CN1421063A - Devices and methods for protection of rechargeable elements - Google Patents

Abstract

A protection circuit for use with a charger (5) and a chargeable element (1), such as a rechargeable lithium ion battery, comprises a shunt regulator (2) having a threshold ON voltage coupled in parallel across the chargeable element, and a temperature-dependent resistor (3), e.g., a positive temperature coefficient device, coupled in series between the charger and the chargeable element. The temperature dependent resistor is thermally and electrically coupled to the shunt regulator, wherein the first variable resistor limits current flowing through the shunt regulator if the current reaches a predetermined level less than that which would cause failure of the regulator, due to ohmic heating of the regulator.

Description

Be used to protect the device and method of rechargeable elements

The data of related application

The application is that the application number of submitting to April 15 in 1998 is 09/060, the further part of 863 U. S. application, also be that the application number of submitting on March 25th, 1999 is 60/126, the further part of 952 U.S. Provisional Application, the elaboration of these files and disclosed content will be all as the application's list of references.

The technical field of the invention

The present invention belongs to the protection system of voltage overload and current overload in a broad sense, more particularly, is the device and method of the rechargeable elements of protection such as rechargeable battery etc. under voltage overload and current overload condition.

Background technology related to the present invention

The circuit of protection such as rechargeable elements such as rechargeable battery pack is widely known for people, and still, these rechargeable elements, particularly chargeable lithium cell are danger closes when operating voltage surpasses safety margins.

For example shown in Figure 1 is the charging curve of a standard, that is, the battery both end voltage is over time beyond continuing to charge to maximum safe range the time for common lithium battery group (for example being used for radio mobile telephone set).As Fig. 1 institute mark, this curve can be divided into 3 big zones.

First zone is voltage V less than 4.5 volts zone.In this zone, battery charge is safe, and the temperature of battery remains and is lower than 60 ℃ to 70 ℃, and inner pressure of battery is lower than 3 crust by force.

Second zone is the zone of voltage between 4.5 volts and 5.3 volts.Charge in this zone, battery begins to move under the pattern of a danger, and temperature surpasses 70 ℃, and the pressure in the battery rises to the scopes of 3 crust to 10 crust, even the scope that raises slightly at this voltage, battery also may explode.

The 3rd zone is that voltage surpasses 5.3 volts zone.In this stage, it is late to save battery, and it meets with inner the degeneration, may explode or burn.It should be noted that battery is dangerous more at " full charging " state, be more prone to blast than battery in discharge condition.

Especially,, must satisfy one of following 3 conditions: 1) temperature＜60 ℃, 2 for the charging operations that ensures to lithium cell charging is under secure mode of operation) pressure＜3 crust, perhaps 3) voltage＜4.5 volt.

For this reason, usually use " intelligence " circuit to connect during the charging of rechargeable lithium ion batteries group, in case run into excessive voltage or electric current with battery.This intelligent protection circuit can also prevent because the undertension state that the battery pack over-discharge can causes.

For instance, Fig. 2 has shown a kind of common " intelligence " protective circuit 21 that is used for the rechargeable lithium ion batteries group.Wherein, first and second mos field effect transistor (MOSFET) switch 20,22 and one or more battery 24 are cascaded, mos field effect transistor switch 20 and 22 open or close control circuit 26 decision by voltage on the monitoring battery 24 and electric current.In normal running, control circuit 26 makes mos field effect transistor switch 20 and 22 get to " opening ", allows electric current with any direction flow through battery 24, charging or discharge.But if voltage on the battery 24 or electric current have surpassed corresponding threshold value, control circuit 26 cuts out mos field effect transistor 20 and 22, so open circuit 21.Control circuit 26 is also monitored the voltage and current on the charging source 28, and when decision could belong to oxide semiconductor field effect transistor 20 and 22 by the safety hit karat gold.

The personnel that are familiar with this field are understood that, intelligent protection circuit 21 more complicated, and with respect to whole costs of a conventional batteries group, its implementation cost is also too high.And the series resistance on the mos field effect transistor 20,22 is than higher, thereby reduced the efficient of charging source 28 and battery 24.It should be noted that when circuit disconnects that flow to either direction in order not make electric current, mos field effect transistor 20,22 all needs.That is, body diode 23,25 has improved complexity, price and the whole series resistance of protective circuit 21 separately to the different directions biasing.Simultaneously; because mos field effect transistor 20,22 can be damaged in the face of precipitate high voltage (or having used inappropriate high-tension charger); battery 24 also needs second class protection, for example, and the reset insurance of each battery positive temperature coefficient of series connection (PTC).

By these background informations, the device with positive temperature coefficient resistance effect is known for people, can be based on the ceramic material such as barium titanate, or the polymerizable compound of conduction.The polymerizable compound of this conduction contains a kind of polymerization content, is dispersed in and forms a kind of special conductive filler in the compound.During low temperature, the resistance of compound is lower, yet when compound was in high temperature, such as ohm heat that is risen by high-current leading, the resistance of compound raise, and perhaps claimed " conversion " often to change several magnitude.Generation is converted to high-resistance temperature by low resistance and is called inversion temperature Ts.Get back to below the inversion temperature Ts when the device cooling, can get back to low-resistance state again.Therefore, if current limiter as a kind of series connection, this positive temperature coefficient device is just thought " can reset ", as the inversion temperature Ts that is heated to it, its meeting " tripping operation " is to high resistance, therefore reduce the electric current in the circuit, and when being cooled to be lower than Ts automatically " replacements " thereby make in the circuit overload current state remove the back to recover to expire current flow to low resistance.

In this is used, " PTC " this speech is used to represent a kind of compound, the R14 value is minimum to be 2.5, and/or the R100 value minimum be 10, preferably the R30 value of this compound should be at least 6, here the R14 value is in the end of one 14 ℃ scope and begins to locate the ratio of resistance value, and the R100 value is in the end of one 100 ℃ scope and begins to locate the ratio of resistance value, and the R30 value is one 30 ℃ end of extent (EOE) and begins to locate the ratio of resistance value.Generally, the shown resistance that goes out of the employed compound of device of the present invention raises and will be much higher than these minimum values.

Suitable conducting polymer compound is published in United States Patent (USP) the 4th, 237, No. 441 (vanKonynenburg etc.), United States Patent (USP) the 4th, 545, No. 926 (Fouts etc.), United States Patent (USP) the 4th, 724, No. 417 (Au etc.), United States Patent (USP) the 4th, 774, No. 024 (Deep etc.), United States Patent (USP) the 4th, 935, No. 156 (van Konynenburg etc.), United States Patent (USP) the 5th, 049, No. 850 (Evans etc.), United States Patent (USP) the 5th, 250, No. 228 (Baigrie etc.), United States Patent (USP) the 5th, 378, No. 407 (Chandler etc.), United States Patent (USP) the 5th, 451, No. 919 (Chu etc.), United States Patent (USP) the 5th, 582, No. 770 (Chu etc.), United States Patent (USP) the 5th, 701, No. 285 (Chandler etc.), United States Patent (USP) the 5th, 747, No. 147 (Wartenberg etc.), and among common unsettled U. S. application the 08/798th, No. 887 (Toth etc. are in submission on February 10th, 1997).Content that these patents and application are announced will be all as the application's list of references.

Referring to Fig. 3 A, the protective circuit 31 of short-circuiting device form also is that people know.Especially, switch element 30 is in parallel with battery 24, and the Push And Release of switch 30 is responsible for by the control circuit 36 of the voltage and current on the monitoring battery 24.In normal running, switch 30 is opened, still, if voltage on the battery 24 or electric current have surpassed corresponding threshold value, control circuit 36 off switch 30, thereby the circuit of short circuit battery 24.

The electric current of process switch was with respect to the curve 35 of voltage when Fig. 3 B had shown switch element 30 closures.It should be noted that the characteristic that is subjected to specific power surges and the control of continuation, electric current can the higher level of very fast arrival.In this course, the first current overload element 32 can be placed between switch element 30 and the charge member 28, avoids damaging switch element 30 from the continuous current of charge member 28.Similarly, the second current overload element 34 can be placed between switch element 30 and the battery 24, in order to protection battery 24.But total series resistance of current overload element 32 and 34 does not wish to obtain on the battery path.

It is another kind of voltage overload protection clamp circuit 41 that Fig. 4 A illustrates, and especially, is used in the position of switch element 30 such as the voltage clamp element 40 of Zener diode, in parallel with battery 24.Under the state of voltage overload, clamper element 40 can be limited in the voltage on the battery 24.

Fig. 4 B illustrate be in the clamp circuit 41 electric current with respect to the curve 45 of voltage.Identical with short-circuiting device circuit 31, be subjected to the characteristic of specific voltage impact and the control of continuation, the electric current of the clamper 40 of flowing through can reach quite high level very soon.Equally, increasing current limiting element (not shown among Fig. 4) can protect clamper 40 and/or battery 24 to exempt from the super-high-current infringement.It should be noted that clamper element 40 has higher leakage current, for example,, can cause the very fast in time discharge of battery 24 for Zener diode.

Summary of the invention

According to an aspect of invention described here, the protective circuit that is used for charger and rechargeable elements comprises that one is used for first utmost point in parallel with rechargeable elements and the bypass pressurizer of second utmost point, and this bypass pressurizer has a threshold value cut-in voltage.Temperature resistance and bypass pressurizer calorifics and electrically link together, first utmost point of resistance is connected with charger, and second utmost point is connected with rechargeable elements.

In a preferred embodiment, resistance is a positive temperature coefficient device, can be transformed into higher resistance from lower resistance when being heated to a certain inversion temperature.The inversion temperature of device is selected as, and under the state of voltage overload, the electric current of the bypass pressurizer of flowing through can make the bypass pressurizer produce enough ohm heat, can make device heats to inversion temperature before the bypass pressurizer is damaged.

According to another aspect of invention described here, the control circuit that is used for the protective circuit control bypass pressurizer change over switch of charger and rechargeable elements comprises first and second voltage detecting circuits.The electric leakage of first voltage detecting circuit is less, if the voltage on the rechargeable elements can start second voltage detecting circuit near the threshold value cut-in voltage of change over switch.Second voltage detecting circuit is more accurate, if the voltage on the rechargeable elements reaches the threshold value cut-in voltage, can start change over switch.

Another aspect according to invention described here; the control circuit that is used for the protective circuit control bypass pressurizer change over switch of charger and rechargeable elements comprises an operation amplifier; has the output that links to each other with the enabling gate of transistor switch; also comprise a voltage clamp element that links to each other with the output of operation amplifier, the clamper element is clamper enabling gate voltage effectively.

According to another aspect of invention described here, the bypass pressurizer of protection rechargeable elements overcharge comprises a transistor switch with thermal compensation voltage characteristic.

According to another aspect of invention described here, the protective circuit that is used for charger and rechargeable elements comprises a voltage overload bypass pressurizer, has to be used for first utmost point in parallel with rechargeable elements and second utmost point; Also comprise a undertension protective circuit, have first utmost point and second utmost point that are connected between charger and the rechargeable elements.In a preferred embodiment, voltage overload bypass pressurizer comprises the first transistor switch, and its threshold value cut-in voltage is approximately the selected maximum working voltage of rechargeable elements.The undertension protective circuit comprises the transistor seconds switch, and its threshold value cut-in voltage is approximately the selected minimum of rechargeable elements.

Another aspect according to invention described here; the protective circuit that is used for charger and rechargeable elements comprises a voltage overload bypass pressurizer; it has and is used for first utmost point in parallel with rechargeable elements and second utmost point; the bypass pressurizer comprises a mos field effect transistor switch; it has the threshold value cut-in voltage and is approximately the selected maximum working voltage of rechargeable elements, comprises that also resistance is higher, the body diode of reverse current.

Another aspect according to invention described here; the protective circuit that is used for charger and rechargeable elements comprises a voltage overload bypass pressurizer; it has and is used for first utmost point in parallel with rechargeable elements and second utmost point; the bypass pressurizer comprises a channelled transistor switch; if positive bias; electric current can positive flow be crossed passage, if negative bias then reverse flow is crossed passage.Especially, it is less that transistor switch is configured to the resistance that the forward flow electric current is subjected to, and the resistance that the electric current of reverse flow is subjected to is bigger.

According to another aspect of invention described here, the protective circuit that is used for charger and rechargeable elements comprises voltage overload bypass pressurizer, and it has and is used for first utmost point in parallel with rechargeable elements and second utmost point, and the bypass pressurizer has a threshold value cut-in voltage.First positive temperature coefficient (PTC) device and bypass pressurizer calorifics and electrically link together.First utmost point of this positive temperature coefficient device is connected with charger, and second end is connected with rechargeable elements.Second positive temperature coefficient device is connected with the bypass pressurizer, and wherein, the inversion temperature of first positive temperature coefficient device is lower than the inversion temperature of second positive temperature coefficient device.

