1364 results about "Overcharge" patented technology

In a battery pack manager that manages series-connected rechargeable unit cells, a cell equalizer equalizes the cell voltages by individually discharging the unit cells according to deviations from reference voltages. An overcharge/overdischarge detector detects an overcharge and an overdischarge state of each unit cell. An inhibit circuit prevents the cell equalizer from discharging the unit cells when the overcharge/overdischarge detector is activated to reduce the cell voltage variability, which would otherwise occur as a result of interference from the overcharge/overdischarge detector, so that the overcharge/overdischarge states of all unit cells can be determined with precision. Connecting lines of the unit cells are monitored to detect a line-cut. The inhibit circuit further inhibits the cell equalizer when the connecting lines are being monitored to reduce the cell voltage variability, which would otherwise occur as a result of interference from the line-cut detection, so that false line-cut detection is avoided.

A compact battery pack with high handling ability and restraining degradation of battery cells. The battery pack includes an insertion portion to be inserted into a handle portion of a cordless power tool and an accommodation portion in which all battery cells are accommodatable. A protection board with a protection circuit that protects batteries against overcharge and over-discharge is installed in the insertion portion. A switching element is connected between the battery cells and a drive motor of the power tool. An air passage in communication with the battery pack is formed within the handle and a main housing of the cordless power tool. The switching element is positioned at the air passage.

A redox chemical shuttle comprising an aromatic compound substituted with at least one tertiary carbon organic group and at least one alkoxy group (for example, 2,5-di-tert-butyl-1,4-dimethoxybenzene) provides repeated overcharge protection in rechargeable lithium-ion cells.

A rechargeable lithium-ion cell contains a positive electrode, negative electrode, charge-carrying electrolyte containing charge carrying medium and lithium salt, and an N-substituted or C-substituted phenothiazine compound dissolved in or dissolvable in the electrolyte. The substituted phenothiazine compound has an oxidation potential above the positive electrode recharged potential and serves as a cyclable redox chemical shuttle providing cell overcharge protection.

The invention discloses a preparation method of a lithium ion battery pole piece containing a PTC (Positive Temperature Coefficient) coating. The pole piece prepared by the method is a multilayer coated pole piece. The method comprises the following steps: before coating slurry comprising an anode or a cathode active substance onto a current collector, coating the current collector with a precoated layer with the temperature sensitivity in advance, wherein the precoated layer with the temperature sensitivity comprises ingredients of a binding agent, a positive temperature material and a conductive agent; the weight ratio of the binding agent to the positive temperature material to the conductive agent is (2-8): (1-8): (0-7). The method provided by the invention is used for preparing the lithium ion battery pole piece containing the PTC coating; the battery using the pole piece has good safety characteristics against overcharge, short circuit, squeezing, needling and the like.

Disclosed herein is a secondary battery module comprising a plurality of unit cells stacked one on another, wherein the unit cells are spaced apart from each other such that a channel for heat dissipation is defined between the unit cells, the battery module further comprises at least one piezoelectric sensor mounted in the channel, and the at least one piezoelectric sensor is connected to a battery management system (BMS). According to the present invention, the piezoelectric sensor is mounted in the channel defined between the unit cells of the secondary battery module. Consequently, no additional space for installing the piezoelectric sensor is needed, and therefore, the increase of the size of the battery module is effectively prevented. Furthermore, the change of the internal pressure of the battery is accurately detected by the piezoelectric sensor, and therefore, the expansion or the explosion of the battery caused due to the overcharge or overheating of the unit cells is effectively prevented.

The invention relates to an improvement in a cell which is normally susceptible to damage from overcharging comprised of a negative electrode, a positive electrode, and an electrolyte comprised of an overcharge protection salt carried in a carrier or solvent. Representative overcharge protection salts are embraced by the formula:

M_aQ

where M is an electrochemically stable cation selected from the group consisting of alkali metal, alkaline earth metal, tetraalkylammonium, or imidazolium groups, and Q is a borate or heteroborate cluster and a is the integer 1 or 2.

