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A High capacity oceanographic lithium battery pack is a type of battery pack used by oceanographers. Physical Oceanographers use high capacity lithium battery packs for long term deployments to extend the duration of the deployments and gather more data. Oceanographers often work in far away sites that are difficult to get to. The cost of getting to these remote sites, often by ship, can dominate the cost of an investigation. This motivates oceanographers to extend the duration of their deployments so that they can visit them less often. This means, among other things, increasing the capacity of their battery packs.
When possible, oceanographers use alkaline batteries because they are inexpensive and readily available. However, when alkaline batteries provide insufficient capacity, oceanographers turn to lithium battery packs, which can supply three times the capacity. Battery packs based on lithium thionyl chloride chemistry cost more than alkaline battery packs, but they provide roughly three times the energy density at about 60% of the weight (both by volume). Lithium batteries have other advantages as well. They produce negligible gas, and what gas is produced is contained in hermetically sealed metal containers. The voltage over the life of the pack varies considerably less than the voltage of an alkaline pack. Low current lithium cells also have relative low self-discharge, losing less than 10% of their capacity in 10 years.
Doppler Ltd. oceanographic battery packs use Tadiran's TL6930 [1] low current lithium thionyl chloride primary cells combined with small rechargeable cells called Hybrid Layer Capacitors (HLC). [2] Low current lithium cells cannot supply the currents required for many applications, but they store more energy than high current cells. High current cells use spiral wound electrodes, [3] that is, electrodes built in sheets wrapped in a spiral inside the cell. The large surface area of the sheets increases the current that the cell can supply. Low current cells use bobbin electrodes, [3] a simpler design consisting of an inner anode, an outer layer of metallic lithium, and electrolyte between the two. This design is less costly to manufacture, and it stores more energy.
The TL6930 cells work well over typical ocean temperatures (0-40 °C), and for typical ocean deployments (1 month - 2 years). At a temperature of 5-10 °C, one TL6930 holds roughly three times the energy of the same size alkaline cell. Most of that difference is accounted by the lithium cell's higher voltage (nominally 3.8 VDC vs. 1.5 VDC). Fig. 1 provides an example of how the voltage on these cells varies with time, assuming both cells supply the same continuous power. The lithium cell lasts 3 times as long as an alkaline cell, and sustains a more constant voltage during its life. Primary lithium cells also hold several times the capacity of rechargeable lithium cells.
Most oceanographic instruments use little power most of the time, and they require high currents only for short durations. Examples are instrument systems that telemeter data through Iridium, and acoustic modems (e.g. from Benthos [4] or Link-Quest [5] ). ADCPs also require short pulses of high current to support high power acoustic transmissions. HLCs are the key that enable low current lithium battery packs to supply short pulses of high current. HLCs are actually rechargeable lithium cells that behave like huge capacitors over a narrow voltage range (Fig. 2).
Most alkaline battery packs used by oceanographers are built with strings of cells. A typical alkaline battery pack often consists of a number of strings of alkaline cells, all connected in parallel to increase the total capacity. PulsesPlus packs take the opposite approach. Packs are constructed in "branches" of parallel primary cells, each branch charging one or more HLCs. The HLC sources most of the current when high currents are required, then the HLCs slowly recharge at a low current from the primary cells. The cell's low current enables it to work more efficiently. High current dissipates energy as heat inside low current cells and has other detrimental affects. These reduce the energy available to power instrumentation. Combining the primary lithium cells with HLCs enables the pack to deliver more of its stored energy to the instrument system.
Fig. 3 shows a typical Pulses Plus schematic. The pack includes diodes in each branch to minimize the possibility of reverse charging the cells. PTCs, or positive temperature coefficient thermistors act as resettable fuses. PTCs begin to get warm at a trip current. The warmth increases their resistance which produces even more heat, and the PTC quickly "trips" and shuts off most of the current. The PTC rarely trips in a typical ADCP pack, because the safety circuit is the primary protection against short circuits (defined to be any current above about 8 A). The safety circuit also turns off the pack before its voltage falls below a threshold. If the pack were allowed to fully discharge, one branch could discharge before the others, which could lead to the discharged branch being charged by the remaining cells. Any attempt to charge a lithium cell is potentially dangerous, and turning the pack off at about 75-80% of its starting voltage prevents this from happening. At this voltage, only around 3% of the capacity remains, but the remaining capacity still allows years for disposal of the pack before it discharges fully.