According to another aspect of invention described here, protective circuit has and anodal is in the same place with the battery combination of negative pole with one, and protective circuit comprises the transistor switch of connecting with battery, makes it when transistor switch is opened, and battery passes through load discharge.A temperature resistance is connected with transistor switch calorifics, and temperature resistance has first utmost point that is connected in anode.First utmost point of a fixed resistance is connected in second utmost point of temperature resistance, and second utmost point of fixed resistance links to each other with the negative pole of battery, and temperature resistance and fixed resistance are cascaded like this, and is in parallel with battery again.The enabling gate of transistor switch is connected in the branch laminated structure, extremely links to each other with first of second utmost point of temperature resistance and fixed resistance.

In a preferred embodiment, temperature resistance is from being converted to high electrical resistance than low resistance, selected inversion temperature is, under the state of cell voltage overload, the electric current of transistor switch of flowing through will produce enough ohm heat, before transistor switch breaks down, the temperature resistance device is heated to inversion temperature.

Those skilled in the art is not difficult to find out, hereinafter also will be referred to other aspects of the present invention and advantage.

Accompanying drawing is briefly described

Mode by example is illustrated according to a preferred embodiment of the invention, with the form of appended accompanying drawing but be not limited to this mode.For convenience of description, the like among the different embodiment is with identical labelled notation, wherein:

What Fig. 1 represented is the charging curve of typical chargeable lithium cell;

Fig. 2 is the schematic diagram that has adopted " intelligence " voltage overload protective circuit that pair of transistor elements connects with rechargeable battery pack;

Fig. 3 A is the schematic diagram that has adopted voltage-controlled short switch " short-circuiting device " in parallel with rechargeable battery pack protective circuit;

The relation that Fig. 3 B has drawn short-circuiting device circuital current and voltage among Fig. 3 A;

Fig. 4 A is the schematic diagram that has adopted the zener diode voltage clamper voltage clamp circuit in parallel with rechargeable battery pack;

The relation that Fig. 4 B has drawn clamp circuit electric current and voltage among Fig. 4 A;

Fig. 5-Figure 10 is schematic block diagram and the circuit diagram according to preferred second protective circuit of one aspect of the invention;

Figure 11 is further preferred voltage overload according to another aspect of the present invention, the schematic block diagram of the main protective circuit of current overload, comprises the pressurizer of positive temperature coefficient device of connecting with rechargeable battery pack respectively and the parallel connection of connecting with rechargeable battery pack;

Figure 12 is the schematic diagram of protective circuit among Figure 11, and wherein, positive temperature coefficient device is connected with pressurizer calorifics;

Figure 13 is the schematic diagram of the advantageous variant of protective circuit among Figure 11 and Figure 12;

Figure 14-Figure 16 preferred current-voltage relation of protective circuit according to a further aspect of the present invention that drawn;

Figure 17 a kind of preferred thermal compensation voltage characteristic of preferred protective circuit that drawn;

Figure 18 is that a kind of thermal model circuit of protective circuit among Figure 12-Figure 13 is represented;

Figure 19 has drawn among Figure 12-Figure 13 protective circuit under the voltage overload state, respectively the power that dissipates at pressurizer and positive temperature coefficient device;

Figure 20 is that the preferred voltage that rechargeable battery pack adopts is transshipped, the schematic diagram of current overload protection circuit;

Figure 21 is an alternative preferred embodiment of the protective circuit among Figure 20;

Figure 22 is the schematic block diagram of Figure 20 circuit;

Figure 23 is the schematic block diagram of another alternative preferred embodiment of Figure 20 circuit, has adopted low electric leakage start-up circuit;

Figure 24 is the schematic diagram of another preferred protective circuit according to another aspect of the present invention, has comprised the protective circuit of overload and undertension simultaneously;

Figure 25 is the schematic diagram of the body diode of the pressurizer mos field effect transistor element among Figure 20;

Figure 26 is at the schematic diagram of the body diode series resistance of mos field effect transistor among Figure 25;

Figure 27 is that Figure 26 has connected and is used as the profile of the preferable alloy oxide semiconductor field effect transistor device of bypass pressurizer in the protective circuit of resistance;

Figure 28 represents according to another aspect of the present invention, is used to avoid an alternative preferred semiconductor device of reverse battery discharge;

Figure 29 represents to be used to avoid another alternative preferred semiconductor device of reverse battery discharge;

The drawn preferred current-voltage curve of device among Figure 28 and Figure 29 of Figure 30;

Figure 31 is the simple schematic diagram of another preferred voltage overload protecting circuit;

Figure 32-Figure 33 current-voltage relation of circuit among Figure 31 that drawn;

Figure 34 is the simple schematic diagram of another preferred voltage overload protecting circuit;

Figure 35 current-voltage relation of circuit among Figure 34 that drawn;

Figure 36 is the simple schematic diagram of another preferred voltage overload protecting circuit;

Figure 37-Figure 38 current-voltage relation of circuit among Figure 36 that drawn;

Figure 39 is the simple schematic diagram of preferred three utmost point protective circuits;

Figure 40-Figure 42 is the simple schematic diagram of an alternative embodiment of three electrode protectors among Figure 39;

Figure 43 is the simple schematic diagram of the over-discharge can protective circuit of avoiding the battery over-discharge can of prior art;

The simple schematic diagram of Figure 44 preferred over-discharge can protective circuit according to a further aspect of the present invention;

Figure 45 is the side view of preferred three electrode protectors, comprises a mos field effect transistor pressurizer that is connected with electricity with positive temperature coefficient chip calorifics, and device is partly cut across, and shows the inside of pressurizer;

Figure 46-Figure 47 is respectively the top and bottom perspective views that installs among Figure 45;

Figure 48 is the perspective view that one group of positive temperature coefficient device is cut in a slice PTC material segmentation of when device in assembling Figure 45;

Figure 49 is a perspective view of making the employed preferred transfer box of three-pole device mold shell among Figure 45;

Figure 50 is the perspective view of one group of molding outer casing forming on the transfer box in Figure 49;

Figure 51 is the perspective view that three-pole device is placed in the shell that constitutes according to the drawn step of Figure 49-Figure 50 among Figure 45, does not cover lid;

Figure 52 is the perspective view that three-pole device is placed in the shell that constitutes according to the drawn step of Figure 49-Figure 50 among Figure 45, cover lid;

Figure 53 is a perspective view of making the employed first kind of alternative preferred transfer box of three-pole device mold shell among Figure 45;

Figure 54 is the perspective view of a plurality of molding outer casings of constituting on the transfer box in Figure 53;

Figure 55 is a perspective view of making the employed second kind of alternative preferred transfer box of three-pole device mold shell among Figure 45;

Figure 56 is the perspective view that three-pole device is placed in the shell that constitutes according to Figure 54 or the drawn step of Figure 55 among Figure 45;

Figure 57 is the end view of an alternative embodiment of preferred three electrode protectors among Figure 45;

The upward view that installs among Figure 58 Figure 57;

Figure 59 is the upward view of the part of a printed circuit board (PCB) easily (" pc plate ") that has three utmost point protective circuit sockets that an alternative preferred rechargeable battery pack is installed;

Figure 60 is the upward view of printed circuit board (PCB) among Figure 59, and a mos field effect transistor voltage-stabilizing device is fixed on the positive temperature coefficient device of printed circuit board (PCB) bottom surface through socket among the figure;

Figure 61 is the upward view of printed circuit board (PCB) bottom surface among Figure 59; And

Figure 62 is the end view after printed circuit board (PCB) is partly cut across among Figure 61.

Detailed description of preferred embodiment

According to one aspect of the present invention described here, protection system can protect rechargeable battery not enter a kind of operational mode of danger because of overcharging in charging operations.The protection system of embodiment can be used as back-up system among Fig. 5-Figure 10, generally all is that the intelligent power circuit with the monitoring battery charging uses together.In typical case, this protection system can integrate with battery itself, perhaps can be used as the part of electronics the complete sets of equipment, or the part of charger.

Fig. 5-Fig. 7 has shown basic circuit embodiment according to this aspect of the invention.In Fig. 5, be that 4.5 volts the rechargeable battery 1 of lithium battery is in parallel with the voltage-controlled resistive element such as 4.1 volts of Zener diodes 2 such as maximum working voltage, constitute a parallel circuits.This parallel circuits is connected with a protection component 3 such as positive temperature coefficient device, hot fuse or bimetallic electric brake again.For the startup of acceleration protection element 3, protection component 3 preferably is connected with Zener diode 2 calorifics.The parallel circuits of a charger 5 and a smart circuit 6 is connected with the parallel circuits of battery 1 and Zener diode 2, and charger 5 also links to each other with the power supply (not shown).In this embodiment, because protection component 3 connect with the parallel circuits of battery 1 and Zener diode 2, whole fault currents protection component 3 of all flowing through, so make the protection component startup faster.

Fig. 6 and Fig. 7 have shown the version of Fig. 5 embodiment, comprise having used a new protection component 4.

In above embodiment, because the energy loss in Zener diode is one 1 to 4 watt a big value, this energy loss can cause protection component 3 effective underground heat jump help locks.Protection component 3 and Zener diode 2 can mix and improve calorifics and be connected.

When using the dc charger 5 (this is common situation) of fixed current, very little because of the internal resistance of battery 1, electric current begins to its charging.If smart circuit does not play a role, cell voltage one reaches 4.3 volts, and a little electric current just is diverted to Zener diode 2, makes voltage remain on 4.3 volts.If it is big that charging current becomes, the differential resistance of Zener diode 2 will reduce, and by receiving increasing electric current, make battery 1 keep 4.3 volts constant.In this case, Zener diode 2 is in a kind of pattern out of control, can warm up very soon, and by the heat of Zener diode consumption protection component is overturn quickly, therefore avoid battery 1 to enter a kind of mode of operation of danger.

When using the fixed voltage charger as power supply 5, the circuit among Fig. 5-Fig. 7 all is to work in above-mentioned similar mode.

Fig. 8 has shown another embodiment of the present invention, has wherein used an optical coupler 7.Optical coupler 7 comprises a receiving element, for example phototransistor 8 and a radiated element, for example a LED (light-emitting diode) 9.As shown in Figure 8, rechargeable battery 1 is formed first parallel circuits with in parallel such as the tandem compound of the Zener diode 2 of 3 volts of grades and light-emitting diode 7.Protection component 3 such as fuse, positive temperature coefficient device or bimetallic electric brake is connected with first parallel circuits, and phototransistor 8 is in parallel with the combination of the protection component 3 and first parallel circuits, forms second parallel circuits.Charger 5 is in parallel with second parallel circuits again with the parallel circuits of smart circuit 6, and charger 5 also links to each other with the power supply (not shown).

The embodiment of Fig. 8 is according to above-mentioned similar principle work, and under normal circumstances, the undercurrent in the Zener diode 2 is so that light-emitting diode 9 is luminous.If but meet accident, for example used high-voltage charger, the electric current in the Zener diode 2 will increase, and exciting light coupler 7, the latter and then bypass battery 1.This causes protection component 3 startups and therefore battery 1 is opened circuit.

Fig. 9 has shown another preferred protective circuit.In this embodiment, rechargeable battery 1 is in parallel with the checkout gear 10 that overcharges, and such as Telcom Semiconductor, the model that Inc. makes is the voltage overload checkout gear (for example SOT23B-3 plug-in unit or SOT89-3 plug-in unit) of TC54VN.The parallel circuits of battery 1 and checkout gear 10 is connected with protection component 11, and the latter can be fuse, hot fuse or a positive temperature coefficient device.The combination of battery 1, checkout gear 10 and detecting element 11 is in parallel with an active mos field effect transistor 12, and the MTD 3055EL (VL) of optional Motorola is numbered 369A-10.The parallel circuits of smart circuit 6 and charger 5 is in parallel with battery 1 again, and charger 5 also links to each other with the power supply (not shown).

Mos field effect transistor 12 is setovered by resistor 13, and is driven by transistor 14 by checkout gear 10.Checkout gear 10 comprises a fixed current generator 15, provides electric current to one with reference to Zener diode 16.Use an operation amplifier 17 that is connected with 19 with resistor 18 device as a comparison, with the voltage and the cell voltage comparison of Zener diode 16.When cell voltage reached 4.5 volts, positive voltage of comparator output was closed transistor 14, and then opening metal oxide semiconductor field effect transistor 12, and this is with bypass battery 1, and promptly most of electric current flows through protection component 11.If that protection component 11 uses is fuse (for example AVX-Kyocera of Farnell), will fuse, battery is opened circuit.Thereby the protection battery can not explode.If protection component 11 usefulness positive temperature coefficient devices replace fuse, positive temperature coefficient makes big electric current reduce to little leakage current tripping operation, thereby the protection battery can not explode.

