Solomon Islands Lithium Ion Cell And Battery Pack

How do you make custom lithium-ion battery packs?

Key Takeaway: Manufacturing custom lithium-ion battery packs requires precise engineering, quality control, and safety standards. The process involves gathering requirements, selecting cells, concurrent engineering, prototyping, certification, production planning, and lifecycle support.

What is battery pack production?

At the heart of the battery industry lies an essential lithium ion battery assembly process called battery pack production.

What is battery pack assembly?

The battery pack assembly is the process of assembling the positive electrode, negative electrode, and diaphragm into a complete battery. This involves placing the electrodes in a cell casing, adding the electrolyte, and sealing the cell.

What is advanced lithium battery pack design?

Advanced Lithium Battery Pack Design: These custom batteries are made when the customer has special requests for temperature capabilities, dimensions, discharge current, and/or battery cycles. In this case, our chemistries, enclosure, and battery management system (BMS) experts are required to monitor each project closely.

What makes a custom lithium-ion battery pack unique?

The foundation of any custom lithium-ion battery pack lies in the selection of the integrated cells. Our cell selection for custom packs involves: Lithium-ion cell advancements continue expanding performance boundaries yearly. Leveraging state-of-the-art cell technology is crucial for maximizing custom pack capabilities.

What is a high-performance lithium battery pack?

As the world transitions towards sustainable energy solutions, the demand for high-performance lithium battery packs continues to soar. At the heart of this burgeoning industry lies a meticulously orchestrated assembly process, where individual lithium-ion cells are transformed into powerful energy storage systems.

Do lithium-ion battery storage spaces need fire protection?

Fire protection for lithium-ion battery storage spaces must account for the unique hazards posed by thermal runaway. Standard fire suppression systems may not be enough to manage the risks of lithium-ion battery fires. Facilities need systems specifically designed to detect, suppress, and prevent reignition of these types of fires.

Does a lithium-ion battery fire suppression system protect your facility?

With the growing reliance on lithium-ion batteries, having a fire suppression system designed to mitigate thermal runaway is critical. To learn more about how 3S Incorporated can help you protect your facility and ensure operational continuity, visit their lithium-ion battery fire protection page.

Can a lithium-ion battery energy storage system detect a fire?

Since December 2019, Siemens has been offering a VdS-certified fire detection concept for stationary lithium-ion battery energy storage systems.* Through Siemens research with multiple lithium-ion battery manufacturers, the FDA unit has proven to detect a pending battery fire event up to 5 times faster than competitive detection technologies.

Are LFP batteries safe for energy storage?

Fire accidents in battery energy storage stations have also gradually increased, and the safety of energy storage has received more and more attention. This paper reviews the research progress on fire behavior and fire prevention strategies of LFP batteries for energy storage at the battery, pack and container levels.

How do you protect a lithium ion battery?

Fire protection systems designed for lithium-ion battery storage often use thermal imaging cameras, gas detectors, or specialized sensors to identify abnormal conditions before they lead to combustion. Lithium-ion battery fires require suppression agents capable of cooling affected areas and isolating heat sources.

How to protect battery energy storage stations from fire?

High-quality fire extinguishing agents and effective fire extinguishing strategies are the main means and necessary measures to suppress disasters in the design of battery energy storage stations . Traditional fire extinguishing methods include isolation, asphyxiation, cooling, and chemical suppression .

Can repurposed EV batteries be used in communication base stations?

Among the potential applications of repurposed EV LIBs, the use of these batteries in communication base stations (CBSs) isone of the most promising candidates owing to the large-scale onsite energy storage demand ( Heymans et al., 2014; Sathre et al., 2015 ).

Are lithium-ion batteries used in EV power supply systems?

Owing to the long cycle life and high energy and power density, lithium-ion batteries (LIBs) are themost widely used technology in the power supply system of EVs ( Opitz et al. (2017); Alfaro-Algaba and Ramirez et al., 2020 ).

What is the recycling stage of a lithium ion battery?

In the recycling stage, the collectedLIB packs are dismantled to obtain the main components, such as battery cells, BMSs, and packaging, and various material fractions are recovered from these components separately (Table A1 in the supplementary materials).

Should repurposed lithium batteries be used as a lab system?