It is aimed at stably implementing a protection function of a secondary battery mainly under software control and providing a battery pack characterized by a reduced circuit installation area, parts costs, and power consumption. An AD converter outputs a voltage value between a positive electrode and a negative electrode of a secondary battery. Based on the voltage value, a microcontroller determines a state of the secondary battery out of overcharge, normal operation, and over-discharge states. According to the determined state, the microcontroller controls operations of a discharge current cutoff means and a charge current cutoff means via a FET driver. When it is determined that the secondary battery is placed in an overcurrent state based on the charge and discharge current size of the secondary battery, an overcurrent detection circuit enables the discharge current cutoff means to be a cutoff state in preference to control by the microcontroller.

A non-aqueous electrolyte including a lithium salt, an organic solvent, and an electrolyte additive is provided. The electrolyte additive is a meta-stable state nitrogen-containing polymer formed by reacting Compound (A) and Compound (B). Compound (A) is a monomer having a reactive terminal functional group. Compound (B) is a heterocyclic amino aromatic derivative as an initiator. A molar ratio of Compound (A) to Compound (B) is from 10:1 to 1:10. A lithium secondary battery containing the non-aqueous electrolyte is further provided. The non-aqueous electrolyte of this disclosure has a higher decomposition voltage than a conventional non-aqueous electrolyte, such that the safety of the battery during overcharge or at high temperature caused by short-circuit current is improved.

The invention relates to the field of batteries, in particular to a current collector, a pole piece using the same and a battery. The current collector comprises a PPTC (polymeric positive temperature coefficient) material layer and a metal layer, wherein the PPTC material layer is used for bearing the metal layer; the metal layer is used for bearing an electrode active material layer and is located on at least one surface of the PPTC material layer. The PPTC material layer not only is used for bearing the metal layer, but also can have a rapid resistance increasing function at the stage of temperature rising caused by overcharge and short circuiting because of characteristics of the PPTC material, and generation of joule's heat is inhibited by reducing current value. By means of the current collector, the short-circuiting safety performance because of foreign matter can be improved, and the overcharge safety performance can also be improved.

Using a positive electrode active material including spinel type manganese oxide as the main constituent, a novel low cost and high output power flat type nonaqueous secondary cell for HEVs that has increased safety at overcharge, and superior storage properties and cycle life is provided. A flat type nonaqueous secondary cell that has increased safety and is superior in storage and cycle properties even though the cell is a laminate type cell which does not have a blocking mechanism can be obtained by blending the spinel type lithium manganese oxide of the positive electrode and 5 wt % to 40 wt % of layered type lithium manganese oxide, to suppress storage deterioration at a high temperature and to simultaneously achieve safety when overcharged, and further, by adding a Li compound having a structure as shown in Formula (1) structure, to suppress deterioration of a mixed positive electrode active material during a high temperature cycle.

A high efficiency switching power supply including an analog front end, a battery control circuitry portion, a display and equalization circuitry portion, field effect transistor (FET) drivers, an isolated power supply transformer circuitry (and three associated sets of tap circuitry), microcontroller circuitry, oscillator circuitry, overcharge protection circuitry, programmable logic circuitry portion, and a zero current predictor. Overbiasing of the FET power supply switches, and/or other various circuitry features disclosed herein, helps achieve electrical power efficiencies of preferably greater than 95%, even more preferably greater than 98% and even more preferably greater than 99%. Preferably, the switching power supply has one or more of the following: (1) high electrical power efficiency (>95%. >98%, >99%); (2) overbiasing of a gate of a power supply switch; (3) a power supply switch with a low gate capacitance ratio; (4) multiple modes of operation; and (5) current prediction wherein an inductor voltage is used to control a constant current capacitor whose voltage indicates the level of current in the inductor.

A battery protective device that protects against battery damage and semiconductor destruction from overdischarge and overcharge of the battery. Resistance across switching elements is controllable to prevent current leakage through parasitic dipole elements in the integrated circuit. Current is detected with an overdischarge detecting circuit and an overcharge detecting circuit. Direction of the current to/from the battery is detected by discharge overcurrent and charge overcurrent detecting circuits. Switching discharge FETs and charge FETs are enabled as independently controlled, ON-OFF parallel switching elements, interposed in series in the charge/discharge current path of the battery. Only a part of the discharge or charge switching FETs can be turned ON and OFF for accurate current control in accordance with the detected current and its direction.

