CN101416330A

CN101416330A - Protection methods, protection circuits and protection devices for secondary batteries, a power tool, charger and battery pack adapted to provide protection against fault conditions in the battery pac

Info

Publication number: CN101416330A
Application number: CNA200480030330XA
Authority: CN
Inventors: 戴夫·卡里尔; 史蒂夫·菲利普斯; 杰弗里·J·弗朗西斯; R·罗比·贝利; 丹·T·特林; 小安德鲁·E·西曼; 克里斯托弗·R·扬克; 丹尼尔·C·布罗托
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2003-10-14
Filing date: 2004-10-07
Publication date: 2009-04-22

Abstract

In a cordless power tool system, protection methods, circuits and devices are provided to protect against fault conditions within a battery pack that is operatively attached to a power tool or charger, so as to prevent internal or external damage to the battery pack or attached tool or charger. The exemplary methods, circuits and devices address fault conditions such as over-charge, over-discharge, over-current, over-temperature, etc.

Description

The guard method of secondary cell, protective circuit and protection device, electric tool, charger and be adapted at providing in the battery pack protection in case the battery pack of fault state

Cross

The following relevant U.S. Provisional Patent Application that the application's subtend United States Patent and Trademark Office proposes requires the national priority by 35 U.S.C. § 120: the U.S. Provisional Application the 60/510th that on October 14th, 2003 proposed, No. the 60/551st, 803, the U.S. Provisional Application that No. 128 and on March 11st, 2004 propose.Quote hereby these provisional application each open text totality for your guidance.

Technical field

The present invention relates to guard method, protective circuit and the protection device of rechargeable battery; relate to the electric tool and the charger that are fit to the battery of attached battery group is provided protection; with the battery pack that relates to comprising protection control, each protection control is all protected battery pack in case various incipient fault situation.

Background technology

In the past few years, lithium ion (Li in the low-pressure portable electronic equipment such as notebook personal computer ⁺) battery begun to replace NI-G (NiCd), nickel metal hydride (NiMH) and lead-acid battery.Compare with the NiMH battery with NiCd, lithium ion battery is lighter, but has bigger unit volume capacity.For this reason, lithium ion battery is applicable to the best light low-voltage equipment that uses with requirement tolerance long-time continuous usually.But under over-discharge state, lithium ion battery degenerates rapidly, and therefore, lithium ion battery needs over.

Be used in a plurality of batteries that battery pack in the portable electric appts contains series connection usually.The maximum number of series-connected cell is by the output voltage decision of battery pack in battery pack.For example, the typical output voltage of a NiCd battery or a NiMH battery is 1.2V.Suppose to be fit to most of universal electronic devices from the 18V output voltage of battery pack, series connection NiCd or the maximum a plurality of of NiMH battery are 15 in the battery pack.On the other hand, the typical output voltage of a lithium ion battery approximately is 3.6V.Therefore, the maximum number of cascaded lithium ion batteries is 5 in the lithium ion battery group of a hypothesis 18V.

Different with the NiMH battery pack with the NiCd battery pack, the lithium ion battery group can comprise provides protection in case the function of the inside and outside fault state of lithium ion battery group.So just prevented that battery in the lithium ion battery group from degenerating and shorten useful life of battery pack.For example, if in the inside of lithium ion battery group or the outside fault state that occurs such as short circuit, can be equipped with fuse to cut off overdischarge electric current or overcharge current, if discharging current or charging current become greater than given current level.

Current, the protective circuit in the battery pack such as the lithium ion battery group mainly be for require voltage generally on 2 to 4V the order of magnitude, such as the low-pressure portable electronic device design of notebook personal computer and cellular phone etc.Such equipment is characterised in that, uses the battery pack of being made up of the battery (for example, lithium ion, NiCd, NiMH battery) of the maximum output voltage that about 4.2 volts/each battery is provided.For lithium ion battery,, must carefully prevent the infringement that causes from electric and mechanical stress because lithium is the high activity material.

The traditional protection circuit of these A-battery groups can monitoring battery voltage, to prevent given battery overcharge or overdischarge and can standby current, to prevent electric current rising De Taigao.Other protective circuit can contain during charge or discharge, before battery pack cools down, forbids one or more temperature inputs of electric current.Also have some protective circuits can be designed to help to keep charge balance on the battery, these circuit are commonly referred to equalizing circuit.Typical protective circuit can be connected with a given battery or the Battery pack in the battery pack, to avoid these situations generations.For example, the traditional protection circuit can comprise a pair of MOSFET (mos field effect transistor) or other semiconductor that can prevent that electric current from flowing into along each direction usually.

But, for the higher-wattage electronic equipment such as cordless power tool, voltage that need be more much higher than above-mentioned voltage.Therefore, people are developing the battery pack of higher-wattage for cordless power tool." high power " battery pack like this can provide than traditional NiCd and the high voltage output (with than the much higher power of traditional lithium ion battery group that is used for PC and cellular phone) of NiMH battery pack, also alleviates many (with comparing as the traditional NiCd or the NiMH battery pack of the power supply in traditional cordless power tool) with weight.These battery pack are characterised in that this battery pack can present than traditional NiCd, NiMH and/or even the much lower impedance operator of lower-wattage lithium ion battery group.

And,, introduce and to develop the secondary cell that generates much higher output voltage (for example, 18V and Geng Gao) than Low ESR chemical composition and version and may cause other several protection problem along with these battery technologies constantly develop.The lower battery pack of impedance means that also battery pack can be to adhere to the much higher electric current of electronic unit supply such as electric tool.Along with the electric current that flows through the motor that adheres to electric tool increases, demagnetization magnetic potential (for example, the armature number of turn * electric current (ampere-turn) of motor) can increase to expectation or design limit above motor significantly.Therefore, this undesirable degaussing may burn out motor.

For example, when instrument is in stall (stall) state following time, can damage the motor of instrument than low-impedance power.During motor stall, because motor can not produce inverse electromotive force, a motor and battery impedance play the restriction electric current.The battery pack impedance is more little, and electric current is just big more.Higher electric current flows through the possibility that motor will increase the permanent magnet degaussing in the instrument motor.

In addition, the starting of instrument will produce extra starting current and cause the motor degaussing.Because it is longer and more durable that new battery may be designed to get than former wireless tool system work, in existing electric tool, use low-impedance power also can cause thermal overload.

Therefore; may need different protections to control and suitably solve the incipient fault situation that appears in the high-power battery group, these high-power battery groups are fit to use the processing line of the electric tool of making to use for existing cordless power tool with in conjunction with these higher-wattage battery pack.Specifically; need develop protection control; appear at battery pack (for example with processing; lithium ion or NiCd battery pack) one or more batteries in such as overcharge, fault state overdischarge, overcurrent, excessive temperature and battery are unbalance so that prevent to battery pack, such as charger or instrument auxiliary device or with battery pack that charger or instrument link to each other near the user cause inside or external damage.

Summary of the invention

In comprising the cordless power tool systems of battery pack; one exemplary embodiment of the present invention is intended at providing protection in case fault state in the battery pack that is designed on operationally being attached to electric tool or charger, so that prevent from battery pack or outfit or charger are caused guard method, protection structure (arrangement) and/or the device of inside or external damage.These exemplary method, circuit and device solved such as overcharge, fault state problem in the battery pack such as overdischarge, overcurrent, excessive temperature.

Description of drawings

Provide detailed description by the reference accompanying drawing, can understand one exemplary embodiment of the present invention more completely, in the accompanying drawings, represent identical unit with identical label, just represent one exemplary embodiment of the present invention with these accompanying drawings, rather than be limited to one exemplary embodiment of the present invention.

Fig. 1 represents the partial block diagram according to the protection structure of an one exemplary embodiment of the present invention;

Fig. 2 represents the partial block diagram according to the protection structure of another one exemplary embodiment of the present invention;

Fig. 3 A is exemplary battery pack and parts example battery charger between and the calcspar that be connected of expression according to an one exemplary embodiment of the present invention;

Fig. 3 B is exemplary battery pack and the parts exemplary electric tool between and the calcspar that be connected of expression according to an one exemplary embodiment of the present invention;

Fig. 4 is according to the battery pack of the expression additives for overcharge protection of an one exemplary embodiment of the present invention and the partial block diagram of the connection between the charger;

Fig. 5 is according to the battery pack of the expression additives for overcharge protection of another one exemplary embodiment of the present invention and the partial block diagram of the connection between the charger;

Fig. 6 is the voltage change curve in time of the automatic cut-out of the over carried out according to the expression protective circuit of an one exemplary embodiment of the present invention;

Fig. 7 is according to the voltage of the correction threshold of the expression over of an one exemplary embodiment of the present invention change curve in time;

Fig. 8 A and 8B represent the exemplary devices that is used for overcurrent protection according to an one exemplary embodiment of the present invention;

Fig. 9 represents the device that the excessive temperature protection is provided according to an one exemplary embodiment of the present invention;

Figure 10 represents the syndeton according to the thermistor of an one exemplary embodiment of the present invention;

Figure 11 is the flow chart that the method that is about to the situation of breaking down in operating personnel's battery pack of electric tool is reminded in expression;

Figure 12 is that expression is according to the definite SOC of an one exemplary embodiment of the present invention and the calcspar of the demonstrative structure that changes the current of electric switching frequency;

Figure 13 A is the isometrical drawing of individual layer battery;

Figure 13 B and 13C represent to protect in case the device of the situation of overcharging according to providing of an one exemplary embodiment of the present invention;

Figure 14 A and 14B represent to protect in case the device of the situation of overcharging according to providing of another one exemplary embodiment of the present invention;

Figure 15 A and 15B represent to protect in case the device of the situation of overcharging according to providing of another one exemplary embodiment of the present invention;

Figure 16 A and 16B represent to protect in case the device of the situation of overcharging according to providing of another one exemplary embodiment of the present invention; With

Figure 17-19 expression is according to the exemplary cordless power tool of the cordless power tool systems of an one exemplary embodiment of the present invention.