From the resource point of view, the MDP of repurposed LIBs isnot always preferable to that of the conventional LAB system. Recently, the environmental and social impacts of battery metals such as nickel, lithium and cobalt, have drawn much attention due to the ever-increasing demand ( Ziemann et al., 2019; Watari et al., 2020 ).

Can EV libs be used as energy storage modules?

In addition, since most spent EV LIBs still have 80% of their nominal capacities ( Ahmadi et al., 2014a ),they can be repurposed as energy storage modules for less demanding systems, such as peak shaving, swapping power stations, and renewable energy storage ( Han et al., 2018 ).

Does secondary use of lithium ion batteries reduce the MDP value?

The findings of this study indicate a potential dilemma; more raw metals are depleted during the secondary use of LIBs in CBSs than in the LAB scenario. On the one hand, the secondary use of LIBsreduces the MDP value by extending the service life of the batteries, although more metal resources are consumed during the repurposing activities.

What is a lithium-ion battery pack?

Lithium-ion battery packs for electric vehicles and energy storage systems undergo specialized engineering to meet high power and capacity demands. These packs often employ advanced thermal management and safety features to ensure reliable performance. Part 4. Lithium-ion battery pack combination Increased voltage:

What are the different types of lithium ion battery packs?

Lithium ion battery packs come in various forms, optimized for different applications. Here are a few prominent types: Cylindrical cells are one of the most common forms of lithium ion batteries. They are often found in consumer electronics like laptops and power tools.

Do all batteries use lithium?

No, not all batteries use lithium. Lithium batteries are relatively new and are becoming increasingly popular in replacing existing battery technologies. One of the long-time standards in batteries, especially in motor vehicles, is lead-acid deep-cycle batteries.

How long do lithium ion batteries last?

The lifespan of a Li-ion battery pack varies based on factors like usage, charging habits, and environmental conditions. Typically, they last around 2,000 to 3,000 charge cycles or roughly 5 to 10 years before experiencing significant capacity loss. How do you charge a lithium-ion battery pack?

How do lithium batteries store energy?

Lithium batteries rely on lithium ions to store energy by creating an electrical potential difference between the negative and positive poles of the battery. An insulating layer called a “separator” divides the two sides of the battery and blocks the electrons while still allowing the lithium ions to pass through.

What are Li-ion batteries used for?

Lithium-ion battery packs are widely used in various applications such as consumer electronics (like smartphones and laptops), electric vehicles (EVs), renewable energy storage systems, power tools, and more due to their high energy density and rechargeable nature. How long do li-ion batteries last?

Can repurposed EV batteries be used in communication base stations?

Among the potential applications of repurposed EV LIBs, the use of these batteries in communication base stations (CBSs) isone of the most promising candidates owing to the large-scale onsite energy storage demand ( Heymans et al., 2014; Sathre et al., 2015 ).

What is a green base station?

Another feature of the green base station concept is its ability to create value during ordinary times as well, by controlling the supply of power from appropriate power sources according to conditions and reducing use of com- mercial power, thus contributing to environmental protection.

What is a green base station test system?

Environmentally-Friendly, Disaster-Resistant Green Base Station Test Systems tions, which are radio base stations with environmentally friendly, disaster resistant energy systems.

What is the difference between green base stations and conventional base stations?

The differences in configuration between conventional base stations and green base stations are different storage batteries (from lead batteries to LIB), the use of ecological power generation, and the addition of equipment to con- trol them.

Are lithium-ion batteries used in EV power supply systems?

Owing to the long cycle life and high energy and power density, lithium-ion batteries (LIBs) are themost widely used technology in the power supply system of EVs ( Opitz et al. (2017); Alfaro-Algaba and Ramirez et al., 2020 ).

Does secondary use of lithium ion batteries reduce the MDP value?

The findings of this study indicate a potential dilemma; more raw metals are depleted during the secondary use of LIBs in CBSs than in the LAB scenario. On the one hand, the secondary use of LIBsreduces the MDP value by extending the service life of the batteries, although more metal resources are consumed during the repurposing activities.

What influences charge discharge efficiency in lithium ion batteries?

Charge discharge efficiency in lithium-ion batteries is influenced by a multitude of factors, including the battery's internal chemistry, the operational environment, and the charging/discharging protocols employed. Temperature Impact: Temperature significantly influences charge discharge efficiency lithium ion batteries.

