Battery pack

Last updated
Automobile battery pack consisting of 28 Optima Yellow Tops Acp tzero dsc00309.jpg
Automobile battery pack consisting of 28 Optima Yellow Tops

A battery pack is a set of any number of (preferably) identical batteries or individual battery cells. [1] [2] They may be configured in a series, parallel or a mixture of both to deliver the desired voltage and current. The term battery pack is often used in reference to cordless tools, radio-controlled hobby toys, and battery electric vehicles.

Contents

Components of battery packs include the individual batteries or cells, and the interconnects which provide electrical conductivity between them. [3] Rechargeable battery packs often contain voltage and temperature sensors, which the battery charger uses to detect the end of charging. [4] Interconnects are also found in batteries as they are the part which connects each cell, though batteries are most often only arranged in series strings.

When a pack contains groups of cells in parallel there are differing wiring configurations which take into consideration the electrical balance of the circuit. Battery Management System are sometimes used for balancing cells in order to keep their voltages below a maximum value during charging so as to allow the weaker batteries to become fully charged, bringing the whole pack back into balance. [5] Active balancing can also be performed by battery balancer devices which can shuttle energy from strong cells to weaker ones in real time for better balance. [5] A well-balanced pack lasts longer and delivers better performance. [6] [1]

For an inline package, cells are selected and stacked with solder in between them. The cells are pressed together and a current pulse generates heat to solder them together and to weld all connections internal to the cell.

Calculating state of charge

SOC, or state of charge, is the equivalent of a fuel quantity remaining. SOC cannot be determined by a simple voltage measurement, because the terminal voltage of a battery may stay substantially constant until it is completely discharged. In some types of battery, electrolyte specific gravity may be related to state of charge but this is not measurable on typical battery pack cells, and is not related to state of charge on most battery types. Most SOC methods take into account voltage and current as well as temperature and other aspects of the discharge and charge process to in essence count up or down within a pre-defined capacity of a pack. [7] [8] More complex state of charge estimation systems take into account the Peukert effect which relates the capacity of the battery to the discharge rate. [9]

Advantages

An advantage of a battery pack is the ease with which it can be swapped into or out of a device. This allows multiple packs to deliver extended runtimes, freeing up the device for continued use while charging the removed pack separately.

Another advantage is the flexibility of their design and implementation, allowing the use of cheaper high-production cells or batteries to be combined into a pack for nearly any application.

At the end of product life, batteries can be removed and recycled separately, reducing the total volume of hazardous waste.

Disadvantages

Packs are often simpler for end users to repair or tamper with than a sealed non-serviceable battery or cell. Though some might consider this an advantage it is important to take safety precautions when servicing a battery pack as they pose a danger as potential chemical, electrical, and fire risks.

See also

Related Research Articles

<span class="mw-page-title-main">Electrochemical cell</span> Electro-chemical device

An electrochemical cell is a device that generates electrical energy from chemical reactions. Electrical energy can also be applied to these cells to cause chemical reactions to occur. Electrochemical cells that generate an electric current are called voltaic or galvanic cells and those that generate chemical reactions, via electrolysis for example, are called electrolytic cells.

<span class="mw-page-title-main">Nickel–metal hydride battery</span> Type of rechargeable battery

A nickel–metal hydride battery is a type of rechargeable battery. The chemical reaction at the positive electrode is similar to that of the nickel-cadmium cell (NiCd), with both using nickel oxide hydroxide (NiOOH). However, the negative electrodes use a hydrogen-absorbing alloy instead of cadmium. NiMH batteries can have two to three times the capacity of NiCd batteries of the same size, with significantly higher energy density, although only about half that of lithium-ion batteries.

<span class="mw-page-title-main">Lithium-ion battery</span> Rechargeable battery type

A lithium-ion or Li-ion battery is a type of rechargeable battery that uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. In comparison with other commercial rechargeable batteries, Li-ion batteries are characterized by higher specific energy, higher energy density, higher energy efficiency, a longer cycle life, and a longer calendar life. Also noteworthy is a dramatic improvement in lithium-ion battery properties after their market introduction in 1991: within the next 30 years, their volumetric energy density increased threefold while their cost dropped tenfold.

<span class="mw-page-title-main">Rechargeable battery</span> Type of electrical battery

A rechargeable battery, storage battery, or secondary cell, is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primary battery, which is supplied fully charged and discarded after use. It is composed of one or more electrochemical cells. The term "accumulator" is used as it accumulates and stores energy through a reversible electrochemical reaction. Rechargeable batteries are produced in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of electrode materials and electrolytes are used, including lead–acid, zinc–air, nickel–cadmium (NiCd), nickel–metal hydride (NiMH), lithium-ion (Li-ion), lithium iron phosphate (LiFePO4), and lithium-ion polymer.