One exemplary embodiment describes in detail

Now prevailingly with reference to accompanying drawing, the system of the cordless power tool that the principle according to one exemplary embodiment of the present invention constitutes is described.Shown in the exemplary cordless power tool of this system comprise, for instance, annular electric saw 10 (Figure 17), back and forth electric saw 20 (Figure 18) and electric drill 30 (19).

Instrument

10,20 and 30 each can comprise traditional DC (direct current) motor (not shown) that is fit to by power supply power supply with given load voltage value.In an exemplary embodiment,

instrument

10,20 and 30 can be by having the detachable power drives of the load voltage value of 18V at least.For the person of ordinary skill of the art, apparent, the present invention both had been not limited to concrete tool types as shown in the figure, also was not limited to specific voltage.About this point, in fact principle of the present invention can be applicable to the cordless power tool and any power source voltage of any kind.

Continue with reference to accompanying drawing now, detachable power supply can be embodied in battery pack 40.In represented one exemplary embodiment, battery pack can be a rechargeable battery 40.Battery pack 40 can comprise a plurality of batteries and/or a plurality of series-connected cell string of series connection, and wherein battery strings is parallel with one another.One exemplary embodiment of the present invention for convenience of description, battery pack 40 can be made up of the battery that contains the lithium ion battery chemical composition.Because one exemplary embodiment is intended at the cordless power tool environment, this needs voltage rating than the conventional low equipment that uses the lithium-ion electric pool technology (for example, laptop computer and cellular phone) much higher power supply, so the load voltage value of battery pack 40 can be 18V at least.

But, with regard to the chemical composition of each battery, electrode and the electrolyte of battery pack 40 constituted, battery pack 40 for example can be made up of the battery of another kind of lithium base chemical composition such as lithium metal or lighium polymer or other chemical composition such as NI-G (NiCd), nickel metal hydride (NiMH) and plumbic acid.

Fig. 1 represents the partial block diagram according to the protection structure of an one exemplary embodiment of the present invention.Fig. 1 represents the protection device separately 102 of each battery 105 of the battery pack that the battery pack 40 among a part of battery circuit and the concrete expression image pattern 17-19 is such.In Fig. 1, each protective circuit 102 is fit to carry out current-limiting function.In an example, protective circuit 102 can be embodied in thermal-sensitive electric resistance device, wherein, thermal-sensitive electric resistance device is the part of battery or is included in the battery.

Thermistor is that to be used to describe its key property be the type of electrical component that their resistance changes with their temperature change, that is, and and the term of ' thermistor '.Thermistor can further be categorized into ' positive temperature coefficient ' device (PTC device) or ' negative temperature coefficient ' device (NTC device).The PTC device device that to be its resistance value raise and increase with their temperature.The NTC device device that to be its resistance value raise and reduce with their temperature.The NTC thermistor is made by the proprietary prescription based on the ceramic material of transition metal oxide usually.

In Fig. 1, protection device 102 can be embodied in the PTC device, it can protect a string battery to avoid thermal overload.If the resistance of the PTC device in the some battery heating, that battery just increases, the restriction electric current flows through whole crosstalk pond.The shortcoming of the method for this protection battery is that it needs the device of many execution current-limiting functions (in this example, PTC) as protection device 102.

Fig. 2 represents the partial block diagram according to the protection structure of another one exemplary embodiment of the present invention.The alternative scheme that uses a plurality of protection devices 102 is that each battery all comprises a privacy protection circuit 210, and it for example detects the one or more battery pack parameters in the battery pack of battery pack 40.These parameters comprise electric current, temperature, voltage and the impedance of flowing through battery pack, but are not limited to these.Protective circuit 210 operationally is connected with respective drive circuit 220.Level shift circuit 220 can be connected with a plurality of AND (" with ") doors (shown in a square frame 230), so that the main device 240 of protective circuit 210 with the execution current limliting or the function that stops linked.If some protective circuits detect a problem, it can change to the low level output state from the high level output state.The AND door has guaranteed to have only the output of all protective circuits all to be on the high level (OK) main device 240 and has just connected.In addition, it is contemplated that opposite logical circuit can use with the protection device of using NOR (distance) door in normal output low level and generation.As shown in Figure 2, main device 240 can be embodied in the semiconductor device such as mos field effect transistor (MOSFET).Therefore, if battery pack contains a plurality of batteries 105 of series connection, so, exemplary configuration it is contemplated that with such as MOSFET, and the main device 240 that allows/forbid electric current to flow through connects and control its one group of protective circuit 210 (each battery is specified one).

Such as discussed above, use a plurality of privacy protection circuit 210 for example may need as shown in Figure 2 corresponding level shift circuit 220, it makes the voltage variety from the maximum potential battery be reduced to normal level with switch main semiconductor device 240.If it is too much monitoring each battery, so, can monitor array battery or whole battery group with single protective circuit 210 and the single main device that is used for current limliting or cutout 240.

Fig. 3 A is exemplary battery pack and parts example battery charger between and the calcspar that be connected of expression according to an one exemplary embodiment of the present invention.Fig. 3 A only is demonstrative circuit configuration and provides as the background of more clearly describing according to various guard methods, circuit and the device of one exemplary embodiment.

With reference to Fig. 3 A, battery pack 100 can comprise a plurality of batteries 105 (for simplicity, show 6, battery pack 100 can comprise the battery greater or less than 6, or can be made up of series connection string series-connected cell string parallel with one another) of series connection.The one exemplary embodiment of battery pack 100 for convenience of description, battery pack 100 can be made up of the battery that contains the lithium ion battery chemical composition.Because one exemplary embodiment is intended at the cordless power tool environment, this needs voltage rating than the much higher voltage of legacy equipment that uses the lithium-ion electric pool technology, so the load voltage value of battery pack 100 can be 18V at least.

Therefore, the battery pack 100 of (in Fig. 3 B) can be applicable to comprise at least the cordless power tool systems of cordless power tool, battery pack and charger and/or for this cordless power tool systems design among Fig. 3 A.Battery pack 100 can be understood as the detachable power supply that is used for the operation of high power electric tool.In an example, battery pack 100 can have the load voltage value of 18V at least and/or have maximum power output at least about 385W.But apparent for the person of ordinary skill of the art, the present invention both there is no need to be confined to the concrete tool types shown in Figure 17-19, also there is no need to be confined to aforesaid specific voltage value and/or power output regulation.

With regard to the chemical composition of each battery, electrode and the electrolyte of battery pack 100 constituted, battery pack 100 can further for example be made up of the battery of another kind of lithium base chemical composition such as lithium metal or lighium polymer or other chemical composition such as NI-G (NiCd), nickel metal hydride (NiMH) and plumbic acid.

In Fig. 3 A, show seven line ends (line end 1-7).But, owing to depend on the information needed of process between battery pack 100 or charger 150, or the parameter of battery pack 100 or charger 150 supervision, can comprise more or less line end, these one exemplary embodiment should not be confined to this line end configuration.

Battery pack 100 is used to discern the battery pack ID 110 that is connected with output (line end 1) of battery pack 100 in the time of can also comprising in inserting charger 150.Battery pack ID 110 can comprise, for example model, version, cell arrangement and the battery types such as lithium ion, NiCd or NiMH (chemical composition).Battery pack ID 110 can be embodied in as at the United States Patent (USP) the 5th that is presented to people such as Hiratsuka, 680, as described in No. 027, by the one or more communication cryptologies of the asynchronous, full duplex communication system in the battery pack 100 from output 1 reception of battery pack 100.But, this is an example, because battery pack ID 110 also can specialize by the field in the frame of ID resistance, the data that show the light-emitting diode display of the identification data of battery pack, the serial data that sends and for example detected by line end 2 by instrument/charger according to a preconcerted arrangement and/or send to instrument/charger by air-interface etc.

Battery pack 100 may further include one or more temperature sensors 120.Temperature sensor 120 can be embodied in NTC or PTC thermistor, temperature detection integrated circuit or thermoelectric coupling.Temperature sensor 120 can be sent to the temperature in the battery pack 100 intelligent parts in the battery pack 100 and/or be sent to intelligent parts in the charger 150 that for example links to each other by line end 3.Because the function of temperature sensor is well-known like this, for the sake of brevity, omits the detailed description to feature operation here.The electrical connection that is used to charge and discharges is expressed as

line end

1 and 7.

