulfuric acid, resulting in a thick, putty-like substance that remains stationary. This gel composition not only makes the batteries spill-proof and highly stable but also contributes to their robust design, allowing for consistent power delivery and reduced corrosion inside the battery. The solidified electrolyte minimises the risk of leakage, making these batteries ideal for applications where leaks are unacceptable or in environments subject to frequent movement or vibration.
Now that we've explored the basics of gel batteries, let's dive into their high-energy counterparts.
What are Lithium Batteries?
Lithium batteries are a category of rechargeable batteries that utilise lithium ions moving from the negative electrode to the positive electrode during discharge and back when charging. They are known for their high energy density, allowing them to store a significant amount of energy in a relatively small and lightweight package. A notable variant, lithium iron phosphate batteries, exemplifies this by offering rapid charging capabilities and enduring numerous charge/discharge cycles with minimal degradation. This makes lithium batteries particularly efficient and durable for a wide range of applications.
Understanding lithium batteries sets the stage for a deeper comparison of their material makeup and environmental impact.
In-Depth Material and Environmental Analysis of Gel and Lithium Batteries
When choosing a battery, it's important to consider what it's made of and the environmental impact it may have. This analysis looks closely at gel and lithium batteries, focusing on their materials and how these affect the environment.
Material Composition Analysis
Gel Batteries:
- Part of the lead-acid battery family, gel batteries have a silica gel electrolyte that helps keep them stable over time.
- They're not as energy-dense as lithium batteries but are built to last and can be recycled, which is a plus for the environment.
Lithium Batteries:
- These batteries are known for packing a lot of energy into a small, light package thanks to the lithium ions that move between electrodes.
- The type of material used for the cathode, like lithium iron phosphate or lithium cobalt oxide, can change how long the battery lasts and how well it works.
Environmental Implications
Gel Batteries:
- Making gel batteries involves lead, which can be harmful if not handled properly, especially during mining and processing.
- They can be recycled effectively, which helps reduce their environmental impact, but the production of lead is energy-intensive and can lead to pollution.
Lithium Batteries:
- Mining for lithium can use a lot of water and affect local wildlife and plants.
- These batteries need a lot of energy to make, which adds to their carbon footprint, but new ways to recycle them are being developed to lessen their environmental impact.
Lifecycle Analysis
Looking at the full life of gel and lithium batteries—from getting the raw materials to throwing them away—shows different environmental costs. Gel batteries have the issue of lead use and recycling, while lithium batteries deal with the effects of mining lithium and the energy used to make them. Recycling is becoming more important for both types. Knowing about these materials and environmental factors can help you choose a battery that meets your energy needs and fits with your environmental goals. Both gel and lithium batteries have their place in moving towards more sustainable energy storage.
With the environmental and material aspects in mind, let's examine the factors that influence the lifespan of these batteries.
What Factors Affect Battery Lifespan?
When it comes to powering our world, from the smallest gadgets to the largest electric vehicles, the choice of battery plays a pivotal role in both performance and longevity. Among the myriad of options, gel and lithium batteries stand out for their unique properties and applications. However, the lifespan of these batteries can vary significantly, influenced by several key factors. As we delve into the intricacies of battery technology, understanding how these factors impact the durability of gel versus lithium batteries is crucial for making informed decisions. Whether for personal use or large-scale applications, knowing what affects battery lifespan can help optimize efficiency and sustainability. Let's explore the essential factors that determine how long gel and lithium batteries last, shedding light on this critical aspect of modern energy solutions.
1. Temperature
Heat plays a big role in battery life. Gel and lithium batteries both react to temperature changes. In cold weather, both types might lose power and perform less well. Temperature significantly influences the longevity of gel batteries; they thrive at moderate temperatures but suffer under heat. Kept unused and charged, a 12-volt Gel or AGM battery can last up to six years, maintaining 80% capacity at an ideal 25°C. Yet, life expectancy drops as temperatures rise, halving for every 15°F increase above 77°F. Despite this, gel batteries outperform traditional lead-acid counterparts in extreme temperature conditions, showcasing their resilience and making them a reliable choice for diverse environments.
