CN101728841B - Battery case - Google Patents
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- CN101728841B CN101728841B CN200810169639.7A CN200810169639A CN101728841B CN 101728841 B CN101728841 B CN 101728841B CN 200810169639 A CN200810169639 A CN 200810169639A CN 101728841 B CN101728841 B CN 101728841B
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- battery case
- thermistor
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- secondary cell
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Abstract
The invention aims to provide a battery case being capable of carrying out temperature protection on a storage battery with high precision. The battery case (10A) is arranged in a series circuit of a thermistor (R13) and a resistor (R14) which are connected in parallel with a lithium-ion battery (12), and an MOS thermistor (M13) is connected between the resistor (R14) and an anode power supply (Vss). When the overdischarge of the lithium-ion battery (12) is detected, an MOS thermistor (M11) and the MOS thermistor (M13) are shut off.
Description
Technical field
The present invention relates to a kind of battery case, particularly relate to and have by the battery case detecting the overcharge of secondary cell, overdischarge, overcurrent close the protective circuit being arranged on secondary cell and load or the switch element between secondary cell and charging device.
Background technology
In recent years, lithium ion battery was mounted in the portable sets such as digital camera as secondary cell.Because lithium ion battery is difficult to bear overcharge and overdischarge, therefore come into operation with the form with the battery case of overcharge and over-discharge protection circuit.
Fig. 4 and Fig. 5 represents the block diagram of each example of existing battery case.In the diagram, the series circuit of resistance R1 and capacitor C1 is connected in parallel in lithium ion battery 2.The positive pole of lithium ion battery 2 is connected to the outside terminal 3 of battery case 1, and negative pole, by n channel MOS (metal-oxide semiconductor) transistor M1, M2 of current chopping, is connected to the outside terminal 4 of battery case 1.
The drain electrode of MOS transistor M1, M2 is connected, and the source electrode of MOS transistor M1 is connected to the negative pole of lithium ion battery 2, and the source electrode of MOS transistor M2 is connected to outside terminal 4.Further, each MOS transistor M1, M2 distinguish between the drain and source equivalently connector diode D1, D2.
Built-in overcharge testing circuit, overdischarge testing circuit, overcurrent sensing circuit in protection IC (integrated circuit) 5.Protection IC5 to be switched on power Vdd by resistance R1 by the positive pole of lithium ion battery 2, and carrys out work by the negative pole of lithium ion battery 2 Vss that switches on power.
When protecting IC5 overdischarge or overcurrent to be detected by overdischarge testing circuit or overcurrent sensing circuit, the output of DOUT is made to be low (low), to disconnect the connection of MOS transistor M1; When detecting overcharge by overcharge testing circuit, the output of COUT is made to be low (low), to disconnect the connection of MOS transistor M2.
In Figure 5, thermistor R3 is set further in battery case 1.One end of thermistor R3 is connected to the terminal 6 of battery case 1, and the other end is connected to outside terminal 4.When charging, the terminal 6 of battery case 1 is subject to certain voltage from charging device by divider resistance.Because the resistance value of thermistor R3 can change according to the temperature of battery case 1, therefore the voltage of terminal 6 can change.The voltage of charging device detection terminal 6, when the temperature of battery case 1 exceedes predetermined value, stops charging.
At this; No. 2004-152580, Japanese Patent Publication describes following content; the diode be connected in series with temperature protection component (PTC element) and the diode be connected in antiparallel with these elements is connected at secondary cell; even if thus reach a high temperature in common electric discharge, do not allow temperature protection component (PTC element) work yet.
Existing example shown in Fig. 4 is not to the defencive function of battery case temperature.And the existing example shown in Fig. 5; although have the temperature protection function to battery case; but because battery case has certain voltage from charging device by divider resistance connection; therefore when the predetermined voltage of charging device changes or the divider resistance of charging device has an error; be difficult to the temperature correctly detecting battery case, and be difficult to the control carrying out correct stopping charging.