Under normal circumstances, when smart circuit 6 operate as normal, cell voltage is lower than the voltage of Zener diode 16.Negative voltage of comparator 17 outputs, its turn-on transistor 14 makes active mos field effect transistor 12 be in closed condition.

In the embodiment of Fig. 9, the charger of use fixed current just can not be dangerous.The maximum charging current of supposing battery 1 is 2C, and C is the defined battery capacity of manufacturer here, if charging current surpasses 2C, fuse can fuse, and battery 1 and charger 5 are opened circuit.But, if charging current less than 2C, and charging voltage is higher than 4.5 volts, checkout gear 10 will detect fault and bypass battery 1, blow a fuse.

In the embodiment of Fig. 9, the charger of use fixed voltage can be not dangerous yet.If the overtension on the charger 5, and cause charging current greater than 2C, fuse will fuse in case battery explosion.On the other hand, if charging current less than 2C, makes the voltage on the battery surpass 4.5 volts because of the high voltage on the charger 5, voltage overload checkout gear 10 will play a role, the bypass battery and the fuse that fuses.If replace fuse with positive temperature coefficient device, positive temperature coefficient device will trip, the protection battery.

In the embodiment of Fig. 9, all constituents (that is, protection component, the checkout gear that overcharges, resistor and active mos field effect transistor) preferably all are surface mounted device (being called for short SMD).

Referring to Figure 10, in parallel such as the rechargeable battery 1 of lithium ion battery in a further advantageous embodiment with a kind of alternative checkout gear 27 that overcharges, TelcomSemiconductor for example, the model of Inc. is the product of TC54VC.Checkout gear 27 comprises a fixed current generator 15, Zener diode 16, resistor 18 and 19, operation amplifier 17, p-type field-effect transistor (FET) Q1, a n-type field-effect transistor Q2.The parallel circuits of battery 1 and checkout gear 27 is connected with first protection component 99 again.The output of checkout gear 27 is by resistance R 1 control thyristor (being called for short SCR) 43.Second protection component 98 is connected with the parallel circuits of first protection component 99, thyristor 43, checkout gear 27, battery 1, and charger 5 links to each other with entire circuit again, and charger 5 also links to each other with the power supply (not shown).In a preferred embodiment, two protection components 99 and 98 are the fuse for having lag characteristic respectively, such as the SMD Slo-Blo fuse 2A that is produced by Littelfuse company.

Such fuse fuses in that big electric current takes place has about 20 milliseconds delay as last, if big electric current has disappeared within during this period of time, fuse just can not fuse.In addition, R1 can be that a resistance value is 22 kilo-ohms a SMD resistance, the ST 1220-600B thyristor that the example of thyristor 43 can have ST Microelectronics (France) company to produce.Under normal circumstances, charger 5 provides the electric current of stable 4.3 volts of voltages and 2 amperes by protection component 99 and 98 to battery 1.Detection voltage Vd utilization and operation amplifier device is as a comparison compared with reference voltage Vref.In this case, detect voltage Vd and be lower than reference voltage Vref, so the positive voltage of a turn-on transistor Q2 of comparator 17 outputs, and transistor Q1 keeps closing.Because do not have the electric current resistor R 1 of flowing through, thyristor 43 does not start, circuit is carried out normal charging operations.

Under the situation of using the error in charging device, that is, high-voltage charger, one 12 volts charger for example, cell voltage Vbat will be above 4.3 volts above behind the Vref at Vd.Under these circumstances, the negative voltage of a turn-on transistor Q1 of comparator 17 output, and transistor Q2 closes makes the flow through gate of resistor R 1 and thyristor 43 of electric current.Therefore thyristor 43 starts short circuit battery 1 and charger 5.Cause big electric current not walk battery 1 and charger 5, and through thyristor 43 ground connection.Big electric current makes and protection component 99 and 98 fusing (mistake) charger 5 and battery 1 is opened circuit.Protection component 99 and 98 lag characteristic have been got rid of the accidental short circuit that only continues the battery of very short time effectively.

It should be noted that; following Fa Ming preferred embodiment and show thus and the invention characteristic that illustrates mainly is meant independent protection or voltage regulator circuit;---promptly, not as second reserve of smart circuit, the situation of the preferred embodiment described in above Fig. 5-Figure 10.

Following for convenience of description preferred embodiment of inventing and the invention characteristic of showing thus and illustrating, the primary element of selected voltage overload, current overload protection circuit 37 is drawn among Figure 11.Wherein, Voltagre regulator (for example voltage control mos field effect transistor switch) 39 is in parallel with battery 24, a positive temperature coefficient device 38 is between pressurizer 39 and charge member 28, and wherein positive temperature coefficient device 38 is connected with battery 24.

Referring to Figure 12, pressurizer 39 preferably links together with positive temperature coefficient device calorifics, represents with arrow 48.Under the state of voltage overload, pressurizer 39 has limited the voltage on the battery 24, makes the form consumption of energy with the pressurizer 39 of flowing through.Electric current produces heat on pressurizer, conduct to positive temperature coefficient device 38 again, makes i.e. " tripping operation " temperature of conversion that the temperature of positive temperature coefficient device is raised to it.At this moment the resistance of positive temperature coefficient device rises rapidly, and the electric current of the pressurizer 39 of flowing through is reduced, and the heat balance of circuit 37 has determined final working point, up to the state that has overcome the voltage overload.At this moment, pressurizer 39 stops conduction current, and the positive temperature coefficient device cooling is got back to below its trip temperature, makes circuit 37 return to normal operating state.

Those skilled in the art is not difficult to find out that positive temperature coefficient device 38 also can be placed on the grounded circuit of battery charger, another protective circuit embodiment 37 ' as shown in figure 13.As situation about being described in detail here, the design alternative between the embodiment 37 and 37 ' depends on that the calorifics that how physically shows between positive temperature coefficient device 38 and the pressurizer 39 connects 48.

In embodiment 37 or 37 ', positive temperature coefficient device 38 also is used for preventing the overload current that the unexpected charge or discharge by battery 24 cause.Wherein, if electric current increases suddenly, positive temperature coefficient device 38 can produce an ohm heat rapidly owing to a large amount of consumed energies of burst impact, stops electric current significantly up to tripping.

Importantly, for battery 24 being charged fully and discharging, the electric leakage of the series resistance of positive temperature coefficient device 38 and voltage-stabilizing device 39 is preferably all very little.

It should be noted that current-voltage relation that the bypass pressurizer 39 of protective circuit embodiment 37 and 37 ' be should bear is by 45 expressions of the curve among Fig. 4 B.If but voltage surge on the low source resistance at charger or battery two ends 24, bypass pressurizer 39 will transship, and be easy to damage.

For this reason, the circuit of prior art generally all uses silicon bypass pressurizer, has the characteristic of low fluctuation ratio ability.But according to another aspect of the present invention, the bypass pressurizer can be configured to have specific superior current-voltage relation, needs with the energy consumption that limits pressurizer,, can optimize the pressurizer of battery protecting circuit that is.

Figure 14-Figure 16 has represented the other three kinds of preferred I-E characteristics of protective circuit bypass pressurizer.

In Figure 14, I-V curve 421 reaches steady section 422 when electric current I reaches selected maximum current level I_lim, in other words, the short of maximum current limit I_lim that surpasses particular design, the pressurizer device is designed to bear specific overload.Especially, to a specific pressurizer design limit maximum current and a correspondent voltage, the energy of required dissipation also just is restricted.

If adopt a kind of more complicated circuit, introduce second current limliting that excites by the voltage Vt that pre-establishes, can further reduce dissipation.For this reason, in Figure 15, the initial part 423 of curve is similar with curve 421, reaches the steady section 424 that is similar to steady section 422 when electric current reaches I_lim1.But along with the rising of voltage at fixed current I_lim1 place, the energy dissipation demand of bypass pressurizer also is improved, and electric current falls at excitation voltage Vt place.When voltage reaches the Vt that pre-establishes, electric current I drops to low current level I_lim2 (425) from I_lim1.This electric current decline has reduced the energy dissipation demand in the bypass pressurizer effectively.

Figure 16 has shown another embodiment of preferred I-V relation, and it has reduced the dissipation demand of bypass pressurizer under the big electric current.Initial oblique line 426 is the same with 423 with the curve 421 of steady section front.But when the value of voltage with reference to the corresponding I_max of arrival, bypass pressurizer element locks onto a low-voltage/big current-mode, by steady section 427 expressions.At the Imax place, the I-V characteristics design of bypass pressurizer drops to Von for being supported in Imax place voltage.At the voltage levvl of this reduction, the bypass pressurizer just can be dealt with big electric current, shown in curve 428.

Figure 17 is compared with the preferred embodiment of protective circuit among Figure 12-Figure 13, and the changing voltage of pressurizer 39 can also be realized with a temperature funtion.Wherein, it can require to realize the thermal compensation voltage characteristic in the pressurizer 39, and is represented as temperature-voltage curve 49.Wherein, a pressurizer 39 of following the transfer characteristic of temperature-voltage curve 49 can be configured in changing voltage the normal working temperature that is significantly less than battery 24.

For example, on a certain safe working temperature,,, realize that temperature-voltage curve 49 will allow battery 24 by pressurizer 39 discharges if surpassed the safe working temperature of battery 24 as 80 ℃.In other words, pressurizer 39 also similarly is a passive overheat protector except being a voltage overload and the overcurrent protection device.

An embodiment who it will be apparent to those skilled in the art that here institute's preferred pressurizer of showing and illustrating, though be not whole also have many can design or be embodied as comprise the voltage characteristic of one of them at least shown in Figure 14-Figure 17.

Figure 18 drawn with Figure 12-Figure 13 in the calorifics circuit model of protective circuit equivalence, that is, can be expressed as a RC circuit.

Especially, for a positive temperature coefficient device (as positive temperature coefficient device 38), temperature T can be determined by following equation: $\left(1\right)---\frac{\mathrm{dE}}{\mathrm{dt}}=m{C}_p\frac{\mathrm{dT}}{\mathrm{dt}}+k(T-T_a)$

Wherein

Be the energy (power) of unit interval, m is a quality, C _pBe specific heat, k

Be thermal resistance and T _aIt is ambient temperature

For a RC circuit in parallel, the voltage V of circuit is: $\left(2\right)---I=C\frac{\mathrm{dV}}{\mathrm{dt}}+\frac{V}{R}$

Wherein I is the electric current in the circuit, and C is that electric capacity and R are resistance. $\left(1\right)---\frac{\mathrm{dE}}{\mathrm{dt}}={\mathrm{mC}}_p\frac{\mathrm{dT}}{\mathrm{dt}}+k(T-T_a)$

Wherein Be the energy (power) of unit interval, m is a quality, C _pBe specific heat, k

Be thermal resistance and T _aIt is ambient temperature

Compare equation (1) and (2), Be equivalent to electric current I, T is equivalent to voltage V, MC _pBe equivalent to capacitor C, k is equivalent to electricity and leads I/R. $\left(2\right)---I=C\frac{\mathrm{dV}}{\mathrm{dt}}+\frac{V}{R}$

Wherein I is the electric current in the circuit, and C is that electric capacity and R are resistance.

Get back to the thermal modeling among Figure 18, electric capacity 52 is represented the thermal capacitance (mC of pressurizer device 39 _p) _Reg, resistance 54 is represented the thermal resistance R of pressurizer to the extraneous heat-transfer path _{θ (Reg-Ambient)}, the power loss P on the pressurizer _{D (reg)}Represent with current source 46.Especially, how many energy are the temperature of thermal capacitance decision rising pressurizer 39 need, that is, thermal mass is big more, and the intensification energy needed is just big more.The validity of thermal resistance decision heat dissipation, big thermal resistance means to dissipate the heat into does not on every side have low thermal resistance effective like that.

With same form, the thermal capacitance (mC of electric capacity 60 expression positive temperature coefficient devices 38 _p) _PTC, the thermal resistance R of resistance 58 expression positive temperature coefficients to the extraneous heat-transfer path _{θ (PTC-Ambient)}, the power loss P on the positive temperature coefficient device _{D (PTC)}By current source 47 expressions.