Battery electron control unit 125 can be responsible for protecting battery 105 in case any fault state that is caused on line end by user's (by charger 150, outfit, and/or because user intervention).Battery electron control unit 125 can be embodied in digital microcontroller, microprocessor, analog circuit, digital signal processor with hardware or software, or for example specializes by the one or more digital IC as application-specific integrated circuit (ASIC) (ASIC).

Discharging current and charging current can utilize semiconductor device 130a (discharge FET) and 130b (charging FET) to connect or interruption under the control of battery electron control unit 125.Battery electron control unit 125 can be by drive circuit 140 links by as shown in the figure internal electric source 135 power supply and

semiconductor device

130a and 130b.

Battery pack 100 may further include the current detector 145 that detects electric current and signal is offered battery electron control unit 125.Current detector 145 can be embodied in can offer the signal of representing the detection electric current in the battery pack 100 battery electron control unit 125, such as the well-known components of the current detection device of shunt resistance, power pack etc.Semiconductor device 130a can comprise as device 130a and disconnecting and battery pack 100 plays the pull down resistor 147 of bypass semiconductor device 130a effect when being in resting state.

Battery pack 100 can also comprise voltage monitoring circuit 115.Voltage monitoring circuit 115 can for example be specialized by any known voltage monitoring circuit, total battery voltage (' superimposed voltage ') with being configured to detect each cell voltage and/or detecting battery strings 105 offers battery electron control unit 125 with the signal of representing each battery or superimposed voltage.As a kind of modification, be configured to detect the single voltage monitoring circuit 115 of each battery and total superimposed voltage with replacement, battery pack 100 can comprise voltage monitoring circuit as shown in Figure 3A, and it for example comprises a plurality of first voltage monitoring circuits (summarizing demonstration as 115A) that detect each cell voltage and the second voltage monitoring circuit 115B that detects total superimposed voltage of battery 110.

Refer back to for example Fig. 2; protective circuit 210 can comprise battery electron control unit 125, current detector 145, voltage monitoring circuit 115 and temperature sensor 120 at least; alternatively, may further include battery pack ID 110 and the internal electric source such as power supply 135.Drive circuit 140 can be with the drive circuit 220 among Fig. 2 similar and semiconductor device 103a and 130b can represent the main device 240 that under the control of protective circuit 210, has limit/cutout function single or together.

With reference to Fig. 3 A, at interdischarge interval, battery electron control unit 125 can output pulse width modulation (PWM) control signal drive drive circuit 140.For example, in electronics industry, use the semiconductor (pulse width modulator (PWM)) that forms pulse to produce the average voltage that is directly proportional with duty ratio usually.The PWM modulation that to be pulse duration change with certain specific character of modulation signal.Alternately, can use pulse frequency modulation to produce this average voltage.In each case,

semiconductor device

130a and 130b (can be embodied in discharge FET and charging FET respectively) can switch switching on and off between the state, to produce the average voltage that is directly proportional with the duty ratio of switching.

At interdischarge interval, the PWM of drive circuit 140 level mobile battery electronic control units 125 output to drive the grid of semiconductor device 130a, makes semiconductor device 130a depend on the situation of detection, circulates between switching on and off.Because semiconductor device 130a is back-biased, device 130b only just allows electric current pass through existing under the situation of diode drop.If electric current is the forward voltage that 20A and device 130b have 0.6V, power consumption has only 12W.If this power consumption meets the requirements, battery electron circuit 125 can output to status signal drive circuit 140, and drive circuit 140 order semiconductor device 130b are remaining on on-state to semiconductor device 130a generation PWM between action period.Now, the power of device 130b loss will be square (I that its on-state multiply by electric current ²R _ON).The MOSFET of today has the on-state (R of 10m Ω usually _ON), therefore, on 20A, power consumption has only 4W.Consequently discharge is controlled and to pass through the loss of semiconductor device lower.

At interdischarge interval, can use inverted logic circuit.Semiconductor device 130a is back-biased with respect to current direction, although be conducting under off-state, in order to make the waste minimum, device 130a should remain on on-state.Semiconductor device 130b can be according to from the information Control charging current of battery electron control unit 125 through overdrive circuit 140.The component layouts that comprises drive circuit 140 is known in the prior art, for the sake of brevity, is no longer described here.

When battery pack 100 is connected with charger 150, can be by charger electronic control unit 155 power supplies of

line end

1 and 6 from 135 pairs of chargers 150 of inside battery power supply.This is a kind of exemplary connectivity scenario, because can use other device to 155 power supplies of charger electronic control unit.Charger 150 can have its power supply or directly draw from cell voltage.Charger electronic control unit 155 also can be embodied in digital microcontroller, microprocessor, analog circuit, digital signal processor with hardware or software, or for example specializes by the one or more digital IC as application-specific integrated circuit (ASIC) (ASIC).Battery and charger data and control information can be by the exchanges of the serial data path on the line end 4 and 5.Charger electronic control unit 155 can be sent to battery pack 100 with required voltage and electric current from power supply 165 by

line end

1 and 7 with voltage being set and current drives power controller 160 being set.

Fig. 3 B is exemplary battery pack and the parts exemplary electric tool between and the calcspar that be connected of expression according to an one exemplary embodiment of the present invention.Fig. 3 B only is demonstrative circuit configuration and provides as the background of more clearly describing according to various guard methods, circuit and the device of one exemplary embodiment.The battery pack of Fig. 3 B and tool configuration can be applicable to exemplary cordless power tool and the equivalent in any one of Figure 17-19.In Fig. 3 B, expression ' clever ' electric tool 170, self-evident, battery pack 100 also is fit to ' fool ' electric tool, that is, the not electric tool of intelligent device such as microprocessor or microelectronics control assembly power supply.

With reference to Fig. 3 B, can by

line end

1 and 6 internally battery supply 135 to electric tool 170 power supply.Instrument 170 can comprise when semiconductor device 130a (discharge FET) disconnects the mechanical switch of line end 7 being shifted onto on the high level 175.If semiconductor device 130a keeps disconnecting when battery pack 100 is in resting state, because pull down resistor 147, the voltage on the line end 7 is on the low level.This resistance should have quite high resistance, because it plays bypass semiconductor device 130a.This pull down resistor 147 suitably and semiconductor device 130a be under the situation of off-state, the voltage on the line end 7 remains on the low level, the switch 175 in instrument 170 is activated.Consequently, the voltage of mains terminals 7 raises at once and can be used for battery pack 100 is waken up from sleep mode of operation through the signal of mains terminals 7.Instrument 170 can comprise instrument electronic control unit 180.Instrument electronic control unit 180 also can be embodied in digital microcontroller, microprocessor, analog circuit, digital signal processor with hardware or software, or for example specializes by the one or more digital IC as application-specific integrated circuit (ASIC) (ASIC).

Instrument electronic control unit 180 is programmable, so as to read the toggle position of trigger 181 and by the serial data path on the

line end

4 and 5 to battery electron control unit 125 report triggering device positions.According to the toggle position data, battery electron control unit 125 can change the PWM duty ratio by semiconductor device 130a, to obtain the required motor speed of instrument motor 190.When semiconductor device 130a disconnected, the diode 195 in the instrument 170 can the remaining motor induced current of recirculation, in case voltage spike wherein occurs.Forwards/reverse switch 185 is generally used for wireless instrument, will no longer be described here.

Fool's instrument (not shown) can only contain and is configured to potentiometer and connects and the trigger 181 that is connected with line end 6 with one of

line end

1,4 or 5.Whether battery electron control unit 125 can be discerned serial data communication and exist and the voltage on

line end

4 or 5 is carried out sunykatuib analysis.According to analysis result, battery electron control unit 125 can send pwm control signal by drive circuit 140, makes semiconductor device 130a by required duty ratio switch, so that produce predetermined motor speed.Also can there be more fool's instrument as the on/off instrument.In order to operate, only require that these instruments are connected with 7 with line end 1.

Additives for overcharge protection

There are two kinds of basic battery chargers that battery pack is recharged of being used for: thread formula charger and quick charger.Thread formula charger is than quick charger considerably cheaper; But thread formula charger recharges about needs 1/2 day to battery pack.Quick charger can recharge battery pack in about one hour.Because the fault state that overcharges may appear in some fault state or the system failure in charger or the battery pack.Usually, the protective circuit in the battery pack can be by the voltage detecting at the monitor battery pack two ends fault state that overcharges.Between charge period, voltage can reach certain threshold level.Therefore charger thinks that battery pack ' is charged fully ' and stopped charging current.If charger is locked on the on-state because of unit failure, preferably make the battery pack can be under the control of battery electron control unit 125, use such as charging FET (semiconductor device 130b) its semiconductor device to forbid that charging current flows through.

The control of overcharging can utilize the charging locking between battery pack and the charger to connect testing circuit, and (being also referred to as ' hardware watchdog circuit ' provides.In general, if charger is locked on the on-state and chopping data (for example, offering the clock pulse of charger from battery pack by suitable serial data path) have stopped, so, hardware watchdog can flow by the automatic disconnection electric current.