<span class="mw-page-title-main">Lithium polymer battery</span> Lithium-ion battery using a polymer electrolyte

A lithium polymer battery, or more correctly lithium-ion polymer battery, is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyte. Highly conductive semisolid (gel) polymers form this electrolyte. These batteries provide higher specific energy than other lithium battery types and are used in applications where weight is a critical feature, such as mobile devices, radio-controlled aircraft and some electric vehicles.

<span class="mw-page-title-main">Jump start (vehicle)</span> Method of starting a motor vehicle

A jump start, also called a boost, is a procedure of starting a motor vehicle that has a discharged battery. A temporary connection is made to the battery of another vehicle, or to some other external power source. The external supply of electricity recharges the disabled vehicle's battery and provides some of the power needed to crank the engine. Once the vehicle has been started, its normal charging system will recharge, so the auxiliary source can be removed. If the vehicle charging system is functional, leaving the engine running will restore the charge of the battery.

<span class="mw-page-title-main">Automotive battery</span> Rechargeable battery for starting a cars combustion engine

An automotive battery, or car battery, is a rechargeable battery that is used to start a motor vehicle. Its main purpose is to provide an electric current to the electric-powered starting motor, which in turn starts the chemically-powered internal combustion engine that actually propels the vehicle. Once the engine is running, power for the car's electrical systems is still supplied by the battery, with the alternator charging the battery as demands increase or decrease.

Peukert's law, presented by the German scientist Wilhelm Peukert in 1897, expresses approximately the change in capacity of rechargeable lead–acid batteries at different rates of discharge. As the rate of discharge increases, the battery's available capacity decreases, approximately according to Peukert's law.

<span class="mw-page-title-main">Battery charger</span> Device used to provide electricity

A battery charger, recharger, or simply charger, is a device that stores energy in a battery by running an electric current through it. The charging protocol depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle. Other battery types use a timer to cut off when charging should be complete. Other battery types cannot withstand over-charging, becoming damaged, over heating or even exploding. The charger may have temperature or voltage sensing circuits and a microprocessor controller to safely adjust the charging current and voltage, determine the state of charge, and cut off at the end of charge. Chargers may elevate the output voltage proportionally with current to compensate for impedance in the wires.

<span class="mw-page-title-main">Flow battery</span> Type of electrochemical cell

A flow battery, or redox flow battery, is a type of electrochemical cell where chemical energy is provided by two chemical components dissolved in liquids that are pumped through the system on separate sides of a membrane. Ion transfer inside the cell occurs through the membrane while both liquids circulate in their own respective space. Cell voltage is chemically determined by the Nernst equation and ranges, in practical applications, from 1.0 to 2.43 volts. The energy capacity is a function of the electrolyte volume and the power is a function of the surface area of the electrodes.

State of charge (SoC) quantifies the remaining capacity available in a battery at a given time and in relation to a given state of ageing. It is usually expressed as percentage. An alternative form of the same measure is the depth of discharge (DoD), calculated as 1 − SoC. It refers to the amount of charge that may been used up if the cell is fully discharged. State of charge is normally used when discussing the current state of a battery in use, while depth of discharge is most often used to discuss a constant variation of state of charge during repeated cycles.

<span class="mw-page-title-main">Electric vehicle battery</span> Battery used to power the electric motors of a battery electric vehicle or hybrid electric vehicle

An electric vehicle battery is a rechargeable battery used to power the electric motors of a battery electric vehicle (BEV) or hybrid electric vehicle (HEV).

In electronics, the cut-off voltage is the voltage at which a battery is considered fully discharged, beyond which further discharge could cause harm. Some electronic devices, such as cell phones, will automatically shut down when the cut-off voltage has been reached.

A battery management system (BMS) is any electronic system that manages a rechargeable battery, such as by protecting the battery from operating outside its safe operating area, monitoring its state, calculating secondary data, reporting that data, controlling its environment, authenticating it and / or balancing it.

<span class="mw-page-title-main">Electric battery</span> Power source with electrochemical cells

An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell.

<span class="mw-page-title-main">Battery balancing</span> Techniques that improve the available capacity of a battery pack

Battery balancing and battery redistribution refer to techniques that improve the available capacity of a battery pack with multiple cells and increase each cell's longevity. A battery balancer or battery regulator is an electrical device in a battery pack that performs battery balancing. Balancers are often found in lithium-ion battery packs for laptop computers, electrical vehicles. etc.