Different types of lithium batteries like LiFePO4 can handle high temperatures better than gel ones, but temperature impacts both the efficiency and safety of lithium-ion batteries. They perform best when stored near 15°C, operating optimally between 5°C and 20°C. Below freezing, their capacity drops as chemical reactions slow. Conversely, high temperatures can raise internal heat, reducing performance and risking thermal runaway. The degradation of lithium-ion batteries accelerates with heat. Research in Scientific Reports titled 'Effect of Temperature on the Aging rate of Li Ion Battery Operating above Room Temperature' highlights that high temperatures significantly speed up the loss of maximum charge capacity during use (1).
Remember that extreme temperatures can still shorten the lifespan of any battery type, so always keep them away from very hot or cold places.
Heat management is key for long-lasting performance in batteries used every day.
2. Depth of Discharge
Gel batteries need careful usage; they should only go down to a 50% depth of discharge. This means you can't use all the power they store and if you do, they may not last as long and could get damaged. The lifespan of gel batteries is greatly affected by their depth of discharge (DoD). On average, these batteries can endure for around 10 years, with the exact length heavily dependent on the DoD.
On the other hand, lithium batteries are much tougher. They handle deep discharges well, even up to 80% or more. This gives them a higher usable capacity.
Lithium batteries, such as LiFePO4 (Lithium Iron Phosphate) variants, boast an impressive lifespan of up to 15 years, offering up to 5,000 charge cycles. The cycle life of these batteries is heavily influenced by their depth of discharge (DoD); a lower DoD leads to greater longevity in terms of capacity.
The number of times a battery can be charged and used is linked to how deeply it's discharged each time—this is cycle life. Since lithium batteries can deal with deeper discharges, they often have more cycles in their lifespan compared to gel batteries.
They usually outlast them too, which makes them a strong choice for heavy-duty uses.
In summary, to maximise the lifespan of gel and lithium batteries, it is advisable to maintain a shallower DoD, avoid extreme temperatures, and follow proper charging practices. These factors, when optimised, can significantly extend the operational life of the batteries.
3. Charge and Discharge Cycles
Charge and discharge cycles play a crucial role in the lifespan of a battery. They show how many times you can charge and use a battery before it starts losing power. Gel batteries, known for their stability, have fewer charge/discharge cycles compared to lithium batteries. This means you may have to replace them more often.
Lithium batteries outshine gel ones with longer lasting charge/discharge cycles. They can handle high currents well when charging or using energy. With this advantage, lithium-ion types fit better for systems needing frequent and heavy usage without quick wear-out. Their ability to recharge faster also helps in reducing downtime in professional settings where time is critical.
The table below shows some of the average charge/discharge cycles of the different battery types:
| Battery Type | Depth of Discharge (DoD) | Estimated Cycles |
|---|---|---|
| Gel Battery | 50% | Up to 1,000 |
| Lithium Battery (General) | 50% | 1,500 - 3,000 |
| LiFePO4 Battery | 80% | Up to 5,000 |
| 100% | 2,000 to 3,000 |
This table showcases the robustness of lithium battery variants, especially LiFePO4, in terms of cycle life compared to gel batteries. The cycle life significantly varies with the depth of discharge, illustrating that less intensive use (lower DoD) substantially extends the battery's usable life. Lithium batteries, particularly LiFePO4 types, demonstrate superior performance with a higher number of cycles across different DoDs, making them a more durable option for applications requiring long-term energy storage solutions. It's important to note that these figures are general estimates and actual cycle life can vary based on factors such as battery design, manufacturer, and operating conditions.
What are the Lifespan Comparisons Between Gel and Lithium Batteries?
When it comes to choosing the right battery for your needs, understanding how gel and lithium batteries stack up against one another in terms of longevity is crucial—delve deeper to discover which type might give you the edge in performance and durability.