The conventional hardware watchdog circuit is usually located in the charger.This circuit monitors charging current and the 10ms electric current of seeking in the charging current disconnect the replacement pulse.In typical charging situation, the microprocessor in the charger (for example, the charger electronic control unit 155) can utilize charging control line I _CTRLProduce this replacement pulse.Under abnormal conditions (for example, the charger microprocessor is completely locked at electric current on the on-state or the charger power supply is completely locked at electric current on the on-state), the hardware watchdog circuit is with break-off and utilize charging FET to disconnect charging circuit.But, in traditional structure,, and never stop quick charge (for example) because inappropriate microprocessor behavior if the microprocessor in the charger continues to produce the replacement pulse, still can make battery pack overcharge.

Fig. 4 is according to the battery pack of the expression additives for overcharge protection of an one exemplary embodiment of the present invention and the partial block diagram of the connection between the charger.In Fig. 4, for convenience's sake, show seven line ends and six batteries.Self-evident, also can represent more or less line end and battery in an exemplary embodiment.

In Fig. 4, battery pack 100 comprises battery electron control unit 125, semiconductor device 130b (for example, charging control FET) and temperature sensor 120 at least.Temperature sensor 120 can for example be embodied in inner NTC thermistor.Charger 150 can comprise charger electronic control circuit 155, charging FET 157 and hardware watchdog circuit 158 at least.

Battery electron control unit 125 can receive from the battery temperature value of inner NTC thermistor and can this information be sent to charger electronic control circuit 155 by the serial data path on line end 3 and/or 4.Because the situation of overcharging is causing under the situation of extreme battery temperature, battery electron control unit 125 sends pwm control signals or pulse to disconnect semiconductor device 130b by drive circuit 140, can stop charging current.Alternately, this control signal can send to charger electronic control circuit 155 by the serial data path on line end 3 and/or 4, with disconnect in the charger 150 charging FET 157.But, in battery pack 100, exist under the situation of two point failures-short circuit semiconductor device 130b (charging control FET) and appearance inappropriate unit behavior in one of battery electron control unit 125 or charger electronic control circuit 155, battery pack 100 is overcharged.

Band arrow among Fig. 4 has been shown in dotted line the hardware watchdog circuit 158 (hereinafter referred to as house dog 158) that contains a plurality of replacement inputs.Except monitoring charging current replacement pulse, house dog 158 monitors serial communication clock pulse path (by line end 3) also as the replacement pulse.If the some of these replacement pulses do not occur, house dog is with break-off and disconnect charging current.In battery pack 100, exist two point failures-short circuit charging (for example to control FET, device 130b) occurs and in one of battery electron control unit 125 or charger electronic control circuit 155 under the situation of inappropriate unit behavior battery pack 100 being overcharged.

Except monitoring charging current replacement pulse, the battery pack temperature on the also direct monitor temperature sensor 120 of house dog 158 (for example, the NTC thermistor) is with the detection situation of overcharging.In Fig. 4, any fault in short circuit battery charging control FET (semiconductor device 130b) and battery electron control unit 125 or the charger electronic control circuit 155 do not influence house dog 158 in order to detect and stop the situation of overcharging the ability of monitor battery pack temperature.

Except monitoring charging current replacement pulse, house dog 158 also utilizes circuit 415A and line end 6 to monitor each cell voltage, to detect the overvoltage situation of representing the situation of overcharging.In Fig. 4, any fault in short circuit battery charging control FET (semiconductor device 130b) and battery electron control unit 125 or the charger electronic control circuit 155 does not influence house dog 158 in order to detect and to stop the situation of overcharging and monitor the ability of each cell voltage.

Except the control hardware house dog, the voltage monitoring circuit 415A that is used for monitoring each cell voltage can also be by the direct charging FET 130b of control battery pack 100 of drive circuit 140, and/or directly control charging FET in the charger (157) by AND logical circuit (151) and line end 6.This is by being shown in dotted line between voltage monitoring circuit 415A and the drive circuit 140.This control makes circuit 415A can stop the situation of overcharging that the overvoltage by each battery causes.

Except monitoring charging current replacement pulse, house dog 158 also utilizes voltage monitoring circuit 415B and line end 7 monitoring battery superimposed voltage, to detect the overvoltage situation of representing the situation of overcharging.In Fig. 4, any fault in short circuit battery charging control FET (semiconductor device 130b) and battery electron control unit 125 or the charger electronic control circuit 155 do not influence house dog 158 in order to detect and stop the situation of overcharging the ability of monitoring battery superimposed voltage.

Except the control hardware house dog, the voltage monitoring circuit 415B that is used for the monitoring battery superimposed voltage can also directly control the charging FET (130b) (referring to optional dotted line 425) of battery by drive circuit (140), and/or directly controls charging FET in the charger (157) by AND logical circuit (151) and line end (7).This control makes voltage monitoring circuit 415B can stop the situation of overcharging that the overvoltage by the entire cell superimposed voltage causes.

Fig. 5 is according to the battery pack of the cordless power tool systems of the expression additives for overcharge protection of another one exemplary embodiment of the present invention and the partial block diagram of the connection between the charger.For the sake of clarity, Fig. 5 has omitted voltage monitoring circuit 415A and 41B, and is self-evident, to similar as shown in Figure 4, each cell voltage and total superimposed voltage both can import hardware watchdog circuit 158 among Fig. 5 ' in.

Fig. 5 be Fig. 4 with expression have the house dog 158 of a plurality of inputs ' mix.House dog 158 ' supervision charging replacement pulse, clock resetting pulse and NTC signal, cell voltage and/or cell stack voltage are so that detect charging locking connection situation.Even in battery pack 100, exist under the situation of short circuit charging control FET 130b and appearance inappropriate unit behavior in one of battery electron control unit 125 or charger electronic control circuit 155, still charging current can be cut off and the NTC output can be reduced and the shared required line end quantity of clock pulse line end.Therefore, the exemplary hardware watchdog circuit in the Figure 4 and 5 can prevent battery overcharge by both situations of monitor battery pack 100 and charger 150.Even there are two point failures in one of battery pack 100 and charger 150 (or both), for example, under the situation of short circuit battery charging FET and inappropriate microprocessor behavior, additives for overcharge protection is still remained valid.

The definite of the malfunction of overcharging also can be finished by other device.If the current detector in the interdischarge interval battery pack (for example, current detector 145) carries out accurate current measurement, so, battery electron control unit 125 can carry out electrical measurement, and the energy that takes out is replaced.This measurement can combine or not combine and be used for detecting the fault state that overcharges with the voltage measurement that the protective circuit 210 in the battery pack 100 is carried out.

Over

When discharge surpassed the recommendation of manufacturer, various battery technologies all can come to harm.According to one exemplary embodiment, the battery pack 100 shown in top Fig. 3 A or 3B can comprise when cell voltage drops to and stop electric current to flow through when being lower than given voltage threshold, therefore, and under voltage locking dead circuit.Protective circuit 210 in the battery pack can detect cell voltage, is lower than given voltage level if cell voltage drops to, and turn-offs discharge FET (semiconductor device 130a).Battery 105 still easily is recharged, but also no longer discharge.Threshold value for example can be the absolute threshold that is provided with during fabrication, or the threshold value that can change with the quantity of given factor.

Fig. 6 is the voltage change curve in time of the automatic cut-out carried out according to the expression protective circuit of an one exemplary embodiment of the present invention.In order in the battery pack of cordless power tool systems, to provide protection in case the overdischarge fault state; if voltage reaches given threshold value, exemplary protective circuit 210 among Fig. 3 A-5 (as shown in Figure 2) and/or battery electron control unit 125 can cut off the electric current in the battery pack 100 automatically.

A kind of improvement to above-mentioned voltage threshold can be that threshold value and a part of discharging current are combined, with the impedance of balancing battery group 100.Make threshold value based on absolute level with deduct the alternative that a part of transient current can provide under voltage locking to disconnect.

Fig. 7 is according to the voltage of the correction threshold of the expression over of an one exemplary embodiment of the present invention change curve in time.Fig. 7 for convenience of description, the protective circuit 210 of Fig. 2 or battery electron control unit 125 can be configured to carry out following calculating and/or cut off automatically.Fig. 7 shows the example that battery pack is in 10% charged state.By adding the impedance of a part of discharging current with balancing battery group 100, battery pack 100 is still on the given discharge threshold of 2.7V.

For example, if the 10A pulse load is applied on the battery pack 100, battery impedance drops under the threshold value voltage at once, when removing current impulse, turns back to its quiescent value.Although battery pack 100 also keeps 10% charging, protective circuit flows interruptive current.But, if low pressure threshold by as current segment compensation described in the epimere, threshold value will descend during big electric current outflow, cutting phenomenon can not occur.In other words,, can change low pressure threshold, thereby avoid unnecessary automatic cut-out by deducting a part of instantaneous discharge electric current with the impedance of balancing battery group.

In case the impedance of battery pack is known, so, just can calculate and that current related a part of low pressure threshold.The other battery factor that may influence low pressure threshold may comprise fall off rate of battery temperature, battery age and cell voltage etc.