Why do lithium ion batteries need to be charged efficiently?

Efficient charging reduces heat generation, which can degrade battery components over time, thus prolonging the battery's life. Several factors influence the charging efficiency of lithium ion batteries. Understanding these can help in optimizing charging strategies and extending battery life.

How can lithium-ion batteries improve battery performance?

The expanding use of lithium-ion batteries in electric vehicles and other industries has accelerated the need for new efficient charging strategies to enhance the speed and reliability of the charging process without decaying battery performance indices.

How does a lithium-ion battery pack work?

However, a battery pack with such a design typically encounter charge imbalance among its cells, which restricts the charging and discharging process . Positively, a lithium-ion pack can be outfitted with a battery management system (BMS) that supervises the batteries' smooth work and optimizes their operation .

Is a lithium-ion battery energy efficient?

Therefore, even if lithium-ion battery has a high CE, it may not be energy efficient. Energy efficiency, on the other hand, directly evaluates the ratio between the energy used during charging and the energy released during discharging, and is affected by various factors.

Why is lithium ion battery discharge management important?

Discharging a lithium-ion battery allows it to supply power to devices. This process moves lithium ions and generates an electric current. Proper discharge management ensures efficiency, extends battery life, and prevents damage. How Does Discharging a Lithium-Ion Battery Work?

What are the advantages of lithium batteries?

Applications Related Lithium Batteries A. Extremely safe and stable chemistry: PCB and/or BMS built inside to balance protect the battery. B. Long life-cycle: Can be circularly used, best can up to 2000 times recycles, 8 times of Lead acid battery. C. Lighter weight, with the best power-to-weight ratio: 1/3 of Lead acid battery weight.

What is aegis 60V 30ah lithium ion battery?

Policy The Aegis 60V 30Ah Li-ion Battery is a state of the art rechargeable battery pack made with 18650 cells designed for 60V devices. It is perfect for e-scooters, e-bikes, solar applications, robots, and other applications that require a higher-energy density battery.

How many times can a lead acid battery be recycled?

Long life-cycle: Can be circularly used, best can up to 2000 times recycles, 8 times of Lead acid battery. - Lighter weight, with the best power-to-weight ratio: 1/3 of Lead acid battery weight. - Low self-discharge rate, less than 3% monthly. - No memory effects and highly efficient charge.

Are lithium forklift batteries safe?

Yes. Many lithium forklift batteries are engineered with integrated heating elements and thermal management systems, allowing them to perform safely in environments as cold as -4°F (-20°C). It's important to select a battery model that's rated for the specific temperature conditions of your application.

When should a lithium forklift battery be recharged?

Lithium forklift batteries should be recharged before they drop below 20-30% capacity. Temperature Control: Lithium-ion batteries operate most safely between 10°C and 30°C (50°F to 86°F). Extreme temperatures (either high or low) can damage the battery or cause it to malfunction. 3. Monitoring and Maintenance

What if a lithium ion forklift battery is too hot?

Monitor Temperature: Some lithium-ion batteries include temperature sensors. If the battery becomes too hot, it should be removed from use immediately and allowed to cool down. By following these safety precautions, the risk of accidents, damage, or injury from lithium-ion forklift batteries can be significantly reduced.

What are the safety precautions for lithium-ion forklift batteries?

Safety precautions for lithium-ion forklift batteries are essential to ensure proper operation, longevity, and safety. Here are key safety guidelines to follow: 1. Proper Charging Procedures Use Compatible Chargers: Always use a charger specifically designed for lithium-ion batteries. Avoid Overcharging: Do not overcharge the battery.

How long can a lithium battery last in a forklift?

Lithium batteries typically support 2,000 to 4,000+ charge cycles, depending on how frequently and deeply they're discharged. This equates to several years of use in daily operations. Are lithium batteries safe to use in industrial equipment like forklifts? Yes.

Can a lithium battery be used in a cold environment?

Yes — when built and used properly. Industrial lithium batteries include Battery Management Systems (BMS) that monitor voltage, current, and temperature. Many are UL 2580 or UL 2271 certified for industrial safety. ✅ Will it work in cold environments?

How to activate a lithium battery?

A regular deep discharge of a lithium battery is beneficial to "activating" the lithium battery and can slightly increase the capacity of the lithium battery. Perform a full discharge of the lithium battery on a regular basis. The full discharge is the first under-voltage protection after cycling under normal load on a flat road.