When power on pressurizer 39 during loss, temperature is that " voltage " on the thermal capacitance will raise thermal resistance R _{θ (Reg-Ambient)}With heat conduction towards periphery, prevent that the temperature on the pressurizer 39 from increasing without limitation.From this aspect, low more to thermal resistance on every side, temperature rises lowly more on the pressurizer element.

Equally, some heat will be from pressurizer 39 by the thermal resistance R between pressurizer 39 and the positive temperature coefficient device 38 _{θ (Reg-PTC)}56 conduct to positive temperature coefficient device 38, and this hot link causes the temperature on the positive temperature coefficient device to raise and raise along with the temperature on the pressurizer.In case positive temperature coefficient device 38 arrives its inversion temperature, positive temperature coefficient device 38 can trip, the power on the restriction pressurizer 39.Therefore, for the temperature that limits on the pressurizer 39 raises, need positive temperature coefficient device 38 to arrive its inversion temperature as soon as possible.What for this reason, the thermal resistance between positive temperature coefficient device 38 and the pressurizer 39 should be done is as far as possible little.

Temperature on the pressurizer 39 rises and can also be limited with a lower positive temperature coefficient device of inversion temperature, and like this, when pressurizer 39 begins adstante febre under voltage overload or current overload state, positive temperature coefficient device 38 will be than very fast tripping operation.In addition, by reducing the quality of positive temperature coefficient device 38, its thermal capacitance 60 will reduce, and when positive temperature coefficient device 38 is arrived in heat conduction, its temperature will rise faster.By the hot road model of Figure 18 as can be seen, the thermal capacitance 60 of positive temperature coefficient is the smaller the better.For example, quote in full its described content as this paper reference content, be presented to the United States Patent (USP) of Chandler etc. and just announced a kind of preferred cold-starting, low-quality PTC material for the 5th, 801, No. 612.

Figure 19 represents for the accompanying drawing of the protective circuit power loss under the voltage overload state among Figure 12-Figure 13.

Below 63, the power of pressurizer 39 or 38 losses of positive temperature coefficient device can be ignored in particular threshold voltage, that is, battery circuit is worked under normal operating voltage or is recharged.If but voltage has surpassed greatest limit, pressurizer 39 beginning conduction current and heat dissipations, this is by curve 64 expressions.Along with positive temperature coefficient device 38 owing to the heat from pressurizer 39 improves temperature, reach its inversion temperature and the more substantial power that begins to dissipate, shown in curve 66.Along with the more power of positive temperature coefficient device 38 dissipation, the electric current of the pressurizer 39 of flowing through reduces, and pressurizer 39 has also just correspondingly reduced the power that dissipates.Whole power dissipation under the voltage overload state are kept constant by curve 68 expressions substantially.

Figure 20 has drawn, and a preferred voltage is transshipped, current overload protection circuit 69, and wherein positive temperature coefficient device 62 and bypass pressurizer 50 are connected with battery 24 respectively and be in parallel.Shown in arrow 71, can select the Raychem model for use is that the positive temperature coefficient device 62 of VTP210 links together with bypass pressurizer 50 calorifics.Bypass pressurizer 50 comprises a mos field effect transistor switch 51, operation amplifier controller 53, the reference 55 of precision voltage and voltage divider 75, all is assembled on the independent silicon device.

Especially, mos field effect transistor 51 by 53 controls of operation amplifier (promptly, open or close), the door of a voltage signal opening metal oxide semiconductor field effect transistor 51 of output when the voltage of the latter on detecting battery 24 reaches specific threshold value.For this reason, the positive pole of operation amplifier 53 is connected to voltage divider 75, and the latter comprises a pair of and battery 24 parallel resistor 57 and 59.The negative pole of operation amplifier 53 connects precision voltage with reference to 55, and the latter links to each other with the negative pole (earth terminal) of battery 24 again.By regulating electric bridge (that is, resistance 57 and 59) decision upper voltage limit, in a preferred embodiment, resistance 57 and 59 is accurately to allocate.

Voltage on battery 24 is raised to threshold value, and the door of mos field effect transistor 51 starts, and the electric current mos field effect transistor 51 that begins to flow through has limited the voltage on the battery 24, thereby vised voltage.The door of mos field effect transistor 51 is modulated to the maintenance output voltage, from the above mentioned, the current flow heats silicon bypass pressurizer 50 of the mos field effect transistor 51 of flowing through, the latter heats positive temperature coefficient device 62 again.Positive temperature coefficient device 62 1 reaches its inversion temperature, the electric current of entire circuit, and the therefore electric current on bypass pressurizer 50, all to be subjected to tangible obstruction, this has just reduced the heat that is produced by the bypass pressurizer, therefore circuit 69 will finally be operated in its thermal equilbrium state, and electric current is subjected to the obstruction of positive temperature coefficient device 62, and voltage is subjected to bypass pressurizer 50 and clamps down on.Because voltage is subjected to clamping down on of current limliting pressurizer 50, current flow can increase rapidly.Hereinafter will and the optimization technique that passes through pressurizer Control current and voltage be described in conjunction with other preferred embodiments displayings.

Figure 21 preferred embodiment of another protective circuit 69 ' that drawn, wherein, operation amplifier and voltage separate with mos field effect transistor 51 and voltage bridge 75 with reference to 55, separately on a silicon device 72.For example, a kind of suitable reference 55 and the combination of operation amplification controller are the controllers of the LTC1541 model of Linear Technologies Corporation production.

Referring to Figure 22, voltage regulator circuit 69 (or 69 ') is actually an accurate clamp device, and it drives the voltage on mos field effect transistor 51 stable cells 24.Certainly, voltage need a certain amount of operating current with reference to 55 operation.Those skilled in the art will be understood that reference 55 is accurate more, and moving needed electric current will be big more.Although the magnitude of current is still smaller in typical application, for example in the scope of microampere, this current flow also can surpass the required electrical leakage quantity of battery 24.When having only voltage to surpass its normal range of operation just to open bypass pressurizer 50, this point will be paid special attention to.

With reference to Figure 23, in order to reduce running precision voltage as far as possible, can adopt a kind of start-up circuit 80 with reference to 55 required leakage currents, by the second mos field effect transistor switch 81, start regulator control circuit 55/53 selectively.Wherein, what start-up circuit 80 used is a kind of voltage detection method (not shown) more much lower than bypass pressurizer 50 precision, but leakage current is also much smaller simultaneously.Have only voltage on the battery 24 to reach level near maximum permissible voltage, start-up circuit 80 is just opened mos field effect transistor switch 81, thereby startup regulator control circuit 55/53.Because battery circuit is all worked below maximum permissible voltage basically, precision voltage just is out of question with reference to 55 bigger electric leakage.

Up to the present, described method and apparatus all is in order to prevent the purpose of voltage overload and current overload, still, our rechargeable elements that also needs protection, rechargeable battery for example exempts from because over-discharge can and the state of undertension.

For this reason, Figure 24 has shown a kind of preferred voltage overload or undertension protective circuit 100 that is used between charger 101 and the rechargeable battery 124.The undertension protective circuit 103 that protective circuit 100 generally includes voltage overload protective circuit 102 and is connected in parallel.Voltage overload protective circuit 102 comprises the bypass pressurizer 105 that a positive temperature coefficient device 104 of connecting with battery 124 and and battery 124 are in parallel.Bypass pressurizer 105 comprises an operation amplification controller 110, drives a n-channel mos field-effect transistor 114.The positive pole 128 of operation amplifier 110 connects the resistance 106 and 108 in the voltage dividing branch configuration, and resistance 106 and 108 is connected on the back of positive temperature coefficient device 104, between the height two ends of battery charger 101 and battery 124.The negative input end 130 of the comparator 120 in negative input 126 and the undertension protective circuit 103 of operation amplifier 110 is connected, and voltage reference 140 is connected to also ground connection of negative input end 126 and 130.

The output of operation amplifier 110 is connected to the door of mos field effect transistor 114; the drain electrode of mos field effect transistor 114 links to each other with the high low-voltage of battery 124 and charger 101 respectively with source electrode, and the positive input 132 of the comparator 120 of undertension protective circuit 103 is connected the resistance 116 and 118 in the voltage dividing branch configuration.Resistance 116 and 118 is connected between the height two ends of battery charger 101 and battery 124, the output of comparator 120 is connected to the door of n-channel mos field-effect transistor 122, and the latter's source electrode and drain electrode are connected with the low side (ground connection) of battery 124.

Voltage difference between operation amplifier 110 its positive negative outputs of monitoring, and respective drive output.For the operation amplifier, if the voltage of positive input greater than the voltage of negative input, the output of operation amplifier is tending towards high, if the voltage of positive input less than the voltage of negative input, the output of operation amplifier is tending towards low.Negative input links to each other with reference to 140 with precision voltage, and resistance 106 and 108 constitutes a branch breaking the bridge, makes the designer can select the limit of voltage overload.

In a preferred embodiment, resistance 106 and 108 is selected as when the voltage on the battery 124 reaches a certain threshold level, makes the voltage of the positive input 128 of operation amplifier 110 be equal to reference voltage.In the malfunction of voltage overload, the voltage on the battery 124 surpasses threshold value, and the voltage of the positive input of operation amplifier 110 becomes and is higher than voltage with reference to 140.Move the voltage difference that amplifier 110 amplifies between positive input terminals 128 and the negative input end 126, and provide amplifying signal, this unblanking mos field effect transistor 114 at its output 134.

When mos field effect transistor 114 conduction currents, the voltage on the battery 124 is vised, and obviously descends.The corresponding reduction of voltage on the positive input 128 of operation amplifier 110, identical with output 134.The reduction of the output 134 of operation amplifier 110 has caused the inlet resistance R of mos field effect transistor 114 (it is actually a variable resistor) _DS-ON increases, R _DSIncrease force the voltage on operation amplifier 110 positive inputs 128 to raise again, the lifting repeatedly of the voltage that this is taken place on 128 in input lasts till always and reaches balance, output voltage drives the door of mos field effect transistor 114, makes the voltage on the resistance 108 equal voltage with reference to 140.

For the state of voltage overload, mos field effect transistor 114 is opened, bypass pressurizer 105 dissipation energies, again by heat transfer to positive temperature coefficient device 104.As mentioned above, when the temperature of positive temperature coefficient device 104 reaches its trip temperature, its resistance will greatly improve, thereby stop the electric current of the mos field effect transistor 114 of flowing through.Power consumption is shared by bypass pressurizer 105 and positive temperature coefficient device 104 like this, in case mos field effect transistor 114 is damaged by ultra-high temperature.

The working method of undertension protective circuit 103 has some similar to voltage overload protective circuit 102.The negative input 130 of comparator 120 links to each other with reference to 140 with voltage, and the positive input of comparator 120 links to each other with comprising the dividing potential drop electric bridge of resistance 116 with 118, and in fact the voltage on the monitoring battery 124 also be provided with the limit of undercurrent.The door of the output 138 driving N channel fet 122 of comparator 120 is connected with load.

Under normal operation, voltage on the battery 124 is higher than the limit of undertension, and the voltage on the positive input pin 132 of comparator 120 is higher than reference voltage, so the output 138 of comparator 120 is tending towards high, transistor 122 is opened, and makes battery 124 pass through load discharge.When the voltage on the battery 124 drops in advance the undertension limit of selecting when following, the output 138 of comparator 120 is tending towards low, and transistor 122 is closed, battery 124 and load cut-off.The charging of battery 124 makes again and stops the undertension protection, and in a single day the voltage on the battery surpassed the undertension limit, and transistor 122 is opened again, allows to discharge.

Under the malfunction of voltage overload, the output of operation amplifier 110 is tending towards high-order, and therefore starts N-channel fet 114.Although discussed here is the N-channel fet, also can the utilization and operation amplifier, it provides a low output and drives the door of P-channel fet when fault.Similarly, also can use comparator, it provides a low output voltage and drives the high-end door of P-channel fet of connecting with load with it when undertension.Operation amplifier 110, comparator 120, mos field effect transistor 114 and 122 configuration are flexibly.In addition, the designer of cell apparatus can choose at random the voltage overload and the undertension limit, to satisfy any needs.

For battery charger, need prevent reverse battery charging or reversed charge accumulation.The side that the reverse battery charging occurs in deleterious current and battery inductive charging moves in the opposite direction.Reverse current has not only reduced the efficient of charging circuit, also can cause the damage of battery.An advantage of preferred protective circuit 69 is that its current limitation characteristic can also the blocking harmful reverse current flows.