Overcurrent protection

Fig. 8 A and 8B represent the exemplary devices that can be used for overcurrent protection in battery pack according to an one exemplary embodiment of the present invention.For the sake of brevity, Fig. 8 A and 8B only represent a part of battery circuit.But the device among Fig. 8 A and the 8B can be the part of battery pack 100 such shown in any one of image pattern 3A-5.The another kind of mechanism that battery is damaged is overcurrent.All may there be electronic switch troublesome shortcoming under short-circuit state in various electronic switch methods.When this thing happens, operating personnel can make the motor overload of outfit.For the battery circuit design that comprises the discrete impedance branch road, the device such as fuse or fuse can be used to limit the maximum current through that circuit branch.

Because the basic function of fuse is to prevent short circuit, so fuse generally is not designed to provide overload protection.Yet dual-element (two elements) fuse or time delay fuse can provide the stand-by motor overload protection, but because these fuses are nonupdatable, when being blown, must replace.Therefore, such fuse can be represented secondary failure and be intended to for example prevent further operation.

Therefore, such simple fuse can be designed to the electric current of limit battery 105 shown in the image pattern 8A, still, in case surpass its rated value, also can cause permanent lesion.The fuse that other device such as positive temperature coefficient (PTC) element and reconfigurable fuse can replace among Fig. 8 A is used for overcurrent protection.Such as discussed above, known PTC device or element are crossed the protection component of the electric current of the circuit that will protect as control flows, increase because their resistance value is emitted heat with them under over-current condition.For example, the PTC thermistor is as over-current protecting element.When circuit became overload, conducting polymer heating and thermal expansion with PTC thermistor of ptc characteristics became big resistance value, thereby the electric current of circuit is reduced on the safe relatively little current level.

Therefore, if PTC device as described above connect with battery, Zong the battery pack impedance will increase and increase with electric current.Quite low if desired impedance and do not have single commercial PTC device that required Low ESR and/or current capacity can be provided so for example shown in Fig. 8 B, can make a plurality of PTC electric current of sharing parallel with one another.

If in battery pack, dream up discrete charging and discharge path or branch road, so, the thermo-fuse such as the PTC element can be placed on every current path.The benefit of doing like this is that charge path uses low current device and discharge path to use high-current device.

Near the more approaching position of fuse and line end can also provide the additional benefit that the downstream branch of electronic equipment and non-isolation charger are kept apart.If battery pack 100 fully fusing comes out battery 105 and electronic circuit; the fuse approaching with line end (blowing) will make exposing metal and non-isolation charger output disconnect; isolate thereby form electricity, might protect the electronic unit in the attached charger (or instrument).Therefore, the fuse among Fig. 8 A (or PTC element) is placed to such an extent that can in battery pack 100, provide additional overcurrent protection with line end is approaching.

In case reaching the overcurrent threshold value, just to utilize current detecting means (for example, the current detector 145 of Fig. 3 A and 3B) and semiconductor device (for example,

semiconductor device

130a and 130b) to stop that electric current flows may be the method that caters to the need that prevents the battery infringement.For example, current detector 145 goes for detecting battery pack current, generates control signal according to the detection electric current that surpasses given current limitation or threshold value.Semiconductor device (for example,

semiconductor device

130a and 130b) with current limliting or cutout function can directly be connected with current detector 145.Semiconductor device goes for according to direct control signal from current detector 145 receptions, rather than by control signal restriction or the interruptive current of driver 140 from 125 receptions of battery electron control unit.

If instantaneous high current loads is acceptable, but the high electric current of stable state is unacceptable, and current detecting is combined with asking average algorithm.Current limitation that is suitable for or threshold value also can be variable and be directly proportional with the temperature of battery.This benefit of doing is, if battery is awfully hot, the maximum current of outflow with regard to deficiency so that the internal cell chemical composition is overheated.

The excessive temperature protection

Some batteries also may be subjected to extreme temperature (thermal extremes or low temperature) infringement or because extreme temperature has the performance (that is the voltage of decline and/or electric current output) of decline.This is especially relevant with the battery pack that contains the lithium ion battery chemical composition.The battery temperature threshold value can be arranged on it be cooled to required or give below the fixed temperature before cut off battery pack.Equally, the battery temperature threshold value can be arranged on it be elevated to required or give more than the fixed temperature before cut off battery pack.These threshold values also can be based on the limit that is provided with that depends in part on electric current, voltage, age and temperature rising or fall off rate.Such as discussed above, one or more temperature sensors can be used for determining the state of battery pack temperature.

Fig. 9 represents the device that the excessive temperature protection is provided according to an one exemplary embodiment of the present invention.Excessive temperature fault state in the battery can cause permanent lesion.Therefore, be configured to monitor that the protective circuit of absolute temperature can be used for preventing the excessive temperature situation.For the sake of brevity, Fig. 9 only represents a part of battery circuit.But the device among Fig. 9 can be the part of battery pack 100 such shown in any one of image pattern 3A-5.

As shown in Figure 9, protective circuit 210 can be embodied in the thermal switch 910 of opening big current contact 920.These contacts can be positioned at circuit, so that before temperature drops to acceptable level, stop battery pack 100 inside and outside any electric currents and flow.These devices can be arranged in usually on the predetermined temperature and to disconnect and for example can find in coffee pot usually.In case the boiling of the water in the coffee pot, temp of heating element just is elevated to more than 212 ℉.Temperature switch detects this temperature and break-off signal control switch.When battery pack (or battery) temperature became too high, charging and/or discharging function in the battery pack 100 just were under an embargo.

Alternately, the thermal control relieving mechanism can and stop it to insert again before battery pack 100 coolings with battery pack 100 ' ejection ' instrument 170 or charger 150.As seeing from following further details, this device and purpose are to provide that to be limited in " the ejection timer " of the locking mechanism in the battery pack 100 similar with ejecting device.Provide protection in case the another kind of device of excessive temperature fault state is the use in the thermistor.Thermistor can be used in the battery pack 100, monitor temperature situation when keeping the electric fully isolation of thermistor and battery 105.

Current, manufacturer can make thermistor be included in the battery pack usually, monitors the temperature of core battery pack and under the situation that the excessive temperature situation occurs, stops charging.These thermistors have that an end wherein goes out to be connected with the line end of charger 150 and the other end by with battery pack in the syndeton of negative terminal lead-in wire constraint ground connection.

In order to make high-power battery group such as the lithium ion battery group be fit to make it to use the processing line of the electric tool of these high-power battery groups to be used in combination with existing cordless power tool and its manufacturing, above this syndeton may have problems because this syndeton is through producing current potential on the charge path of thermistor.If small amount of current is through thermistor, may be in the protection control in being provided in battery pack 100 and charger 150 and circuit outside to batteries charging.This may cause battery pack 100 be not intended to overcharge a kind of potential hazard situation.

Figure 10 represents the syndeton according to the thermistor of an one exemplary embodiment of the present invention.In Figure 10, for the sake of clarity, the negative terminal and the positive terminal of battery pack 100 only is shown.For the sake of brevity, Figure 10 only represents a part of battery circuit.But the thermistor among Figure 10 can be the part of battery pack 100 such shown in any one of image pattern 3A-5.Two lead-in wires (Th+ and Th-) of thermistor can be guided on the

independent line end

2 and 3 outside the battery pack.These line ends can with for example temperature monitor circuit handing-over (for the sake of clarity, not shown in Figure 10) in the charger 150 as the temperature monitor circuit of charger electronic control unit 155.So just can be when the charge path in keeping thermistor and battery pack 100 be isolated fully, the temperature of monitor battery pack 100.Do like this, just do not have the charge path of process thermistor and do not have the current potential that battery pack 100 is overcharged by thermistor.

Can listen/visual cautionary mechanism

Before cutting off powered battery, preferably the operating personnel to the wireless instrument of being powered by the attached battery group provide certain warning.With the situation of breaking down or the situation that is occurring in the process similar, in car owner's automobile, because fault state makes engine suffer to destroy (for example, the piston that is caused by leakage of oil damages) before, can be in the given duration on fascia to car owner's light that gives a warning.

Under voltage and temperature limitation may be used to cut off, that is, in case reach threshold value, battery pack 100 just stops output current.But, such fault state is appearring (for example, reach under voltage or excessive temperature threshold value) before, the alert mechanism in battery pack or the instrument can alert operator, and operating personnel are near being about to occur operating limit in the battery powered battery pack that may cut off automatically in the battery pack.Alert mechanism can be audible (by means of loudspeaker or a buzzer) or for example utilize required illumination scheme as LED, can be observable.

Can will can listen and/or visual cautionary mechanism is attached in the present circuit in battery pack 100 or the instrument 170.Such as discussed above, the battery pack 100 in any one of Fig. 3 A to 5, instrument 170 or charger 150 can be controlled by the intelligent parts in battery pack, instrument, the charger etc.Intelligent parts as battery electron control unit 125 or instrument electronic control unit 180 can be configured to control the alert mechanism that is about to the appearance or the situation that broken down for various.For instance, can provide discrete listening or visual cautionary, so that remind in overdischarge situation in operating personnel's battery pack 100 of instrument, the over-current condition in the battery pack 100, the battery pack 100 or the under voltage situation that causes by the overcurrent that from battery pack 100, flows out in excessive temperature situation in the motor 190 of outfit 170 and/or the battery pack 100.