1. Capacity and Weight
When comparing gel and lithium batteries, one of the most notable differences lies in their capacity and weight. Lithium batteries, with their higher energy density, offer more power for less physical bulk, making them a superior choice for applications where space and weight are critical.
| Battery Type | Energy Density (Wh/kg) | Weight | Typical Capacity (Ah) |
|---|---|---|---|
| Gel Battery | 30 - 50 | Heavier | Varies by size, generally lower |
| Lithium Battery | 100 - 265 | Lighter | Varies by size, generally higher |
Lithium batteries stand out for their higher energy density compared to gel batteries, making them ideal for uses where weight and efficiency matter most, like in electric vehicles and handheld devices. Though gel batteries pack less energy per unit of weight, they are valuable in scenarios where the weight of the battery isn't a deal-breaker, offering advantages like durability, no need for upkeep, and better performance across various temperatures.
2. Cycle Life
Understanding the cycle life of a battery is critical for users assessing the long-term value and operational efficiency of energy storage solutions. Cycle life refers to the number of complete charge and discharge cycles a battery can undergo before its capacity falls below 80% of its original capacity.
Here's a comparative look at the cycle lives of gel and lithium batteries in a tabular format:
| Battery Type | Estimated Cycle Life | Depth of Discharge | Lifespan |
|---|---|---|---|
| Gel Battery | Up to 1,000 cycles | Up to 50% | Around 3 years |
| Lithium Battery | 2000+ cycles | Up to 80% | Over 3 years depending on battery type |
The above table is an estimation. To provide a more specific answer regarding the lifespan in years, we would need to know the frequency of the cycles. It's important to note that actual cycle life and lifespan can vary based on factors such as usage patterns, maintenance, battery design, and operating conditions.
Gel batteries, with a cyclical endurance ranging between 500 to 1000, typically have a shorter operational life compared to their lithium counterparts. Lithium batteries can exceed 2000 cycles and maintain a higher depth of discharge, allowing for more extensive use and a significantly extended lifespan of up to 12 years depending on the battery chemistry. Such longevity positions lithium as a robust option for industries demanding high cycle counts and durability. It's important to note that both types of batteries will gradually lose capacity over time, but lithium batteries tend to maintain their capacity for a greater number of cycles than gel batteries.
3. Discharge Rate
In the arena of battery performance, the discharge rate stands as a pivotal factor distinguishing gel and lithium batteries. Here's a comparative glance at how each battery type handles discharge rates:
| Aspect | Gel Battery | Lithium Battery |
|---|---|---|
| Maximum Discharge Rate | Slower, typically around 0.05C | Faster, can exceed 1C, often up to 3C or higher |
| Discharge Efficiency | Good at low rates, but efficiency drops with increased rates | Retains high efficiency across a wide range of rates |
| Peukert's Effect | More susceptible, leading to reduced capacity at higher discharge rates | Less affected, thus better maintains capacity even at high discharge rates |
| Impact on Lifespan | High discharge rates can significantly shorten lifespan | Can handle high discharge rates with less impact on lifespan |
Gel batteries cater to applications with lower power demands due to their slower discharge capabilities. Conversely, lithium batteries excel in high-drain environments. Users benefit from lithium's robust discharge performance but must consider the trade-offs, including cost and application suitability. However, specific discharge rate figures for gel batteries and for lithium batteries should be verified with technical specifications from battery manufacturers, as these can vary based on the exact battery design and chemistry. A study titled 'Correlation Between Changes in Environmental Temperature and Performance of High-Discharge Lithium-Polymer Batteries' focussing on high-discharge lithium-polymer batteries (with the same chemical structure as lithium-ion) reveals that environmental temperature significantly impacts battery performance. Lower temperatures and higher discharge rates lead to decreased performance, while higher temperatures enhance battery efficiency. Heat generation increases with lower temperatures and higher discharge rates. The study establishes a relationship between heat generation, discharge rate, and temperature, crucial for designing effective thermal management systems. Understanding these dynamics is vital for optimising battery performance in varying environmental conditions (2).
4. Charge Rate
Gel batteries have a more cautious charging process. They should not endure high charge currents, which means they fill up slower than other types. Gel batteries need a slower charge to avoid overheating and damage. On the other hand, lithium-ion batteries embrace rapid recharging. They can charge more quickly and efficiently than gel batteries, thanks to their ability to accept higher charge currents. This feature is especially handy when you're short on charging time.