Because oceanographers spend considerable time and money in long term deployments, then wait to see the results, oceanographers invest extraordinary efforts prior to deployments to ensure the success of their experiments. One of their concerns is battery failure. [6] Doppler Ltd's Acoustic Doppler Current Profiler (ADCP) batteries [7] provide an example of lithium battery packs that an oceanographer can test prior to deployment. These battery packs are commonly used in RD Instruments [8] Workhorse Sentinel [9] and Long Ranger [10] and in Nortek's [11] AWAC. [12] These lithium packs, based on Tadiran's PulsesPlus [13] technology are designed considerably differently from typical alkaline battery packs.
In additions to its safety functions, the safety circuit also provides a self test that confirms the health of the pack in advance of a deployment. If there is no window with an LED behind it, the pack should not be shorted. Only battery packs with safety circuits instantly turn off the pack in response to a short circuit.
The self test indicates that the battery and its safety circuit work, that the battery voltage is within an acceptable range, that the battery can supply an 8 A pulse of current, and that the battery will protect itself against a short. The test confirms that the battery pack is new. If a new battery tests used, the supplier should be contacted. In some circumstances, a battery that is stored at a cold temperature could produce a test result that indicates it has been used, even though it holds its full original capacity.
Some instruments have current limiters on their inputs. The most common example is the RD Instruments Workhorse. When a current limiter fails, the instrument draws enough current to trigger the battery's short circuit protection, and the instrument fails to run. When this happens, plug in the AC adapter (which charges the ADCP's internal capacitor bank), then plug in the battery. The instrument will now run normally.
The safety circuit determines that a pack has been used when its voltage falls below a threshold, or if it detects a minimum number of pulses. Testing a pack is not normally sufficient to cause it to become "used", but normal operation should make it "used" around the time 1% of its capacity has been depleted. The safety circuit causes the pack to become "depleted" when it falls below its end-of-life voltage and turns off. A used pack will continue to function normally, but a depleted pack can no longer be used.
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.
The nickel–cadmium battery is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. The abbreviation Ni–Cd is derived from the chemical symbols of nickel (Ni) and cadmium (Cd): the abbreviation NiCad is a registered trademark of SAFT Corporation, although this brand name is commonly used to describe all Ni–Cd batteries.
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: over the following 30 years, their volumetric energy density increased threefold while their cost dropped tenfold.
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.
Memory effect, also known as battery effect, lazy battery effect, or battery memory, is an effect observed in nickel-cadmium rechargeable batteries that causes them to hold less charge. It describes the situation in which nickel-cadmium batteries gradually lose their maximum energy capacity if they are repeatedly recharged after being only partially discharged. The battery appears to "remember" the smaller capacity.
An alkaline battery is a type of primary battery where the electrolyte has a pH value above 7. Typically these batteries derive energy from the reaction between zinc metal and manganese dioxide.
A primary battery or primary cell is a battery that is designed to be used once and discarded, and it is not rechargeable unlike a secondary cell. In general, the electrochemical reaction occurring in the cell is not reversible, rendering the cell unrechargeable. As a primary cell is used, chemical reactions in the battery use up the chemicals that generate the power; when they are gone, the battery stops producing electricity. In contrast, in a secondary cell, the reaction can be reversed by running a current into the cell with a battery charger to recharge it, regenerating the chemical reactants. Primary cells are made in a range of standard sizes to power small household appliances such as flashlights and portable radios.
The AA battery is a standard size single cell cylindrical dry battery. The IEC 60086 system calls the size R6, and ANSI C18 calls it 15. It is named UM-3 by JIS of Japan. Historically, it is known as D14, U12 – later U7, or HP7 in official documentation in the United Kingdom, or a pen cell.