What is the activation stage of lithium battery pack?

The activation stage of lithium battery pack includesprecharge, formation, aging, constant capacityand so on. There are two main factors influencing the performance of lithium battery pack, namely aging temperature and aging time. What's more, it is important that the battery tested in the aging test chamber is in a sealed state.

How should lithium batteries be packed?

Lithium batteries with a mass of 12 kg (26.5 lbs) or more, having a strong, impact-resistant outer casing, may be packed in strong outer packaging (such as crates) or banded to pallets or other handling devices instead of using UN specification packages.

How do you pack a lithium ion battery?

Sealing - In addition to filling and degassing, you will also need vacuum to seal the lithium-ion batteries. Vacuum removes moisture, air, and any impurities in the battery before packing. You will notice that lithium-ion batteries have plastic wraps packed tightly around them. This is done using vacuum pumps.

Does pack & send deliver lithium batteries?

At PACK & SEND we can provide you with a complete packing and delivery service for lithium battery-powered equipment within the constraints of international regulations but be aware that this is a specialist and costly service and not appropriate for domestic lithium batteries not contained in their equipment.

Can a lithium based battery be recharged?

Do not boost lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer. Copper shunts may have formed inside the cells that can lead to a partial or total electrical short. When recharging, such a cell might become unstable, causing excessive heat or show other anomalies.

How does a lithium ion battery short circuit work?

An electrode releases electrons into the circuit. At the same time, the other electrode picks up electrons from the circuit. This overall favorable chemical reaction drives the flow of electricity in the circuit. What is Li-ion battery short circuit?

What happens if you short circuit a lithium battery?

Incorrect use When lithium-ion batteries are exposed to special temperatures and humidity or are subject to impact, metal friction, or poor contact, the instantaneous current may be excessive, which may cause the battery to short-circuit and explode. Part 3. What are the dangers of short circuiting lithium batteries? 1. Battery leakage

Can You short a lithium ion battery?

Don't short a lithium battery. It will burn the internal wires, and/or it will shut down. Some battery chargers actually can do a controlled discharge (for instance my NiMH charger can do it). What's the best and fastest way to drain lithium ion batteries?

What is the fastest way to short a battery?

The fastest way is shorting the battery, the best way is to not short the battery, but have a controlled discharge, like you are doing with the lamp. While I will suggest this, with the preface of exercising caution, you could connect a couple lamps together in parallel to reduce the resistance of the circuit.

What happens if you short circuit a battery?

A short circuit usually produces damaging conditions for the battery, and the load, if maintained for enough time. At best, the battery will be run down quickly. At worst, the battery may catch fire, burst itself or its container, or the load start a fire.

Is a short circuit a high-amperage battery?

If it's a high-amperage battery it takes stupidity. 'Short Circuit' gets used in two different ways. In the context of a battery (or any power source), we usually mean it to be a load that is far too large for the source.

What is the best packaging material for lithium-ion batteries?

Owing to the popularity of the cylindrical cell geometry, cylindrical cell packaging material is the most commonly available packaging for lithium-ion batteries today. With the advent of portable consumer electronics, use of the prismatic cell design has grown considerably over the course of the last decade.

How are lithium ion batteries packaged?

Each battery or cell must be entirely enclosed to prevent contact with other equipment or any conductive materials. The inner packaging containing lithium ion batteries can be placed in containers crafted from various materials, including metal, wood, fiberboard, or solid plastic jerrycans.

What Li-ion battery packaging materials does Targray offer?

Targray supplies customizable Lithium-ion Battery packaging materials for the 3 primary geometric battery configurations - cylindrical, prismatic and pouch cell. Our li-ion cell packaging solutions include high-performance tabs, tapes (films), cases, cans and lids.

Should lithium ion batteries be packaged?

A guiding principle is that lithium ion batteries must be packaged to eliminate movement or contact with other materials, and each package must display a hazard communication label. Battery Type

What materials are used in a lithium ion battery cell?

For example, a lithium-ion battery cell will have an anode made from lithium, lithium-alloying materials, graphite, intermetallic, and silicon. The cathode will typically be made of lithium-metal oxides, rechargeable lithium oxides, olivine, and vanadium oxides.