A secondary battery is comprised of a positive electrode, a negative electrode formed from a lithium storage material, and a non-aqueous electrolyte. The non-aqueous electrolyte includes a lithium salt, non-aqueous aprotic solvent(s), such as ethylen carbonate, propylene carbonate, dimethyl carbonate, ethymethyl carbonate and diethyl carbonate, and a small percentage of at least one organic additive. The negative electrode may comprise a carbon such as graphite, and the positive electrode may comprise a lithiated metal oxide or phosphate, such as LiCoO₂, LiNiO₂, LiMn₂O₄, LiFePO₄, or mixtures thereof. The organic additives have one or more unsaturated bonds activated with respect to oxidation by electron-pushing alkyl groups. They are in most cases known to be able to undergo polymerization reactions, such as an anodically induced polymerization especially under certain conditions. The additives are oxidized at the cathode at a potential of more than 4.3 V vs. Li/Li⁺. With these additives in amounts of 0.001 to 10%, a passivation layer is formed on the cathodes, and the sensitiveness of the battery against overcharge is reduced. The electrolyte mixtures do not deteriorate the properties of the battery anodes.

The sudden generation of heat being frequently caused in the case of the overcharge of a lithium secondary cell which have a positive electrode comprising a composite metal oxide of lithium and cobalt or a composite metal oxide of lithium and nickel, a negative electrode comprising metallic lithium, a lithium alloy or a material capable of occluding and releasing lithium, and a nonaqueous electrolyte solution comprising a nonaqueous solvent and an electrolyte dissolved therein can be efficiently prevented by the addition, to the nonaqueous electrolyte solution, of an organic compound which, when the lithium secondary cell is overcharged, decomposes into a decomposition product capable of dissolving out the cobalt or nickel contained in the positive electrode and depositing it ion the negative electrode (for example, a tert-alkylbenzene derivative).

Described herein is, for example, a battery or capacitor over voltage (overcharge) and under-voltage protection circuit, that, for example, is adapted to not draw current from the battery or capacitor to be charged unless charge energy is detected and to not charge an energy storage device when an over-charge condition is sensed. The protection circuit may, for example, not be turned on unless an over voltage condition is present. Incoming energy to the system can be shunted to ground via a shunt load of various types including resistive loads and active components such as a zener diode. In some embodiments, no switching of the inbound power is required. Within limits, no regulation of inbound power is needed. When inbound power is sufficient to charge the battery or capacitor, regulation can occur via the applied shunt regulator if overcharge voltage conditions exist. Either type of charge source, voltage or current, can be used to provide charge energy. Combining said battery or capacitor over voltage (overcharge) and under-voltage protection circuit with electronic loads, such as wireless sensors, may lead to autonomously-powered wireless sensor systems.

A rechargeable battery adapted to prevent or reduce overcharge. A rechargeable battery includes a case containing an electrode assembly; a cap plate coupled to the case and sealing an opening of the case; a first electrode terminal connected to a first electrode of the electrode assembly and electrically connected to the case; a second electrode terminal connected to a second electrode of the electrode assembly and electrically insulated from the case when a pressure inside the case is less than a threshold pressure; and a short-circuit unit including a short-circuit member connected to the second electrode terminal, the short-circuit unit adapted to short-circuit the second electrode terminal to the case by swelling a portion of the case to contact the short-circuit member when the pressure inside the case is equal to or greater than the threshold pressure.

A charging current is maintained at a predetermined constant quick charging current (S1), and full charge is judged at a point in time (S7) when the terminal voltage V1 (S6) reaches the charge end voltage Vf'. A voltage drop VD (S4) obtained by multiplying an internal resistance (S3) estimated from the temperature T (S2) of a secondary battery by a quick charge current value is added to a predetermined initial charge end voltage Vf to obtain a voltage (S5) which is employed as the charge end voltage Vf'. Consequently, a quick charge can be performed up to a full charge in place of conventional CC-CV charging by supplying a constant large current from the start to the end while preventing overcharge.