Users appreciate that lithium technology allows for quick turnaround times in applications requiring fast charge cycles. Gel battery setups require patience and time when replenishing energy levels. This difference is crucial in environments where downtime affects productivity or safety, making lithium batteries a go-to for efficiency seekers.
In essence, lithium-ion batteries can be powered up faster due to their higher charging capacity, whereas gel batteries demand a more cautious approach to charging, resulting in longer times to achieve a full charge to prevent overheating and potential harm. However, battery owners should take note that the actual charging capacity of lithium-ion batteries decreases when charged at high currents compared to low currents according to an article in the journal 'Batteries' titled 'Effects of Different Charging Currents and Temperatures on the Voltage Plateau Behavior of Li-Ion Batteries'. Charging at high currents results in a lower actual charging capacity due to increased energy loss generated as the active material reacts faster, leading to a decrease in capacity. At low temperatures, the charging capacity drops significantly due to factors like increased electrolyte viscosity and reduced ion conduction rate. This information can guide the design of charging protocols for lithium-ion batteries to optimise performance (3).
5. Temperature Performance
Choosing the right battery for your needs means understanding how they handle different temperatures. Gel and lithium batteries are popular choices, but they react differently to heat and cold, impacting how long they last.
Gel Batteries: Tough in All Weathers
Gel batteries are sturdy and great for outdoor use because they can handle both hot and cold weather well. Their special gel electrolyte keeps them safe from leaking and helps them perform consistently, even when temperatures drop or rise significantly. However, if gel batteries get too hot or too cold for too long, it can shorten their life.
Lithium Batteries: Power and Efficiency
Lithium batteries, especially the LiFePO4 type, are also good at dealing with temperature changes. They keep their power in cold weather better than many other batteries. But, high heat can be a problem for lithium batteries, potentially reducing their lifespan if they're not managed with care. A battery management system can help keep them running safely in extreme heat.
Considering Lifespan
Both gel and lithium batteries can last a long time, but how you use them and the temperatures they're exposed to can make a big difference. Gel batteries might need replacing more often in very hot climates. Lithium batteries generally last longer but facing high temperatures without proper management can also shorten their life.
The Bottom Line
Gel and lithium batteries each have their strengths when it comes to temperature. Gel batteries are reliable for places with big temperature swings, while lithium batteries offer more power and efficiency but need careful handling in the heat. When picking a battery, think about the temperatures it'll face to make sure you get the best performance and lifespan for your needs.
Having looked at lifespan, let's delve into the safety and environmental considerations that come with choosing between gel and lithium batteries.
What are the Safety and Environmental Impact Considerations for Gel and Lithium Batteries?
When it comes to choosing a battery, safety and environmental repercussions play a pivotal role; every technology has its trade-offs. Let's delve into how gel batteries stack up against lithium in terms of operational hazards and their ecological footprint—essential considerations for professionals committed to sustainable practices.
1. Safety
Gel batteries, while reliable, come with their own safety concerns. They contain lead-acid, which can be harmful to both the environment and human health if not handled correctly. If a gel battery breaks or leaks, it could release dangerous substances into the ground. Users must pay attention to how they maintain and service gel batteries. These tasks often need more frequent attention adding risk for accidents or injuries.
Lithium batteries pack more energy but also carry risks such as thermal runaway - this can lead to fires if they're damaged or improperly managed. Despite these dangers, lithium options tend to have robust systems in place to prevent overheating.
However, caution with lithium-ion batteries is still required. A study titled 'Understanding Adverse Effects of Temperature Shifts on Li-Ion Batteries: An Operando Acoustic Study' in the Journal of the Electrochemical Society, underscores the significant safety concerns surrounding lithium-ion batteries when exposed to extreme temperature fluctuations. It reveals that shifts from low to high temperatures can trigger catastrophic battery failures, emphasising the vital role of integrated temperature and current controls within battery management systems. This crucial insight highlights the necessity of monitoring and managing temperature variations to prevent safety hazards, thereby ensuring the durability and reliability of lithium-ion batteries in various operational environments (4).