What materials are used in a battery?

Throughout the battery from a single cell to a complete pack there are many different materials. Aluminium, copper, nickel plating etc

What is a lithium titanate battery?

A lithium-titanate battery is a modified lithium-ion battery that uses lithium-titanate nanocrystals, instead of carbon, on the surface of its anode. This gives the anode a surface area of about 100 square meters per gram, compared with 3 square meters per gram for carbon, allowing electrons to enter and leave the anode quickly.

What are the advantages of lithium titanate batteries?

Lithium titanate batteries come with several notable advantages: Fast Charging: One of the standout features of LTO batteries is their ability to charge rapidly—often within minutes—making them ideal for applications that require quick recharging.

Are lithium ion titanate batteries safe?

Enhanced Security and Stability: Lithium-ion titanate batteries exhibit higher potential compared to pure metal lithium, minimizing the formation of lithium dendrites.

How long do lithium titanate cells last?

Lithium-titanate cells last for 6000 to 30000 charge cycles; a life cycle of ~1000 cycles before reaching 80% capacity is possible when charged and discharged at 55 °C (131 °F), rather than the standard 25 °C (77 °F).

Why is lithium titanate better than carbon anode?

Thanks to the higher lithium-ion diffusion coefficient in lithium titanate compared to traditional carbon anode materials, LTO batteries can be charged and discharged at high rates. This not only drastically reduces charging time—often to just about ten minutes—but also has minimal impact on the cycle life and thermal stability of the battery.

Are lithium ion titanate batteries able to withstand extreme temperatures?

Resilience to Wide Temperature Ranges: Unlike many electric vehicle batteries facing challenges at sub-zero temperatures, lithium-ion titanate batteries exhibit robust resistance in extreme climates, functioning normally at temperatures ranging from -50℃ to -60℃, ensuring stability regardless of geographical location.

Are series and parallel connection of lithium batteries safe?

The series and parallel connection of lithium batteries is a key technology to increase voltage and capacity, but it also contains safety risks. This article will analyze in detail the principles, methods and precautions of series and parallel connection of lithium batteries to help you avoid potential risks and build a battery system correctly.

Why is a lithium battery a series-parallel combination?

Due to the limited voltage and capacity of the single battery, in actual use, a series-parallel combination is required to obtain a higher voltage and ability to meet the existing power supply requirements of the equipment. Lithium batteries in series: the voltage is added, the capacity remains unchanged, and the internal resistance increases.

What is a series-parallel battery system?

With series-parallel, batteries first link in series, then in parallel, boosting both voltage and capacity. Linking four 12V 26Ah batteries in series gives 48V and 26Ah. However, parallel connecting four 12V 100Ah batteries gives a 12V 400Ah system. Knowing how to connect batteries in series and parallel is key when you design power systems.

What is the difference between series and parallel battery packs?

The key differences between battery packs in series and parallel involve voltage and capacity configurations. Series battery packs increase voltage while maintaining the same capacity. In contrast, parallel battery packs increase capacity while maintaining the same voltage.

How to charge parallel lithium battery packs?

Specific principles must be followed when charging parallel lithium battery packs: Use a matching charger: The voltage must be suitable for the nominal voltage of the individual batteries. The current setting is reasonable: usually 0.2-0.5C of the total capacity after parallel connection.

What is lithium battery parallel connection?

Lithium battery parallel connection is to connect the positive poles of multiple batteries together, and the negative poles together, so that the total capacity can be increased while keeping the voltage unchanged.

What is a lithium ion battery voltage chart?

Lithium-ion battery voltage charts are a great way to understand your system and safely charge batteries. Lithium-ion batteries are rechargeable battery types used in a variety of appliances. As the name defines, these batteries use lithium-ions as primary charge carriers with a nominal voltage of 3.7V per cell.

How many volts does a lithium ion battery have?

50% capacity in a lithium battery often correlates to approximately 3.6V to 3.7V per cell for most lithium-ion batteries. This voltage range represents the mid-point of the battery's discharge cycle. What is the cutoff voltage for a 12V lithium-ion battery?

What is a lithium battery state of charge chart?

Here's the lithium battery state of charge chart: A typical lithium-ion battery voltage curve is the relationship between voltage and state of charge. When the battery discharges and provides an electric current, the anode releases Li ions to the cathode to generate a flow of electrons from one side to the other.