Referring to Figure 25, all reverse currents of assembling by bypass pressurizer mos field effect transistor 51 will be by its body diode 148 conduction.Wherein, the reverse current of certain flow will be opened up thermal conducting path through diode 148, thereby because the power consumption of electric current produces ohm heat of bypass pressurizer 50.By top going through, heat from bypass pressurizer 50 to positive temperature coefficient device 62, reaches its upset temperature and tripping operation up to positive temperature coefficient device through heat passage (by arrow 151 expression), thereby block reverse current fully.

If also need other protection; for example body diode 148 can not be accepted the situation of big power consumption; preferably connect another diode resistance 152 (as shown in figure 26) (promptly with body diode 148; in the mos field effect transistor silicon device), in order to when conducting reverse current, to produce heat.The heat of Chan Shenging helps to open up the heat passage to positive temperature coefficient device 62 in addition, and not only relies on body diode 148, importantly, does not need diode 148 to consume so much power as positive temperature coefficient device 62 tripping operations.In fact, can increase the reliability and the life expectancy of mos field effect transistor 51 through the resistance path of diode resistance 152.In addition, because resistance 152 can produce more heat than independent body diode, can open up the heat passage that leads to positive temperature coefficient device 62 quickly.

Figure 27 is the profile as the preferable alloy oxide semiconductor field effect transistor device 170 of bypass pressurizer of connecting with additional resistance in Figure 26 protective circuit.The passage 164 that mos field effect transistor 170 is designed to it will produce heat.Wherein, a positive temperature coefficient device 156 links to each other with N-type silicon 166 by transfer box 158, and the diode of Figure 16/resistance combination 148 and 152 can be realized that wherein, the resistance of diode can be determined by the body path in the transistor by p-n junction.In order to make the body path have resistance more, can do path longer.In order to improve the resistance of body path, the position of body contact 160 is away from passage 164.If the body utmost point arrives the drain diode forward bias, as install source electrode 162 and 163 situations about disposing respectively of drain electrode in 170, P-drift region 168 can be heated when conduction current.

If the diode of common metal oxide semiconductor field effect transistor does not have additional resistance, a forward biased diode will damage components and parts before the enough heat of generation makes the positive temperature coefficient device tripping operation.By employing the diode of more resistance is arranged, just can produce more hot in order to open up the heat passage of derivation reverse current.The configuration of more high-resistance diode provides higher breakdown point, and this can make heat passage more promptly produce in certain embodiments.Another advantage of " intelligence " semiconductor device is that the back positive temperature coefficient device that breaks down still can be discharged duties, and stops destructive electric current effectively.

Another aspect according to announce invention, Figure 28 and 29 has shown the preferred semiconductor device that prevents the reverse battery charging---channel current is limited in the acceptable level of direction of " reverse ", and provides a little Ohmic resistance in " forward " direction.

In detail, Figure 28 diffusion structure 450 that dome contacts 451 and contact, the end 452 are connected with junction field effect transistor zone 454 that drawn.Dome contacts is connected with a metal or ohm contact 453.When dome contacts 451 during with respect to contact, the end 452 forward bias, big electric current will flow through junction field effect transistor zone 454.This positive bias is with 458 expressions of the curved section among Figure 30.If voltage reversal, (that is, dome contacts 451 is negative with respect to contact, the end 452), the electric current that flows through junction field effect transistor zone 454 has an ohm behavior with beginning.

Reverse bias is by 457 expressions of the curved section among Figure 30.Along with reverse current increases, the pn knot between the zone 455 and 456 begins to increase reverse bias, and reverse bias is opened up a loss district, further stops the electric current in the junction field effect transistor zone 454 of flowing through.To be electric current be limited in manageable level with the maximum of reverse current in this constraint.

Figure 29 groove structure that dome contacts 461 and contact, the end 462 are connected with junction field effect transistor zone 464 that drawn.Dome contacts is connected with a metal or ohm contact 463.When dome contacts 461 during with respect to contact, the end 462 forward bias, big electric current will flow through junction field effect transistor zone 464.This positive bias is with 458 expressions of the curved section among Figure 30.If voltage reversal, (being that dome contacts 461 is negative with respect to contact, the end 462), the electric current 464 that flows through the junction field effect transistor zone has an ohm behavior with beginning.Reverse bias is with 467 expressions of the curved section among Figure 30.Along with reverse current increases, a door effect is opened up a loss district in gutter channel 465 the insides, and the loss district further stops the electric current in the junction field effect transistor zone 454 of flowing through, and the maximum of reverse current is limited in manageable level.

Refer again to Figure 16, the electric current front and back of restriction positive temperature coefficient device 62 and bypass pressurizer 50 are being protected battery 24 to exempt from undercharge or are being subjected to the influence of voltage overload state.When the state that voltage overload takes place, unnecessary power must wear away from pass devices 50 (particularly mos field effect transistor 51), to avoid any damage or the short circuit of equipment.

Especially, in order to protect battery 24, bypass voltage-stabilizing device 50 must be able to stand the impact of big electric current, up to positive temperature coefficient device 62 tripping operations.Discussed in the past one makes that this to impact minimum way be that design positive temperature coefficient device 62 is in lower temperature tripping operation.But this way has limitation, and positive temperature coefficient device 62 must (that is, charge or discharge) allow the enough big electric current of conduction under the battery normal operation, can be because of inner ohm thermal tripping.

Usually,, can use the lower device of price, also can use the better simply circuit of layout (that is, " silicon device) for needing not be subjected to high power or high-tension protective circuit.

Such just as already explained, along with electric current flows to pressurizer, the resistance of pressurizer heating and raising positive temperature coefficient device, the electric current in the restriction pressurizer.The power consumption of current stabilization in pressurizer and the positive temperature coefficient device on each device is enough to keep positive temperature coefficient device and is in its resistance and temperature (promptly, " R (T) ") on the curve on the value of precipitous part (for example, use Raychem VTP210 positive temperature coefficient device 1 to 1.5 watt), this technology is adapted at preventing under the state of smaller and medium current overload the damage for pressurizer.

But, can reach the more high power transient phenomenon of high value for electric current, depend on the hot time coefficient of hot-fluid from the delay that the heat of pressurizer trips positive temperature coefficient device to positive temperature coefficient device.Because this lags behind, the silicon of pressurizer can reach very high temperature, just may be damaged before the positive temperature coefficient device tripping operation.Though the size that can strengthen pressurizer silicon will obviously improve the price of device to deal with the impact of big electric current.

Figure 31 has drawn and has used the protective circuit of the battery 180 of bypass pressurizer 182 and positive temperature coefficient device 184.Because the device parallel connection, the voltage on the battery 180 must with bypass 182 on identical.Actual conditions are different with ideal situation, and the clamper district of device can not be absolute as shown in Figure 32 vertical.For the electric current that flows to pressurizer, the voltage on it must improve a little Δ V, because this little Δ V also can be added on the battery 180, battery 180 will charge and draw the part electric current from power supply 186.The electric current of this increase positive temperature coefficient device 184 of flowing through, and help tripping operation.Δ V is big more, and the electric current that flows through battery 180 is also just big more, and positive temperature coefficient device 184 also will be by hot link 188 faster tripping operations.

For the state of moment, battery 180 can be imagined as a voltage source (perhaps very large electric capacity), and its series resistance is equal to the internal resistance of battery 180.The voltage of voltage source (or electric capacity) is equal to the voltage that preceding battery 180 takes place momentary status.As an example, if the internal driving of battery is 0.1 ohm, voltage is from 1 volt of raising Δ V, and battery will draw 10 amperes from positive temperature coefficient device more, and the electric current of the pressurizer of flowing through will be that I-V curve (referring to Figure 32) is gone up the electric current at the high voltage place.When voltage is higher, whole electric currents of the positive temperature coefficient device 184 of flowing through will increase, and the situation that will make tripping operation when not having battery 180 is faster.

Be used under momentary status, protecting silicon device if having the pressurizer that delays oblique clamper district, but changing slowly in the fault and can negative effect arranged the performance of battery 180.If it is very slow that voltage raises, will go wrong because voltage slowly rising can make battery 180 " trickle charge ", big Δ V just can not appear in the battery two ends when voltage raise.Cell voltage will conduct abundant electric current up to pressurizer and make positive temperature coefficient device heating and tripping operation along the I-V curve of pressurizer.But in some cases, the extra voltage that increases will obviously reduce the performance of battery or damage battery 180.In fact, in order to obtain optimum performance, the I-V characteristic must be steep as far as possible, in case battery 180 is because " trickle charge " and overcharged.

Therefore, two requirements are just arranged simultaneously.On the one hand, high instant of failure needs big silicon device or slow oblique clamper district, and on the other hand, changing fault slowly then needs more precipitous clamper district.Under the perfect condition, answer is to make the device with I-V characteristic as shown in figure 33.For low current fault, such as the state that voltage slowly rises, the effect of device such as same pliers prevent that voltage from rising clamp voltage.For the minimum current of the device of flowing through that makes positive temperature coefficient device tripping operation is positioned at precipitous part 190.For the variation fault slowly of low-tension current, device should be worked as the pliers in extremely precipitous clamper district 190.For big failure of the current, clamper is limited in set point 192 with electric current and allows voltage to raise.After connecting battery, this rising of voltage will be drawn big electric current and help the positive temperature coefficient device tripping operation from battery.Positive temperature coefficient device is tripping operation in a single day, and the voltage on protective device and the battery will reduce, and the maximum voltage on battery that can obtain this moment and the device is exactly the voltage on precipitous regional 190.It should be noted that because the required minimum current of positive temperature coefficient tripping operation is the precipitous zone at curve, is the voltage overload state that can not occur continuing.

In the preferred protective circuit in Figure 34, operation amplifier 200 is monitored the voltage difference between its positive and negative input 202 and 203 respectively, and correspondingly drives output 206.If greater than the voltage in negative output 204, operation amplifier output 206 just is tending towards high-order at the voltage of its positive input 202, if be lower than voltage in negative input 204 at the voltage of positive input 202, the output 206 of operation amplifier 200 is tending towards low level.Negative output is connected to voltage with reference to 208, and resistance 210 and 212 is formed a dividing potential drop electric bridge, makes the designer can select any voltage overload limit of battery 222.

Especially, operation amplifier 200 is adjusted the gate voltage of field-effect transistor 214, forces device to have a clamper IV characteristic.Fig. 3's one group of I of a n-channel fet 5 has drawn _d-V _DsCharacteristic.As shown in the figure, V _GsCan regulate along vertical line 216, obtain clamping performance.According to door-source voltage, leakage current can be on voltage between specific leakage-source value arbitrarily.

In order to obtain desirable characteristics, the voltage of the door 206 of field-effect transistor 214 can be set to be no more than a set point, for example, can realize by the clamper gate voltage as Figure 36.

Especially, Figure 36 circuit identical that drawn with Figure 34, just Zener diode 220 is connected between output 206 and the ground connection.Add Zener diode, the voltage of the door 206 of field-effect transistor 214 just is restricted.Zener diode 220 is the gate voltage of clamper field-effect transistor 214 effectively, makes voltage on the battery 222 rise and to the more electric current of battery 222 guiding.As shown in figure 37, V _GsCan be adjusted into the voltage that has on clamping performance and the clamper 206, field-effect transistor is worked under saturation condition.

The key of this method be circuit in fact conduct power to battery and away from field-effect transistor 214.This method admits that battery 222 can be like a cork from 206 absorption some extra voltage and electric currents in the time of one section setting in some configuration, and by absorbing extra voltage and electric current, field-effect transistor is protected.Owing to reduced performance requirement, can use the field-effect transistor that price is lower or volume is less to field-effect transistor 214.

The positive temperature coefficient device 224 of connecting with battery 222 also will run into big electric current, and when positive temperature coefficient device 224 ran into big electric current, the positive temperature coefficient device tripping operation was faster, and helps dissipation power more.Use this method, when battery faces higher voltage and current, the positive temperature coefficient device dissipation power that can trip in the past at the power that battery 222 faces any damage battery.In brief, any big electric current that battery 222 is run into also can pass through positive temperature coefficient device 224, and these big electric currents can face harmful power level at battery 222 made the positive temperature coefficient device tripping operation in the past.

Although I-V characteristic shown in Figure 37 has been represented a kind of configuration, more optimal mode can obtain in the back of vertical plane 226 by changing the I-V characteristic, and shown in Figure 38 is exactly several possible I-V characteristics.Electric current by behind the reduction clamper district has reduced the power consumption on the device in momentary status, can also further reduce the size of silicon device.

The advantage that above method has utilized battery 222 can bear some extra electric currents and voltage levvl before the positive temperature coefficient device tripping operation.The same with any embodiment discussed here, in order to guarantee that battery 222 can not run into because the power level of the infringement that the fault of extra voltage and levels of current or pressurizer causes can use hot fuse or pressurizer fuse to isolate battery.