2. Environmental Impact
Choosing the right battery isn't just about power; it's also about picking the option that's better for our planet. Let's dive into how gel and lithium batteries stack up environmentally.
Gel Batteries: Heavy but Steady
Gel batteries, a kind of lead-acid battery, are tough and work well in different temperatures. But, they have a downside: they're made with lead, which can harm the environment if these batteries break or aren't disposed of properly. They're also heavier, meaning they create more carbon emissions when shipped. Plus, they don't last as long as lithium batteries, leading to more waste over time.
Lithium Batteries: Light but Complicated
Lithium batteries pack a lot of power into a lighter package, making them great for tech that needs to be portable or for electric cars. However, making these batteries uses a lot of energy and involves mining for lithium, which can hurt the environment. Even though they last longer, most end up in landfills, which isn't great for the planet.
The Verdict
Both gel and lithium batteries have their pros and cons when it comes to the environment. Gel batteries might need replacing more often and need careful disposal because of the lead. Lithium batteries, while lasting longer and being more efficient, come with the cost of energy-intensive production and mining issues.When picking a battery, think about its whole life—from how it's made to how you'll get rid of it. This way, we can all make choices that are better for the Earth while still meeting our needs.
Safety and environmental impacts are crucial, but maintenance needs also play a big role in the practical use of these batteries.
Whar are the Maintenance Requirements of Gel and Lithium Batteries?
Maintenance is key for the longevity of any battery. Gel and lithium batteries differ in their upkeep needs.
- Gel batteries, also known as sealed lead-acid batteries, need to stay charged. If they go flat, they can get damaged.
- Check gel battery terminals regularly for corrosion. Clean them with a mix of baking soda and water if necessary.
- Avoid placing gel batteries in very hot or cold places. Extreme temperatures can reduce their lifespan.
- Lithium ion batteries can have a built-in Battery Management Systems (BMS). These systems protect the battery from common issues.
- You don't need to check lithium batteries for water levels. They are maintenance-free in this aspect.
- Keep lithium-ion batteries away from sharp objects and high pressure. Their cases can be punctured.
- Store both types of batteries in a dry, cool place when not in use to prevent capacity loss over time.
- Use a compatible charger for your battery type. Wrong chargers can shorten the battery's life.
Maintenance is key, but so is understanding the cost implications of your choice between gel and lithium batteries.
What are the Cost Comparisons of Gel and Lithium Batteries?
Gel batteries are often more budget-friendly upfront than their lithium counterparts. They appeal to those who want an economical option for energy storage. However, gel batteries may need replacing more often over time, which can increase costs. Below is a breakdown:
- Upfront Price:
- Gel batteries are usually less expensive when you first buy them. Lithium batteries can cost about 50% more right off the bat.
- How Long They Last and Replacement Costs:
- Gel batteries can go through 500-1,000 charge cycles. Lithium batteries can handle at least 2,000 cycles, meaning you won't need to replace them as often.
- Over time, the longer life of lithium batteries can make up for their higher starting price.
- Taking Care of Them:
- Gel batteries don't need much upkeep, which can save money.
- Lithium batteries also have low maintenance costs, thanks to needing fewer safety steps during use.
- Getting Your Money's Worth in Energy:
- Lithium batteries let you use more of the energy they store (95%) compared to gel batteries (80-85%), which can mean savings on energy bills.
- Cost for the Energy You Get:
- Even though lithium batteries cost more at first, the price for the energy you get from them is lower than gel batteries when you think about their full life.
- What's Happening in the Market:
- As more people want lithium batteries, their prices might go down because of better technology and making more of them.
In short, gel batteries might be cheaper to buy, but lithium batteries could end up being a better deal because they last longer, are more efficient, and have lower upkeep costs. Plus, lithium battery prices might drop as they become more popular.
Cost considerations bring us to the practical applications of these batteries in real-world scenarios.
What are Some Common Applications of Gel and Lithium Batteries?
Gel batteries often power wheelchairs, golf carts, and marine vessels. Their ability to handle moderate climates and resist vibrations makes them ideal for these uses. They work well in situations where you don't use up all the battery's charge at once.