Such as discussed above, reach be about to occur the alert mechanism of automatic battery power supply before cutting off can be with many multi-form specializing.Above-mentioned listened to warning such as loudspeaker, buzzer and loudspeaker sound is acceptable under a few thing environment, but the tool operation personnel may not hear under loud environment.Visual cues such as specific illumination and instrument tool operation personnel in extremely dark or quite bright working region also might be not aware of.

Remind tool operation personnel's alternative alert mechanism to specialize with the Electric Machine Control of instrument motor.In general, the electronic circuit in one of instrument or battery pack can reduce the maximum power fan-out capability of battery pack and cause " turning back " situation.Operating personnel can hear and feel the situation that this tool performance ' dies down '.Therefore, can alert keep out of the way and avoid being about to the situation of breaking down (for example, under voltage, excessive temperature, cross low temperature situation etc.).

The other method of reminding the user to be about to the situation of breaking down can be to change the pulse-width modulation (PWM) of Electric Machine Control so that produce " vibration " effect in the speed of motor.The gentle cyclic variation of this motor speed is chosen such that it can not cause negative effect to tool performance.This method will to be about to the situation of breaking down listen or but tactile feedback offers the user.

The third method of reminding the user to be about to the situation of breaking down can be that the PWM frequency is reduced to audible frequency range and periodic mode ground change tone.So just can provide the effective alert mechanism that causes that operating personnel note.At least, this alert mechanism gives operating personnel with warning sensation, makes them can finish work at present, but can not continue to transfer to another work before being about to the situation of breaking down battery pack being stopped or recharging to eliminate or to overcome.

No matter top alert mechanism any uses still alert with top warning another kind of or several uses that combine separately, all might improve instrumental function and prolongation instrument and/or battery pack life-span.Describing in detail below is at back a kind of alert mechanism that above-mentioned vibrato is provided in the motor of electric tool according to the charged state in the battery pack.

PWM charged state (SOC) indicating device

The purposes of PWM charged state (SOC) indicating device is to remind operating personnel may cause automatic battery power supply switching, causes the situation of breaking down that is about to of battery pack ' inefficacy '.This can be by determining directly that in as the motor control unit of the part of battery circuit SOC information realizes.According to SOC information, the motor control unit in the battery pack can change the current of electric switching frequency, so that produce ' vibrato ' can be heard by the tool operation personnel and/or can somatosensory arrive in the instrument motor.

Figure 11 is the flow chart that the method that is about to the situation of breaking down in operating personnel's battery pack of electric tool is reminded in expression.With reference to Figure 11, the motor control unit (not shown) in the battery pack can be measured various battery pack parameters, to determine charged state (SOC) information (S1110) in the given time battery pack.Motor control unit can be embodied in for example digital microcontroller, microprocessor or analog circuit with hardware or software, and/or specializes by the digital IC such as digital signal processor or application-specific integrated circuit (ASIC) (ASIC).According to SOC information, the definite required motor current switch frequency (S1120) that the instrument motor is exerted an influence of motor control unit is so that produce the vibrato (S1130) of reminding operating personnel.

The mode that the SOC of many assessments, tracking and definite battery pack is arranged.For example, the battery pack parameter of being measured with definite SOC information by motor control unit can comprise battery voltage, electric weight (coulomb) counting (Ah _In-Ah _Out), total battery pack 100 impedances etc.Then, motor control unit is according to SOC information decision current of electric switching frequency.

The current of electric switching frequency of instrument 170 motors can be handled in many prompting users' mode.Therefore, adjusting the current of electric switching frequency can communicate by letter the motor of instrument with the tool operation personnel.Switching frequency can be selected in audible frequency range, but so that motor sends the noise of operating personnel's sense of touch.Exemplary audible frequency can for example be speak a series of composite multi-frequency rate tones of sound of the constant frequency tone that sends of instrument motor, variable frequency ring tone or imitation tool operation personnel.In addition, motor control unit can offer motor with pulse, so that allowing operating personnel know that for example battery electric quantity exhausts, or makes instrument do to move around or vibrate on health near the mode of the fault state that requires to arouse attention.

The pulse-width modulation motor is to remind operating personnel that the method that is about to the situation of breaking down such as low SOC situation also can be used to pass on other fault state.For example, the current of electric switching frequency can be adjusted to according to battery pack in excessive temperature situation, the excessive temperature situation in the instrument motor, the over-current condition in the battery pack and/or the relevant detection information reminding tool operation personnel of under voltage situation that cause by the overcurrent that from battery pack, flows out.Electric current, temperature and voltage only are the exemplary measurable parameters that can be followed the tracks of given fault state.

Figure 12 is that expression is according to the definite SOC of an one exemplary embodiment of the present invention and the calcspar of the demonstrative structure that changes the current of electric switching frequency.Similar a bit to Fig. 3 B, Figure 12 show battery pack 100 ' and instrument 170 ' between circuit handing-over relation, but for the sake of clarity, only show some parts.

With reference to Figure 12, as top with reference to other several accompanying drawing discuss, IC1, R1 and Q1 are influential to protective circuit and battery equilibrium function.IC1 is the battery pack electronic control unit 125 among representative graph 3A and the 3B for example.DATA3 and DATA4 representative transmit the serial data path of serial data between IC1 and IC2; IC2 among Figure 12 can represent motor control unit.For example, DATA3 can be exclusively used between IC1 and IC2 Data transmission and control signal and DATA4 be used for the tranmitting data register pulse so as to make IC1 and IC2 synchronous, or conversely.

Element REG is the voltage regulator that VCC is supplied to digital device IC2 and IC3.In Figure 12, IC3 can represent as the instrument electronic control unit 180 for example described in Fig. 3 B, and DATA1 and DATA2 representative transmit the serial data path of data and control signal between IC3 and IC2.The tool switch of electric tool M1 is delivered to electric current in the SW1 representative from battery pack.Resistance R 6 and potentiometer R7 constitute the variable velocity input of instrument.Each of IC1, IC2 and IC3 can for example be embodied in digital microcontroller, microprocessor or analog circuit with hardware or software, and/or specializes by the digital IC such as digital signal processor or application-specific integrated circuit (ASIC) (ASIC).

Motor control unit IC2 drives the grid of Q5 and Q6 (can be embodied in MOSFET), so that the output voltage of regulating cell group, thereby control is to the current of electric of motor M 1 power supply of instrument.IC2 can measure one of a plurality of battery pack parameters to determine SOC.For example, IC2 can monitor node N1 and the battery pack output voltage at N2 two ends, or by monitoring that the electric current on the shunt resistance R5 and the trace (by suitable internal clocking) of holding time carry out the electric weight counting.And, IC2 can also by from unloading battery voltage (electric current flow out before record), deduct load battery pack output voltage (when electric current flows) and with the result divided by the current measurement value monitor battery pack impedance of on R5, being done.Any one of these measurable parameters may be used to SOC and measures.Then, IC2 can utilize this SOC information to determine that suitable switching frequency and control Q5 and Q6 reach that switching frequency.

Redundancy

Above-mentioned characteristic Design is become to prevent the infringement of excessive use in any part of control system in battery pack 100, charger 150 or the instrument 170 or trouble unit to battery.By in addition redundant supplementary form, the possibility that battery is subjected to the battery infringement is just littler.For example, in Figure 12, the electric current of charger 150 and instrument 170 all right monitoring battery temperatures and outside line end of process or order wire.Between charge period, also can pass through charger 150 monitoring battery voltages.Also can pass through inspection of tools cell voltage at interdischarge interval.

Figure 13-16 is illustrated in the various devices that additives for overcharge protection is provided under the extreme case prevailingly.Under the situation of overcharging is failed situation that watchdog circuit, other current detecting device and/or intelligent device by above-mentioned Figure 4 and 5 be resolved, the microprocessor in one or more of battery pack 100 or charger 150 will break down (the multiple spot fault in battery pack or the charger).The potential auxiliary protection of Figure 13-16 expression battery pack 100 and/or charger 150.

Figure 13 A is the isometrical drawing of individual layer battery, and wherein battery 1305 (similar with the battery 105 in any one of Fig. 3 A-5) contains the joint 1303 (being also referred to as connector) that is connected with adjacent series-connected cell.Figure 13 B and 13C represent to protect in case the device of the situation of overcharging according to providing of an one exemplary embodiment of the present invention.

The device that Figure 13 B and 13C represent can reduce the current potential of the battery that contains lithium ion battery chemical composition (or other battery chemistries composition), in order to avoid the seriously situation of overcharging that has neither part nor lot in owing to other protective circuit in the battery pack is broken.In general, during the process of overcharging, sheet lithium ion battery 1305 can present serious expansion.Continue if overcharge, this may cause one or more batteries 1305 to break.This break may cause catching fire and may be to battery pack 100, adhere to electronic equipment (charger 150, instrument 170) and/or the user of battery pack 100 causes serious harm.