Referring to Figure 39, a preferred battery protective circuit is implemented by one three end cell protective device 229, and it generally comprises a positive temperature coefficient device 236 that is connected with mos field effect transistor pressurizer switch 232 calorifics.Wherein, first utmost point 231 of protective device 229 is connected the anode of external charge source or discharge load (not shown), is connected on the input of positive temperature coefficient device 236.Second utmost point 233 of protective device 229 is connected the anode of battery (not shown) with the drain electrode of the output of positive temperature coefficient device 236 and mos field effect transistor pressurizer 232, and the 3rd utmost point 235 of protective device 229 is connected to the source electrode of pressurizer 232 and the earth terminal of charging source or discharge load with the negative pole of battery.

Shown in arrow 234, the drain electrode of pressurizer 232 constitutes an end points simultaneously and is connected with electricity to positive temperature coefficient device 236.For example the fuse 230 of joint line or solder bond is connected in series with second utmost point 233, as last one measure of protection battery.

In order more clearly to explain another aspect of invention described here, the various variations of device 229 are described now.

Referring to Figure 40 and Figure 41, in the position of fuse 230 (or additional) can with the mos field effect transistor pressurizer positive temperature coefficient device 237 of connecting again, further protection is provided when pressurizer 232 faults or short circuit.It should be noted that what this added, or " parallel connection " positive temperature coefficient device 237 can be connected to the source electrode (referring to Figure 40) or the drain electrode (referring to Figure 41) of mos field effect transistor pressurizer 232.In a preferred embodiment, Bing Lian positive temperature coefficient 237 cell configuration cause pressurizer 232 faults or short circuit to trip in the past for producing enough ohm heat at electric current through pressurizer 232.

Although positive temperature coefficient device 237 in parallel can not improve the via resistance that battery 222 that device 229 protected is run into; if positive temperature coefficient device 237 in parallel is owing to overheated or other faults are not intended to tripping operation when battery 222 operate as normal, pressurizer 232 will no longer be connected with the battery two ends.A way that reduces this situation generation is to make positive temperature coefficient device 237 in parallel have higher inversion temperature (being higher threshold value tripping current) than series connection positive temperature coefficient devices 236, trips before positive temperature coefficient device 237 in parallel to guarantee series connection positive temperature coefficient device 236.In this case, positive temperature coefficient device 237 in parallel still plays protective effect after 236 tripping operations of series connection positive temperature coefficient device, prevents that battery 222 from further discharging by pressurizer 232.

As shown in figure 42, increase positive temperature coefficient device 237 in parallel after, mos field effect transistor pressurizer 232 preferably is set to by the voltage on 239 monitoring batteries of path, and disregards the additional resistance of positive temperature coefficient device 237 in parallel.

Here another aspect of the present invention more now, people know that generally lithium ion battery will avoid over-discharge can.Figure 43 represents a prior art circuits 470 that typically is used for avoiding battery 472 over-discharge can, and wherein, the field-effect transistor 471 with gate resistor 473 is connected with battery 472 and load 474.In case reach the low battery voltages that sets in advance, field-effect transistor 471 is promptly closed automatically, thereby has prevented that battery 472 from continuing discharge by load 474.But at the discharge process of battery, field-effect transistor 471 is faced with high relatively power consumption, and temperature may be elevated to above the acceptable level.Like this, thermal stress will be damaged field-effect transistor 471, so that over-discharge can protective circuit 470 also just fails.

Referring to Figure 44, be a preferred over-discharge can protective circuit 480, it also provides protection when overcharging, employing be that a FET device 481 is connected with battery 482 and load 483.Wherein, the source electrode 488 of field-effect transistor 481 connects the output of load 483, and drain electrode 489 connects the negative pole of battery 482, and the positive pole of battery 482 connects the input of load 485, and like this, when field-effect transistor 481 was opened, battery 482 will be by load 483 discharges.

Positive temperature coefficient device 484 is in parallel with battery 482 and load 483 respectively, insert back discharge protective circuit 480.The gate pole 487 of field-effect transistor 481 is connected the centre of dividing potential drop configuration positive temperature coefficient device 484 and resistance 485.The distribution of positive temperature coefficient device 484 and resistance 485 (low temperature) resistance separately makes that as long as voltage remains on more than the full discharge level of battery 482, the voltage that the gate pole 487 of FET device 481 is accepted is opened holdout device.In a preferred embodiment, for typical chargeable lithium cell group, the low-temperature resistance of positive temperature coefficient device 484 is chosen as about 10 kilo-ohms, and the value of resistance 485 is 1 megaohms.

According to this one side of described invention, positive temperature coefficient device 484 is connected with FET device 481 calorifics, as further protection, in case battery 482 FET device 481 under the state of overcharging breaks down.Voltage on positive temperature coefficient device 484, therefore, just the voltage on the FET device 481 is near the level that FET device 481 is broken down, the electric current of positive temperature coefficient device 484 of flowing through will be enough to make device 484 to be heated to its trip temperature, in case positive temperature coefficient device 484 trips to its high resistance state, voltage on the device 484 will quickly fall to below the threshold value gate voltage of FET device 481, cause that field-effect transistor closes.

In a preferred embodiment, the value of positive temperature coefficient device 484, FET device 481 and resistance 485, make positive temperature coefficient device 484 cause the state that overcharges to cause before FET device 481 faults because electric current increases, just trip to high resistance and close FET device 481 at FET device 481.Illustrate that with example at the preferred embodiment that is used for protecting chargeable lithium cell, positive temperature coefficient device 484 has about 10 kilo-ohms (non-upset) resistance, resistance 483 is about 1 megaohm.It should be noted that protective circuit 480 can be by revising the ratio optimization various configurations and the field-effect transistor characteristic of resistance 484 and 485.

According to another aspect of described invention, the rechargeable battery protective device is described now again and makes the method for optimizing of assembling.

Referring to Figure 45-Figure 47, be three utmost point battery protecting apparatus 240 that preferably comprise a positive temperature coefficient chip 242, it is connected with electricity with mos field effect transistor pressurizer 244 calorifics.

Positive temperature coefficient chip 242 comprises one deck PTC material 246, and its front is covered with first metal electrode layer 248, and reverse side is covered with second metal electrode layer 250. Metal electrode layer 248 and 250 is covered with one deck dielectric film 249 and 251 respectively.Dielectric film 251 exposes the part of metal electrode layer 250 in an end vacancy of positive temperature coefficient chip 242, constitutes first utmost point of protection device 240.Close on the other end of first utmost point, 262 opposite dielectric films 249, a rectangular window 252 is arranged, expose the part of metal electrode layer 248, pressurizer 244 is fixed on it by weld 253.

According to the protective circuit 69 of Figure 16, pressurizer 244 comprises a mos field effect transistor switch and accuracy control circuit that is integrated on the silicon punch die 254.Silicon punch die 254 is fixed on the fin 256, and the latter is connected with the drain electrode electricity of mos field effect transistor switch.And fin is connected with calorifics with metal electrode layer 248 electricity of positive temperature coefficient chip 242 by weld 253, fin 256 is also drawn from pressurizer 244 with one, and walks around the external wire 258 electricity connection of positive temperature coefficient chip 242 electrodes 262 opposites one end.The source electrode of mos field effect transistor switch is connected with second external wire 259 electricity; this root lead 259 also adjacent conductors 258 is also drawn from pressurizer 244 in the same way, and lead 258 and 259 constitutes the second and the 3rd utmost point of protective device 240 respectively.

When protective device is used for the rechargeable battery (not shown); first utmost point 262 is connected to the positive pole of battery charger or discharge load device; second utmost point 258 is connected to the positive pole of battery, and the 3rd utmost point 259 connects the negative pole of battery pack and the negative pole of battery charger or discharge load device simultaneously.According to this arrangement, respectively by metal electrode layer 250, PTC material 246, metal electrode layer 248, weld 253, fin 256, second utmost point 258 from first utmost point 262 to assembly 240 constitutes a conductive path.If the mos field effect transistor passage is activated (promptly, under the state of voltage overload), by metal electrode layer 250, PTC material 246, metal electrode layer 248, weld 253, fin 256, mos field effect transistor switch passage, also constitute a conductive path respectively from first utmost point, 262 to the 3rd utmost points 259.

During apparatus for assembling 240, the process of fixed stably depressor 244 can integrate with the processes known of making positive temperature coefficient chip 242 at an easy rate on the metal electrode 248 of positive temperature coefficient chip 242.Especially, the formation of PTC material 246 will be according to required performance characteristics, for example, conductivity, upset temperature or the like, and then once according to performance characteristic, thermal mass for example forms a slice of desired thickness. Metal electrode layer 248 and 250 is that the upper and lower surface that the paillon foil by for example nickel, copper or alloy is compressed on PTC material 246 thin slices respectively forms, and insulating thin layer 249 and 250 is that silk screen printing is on corresponding metal layer 248 and 250.This layer is shading selectively, through overexposure, removes the unexposed portion of barrier material again, exposes the respective electrode of the part of electrode layer as positive temperature coefficient chip 242.

Thin slice is cut into polylith positive temperature coefficient chip 242 according to the size of selecting then.The manufacturing process of preferred positive temperature coefficient device and the more detailed details of method are published in United States Patent (USP) the 5th, 852, and No. 397 and the 5th, 831, No. 150, the full content of this patent is all as this paper reference content.

As the part of shading step in the above manufacture process, the window 252 of insulating thin layer 249 can be got any suitable shape according to corresponding positive temperature coefficient chip 242.For instance, shown in Figure 48 is added metal electrode layer 248 and insulation film 249 on the thin slice 270 of PTC material 246, figure line 271 shown on the thin slice 270 is used for dividing separately chip 242 separately, window 252 is opened on the insulation film 249 of every positive temperature coefficient chip 242, exposes the part of metal electrode layer 248.Window 252 is actually the substrate that is used for installing voltage-stabilizing device 244 respectively.

For this reason, welding material 253 is placed on the metal electrode layer 248 that each window exposes, the fin 256 of each voltage-stabilizing device 240 be placed on welding material 253 above, positive temperature coefficient thin slice 270 is in makes welding material 253 fusing under enough heats, the size of window 252 just makes that in fusion process each fin 256 can be in window 252 " alignment ".In case finished fusion process, along the line 271 from thin slice 270 each device 240 of cutting-out.The person skilled in the art is not difficult to find out that the order of above listed manufacturing step is not unique feasible solution, can also change order and does not break away from inventive concept described here.Illustrate with example, also may each voltage-stabilizing device 240 be cut from thin slice making before the solder fusing.

Referring to Figure 49 and 50, adopt the preferred process of mold process manufacturing three-pole device 240 shells as follows:

By flexible conducting metal; for example copper, nickel or aluminium; the transfer box of making 300 comprises the framework 302 and 303 of pair of parallel; framework is injected the moulding machine (not shown) forward; be used for the adjustment (or aligning) of transfer box 300 along the hole that framework distributes, framework 302 and 303 can make the distance of framework 302 and 303 equate by separated from each other across eyelid retractor 301 across eyelid retractor 301; again can be transfer box 300 spaced at equal intervals, section 305 repeats repeatedly.

First tab 304 preferably adopts the elastomeric material identical with transfer box 300 to make, and extends into each section 305 from framework 302.Similarly, second preferably also is to use the elastomeric material identical with transfer box 300 to make with the 3rd tab 306 and 308, extends to each section 305 from framework 303 very abreast mutually.Wherein, the setting of each tab 304,306,308 will be fit to the requirement of whole assembling three electrode protectors 240 mold shells 314, and they preferably have elastic force, can be crooked, can constitute the electrode of various sizes and configuration.

As shown in figure 50, crust of the device 314 constitutes at each section 305 wound joint sheet 304,306,308 of transfer box 300, and wherein, the end of each tab 304,306,308 is stretched in shell 314 the insides.According to known mold technology, the multiple arrangement shell can constitute simultaneously.Before the mold process, the end of tab 304,306,308 can bend to the optimum position, so that be connected with device 240 electricity that are placed on ready-made shell 314 the insides.This bending can also make the wall angle of shell 314 gain in strength.