The lithium–air battery (Li–air) is a metal–air electrochemical cell or battery chemistry that uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.

<span class="mw-page-title-main">Supercapacitor</span> High-capacity electrochemical capacitor

A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than solid-state capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries.

Research in lithium-ion batteries has produced many proposed refinements of lithium-ion batteries. Areas of research interest have focused on improving energy density, safety, rate capability, cycle durability, flexibility, and cost.

<span class="mw-page-title-main">Electric car charging methods</span>

Various methods exist for recharging the batteries of electric cars. Currently, the largest concern surrounding electric vehicle transportation is the total travel range available before the need to recharge. The longest range recorded till date was 606.2 miles, achieved by a Tesla Model 3. However, this was conducted in very controlled conditions where the car maintained a constant speed without the added drain of the air conditioning compressor. Typically, the battery would last for approximately 300 miles - the equivalent to three days of city commuting in warmer weather, or one day in colder weather. With these limitations, long-distance trips are currently unsuited for an electric car unless rapid charging stations are available on the route of the trip.

References

  1. 1 2 Hassini, Marwan; Von Hohendorff Seger, Pedro; Redondo-Iglesias, Eduardo; Pelissier, Serge; Venet, Pascal (27 October 2023). "Capacity Dispersion and Impact of Outliers in a Second Life Battery". 2023 IEEE Vehicle Power and Propulsion Conference (VPPC). Milan, Italy. pp. 1–4. doi:10.1109/VPPC60535.2023.10403384. ISBN   979-8-3503-4445-5. S2CID   267337334.{{cite book}}: CS1 maint: location missing publisher (link)
  2. Li, Wei; Garg, Akhil; Xiao, Mi; Peng, Xiongbin; Le Phung, My Loan; Tran, Van Man; Gao, Liang (2020-10-10). "Intelligent optimization methodology of battery pack for electric vehicles: A multidisciplinary perspective". International Journal of Energy Research. 44 (12): 9686–9706. Bibcode:2020IJER...44.9686L. doi: 10.1002/er.5600 . ISSN   0363-907X.
  3. Harper, Gavin; Sommerville, Roberto; Kendrick, Emma; Driscoll, Laura; Slater, Peter; Stolkin, Rustam; Walton, Allan; Christensen, Paul; Heidrich, Oliver; Lambert, Simon; Abbott, Andrew; Ryder, Karl; Gaines, Linda; Anderson, Paul (6 November 2019). "Recycling lithium-ion batteries from electric vehicles". Nature. 575 (7781): 75–86. Bibcode:2019Natur.575...75H. doi:10.1038/s41586-019-1682-5. ISSN   1476-4687. PMID   31695206.
  4. Simpson, Chester (1995). "Battery charging" (PDF). National Semiconductors.
  5. 1 2 Cao, Jian; Schofield, Nigel; Emadi, Ali (2008). "Battery balancing methods: A comprehensive review". 2008 IEEE Vehicle Power and Propulsion Conference. pp. 1–6. doi:10.1109/VPPC.2008.4677669. ISBN   978-1-4244-1848-0. S2CID   42399871 . Retrieved 2024-01-19.
  6. Duraisamy, Thiruvonasundari; Kaliyaperumal, Deepa (2020-06-01). "Active cell balancing for electric vehicle battery management system". International Journal of Power Electronics and Drive Systems (IJPEDS). 11 (2): 571. doi:10.11591/ijpeds.v11.i2.pp571-579. ISSN   2722-256X.
  7. Shuo Pang; Farrell, J.; Jie Du; Barth, M. (2001). "Battery state-of-charge estimation". Proceedings of the 2001 American Control Conference. (Cat. No.01CH37148). pp. 1644-1649 vol.2. doi:10.1109/ACC.2001.945964. ISBN   0-7803-6495-3. S2CID   57885701 . Retrieved 2024-01-19.
  8. Hassini, Marwan; Redondo-Iglesias, Eduardo; Venet, Pascal (19 July 2023). "Lithium–Ion Battery Data: From Production to Prediction". Batteries. 9 (7): 385. doi: 10.3390/batteries9070385 . ISSN   2313-0105.
  9. "State of charge (SoC) estimation on LiFePO4 battery module using Coulomb counting methods with modified Peukert". doi:10.1109/rICT-ICeVT.2013.6741545. S2CID   5621134 . Retrieved 2024-01-19.