Therefore, battery pack can be designed to utilize this intumescent advantage.Figure 13 B is end view and expression joint pad 1306 or the similar tie point of battery pack under stable state or normal condition, so that the joint 1303 of the adjacent cell 1305 of connecting between the positive-negative power end of battery pack 100.Shown in Figure 13 C, the expansion of one or more given batteries 1305 has the situation that helps prevent seriously overcharge and occurs in the battery pack 100.The tension force that expansion battery 1305 produces its joint 1303 can separate two joints 1303 at joint pad 1306 places.In this example, in circuit, form opening 1308, therefore remove or interrupt battery 130 and charging current.Therefore,, joint connector 1303 and adjacent joint 1303 are thrown off on joint pad 1306, destroy the electrical connection between the battery 1305, thereby the electric current that interrupts in the battery pack 100 flows along with battery 1305 expands.

Figure 14 A and 14B represent to protect in case the device of the situation of overcharging according to providing of another one exemplary embodiment of the present invention.Figure 14 A represents the end view of battery pack 100 under stable state or normal condition, thereby represents another kind of exemplary protection structure.In Figure 14 A, battery 1305 can sequence arrangement in battery case (shown in box sidewall 1401a and box sidewall 1401b summarize), battery case can for example comprise middleboxes wall 1401c.Between series-connected cell 1305 and middleboxes wall 1401c, can be equipped with inserted link 1408, so that stretch in the groove 1409 by wall 1401b and 1401c.In this example, inserted link can retrain by the reaction force that spring 1410 provides, so that form passage 1404 between box sidewall 1401b and middleboxes wall 1401c.Lead-in wire (being shown herein as positive terminal line or circuit track) can penetrating via 1404.

Existing with reference to Figure 14 B, Figure 14 B shows a battery 1305 under the overcharge condition.Along with battery 1305 expands, help inserted link 1408 to overcome antagonistic spring pressure from spring 1410 from the expansive force of battery.Therefore, inserted link 1408 enters in the groove 1409, as such shown in 1415 summaries, cuts off lead-in wire 1405, thereby interrupts the charging current of the battery 1405 of battery pack.Be to be further noted that expansion battery 1305 also makes joint 1303 as throwing off like that shown in 1308 summaries.The redundancy of cutting off or destroy the electrical connection of battery pack inside further is provided.Therefore, this protection feature is by the mobile one or more cell fracture that prevented in the battery pack 100 of interruptive current.

Figure 15 A and 15B represent to protect in case the device of the situation of overcharging according to providing of another one exemplary embodiment of the present invention.Figure 15 A and 15B represent to be designed to eject from charger the inserted link of battery pack.

Figure 15 A is similar to Figure 14 A, therefore, for the sake of brevity, difference only is discussed.Shown in Figure 15 A, under stable state or normal operation, inserted link 1408 is biased to the antagonistic spring pressure of resistance spring 1410, leaves standstill so that inserted link 1408 is pasting charger box sidewall 1501.Charger box sidewall 1501 adjoins with the sidewall 1040b of battery pack 100.The lead-in wire 1405 of battery pack and charger lead-in wire 1505 are operatively coupled on

contact point

1410 and 1510.

Referring now to Figure 15 B, along with battery 1305 expands, inserted link 1408 overcome cause inserted link 1408 from charger from spring 1410 pressure that eject battery pack 100, referring to the gap 1508 between charger box sidewall 1501 and the battery pack sidewall 1401b.This action breaks contact 1410 and 1510.Therefore, in case the situation that occurs seriously overcharging, the displacement of the expansion of battery pack and inserted link 1408 combines and has interrupted charging current and prevented that by ejection battery pack from charger battery pack from breaking.Be to be further noted that expansion battery 1305 also makes joint 1303 as throwing off like that shown in 1308 summaries.The redundancy of cutting off or destroy the electrical connection of battery pack inside further is provided.Therefore, this protection feature is by the mobile one or more cell fracture that prevented in the battery pack 100 of interruptive current.

Figure 16 A and 16B represent to protect in case the device of the situation of overcharging according to providing of another one exemplary embodiment of the present invention.Figure 16 A-B is similar to Figure 14 A-14B in some aspects, therefore, for the sake of brevity, only describes difference.

In Figure 16 A, charger lead-in wire or contact wire 1505 are connected with the battery pack lead-in wire on contact 1405 and 1505.Different with Figure 14 A, charger lead-in wire 1505 adjoins with the inner surface of charger box sidewall 1501.Inserted link 1408 and spring 1410 are as described in Figure 14 A.Referring now to Figure 16 B, Figure 16 B shows a battery 1305 under the overcharge condition.Along with battery 1305 expands, help inserted link 1408 to overcome antagonistic spring pressure from spring 1410 from the expansive force of battery.Therefore, inserted link 1408 is advanced and is entered in the groove 1409, as such shown in 1615 summaries, cuts off lead-in wire 1505, thereby interrupts the charging current of the battery 1405 of battery pack.Be to be further noted that expansion battery 1305 also makes joint 1303 as splitting like that shown in 1308 summaries.The redundancy of cutting off or destroy the electrical connection of battery pack inside further is provided.Therefore, this protection feature is by the mobile one or more cell fracture that prevented in the battery pack 100 of interruptive current.

Though one exemplary embodiment of the present invention is so described, apparent, can change them in many ways.Such change should not be considered to depart from the spirit and scope of one exemplary embodiment of the present invention, and conspicuous for the person of ordinary skill of the art all such corrections all should be included among the scope of described claims.

Claims

1. one kind provides protection in case the protection structure in the battery pack of fault state in battery pack, and battery pack is fit to the cordless power tool power supply and comprises a plurality of batteries, and this protection structure comprises:

A plurality of different protection devices, each battery contain the corresponding protection device that is fit to carry out current-limiting function.

2. structure according to claim 1, wherein, each protection device is embodied to thermistor.

3. structure according to claim 1, wherein,

Battery connect mutually form a string battery and

Each protection device is embodied to when its respective battery reaches fault state, and its resistance value increases positive temperature coefficient (PTC) device with the electric current of restricted passage entire cell string.

4. structure according to claim 1, wherein, battery pack is the lithium ion battery group.

5. structure according to claim 4, wherein, the lithium ion battery group has the load voltage value of 18V at least.

6. one kind is fit to the cordless power tool power supply and comprises the battery pack of a plurality of series-connected cells, and this battery pack comprises and being fit to according to the fault state restriction that detects in battery pack or the protection structure of interrupting the electric current in the battery pack.

7. battery pack according to claim 6, described structure further comprises:

At least one protective circuit is used to detect given battery pack parameter, to determine the fault state in one or more batteries and to generate control signal according to the indication of fault state; With

Main device contains and is fit to basis from the control signal restriction of protective circuit reception or the current limliting or the cutout function of interruptive current.

8. battery pack according to claim 6, described structure further comprises:

Temperature sensor is used to detect battery pack temperature to generate first signal;

Current detector is used to detect battery pack current to generate secondary signal; With

Battery control circuit is fit to receive described first and second signals to determine the fault state in the battery pack and to generate control signal.

9. battery pack according to claim 8, wherein,

The battery electron control unit with control signal send to the semiconductor device that operationally is attached thereto and

Semiconductor device has current limliting or the cutout function according to control signal restriction or interruptive current.

10. battery pack according to claim 6, described structure further comprises:

Current detector is used to detect battery pack current to generate control signal according to the overcurrent fault situation that detects; With

Have current limliting or cutout function and the semiconductor device that operationally is connected with current detector, this semiconductor device is fit to according to the control signal restriction or the interruptive current that receive from current detector.

11. wherein, if the battery pack current that detects surpasses given threshold value, there is the overcurrent fault situation in battery pack according to claim 10.

12. battery pack according to claim 11, wherein, current threshold is based on the temperature of battery.

13. battery pack according to claim 6, described structure further comprises:

Battery control circuit is configured to monitoring battery voltage, battery current and current temperature, so that generate control signal; With

Operationally be subjected to the semiconductor device of battery control circuit control, this semiconductor device is fit to according to control signal restriction or interruptive current.

14. battery pack according to claim 13, described structure further comprises:

Temperature sensor is used to detect battery temperature, so that detection signal is outputed to battery control circuit;

Current detector is used to detect battery current, so that detection signal is outputed to battery control circuit; With

Voltage monitoring circuit is used to detect one of each cell voltage of battery pack and total battery voltage, so that detection signal is outputed to battery control circuit.

15. battery pack according to claim 6, described structure further comprises:

At least one communication ends is used for that information is sent to attached external component and from attached external component detection information.

16. battery pack according to claim 6, described structure further comprises:

At least one protective circuit if be used for reaching given voltage threshold at the potential overdischarge fault state monitor battery pack voltage of battery pack and the voltage that is fit to monitor, automatically perform the electric current that cuts off in the battery pack and flows.

17. battery pack according to claim 6, described structure further comprises:

At least one protective circuit if be used for reaching given dynamic electric voltage threshold value at the potential overdischarge fault state monitor battery pack voltage of battery pack and the voltage that is fit to monitor, automatically perform the electric current that cuts off in the battery pack and flows,

Wherein, change the dynamic electric voltage threshold value, with the impedance of balancing battery group with avoid temporarily dropping to the wrong cut-out automatically that the electric current that causes below the threshold value flows because of the voltage that monitors by from the absolute threshold level, deducting a part of instantaneous discharge electric current.