A zinc–air battery is a metal–air electrochemical cell powered by the oxidation of zinc with oxygen from the air. During discharge, a mass of zinc particles forms a porous anode, which is saturated with an electrolyte. Oxygen from the air reacts at the cathode and forms hydroxyl ions which migrate into the zinc paste and form zincate, releasing electrons to travel to the cathode. The zincate decays into zinc oxide and water returns to the electrolyte. The water and hydroxyl from the anode are recycled at the cathode, so the water is not consumed. The reactions produce a theoretical voltage of 1.65 Volts, but is reduced to 1.35–1.4 V in available cells.
A battery pack is a set of any number of (preferably) identical batteries or individual battery cells. 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.
Lithium metal batteries are primary batteries that have metallic lithium as an anode. The name intentionally refers to the metal as to distinguish them from lithium-ion batteries, which use lithiated metal oxides as the cathode material. Although most lithium metal batteries are non-rechargeable, rechargeable lithium metal batteries are also under development. Since 2007, Dangerous Goods Regulations differentiate between lithium metal batteries and lithium-ion batteries.
The nine-volt battery, or 9-volt battery, is an electric battery that supplies a nominal voltage of 9 volts. Actual voltage measures 7.2 to 9.6 volts, depending on battery chemistry. Batteries of various sizes and capacities are manufactured; a very common size is known as PP3, introduced for early transistor radios. The PP3 has a rectangular prism shape with rounded edges and two polarized snap connectors on the top. This type is commonly used for many applications including household uses such as smoke detectors, gas detectors, clocks, and toys.
A battery charger, recharger, or simply charger, is a device that stores energy in an electric battery by running current through it. The charging protocol—how much voltage, amperes, current, for how long and what to do when charging is complete—depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging after the battery has been fully charged and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type.
A rechargeable alkaline battery, also known as alkaline rechargeable or rechargeable alkaline manganese (RAM), is a type of alkaline battery that is capable of recharging for repeated use. The formats include AAA, AA, C, D, and snap-on 9-volt batteries. Rechargeable alkaline batteries are manufactured fully charged and have the ability to hold their charge for years, longer than nickel-cadmium and nickel-metal hydride batteries, which self-discharge. Rechargeable alkaline batteries can have a high recharging efficiency and have less environmental impact than disposable cells.
A button cell, watch battery, or coin battery is a small battery made of a single electrochemical cell and shaped as a squat cylinder typically 5 to 25 mm in diameter and 1 to 6 mm high – resembling a button. Stainless steel usually forms the bottom body and positive terminal of the cell; insulated from it, the metallic top cap forms the negative terminal.
The lithium iron phosphate battery or LFP battery is a type of lithium-ion battery using lithium iron phosphate as the cathode material, and a graphitic carbon electrode with a metallic backing as the anode. Because of their low cost, high safety, low toxicity, long cycle life and other factors, LFP batteries are finding a number of roles in vehicle use, utility-scale stationary applications, and backup power. LFP batteries are cobalt-free. As of September 2022, LFP type battery market share for EVs reached 31%, and of that, 68% were from EV makers Tesla and BYD alone. Chinese manufacturers currently hold a near monopoly of LFP battery type production. With patents having started to expire in 2022 and the increased demand for cheaper EV batteries, LFP type production is expected to rise further and surpass lithium nickel manganese cobalt oxides (NMC) type batteries in 2028.
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 by facilitating the safe usage and a long life of the battery in practical scenarios while monitoring and estimating its various states, calculating secondary data, reporting that data, controlling its environment, authenticating or balancing it. Protection circuit module (PCM) is a simpler alternative to BMS. A battery pack built together with a battery management system with an external communication data bus is a smart battery pack. A smart battery pack must be charged by a smart battery charger.
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. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach to the positive terminal, thus cause a redox reaction by attracting positively charged ions, cations. Thus 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.