Referring to Figure 51, in case shell 314 is fully fixing, that is, take framework 302 and 303 and separately away across eyelid retractor 301, the three-pole device 240 that assembles is put each shell 314 into.Wherein, device 240 is put shell 314 into the utmost point 262 of winning, second utmost point 258, the 3rd utmost point 259 is connected with the terminal electricity that tab 304,306,308 stretches out respectively.Perhaps, put positive temperature coefficient chip 242 into and voltage-stabilizing device 244 obtains identical functions on 314 li on each shell.Terminal 262,258,259 can connect (for example, by welding) and to corresponding tab 304,306,308, perhaps rely on Mechanical Contact.If but electricity separately connect to rely on is Mechanical Contact, tab 304,306,308 should have enough elasticity, relies on contained spring power to be fixed on separately the terminal 262,258,259.

Then shown in Figure 52, mold or finish the cover 315 of a non-electricity conduction with additive method covers on the opening of shell 314, simultaneously protection and seal 240.The size of shell 314 preferably can be fit to device 240 compactly.Importantly, shell can not restraint device 240, more can not exert pressure to it, because positive temperature coefficient chip 242 must can be expanded (for example to about 10%) ability operate as normal when heating.

In case install in 240 shells 314 that are sealed in separately, tab 304,306,308 just becomes path separately,---promptly, tab 304 is set to connect the positive pole of battery charger or discharge load device, tab 306 is set to connect the positive pole of battery, and tab 308 is set to connect simultaneously the negative pole of battery and the negative pole of corresponding charging device or discharge load device.The flexibility of tab 304,306,308 makes it to be fixed to more easily the electricity joint of corresponding battery both positive and negative polarity (for example, by spot welding) and charging device or electric discharge device.

In another interchangeable embodiment, device 240 can be canned rather than be placed in the shell 314.According to required performance characteristics, selected system tank material should be respectively heat conduction or heat-insulating.

Those skilled in the art is not difficult to find out that mold shell 314 can be made of other non-electricity conductive materials in addition, for example, and plastics or pottery.The characteristic of selected materials, and the size of shell (that is thickness) should be according to selecting such as price, practicality, " molded ability " (that is, how long material solidifies after injecting), intensity, heat conductivity and other factors.Such design considers also to comprise the needs of device insulation and the needs that turn round again.Importantly, sheathing material can not have the interference on the material to the rollover characteristics of installing 240 positive temperature coefficient chip 242.

Especially, fault occurred in case be device flip-flop transition, this device is transformed into the time quantum that high resistance state will be used.If the heat conductivity of packaging material is low excessively, positive temperature coefficient device 242 just may be overheated in normal operation, causes that (" trouble ") upset of not expecting takes place.On the other hand, if packaging material adopt the too high material of heat conductivity, positive temperature coefficient device 242 may overturn slow under the state of voltage overload, current overload.

The material of shell is selected and size also should be considered the environment of running gear 240 in the future, typical design considers to comprise voltage and current service conditions in the future, the ratio of fluctuating current, charging normal/discharging under the scope of ambient operating temperature of maximum operation temperature, expectation of battery pack inside.

One big advantage of three-pole device 240 is that it can be connected with battery pack calorifics, thereby overtemperature protection can also be provided.Be placed in the shell 314 if install 240, the ability that is formed thermal conducting path by battery pack auto levelizer 240 also must be taken into account.

Figure 53-Figure 55 has drawn and has been used for above-mentioned other the transfer box of making three-pole device 240 shell procedures by the mold process and is provided with 320 and 320 '.

Referring to Figure 53, identical with transfer box 300, transfer box 320 is preferably made by the metal of elastic conduction, for example copper or aluminium.Frame 320 contains the framework 322 and 323 of pair of parallel; be set to insert the moulding machine (not shown) forward by reach hole 330; framework 322 and 323 separated from each other by equidistant eyelid retractor 321; eyelid retractor not only makes the distance of framework 322 and 323 equate the section 325a and the 325b that can also make transfer box 320 spaced at equal intervals strike a bargain and replace.Wherein, 325a and 325b mirror image each other.

In section 325a, the first conductive contact sheet 324 stretches out from framework 322, and the second conductive contact sheet 326 stretches out from frame edge 323, and the 3rd conductive contact sheet 328 is from stretching out across eyelid retractor member 321.At section 325b, tab 324 stretches out from frame edge 323, and tab 326 stretches out from frame edge 322.It should be noted that conductive contact sheet 328 is also from stretching out across eyelid retractor 321.Wherein in transfer box 320, connecting the tab separately 328 of adjacent sections 325a and 325b every one across eyelid retractor 321, and other every one across eyelid retractor 321 on do not connect.

Referring to Figure 55, in second alternative preferred transfer box 320 ', each section 325 ' is not a mirror image again, but repeats repeatedly.In other words, except the tab 328 across an adjacent sections 325 ' of eyelid retractor 321 ' support of being separated by, transfer box 320 ' is just the same with transfer box 320.

The same with the tab on the transfer box 300 304,306,308; tab 324,326,328 preferably adopts the elastic metallic identical with transfer box 320 to make; wherein; the setting of each tab 304,306,308 will adapt to the requirement of whole assembling three electrode protectors 240 mold shells; tab 324,326,328 preferably has elastic force; can be crooked, can constitute the electrode of various sizes and configuration.

Shown in Figure 54 and 55, crust of the device 334 constitutes at each the section 325a and the 325b wound joint sheet 324,326,328 of transfer box 320, and wherein the end of tab 324,326,328 is stretched in shell 334 the insides.Before the mold process, just the end of tab 324,326,328 is bent to the optimum position, so that be connected with device 240 electricity that are placed on ready-made shell 334 the insides.Wherein, the end portion 329 of tab 328 curves " diapire " that make molding outer casing 334 and surrounds (that is electric insulation) all only reserves end (being represented by dotted lines) in Figure 54 and Figure 56 shape.The same with shell 314, this bending can also make each the wall angle and the diapire of shell 334 gain in strength.

It should be noted that no matter using transfer box 320 still is 320 ', the shell of finishing 334 is all the same.A shell of finishing 334 is removed each framework 322 and 323 and across eyelid retractor 321, is drawn among Figure 56.Those skilled in the art is not difficult to find out that shell 334 is that the joint guide card 328 that is connected to device 240 earth electrodes (or negative pole) 259 stretches out from the side of shell 334 with the difference of shell 314, rather than stretches out from end.The Shell structure of this variation provides flexibility for the method that three-pole device 240 is fixed to rechargeable battery pack.

The drawn a kind of alternative preferred embodiment 340 of above-mentioned three electrode protectors of Figure 57-Figure 58.Just as protective device 240, protective device 340 comprises a slice positive temperature coefficient chip 342, and chip is connected with electricity with mos field effect transistor pressurizer 344 calorifics.Positive temperature coefficient chip 342 comprises one deck PTC material 346, and its front is covered with ground floor metal electrode layer 348, and reverse side is covered with second layer metal electrode layer 350. Metal electrode layer 348 and 350 is covered with one deck dielectric film 349 and 351 respectively again.

With the same in the device 240, dielectric film 351 exposes the part of metal electrode layer 350 in an end vacancy of positive temperature coefficient chip 342, constitutes first utmost point 341 of protection device 340.Differently with device 240 be that dielectric film 351 exposes the part 363 of metal electrode layer 348, second utmost point 361 of constituent apparatus 340 at the other end of positive temperature coefficient chip 342 also some vacancy.Close on the dielectric film 349 of the extremely same end of chip second, a rectangular window 352 is arranged, expose the part of metal electrode layer 348, fixing at this pressurizer 344 by weld 353.

The same with the pressurizer 244 in the device 240, pressurizer 344 comprises a mos field effect transistor switch and accuracy control circuit that is integrated on the silicon punch die 354.Punch die 354 is fixed on the fin 343, is connected with the drain electrode electricity of mos field effect transistor switch.And fin 343 is connected with calorifics with metal electrode layer 348 electricity of positive temperature coefficient chip 342 by weld 353.The source electrode of mos field effect transistor switch is connected with external wire 345 electricity of drawing from pressurizer 344, and external wire 345 constitutes the 3rd utmost point of protective device 340.

When protective device 340 is used for the rechargeable battery pack (not shown); first utmost point 341 is connected to the positive pole of battery charger or discharge load device; second utmost point 361 is connected to the positive pole of battery, and the 3rd utmost point 345 connects the negative pole of battery pack and the negative pole of battery charger or discharge load device simultaneously.According to this arrangement,, constitute a conductive path from first utmost point, 341 to second utmost points 361 respectively by metal electrode layer 350, PTC material 346, metal electrode layer 348.If the mos field effect transistor passage is activated (promptly, under the state of voltage overload), by metal electrode layer 350, PTC material 346, metal electrode layer 348, weld 353, fin 343, mos field effect transistor switch passage, also constitute a conductive path respectively from first utmost point, 341 to the 3rd utmost points 345.

Referring to Figure 59-Figure 62, another aspect according to invention described here, be with a kind of printed circuit board (PCB) flexibly (" pc plate ") 350, utilize a hole 351, the mos field effect transistor pressurizer 354 that is installed in the front 356 of printed circuit board (PCB) 350 is fixed together with the positive temperature coefficient chip 352 that is installed in 350 second (end) faces 358 of printed circuit board (PCB).

More clear shown in Figure 62, the positive temperature coefficient chip comprises one deck PTC material 371, and its front is covered with 370, the second of ground floor metal electrode layers (that is, anti-) face and is covered with second metal electrode layer 372. Metal electrode layer 370 and 372 is wrapped in one deck dielectric film 377 and 378 respectively.Dielectric film 377 some vacancy under the hole 351 are exposed the part of metal electrode layer 370, and are fixing by weld 357 at the fin 396 of this pressurizer 354.

Closing on an end of positive temperature coefficient chip 352, removing another part of insulating barrier 377, exposing another part of metal electrode layer 370, linking to each other with first lead 360 on the printed circuit board surface 358 here.At the other end of positive temperature coefficient chip 352, metal pathway 382 is connected to the small electrode district 394 of metal electrode layer 370 with one side with metal electrode layer 372.Slit 380 is with electrode district 394 and metal level 370 electrical insulation.Electrode district 394 is connected to second lead 362 of printed circuit board surface 358.In this way, an end is connected by electrode 370 and face lead 360, and the other end is being connected of electrode 394 and face lead 362, and positive temperature coefficient chip 352 is fixed on printed circuit board surface 358.

Pressurizer firmly is fixed on the front 356 of printed circuit board (PCB) 350 by first lead 355 and second lead 392.Wherein, lead 355 and lead 358 are connected respectively to first pad 390 and second pad 391 of printed circuit board (PCB) side 356.Pad 390 electricity are connected to the 3rd lead 364 of printed circuit board surface 356.In this way, the pressurizer device is by connection lead 355 and 392, and fin 396 firmly is fixed on printed circuit board surface 356 to the weld 357 between the positive temperature coefficient chip 352.It should be noted that lead 355 is also connected to the source electrode of mos field effect transistor switch 398.

(not shown) in the time of on being fixed to rechargeable battery pack, printed circuit board conductor lines 362 are set at the positive pole that is connected to battery charger or discharge load device; Printed circuit board conductor lines 360 is set at the positive pole that connects battery; Printed circuit board conductor lines 364 is set at the negative pole that connects battery simultaneously and the negative pole of battery charger or discharge load device.By metal electrode layer 372, PTC material 371, metal electrode layer 370, constitute a conductive path respectively from lead 362 to second polar conductors 360.If the mos field effect transistor passage is activated (promptly, under the state of voltage overload), by metal electrode layer 372, PTC material 371, metal electrode layer 370, weld 357, fin 396, mos field effect transistor switch passage and source electrode 398 and lead 355,364 also constitute a conductive path from lead 362 to lead respectively.

The advantage of the embodiment of Figure 59-Figure 62 is the overcoat that positive temperature coefficient chip 352 can be directly installed on battery pack easily, makes positive temperature coefficient chip 352 cross under the high state in temperature and provides protection (that is, from battery case heat conduction) to battery pack.

Although show and preferred circuit, the Apparatus and method for that rechargeable elements is provided voltage overload, current overload and/or the too high protection of temperature be described; those skilled in the art is not difficult to find out also have many kinds and revise and use and do not depart from the inventive concept here.

For instance, although above preferred embodiment directly relates to three-pole device embodiment, those skilled in the art is not difficult to find out that obviously invention described here can also be implemented in the geometric configuration of the multipole and pin type of varying number.

In addition, although above preferred embodiment generally at be protective circuit and system, notion of the present invention can also be applied to the Voltagre regulator circuit, for example, as the part of batter-charghing system.It will be apparent to those skilled in the art that the positive temperature coefficient device that is implemented in the above-mentioned protective circuit must be according to adjusting through normal temperature upset and replacement in Voltagre regulator is used.