Lithium batteries pack a lot of power for their size, which is why they're great for electric vehicles and portable electronics. Their long lifespans mean they are also chosen for solar energy storage systems.
- Gel Batteries:
- Solar Panels: They're great for holding onto solar energy because they last a long time and are tough.
- Boats: Perfect for the water since they won't leak and can handle the waves.
- Wheelchairs: Safe and easy to use, they don't need much care, making them good for mobility aids.
- Emergency Lights: They can sit for a while without losing charge, so they're ready when you need them.
- Off-Grid Communication: Work well in remote areas because they keep their charge for a long time.
- Lithium Batteries:
- Electric Cars: They give a lot of power and charge up fast, making them ideal for EVs.
- Gadgets: Common in phones and laptops since they're light and keep a charge for ages.
- Green Energy Systems: Great for wind or solar setups because they use energy really efficiently.
- Power Tools: Keep tools running without fading out, even for tough jobs.
- Backup Power: Quick to kick in and reliable for when the power goes out suddenly.
How Does the Gel and LiFePO4 Battery Compare Against Each Other?
When weighing the merits of gel battery and LiFePO4 options for your energy needs, it's like comparing the steadfast endurance of a marathon runner with the swift, powerful sprints of a racer. Gel batteries, akin to the marathoner, offer reliability and a commendable lifespan, making them suitable for scenarios where a steady, long-term energy supply is crucial. On the other hand, LiFePO4 batteries shine in applications demanding high energy output and efficiency, thanks to their remarkable energy density and lightweight nature. Each battery type brings its unique strengths to the table, whether it's the gel's durability and maintenance-free operation or the LiFePO4's high performance and eco-friendliness. For a deeper dive into their differences and to find out which battery best suits your specific needs, explore our detailed comparison on A Comprehensive Comparison: The Gel Vs LiFePO4 Battery.
Conclusion: Which is the Better Choice of Battery For You?
In wrapping up our deep dive into the gel battery versus lithium battery showdown, it's clear that each has its unique strengths tailored to specific applications. Gel batteries, with their robustness and maintenance-free nature, excel in environments where durability and temperature resilience are key. They're the unsung heroes in settings that don't demand high energy density but require reliability and safety.
On the flip side, lithium batteries emerge as the powerhouse for energy-intensive applications, offering unparalleled energy density and efficiency. Their longer lifespan and ability to endure a wider range of temperatures without compromising performance make them a favorite for cutting-edge applications, from electric vehicles to renewable energy systems.
While lead-acid batteries have served us well, the evolution towards lithium technology reflects our growing need for sustainable, high-performance energy solutions. Choosing between gel and lithium ultimately hinges on balancing your project's requirements with the battery's characteristics—whether it's the endurance and cost-effectiveness of gel or the superior capacity and longevity of lithium.
Reference List
(1) Leng, F., Tan, C. & Pecht, M. Effect of Temperature on the Aging rate of Li Ion Battery Operating above Room Temperature. Sci Rep 5, 12967 (2015). https://doi.org/10.1038/srep12967
Research licensed under CC BY 4.0 DEED.
No changes were made to the material.
(2) Choi J and Park H (2022) Correlation Between Changes in Environmental Temperature and Performance of High-Discharge Lithium-Polymer Batteries. Front. Energy Res. 10:830581. doi: 10.3389/fenrg.2022.830581
Research licensed under CC BY 4.0 DEED.
No changes were made to the material.
(3) Wang, X.; Zhang, Y.; Deng, Y.; Yuan, Y.; Zhang, F.; Lv, S.; Zhu, Y.; Ni, H. Effects of Different Charging Currents and Temperatures on the Voltage Plateau Behavior of Li-Ion Batteries. Batteries 2023, 9, 42. https://doi.org/10.3390/batteries9010042
Research licensed under CC BY 4.0 DEED.
No changes were made to the material.
(4) Wesley Chang et al 2020 J. Electrochem. Soc. 167 090503DOI 10.1149/1945-7111/ab6c56
Research licensed under CC BY 4.0 DEED.
No changes were made to the material.