Battery Straps protect rechargeable battery packs.

Press Release Summary:

 

MF-SVS, MF-VSN and MF-VS Multifuse(R) Polymeric Positive Temperature Coefficient straps, with resettable fuses, enhance safety and performance of rechargeable batteries. MF-SVS has initial resistance as low as 14 mOhms and protects Lithium and Ni-MH chemistry cells; MF-VS210N, for GSM battery packs, and MF-VS170N, for lower pulse current applications, have maximum voltage of 12 V, and maximum current of 100 A; and MF-VS protects battery packs rated with maximum voltage of 16 V.

 

Original Press Release:

Bourns Announces Launch of New Battery Strap Products

Bourns Multifuse(R) product line introduces new generation of super-low resistance PPTC resettable fuses for battery pack protection

 

RIVERSIDE, Calif. - Mar. 4, 2002 -- Bourns, Inc., a leading manufacturer of electronic components and integrated solutions, today announced the launch of the next generation of Multifuse(R) Polymeric Positive Temperature Coefficient (PPTC) strap components designed to enhance the safety and performance of rechargeable battery packs.

 

The Multifuse(R) product line offers battery pack manufacturers a reliable and cost effective method of protecting the battery pack from external shorts and abusive charging. The product family has evolved over the years, consistently offering the industry new and improved products. The new products being introduced include the MF-SVS, MF-VSN and MF-VS product families.

 

MF-SVS Family

The MF-SVS product family offers pack designers and manufacturers a strap device with a typical initial resistance as low as 14 mOhms, providing the pack designer an immediate minimum increase in talk time capacity of up to six percent.

 

A key advantage of this product is that it is designed to trip at the optimum switching temperature of 85°C, protecting Lithium or Ni-MH chemistry cells from overheating and ensuring not only that the pack is more than adequately protected, but that it does not suffer from nuisance switching. The MF-SVS family is now available with a width as narrow as 3.6mm for design into the slimmest battery pack.

 

MF-VSN Product Family

The MF-VSN product family answers the need for ultra-slim products to match the reduction in thickness of the new generation Li-ion prismatic cells. The VSN products are rated to a maximum voltage of 12V, maximum current of 100A and consists of two main devices: the MF-VS210N designed for GSM battery packs, and the MF-VS170N designed for lower pulse current applications, both with a maximum width of 3.6mm.

 

MF-VS Family

Bourns' Multifuse(R) MF-VS family has been designed for the protection of battery packs rated with a maximum voltage of 16V and a maximum current of 100A. A hold current of 2.4A makes the product family ideal for use inside battery packs designed for PDAs, portable computers and cell phones. With a resistance as low as 20mOhms, the MF-VS increases the run time of the electronic device powered by the battery pack.

 

"Our product line has evolved in tandem with the battery pack industry. We now see that no two packs have the same requirements," said John Kelly, Product Line Manager for Bourns Multifuse(R). "Each pack is uniquely designed and has different mechanical and electrical requirements. Bourns has addressed these issues, and we can now supply a PPTC that has been designed to match the exact requirements of each pack. Consultation with our design team can result in significant cost savings and enhanced performance." Pricing and Availability Samples of Bourns(R) Multifuse(R) SVS, VSN and VS products are now offered for evaluation. Lead time on the products is currently six to eight weeks. Based on quantities of 100K, pricing for the products begins at $0.20 per piece.

 

About Bourns, Inc.

 

Bourns, Inc. is a leading manufacturer of Trimming Potentiometers, Precision Potentiometers, Modular Contacts, Switches, Resistor/Capacitor Networks, and Analog Input Devices, including Panel Controls, Encoders and Point Stick Navigators. Bourns also sells Chip Resistors, Chip Arrays and Inductive Components. Meeting the circuit protection requirements of next-generation products, Bourns' broad circuit protection offering includes an extensive line of PPTC Resettable Fuses, Thyristor-Based Overvoltage Protectors, and Line-feed Surge Networks. Bourns Communication Protection Product line includes Gas Discharge Tubes (GDT), Telephone Station Protectors, 5-Pin Protectors, Industrial Signal, Irrigation and Petroleum Protectors, CATV Coax Protectors, Signal Data Protectors, and the Indoor and Outdoor POTsplitters and Network Interface Devices (NID) product lines. Headquartered in Riverside, CA, Bourns serves a broad range of markets, including telecommunications, computer, industrial, instrumentation, automotive, consumer, medical, audio and various other market segments. Bourns' products are manufactured according to ISO-9000 and QS-9000 standards under Six Sigma quality programs.

Why the voltage of lithium-ion batteries cannot exceed 4.2V

We are writing this post about lithium-ion batteries 4.2V max voltage. You can find the other definition from Wikipedia.