Claims (44)

1. protective circuit that is used for charger and rechargeable elements comprises:

Bypass pressurizer with first utmost point and second utmost point in parallel with the rechargeable elements two ends, this bypass pressurizer has the threshold value cut-in voltage; And

First variable resistor that is connected with electricity with bypass pressurizer calorifics, this first variable resistor have first utmost point of the charger that is used to be connected in series and second utmost point of rechargeable elements that is used to be connected in series,

Wherein, this first variable resistor under voltage overload or current overload condition, can be before electric current reaches the level that is enough to cause bypass pressurizer fault restriction flow through the electric current of bypass pressurizer.

2. protective circuit according to claim 1; wherein; first variable resistor can be transformed into from lower resistance than higher resistance when being heated to a specific inversion temperature; and wherein, producing ohm heat with the horizontal flow that is predetermined through the electric current of bypass pressurizer in the bypass pressurizer makes the variable resistor of winning reach its inversion temperature fully.

3. protective circuit according to claim 1, wherein, first variable resistor comprises a positive temperature coefficient device.

4. protective circuit according to claim 1, wherein, the bypass pressurizer comprises a transistor switch.

5. protective circuit according to claim 4, wherein, the bypass pressurizer also comprises if the voltage at rechargeable elements two ends reaches the control circuit that the threshold value cut-in voltage just starts transistor switch.

6. protective circuit according to claim 5; wherein; control circuit comprises first and second voltage detecting circuits; the electric leakage of first voltage detecting circuit is lower; second voltage detecting circuit is more accurate, wherein, just starts second testing circuit if first voltage detecting circuit is set to the voltage at rechargeable elements two ends near the threshold value cut-in voltage; and wherein, reach the threshold value cut-in voltage and just start transistor switch if second voltage detecting circuit is configured to the voltage at rechargeable elements two ends.

7. protective circuit according to claim 5; wherein; control circuit comprises that has the operation amplifier that is connected with the enabling gate of transistor switch of output, and comprises that one is exported the voltage clamp element that is connected with moving amplifier, thus the fixing enabling gate voltage of clamper element.

8. protective circuit according to claim 7, wherein, the clamper element comprises a Zener diode.

9. protective circuit according to claim 4, wherein, transistor switch is controlled as the current-voltage relation that has as shown in figure 14.

10. protective circuit according to claim 4, wherein, transistor switch is controlled as the current-voltage relation that has as shown in figure 15.

11. protective circuit according to claim 4, wherein, transistor switch is controlled as the current-voltage relation that has as shown in figure 16.

12. protective circuit according to claim 4, wherein, transistor switch has the thermal compensation voltage characteristic.

13. protective circuit according to claim 12, wherein, transistor switch has temperature-voltage relationship as shown in figure 17.

14. protective circuit according to claim 1 also comprises the undertension protective circuit.

15. protective circuit according to claim 14, wherein, the undertension protective circuit comprises a transistor switch with threshold value cut-in voltage, and its source electrode and drain electrode are configured to be connected in series between charger and the rechargeable elements.

16. protective circuit according to claim 15; wherein; the undertension protective circuit also comprises control circuit; be equal to or greater than a selected minimum voltage and just transistor switch opened if be configured to the voltage at rechargeable elements two ends, and if the voltage at rechargeable elements two ends drop to and be lower than selected minimum voltage and just close transistor switch.

17. protective circuit according to claim 1, wherein, the bypass pressurizer comprises a mos field effect transistor switch with body diode of relative high electrical resistance, reverse current.

18. protective circuit according to claim 1; wherein; the bypass pressurizer comprises a transistor switch that has passage; if just-biasing; the electric current forward flow; the then reverse flow of bear-setovering, the resistance that switch structure runs into when becoming the electric current forward flow is lower, and the resistance that runs into during reverse direction current flow is higher.

19. protective circuit according to claim 18, wherein, transistor switch have as shown in figure 30 separately just-the voltage-to-current relation of biasing and negative-biasing.

20. protective circuit according to claim 1 also comprises a second adjustable resistance of connecting with the bypass pressurizer.

21. protective circuit and rechargeable elements combine, and comprising:

A Voltagre regulator in parallel with rechargeable elements, this Voltagre regulator has the threshold value cut-in voltage; And

One with rechargeable elements series connection and the variable resistor that is connected with calorifics with Voltagre regulator electricity,

Wherein, variable resistor can be before electric current reaches the level that is enough to cause the Voltagre regulator fault under voltage overload or the current overload situation restriction flow through the electric current of Voltagre regulator.

22. combination according to claim 21, wherein, variable resistor can be turned to from lower resistance than higher resistance when being heated to a specific inversion temperature, and wherein, in Voltagre regulator, produce enough ohm heat with the horizontal flow that is predetermined through the electric current of Voltagre regulator, make variable resistor reach its inversion temperature fully.

23. combination according to claim 21, wherein, variable resistor comprises a positive temperature coefficient device, and wherein, Voltagre regulator comprises a transistor switch device.

24. a protective circuit that is used for rechargeable elements comprises:

A smart circuit;

A variable restriction element of connecting with smart circuit; And

One has and is used to connect first utmost point of rechargeable elements and the Voltagre regulator of second utmost point, and this Voltagre regulator has selected threshold value cut-in voltage.

25. protective circuit according to claim 24, wherein, current limiting element is connected with Voltagre regulator calorifics.

26. protective circuit according to claim 24, wherein, current limiting element comprises positive temperature coefficient device, hot fuse or bimetallic lock thrin at least.

27. protective circuit according to claim 24, wherein, Voltagre regulator is Zener diode or field-effect transistor.

28. a protection system that is used for rechargeable elements comprises:

Be used to detect the rechargeable elements status detection device that overcharges;

Respond described checkout gear, be used for the shunting device of bypass rechargeable elements when the state that overcharges takes place; And

The response shunting device, be used for when shunting device bypass rechargeable elements, limiting the protective device that electric current flows through rechargeable elements.

29. protection system according to claim 28,

Wherein, checkout gear comprises that the transfer element of an optical coupler and one have the threshold voltage according controlling resistance element that is not higher than the rechargeable elements maximum working voltage;

Wherein, shunting device comprises the receiving element of a described optical coupler; And

Wherein, if in charging operations; it is predetermined will cause the overcharged level of rechargeable elements the time that the electric current of voltage-controlled resistive element of flowing through reaches; transfer element is activated; and make receiving element bypass rechargeable elements, this starts the flow through electric current of rechargeable elements of protective device restriction again.

30. protection system according to claim 29, wherein, protective device comprises a fuse and comprises the voltage control resistive element of Zener diode.

31. protection system according to claim 29, wherein, protective device comprises a positive temperature coefficient (PTC) device and comprises the voltage-controlled resistive element of Zener diode.

32. protection system according to claim 28,

Wherein, checkout gear comprises the voltage overload checkout gear that is used to detect the voltage overload state;

Wherein, shunting device comprises an active mos field effect transistor that can be started by the voltage overload checkout gear;

Wherein, the voltage that detects rechargeable elements when the voltage overload checkout gear in charging operations has reached predetermined level; the voltage overload checkout gear starts active mos field effect transistor bypass rechargeable elements, thereby starts the electric current that protective device limits the rechargeable elements of flowing through.

33. protection system according to claim 28,

Wherein, checkout gear comprises the voltage overload checkout gear that is used to detect the voltage overload state;

Wherein, shunting device comprises a thyristor, and it can be started by the voltage overload checkout gear;

Wherein, protective device comprises a fuse that is connected between charger and the rechargeable elements;

Wherein, the voltage that detects rechargeable elements when the voltage overload checkout gear in charging operations has reached predetermined level, the voltage overload checkout gear starts thyristor bypass rechargeable elements, thereby makes blown fuse, and the disconnection rechargeable elements is connected with charger.

34. protection system according to claim 33, wherein, protective device also comprises second fuse that is connected between thyristor and the rechargeable elements.

35. protection system according to claim 33, wherein, each fuse has predetermined delay, can be before fusing the bypass rechargeable elements.

36. a protective circuit that is used for charger and rechargeable elements comprises:

One has and is used for first utmost point in parallel with the rechargeable elements two ends and the bypass pressurizer of second utmost point, and this bypass pressurizer comprises:

Transistor switch with threshold value cut-in voltage, and the control circuit that is configured to when the voltage at rechargeable elements two ends reaches the threshold value cut-in voltage, just start transistor switch, this control circuit comprises first and second voltage detecting circuits, the electric leakage of first voltage detecting circuit is lower, second voltage detecting circuit is more accurate, wherein, if being configured to the voltage at rechargeable elements two ends, first voltage detecting circuit just starts second testing circuit near the threshold value cut-in voltage, and wherein, reach the threshold value cut-in voltage and just start transistor switch if second voltage detecting circuit is configured to the voltage at rechargeable elements two ends.

37. a protective circuit that is used for charger and rechargeable elements comprises:

One has and is used for first utmost point in parallel with the rechargeable elements two ends and the bypass pressurizer of second utmost point, and this bypass pressurizer comprises:

Transistor switch with threshold value cut-in voltage, and the control circuit that is configured to when the voltage at rechargeable elements two ends reaches the threshold value cut-in voltage, just start transistor switch, this control circuit comprises that has the operation amplifier that output is connected with the enabling gate of transistor switch, with a voltage clamp element that is connected with operation amplifier output, this clamper element is fixing enabling gate voltage effectively.

38. a protective circuit that is used for charger and rechargeable elements comprises:

One has and is used for first utmost point in parallel with the rechargeable elements two ends and the bypass pressurizer of second utmost point, and this bypass pressurizer comprises:

Transistor switch with thermal compensation voltage characteristic.

39. a protective circuit that is used for charger and rechargeable elements comprises:

One has the voltage overload bypass pressurizer that is used for first utmost point in parallel with the rechargeable elements two ends and second utmost point, and this bypass pressurizer comprises that has the first transistor switch that the threshold value cut-in voltage is approximately selected rechargeable elements maximum working voltage; And

One has first utmost point that is configured to be connected between charger and the rechargeable elements and the undertension protective circuit of second utmost point, and this undertension protective circuit comprises that has the transistor seconds switch that the threshold value cut-in voltage is approximately selected rechargeable elements minimum.

40. a protective circuit that is used for charger and rechargeable elements comprises:

One has the voltage overload bypass pressurizer that is used for first utmost point in parallel with the rechargeable elements two ends and second utmost point, this bypass pressurizer comprises that has a mos field effect transistor switch and higher, the reverse current body diode of resistance that the threshold value cut-in voltage is approximately selected rechargeable elements maximum working voltage.

41. a protective circuit that is used for charger and rechargeable elements comprises:

One has and is used for first utmost point in parallel with the rechargeable elements two ends and the bypass pressurizer of second utmost point, and this bypass pressurizer has the threshold value cut-in voltage;

First positive temperature coefficient (PTC) device that is connected with electricity with bypass pressurizer calorifics, this first positive temperature coefficient device has first utmost point that is used for connecting with charger and second utmost point that is used for connecting with rechargeable elements; And

Second positive temperature coefficient device of connecting with the bypass pressurizer,

Wherein, first positive temperature coefficient device when being heated to first inversion temperature by being converted to high electrical resistance than low resistance, and

Wherein, second positive temperature coefficient device when being heated above second inversion temperature of first inversion temperature by being converted to high electrical resistance than low resistance.

42. the combination of protective circuit and battery, this battery has positive pole and negative pole, and this protective circuit comprises:

But a transistor switch of connecting with battery makes that battery passes through load discharge when transistor switch is opened;

One be connected with transistor switch calorifics be subjected to temperature controlled resistance, and have first utmost point and second utmost point, this first utmost point links to each other with anode; And

A fixed resistance has and second first utmost point that extremely links to each other that is subjected to temperature controlled resistance, and second utmost point that links to each other with battery cathode, thereby this is connected mutually with fixed resistance by temperature controlled resistance, and in parallel with battery,

Wherein, transistor switch has an enabling gate, is connected second utmost point that is subjected to temperature controlled resistance and first utmost point of fixed resistance with the form of voltage divider.

43. according to the described combination of claim 42, be subjected to temperature controlled resistance in a particular conversion temperature, be converted to the second higher resistance from the first lower resistance, wherein, be chosen as by first resistance of temperature controlled resistance and the resistance value of fixed resistance, as long as cell voltage is greater than a selected minimum voltage, the voltage at enabling gate place will keep transistor switch to open.

44. according to the described combination of claim 43, wherein, inversion temperature is chosen as under the cell voltage overload situations, and the electric current of the transistor switch of flowing through will produce enough ohm heat, will be subjected to temperature controlled resistance heating to inversion temperature before causing the transistor switch fault.

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