18. battery pack according to claim 6, described structure further comprises:

Being placed to connects with the series-connected cell in the battery pack provides protection in case the single PTC device of overcurrent fault situation, total this PTC device is fit to increase its battery pack resistance value that raises with the electric current in the battery pack.

19. battery pack according to claim 6, described structure further comprises:

In battery pack, be placed to parallel with one another to form a plurality of PTC devices of PTC string in parallel; this parallel connection PTC string is placed with connect with series-connected cell provides protection in case the overcurrent fault situation, total this parallel connection PTC string is fit to increase its battery pack resistance value of rising with the electric current in the battery pack.

20. battery pack according to claim 6, described structure further comprises:

Be arranged in the battery of battery pack and at least one fuse between the line end, wherein, it is nearer that battery is compared to line end in the body position of fuse, thereby under the situation that occurs overcurrent fault in battery pack, the battery of battery pack is separated with link to each other charger or electric tool with associated electronics.

21. battery pack according to claim 6, wherein, this battery pack is the lithium ion battery group.

22. battery pack according to claim 6, wherein, the lithium ion battery group has the load voltage value of 18V at least.

Can listen alert mechanism 23. battery pack according to claim 6, described structure further comprise, be configured to being about in user's battery pack of indicating battery group and occur or the situation that broken down.

24. battery pack according to claim 6, described structure further comprises visual cautionary mechanism, is configured to being about in user's battery pack of indicating battery group and occurs or the situation that broken down.

25. the method for overvoltage protection is provided in the battery pack on being attached to cordless power tool or charger, and this battery pack operationally is attached on the charger to batteries charging interchangeablely, this method comprises:

Detect the overvoltage fault state in the battery pack; With

According to the charging current in fault state termination battery pack that detects or the charger.

26. method according to claim 25, wherein, this termination step comprises the control signal that generates in the battery pack, so that the semiconductor device in the battery pack of the electric current in the charge path of suitable restriction of disconnection or interruption battery pack.

27. method according to claim 25, wherein, this termination step further comprises:

Generate the control signal in the battery pack; With

Control signal is sent to charger, so that the semiconductor device in the battery pack of the electric current in the charge path of suitable restriction of disconnection or interruption battery pack, the electric current that stops in the battery pack is mobile.

28. the watchdog circuit of a charger, this charger operationally is attached on the battery pack to this batteries charging, this watchdog circuit flows with the electric current that stops in the battery pack at from one or more control signal monitor battery pack of battery pack or charger and the parameter in the charger.

29. watchdog circuit according to claim 28, wherein, described parameter comprise battery pack temperature, each cell voltage, cell stack voltage, from the charging current replacement pulse of battery pack, from the clock resetting pulse of battery pack and/or one or more from the discharging current replacement pulse of charger.

30. in the charger that is fit to batteries charging, the charger of cordless power tool systems and battery pack part, this charger comprises:

The charging current interrupt circuit is used for flowing with the electric current that stops in the battery pack at from the one or more control signal monitor battery pack of battery pack or charger and the parameter of charger.

31. charging current interrupt circuit according to claim 30, wherein, described parameter comprise battery pack temperature, each cell voltage, cell stack voltage, from the charging current replacement pulse of battery pack, from the clock resetting pulse of battery pack and/or one or more from the discharging current replacement pulse of charger.

32. one kind is fit to the cordless power tool power supply with by the battery pack of charger charging, this battery pack comprises a plurality of batteries, and this battery pack comprises:

According to the battery pack temperature that surpasses given temperature threshold or separately battery temperature stop the device of the excessive temperature situation in the battery pack.

33. battery pack according to claim 32, wherein, this device further comprises:

Thermal switch; With

A plurality of big current contact,

Wherein, when battery pack or battery temperature surpassed given threshold value, thermal switch was opened big current contact.

34. in the battery pack that operationally is attached on the charger, at the device that the excessive temperature protection is provided in battery pack between charge period, this battery pack is fit to the cordless power tool power supply, this device comprises:

Thermistor;

First thermistor lead-in wire that the positive terminal that thermistor and battery pack and charger are shared is connected; With

Second thermistor lead-in wire that the negative terminal that thermistor and battery pack and charger are shared is connected.

35. device according to claim 34, wherein, positive terminal that is connected with first and second lead-in wires and the handing-over of the temperature monitor circuit in negative terminal and the charger, thus the charge path in keeping thermistor and battery pack can the monitor battery pack temperature when isolating.

36. a battery pack, this battery pack operationally are attached on the cordless power tool motor power supply to electric tool, this battery pack comprises:

Motor control unit is used for determining at least one measurable parameter of battery pack that can the indication fault situation; With

The pair of transistor of communicating by letter with circuit for controlling motor, but this circuit for controlling motor is controlled the user that this offers one of visible or tactile feedback to transistor instrument.

37. in comprising the cordless power tool systems that is attached to the battery pack on the electric tool, provide listened to warning in the motor of electric tool with operating personnel's battery pack of reminding instrument or the method that is about to the situation of breaking down in the instrument, this method comprises interchangeablely:

Determine at least one measurable parameter in one of battery pack or instrument; With

But one of visible or tactile feedback are offered the user of instrument according at least one measurable parameter of determining.

38. according to the described method of claim 37, wherein, this provides step to comprise according at least one to determine parameter adjustment current of electric switching frequency, to produce the audible tone in the motor of instrument that warning tool operation personnel are about to the situation of breaking down.

39. according to the described method of claim 37, wherein, this provides step to comprise the required PWM duty ratio of adjusting at least one semiconductor device in the battery pack, to produce the vibrato that warning tool operation personnel are about to the motor speed of the situation of breaking down.

40. according to the described method of claim 39, wherein, this set-up procedure comprises minimizing PWM duty ratio, warns the user to be about to the instrument reduction as tool user is felt of the situation of breaking down to produce.

41. a battery pack that has additives for overcharge protection, this battery pack comprises:

Battery case;

Wherein a plurality of series-connected cells; With

The current interruptions mechanism of the electric current in the interruption battery that during the process of overcharging occurring, triggers according to the expansion of at least one battery.

42. according to the described battery pack of claim 41, wherein,

Battery strings is associated between the power end of battery pack and by joint connector and interconnects, and the joint connector of adjacent cell interconnects.

43. according to the described battery pack of claim 42, wherein, current interruptions mechanism is embodied to at least one joint connector of adjacent cell throws off at least one joint connector with the expansion battery of interruptive current.

44. according to the described battery pack of claim 41, wherein, current interruptions mechanism comprises:

Inserted link; With

Spring, inserted link is being constrained under the effect of the reaction force that spring provides between the sidewall of series-connected cell and battery case, the part that comprises inserted link stretches into the part in the groove that forms in the middle of the midfeather of battery box and lateral wall, groove comprises the lead-in wire that comes from battery pack that the battery with battery pack is electrically connected with charger

Wherein, the expansion of at least one battery helps inserted link to overcome spring pressure to cut off lead-in wire in the groove with interruptive current.

45. according to the described battery pack of claim 41, wherein, battery strings is associated between the power end of battery pack and by joint connector and interconnects, the joint connector of adjacent cell interconnects and current interruptions mechanism further comprises with at least one joint connector of adjacent cell and throws off at least one joint connector with at least one expansion battery of interruptive current.

46. according to the described battery pack of claim 41, wherein, current interruptions mechanism comprises:

Inserted link; With

Spring, inserted link is being constrained under the effect of the reaction force that spring provides between the sidewall of series-connected cell and battery case, and inserted link comprises that part stretches into the part in the groove, and groove runs through the sidewall of battery box and the sidewall of charger box extends,

Wherein, the charger that charger is electrically connected with the respective lead of battery pack lead-in wire along the charger box sidewall surfaces and on groove longitudinal extension and

Wherein, the expansion of at least one battery helps inserted link to overcome spring pressure to be breaking at the charger lead-in wire that extends on the groove with interruptive current.

47. according to the described battery pack of claim 46, wherein, battery strings is associated between the power end of battery pack and by joint connector and interconnects, the joint connector of adjacent cell interconnects and current interruptions mechanism further comprises with at least one joint connector of adjacent cell and throws off at least one joint connector with at least one expansion battery of interruptive current.

48. according to the described battery pack of claim 41, wherein, current interruptions mechanism comprises:

Inserted link; With

Spring, inserted link is being constrained under the effect of the reaction force that spring provides between the sidewall of series-connected cell and battery case, and inserted link comprises that part stretches into the part in the groove of battery box and charger box formation,

Wherein, the lead-in wire that comes from battery on contact interface, be electrically connected with the respective lead of charger and

Wherein, the expansion of at least one battery helps inserted link to overcome spring pressure to eject battery box from charger box, contact interface is split with interruptive current.

49. according to the described battery pack of claim 48, wherein, battery strings is associated between the power end of battery pack and by joint connector and interconnects, the joint connector of adjacent cell interconnects and current interruptions mechanism further comprises with at least one joint connector of adjacent cell and throws off at least one joint connector with at least one expansion battery of interruptive current.