 

The voltage of a lithium ion battery is determined by the electrode potential. Voltage, is a physical quantity that measures the energy difference of electric charges in an electrostatic field. The electrode potential of lithium ion is about 3V, and the voltage of lithium ion batteries varies with different materials. For example, a general lithium-ion battery has a rated voltage of 3.7V and a full-charge voltage of 4.2V; while a lithium iron phosphate battery has a rated voltage of 3.2V and a full-charge voltage of 3.65V. In other words, the potential difference between the positive electrode and the negative electrode of a lithium-ion battery in practical use cannot exceed 4.2V. Which is a requirement based on material and use safety. If the Li/Li+ electrode is the reference potential, μA is the relative electrochemical potential of the negative electrode material. μC is the relative electrochemical potential of the positive electrode material. And the interval Eg is the lowest electron unoccupied energy level and the highest electron occupied energy of the electrolyte. The difference between the levels. Then, it is the three factors of μA, μC and Eg that determine the highest voltage value of a lithium-ion battery.

Function introduction of the protection board

Function introduction of the main parts of the protection board R1: Reference power supply resistance; forms a voltage divider circuit with the internal resistance of the IC to control the level inversion of the internal overcharge and overdischarge voltage comparator. Generally the resistance value is 330Ω and 470Ω. When the package form (that is, the standard component The length and width indicate the size of the component. For example, the length and width of the component in the 0402 package mark are 1.0mm and 0.5mm respectively). When it is large, the resistance value will be marked by numbers. For example, the number mark 473 on the chip resistor indicates its resistance. The resistance value is 47000Ω or 47KΩ. R2: Over-current and short-circuit detection resistance; by detecting the voltage of the VM terminal to control the current of the protection board, poor welding or damage will cause the battery to over-current and short-circuit without protection. The general resistance is 1KΩ, 2KΩ and more. R3: ID identification resistor or NTC resistor (described earlier) or both. Summary: The resistor is a black patch in the protection board. The resistance value can be measured with a multimeter. When the package is large, the resistance value will be indicated by numbers. The method of expression is as described above. Of course, the resistance value generally has deviations. All resistors have accuracy specifications. For example, if the 10KΩ resistance specification is +/-5% accuracy, the resistance value is within the range of 9.5KΩ to 10.5KΩ. C1, C2: Since the voltage at both ends of the capacitor cannot change suddenly, it acts as an instant voltage stabilization and filtering.

basic knowledge of lithium battery protection board

1. The composition of the protection board of lithium battery Its characteristics determine the reason why lithium battery (rechargeable) needs protection. The lithium battery material itself determines that it is not allowed over-charged, over-discharged, overcurrent, short-circuited. The lithium battery’s ultra-high temperature charging and discharging lithium battery components will always appear with an exquisite protection board and a current fuse. The protection circuit board and PTC usually complete the protection function of lithium batteries. The protection board is composed of electronic circuits. It can accurately monitor the battery cell’s voltage and the charging and discharging circuit current under the environment of -40℃ to +85℃. Control the current loop on and off; PTC prevents severe damage to the battery in a high-temperature environment.

The protection board usually includes a control IC, MOS switch, resistor, capacitor, and auxiliary device NTC, ID memory, etc. Among them, the control IC controls the MOS switch to turn on under all normal conditions to make the cell communicate with the external circuit. When the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off (tens of milliseconds). Protect the safety of batteries. NTC is the abbreviation of the Negative temperature coefficient, which means a negative temperature coefficient. When the ambient temperature rises, its resistance decreases. The electrical equipment or charging equipment works to respond in time and control internal interruptions to stop charging and discharging. ID memory is often a single-wire interface memory. ID is the abbreviation of Identification, which means Identification, and stores information such as battery type and production date. It can play a role in product traceability and application restrictions.

Advantages and disadvantages of lithium-ion batteries

Advantages of lithium-ion batteryHigh voltage: The single battery’s working voltage is as high as 3.7-3.8V (the cell voltage can be up to 4.2V). That is three times that of Ni-Cd and Ni-H batteries.

Enormous specific energy: The actual specific power that can arrive 555Wh/kg, that is, the material can reach a particular capacity above 150mAh/g (3-4 times Ni-Cd, 2-3 times Ni-MH). That is close to About 88% of its theoretical value.

Long cycle life: generally can reach more than 500 times, even more than 1000 times, and lithium iron phosphate can get more than 2000 times. Regarding small-current discharge electrical appliances, the battery lifespan will double the competitiveness of electrical appliances.

Good safety performance: No pollution, no memory effect. As the predecessor of Li-ion, the lithium-ion battery is prone to short-circuit due to the formation of dendrites, which reduces its application fields: Li-ion does not contain cadmium, lead, mercury, etc. Environmental pollution elements: A significant drawback of Ni-Cd batteries of some processes (such as sintered) is the memory effect. It severely restricts the use of batteries, but Li-ion does not have this problem at all.

Low self-discharge: The self-discharge rate of fully-charged Li-ion at room temperature about 2% after one month. Much lower than 25-30% of Ni-Cd and 30-35% of Ni and MH.