How many volts does a 24V lithium ion battery pack need?

A 24V lithium-ion or LiFePO4 battery pack typically requires a charging voltage within the range of about 29-30 volts. Specialized chargers designed for multi-cell configurations should be considered, and adherence to manufacturer guidelines is crucial for safe and efficient charging.

What are the key parameters of a lithium battery?

The key parameters you need to keep in mind, include rated voltage, working voltage, open circuit voltage, and termination voltage. Different lithium battery materials typically have different battery voltages caused by the differences in electron transfer and chemical reaction processes.

What is the maximum charge voltage of a lithium ion battery?

The Li-ion battery might have a maximum charge voltage of 4.2 volts per cell. The LiFePO4 battery would have a lower maximum charge voltage of 3.6 volts per cell. Discharge Cutoff Voltage Discharge cutoff voltages also vary across different lithium battery types:

Do lithium batteries need a Protection Board?

Protection boards for lithium batteries offer monitoring protection. Low-voltage lithium batteries require a protection board. When using high-voltage lithium batteries, a battery management system (BMS) is typically chosen since these systems contain more functions for monitoring the state of the battery pack.

What are the benefits of lithium battery protection boards?

In addition to basic overcharge, over-discharge, over-current, and over-temperature protection, future lithium battery protection boards will also integrate more functions, such as power estimation, balanced charging, etc. These features will help improve the efficiency and management of lithium batteries. 3. Intelligent

How to protect a lithium battery?

Use special lithium battery protection chip, when the battery voltage reaches the upper limit or lower limit, the control switch device MOS tube cut off the charging circuit or discharging circuit, to achieve the purpose of protecting the battery pack. Characteristics: 1. Only over-charge and over-discharge protection can be realized.

What is a battery protection board?

Hardware-type protection board: Use special lithium battery protection chip, when the battery voltage reaches the upper limit or lower limit, the control switch device MOS tube cut off the charging circuit or discharging circuit, to achieve the purpose of protecting the battery pack. Characteristics: 1.

What are the technical parameters of lithium battery protection boards?

Prevent the battery from being damaged by excessive current. Important technical parameters of lithium battery protection boards include overcharge protection, over-discharge protection, over-current protection, short-circuit protection, temperature protection, internal resistance, power consumption, etc.

Can you get a Protection Board with a custom battery pack?

You can also obtain custom-built protection boards with your custom battery packs. This arrangement is ideal since the battery manufacturer will have a greater understanding of the protection needs of the custom pack that they design for the customer. So, the protection board would cater to these design requirements.

How do you disassemble a lithium-ion battery pack?

When breaking down a lithium-ion battery pack, having the right tools for the job is critical. The tools you use to disassemble a lithium-ion battery pack can be the difference between salvaging a bunch of great cells and starting a fire. 5 pack of flush cut pliers. Perfect for removing the nickel strip that is attached to cells when salvaging.

Can you take apart a lithium-ion battery pack?

Taking apart a lithium-ion battery pack may appear challenging at first, but with a solid approach and some patience, anyone can do it. It's super important to understand the connections between battery cells and to recognize the potential risks, like shoulder shorts.

How do I dismantle a Li-ion battery?

The first step to take before dismantling a Li-ion battery is to identify its type and the amount of charge remaining in it. This information is critical because different types of batteries require different handling procedures. Additionally, the risks associated with dismantling the battery increase with the charge level.

What does it mean if a lithium ion battery pack is split?

It generally means that the other cell groups are just fine. Lithium-ion battery packs are spot welded together. So it's no small feat to separate the cells. In fact, breaking down a lithium-ion battery pack is a rather involved process that takes care and patience. You have to be extremely careful when breaking down a lithium-ion battery pack.

How to disassemble a battery?

When it comes to disassembling a battery, the first important step is removing the battery cover or casing. This outer layer provides protection to the internal components of the battery and prevents any damage from external factors. By following a few simple steps, you can safely remove the cover or casing without causing harm.

What should I bring to a battery disassembly?

Before you start the process, gather the following items: 1. Safety glasses: Protect your eyes from any potential sparks or debris that may fly off during disassembly. 2. Gloves: Wear gloves to safeguard your hands from accidental cuts or exposure to harmful chemicals present in some batteries.