Summary of the invention
The present invention proposes to solve problem as above, its object is to provide a kind of battery case that can carry out the temperature protection of secondary cell accurately.
The present invention, in order to solve above-mentioned purpose, have employed following structure.
Battery case of the present invention, comprise by detecting the overcharge of secondary cell, overdischarge, overcurrent and control the open/close protective circuit of first and second switch element, first and second switch element described is arranged on described secondary cell and load or the distribution between described secondary cell and charging device, wherein, battery case has: the series circuit with thermistor and resistance, described series circuit is arranged near described secondary cell, and is connected in parallel with described secondary cell; Be arranged on the comparison circuit in described protective circuit, described comparison circuit is used for the voltage of the tie point of more described thermistor and resistance and corresponds to the reference voltage of predetermined temperature; And the 3rd switch element between the negative pole being arranged on described resistance and described secondary cell, when the overdischarge of described secondary cell being detected, described protective circuit closes described first switch element and described three switch elements.Thus, the temperature protection to secondary cell can be carried out accurately.
Described first to the 3rd switch element can be n channel MOS transistor.
Described thermistor can for having the NTC thermistor of negative temperature coefficient.
It should be noted that the example that the reference marks in described bracket is just added for the ease of understanding is not defined in diagramatic content.
Accompanying drawing explanation
Fig. 1 is the block diagram of the reference example of battery case of the present invention.
Fig. 2 represents the temperature of NTC thermistor and PTC thermistor, the figure of resistance characteristic respectively.
Fig. 3 is the block diagram of an embodiment of battery case of the present invention.
Fig. 4 is the block diagram of an example of existing battery case.
Fig. 5 is the block diagram of another example of existing battery case.
Primary symbols illustrates:
10,10A is battery case, and 12 is lithium ion battery, and 13,14 is TH outside terminal; 15,15A is protection IC, and 16 is overcharge testing circuit, and 17 is overdischarge testing circuit; 18 is overcurrent sensing circuit; 19 is logical circuit, and 20 is source of stable pressure, and 21 is comparison circuit; 22 is not sensitive time initialization circuit; M11, M12, M13 are MOS transistor, and R11, R12, R23 are resistance, and R13 is thermistor.
Preferred forms of the present invention
(reference example)
Fig. 1 is the block diagram of the reference example of battery case of the present invention.In the drawings, the series circuit of resistance R11 and capacitor C11 is connected in parallel in lithium ion battery 12.The positive pole of lithium ion battery 12 by the outside terminal 13 of connection in battery case 10, negative pole by n channel MOS transistor M11, M12 of current chopping, by the outside terminal 14 of connection in battery case 10.
The drain electrode of MOS transistor M11, M12 is connected, and the source electrode of MOS transistor M11 is connected to the negative pole of lithium ion battery 12, and the source electrode of MOS transistor M12 is connected to outside terminal 14.Further, each MOS transistor M11, M12 distinguish between the drain and source equivalently connector diode D11, D12.
The series circuit of thermistor R13 and resistance R14 is connected in parallel in lithium ion battery 12.Above-mentioned thermistor R13 is disposed near lithium ion battery 12 in battery case, and with lithium ion battery 12 thermal.Thermistor R13 uses NTC (NegativeTemperature Coefficient) thermistor with negative temperature coefficient.
Temperature, the resistance characteristic of the NTC thermistor with negative temperature coefficient and the PTC with positive temperature coefficient (Positive Temperature Coefficient) thermistor are shown in fig. 2 respectively.
Built-in overcharge testing circuit 16, overdischarge testing circuit 17, overcurrent sensing circuit 18 in protection IC (integrated circuit) 15.Protection IC15 switches on power Vdd to terminal 15a by the positive pole of lithium ion battery 12 by resistance R11, and carrys out work by the negative pole of lithium ion battery 12 Vss that switches on power to terminal 15c.
Overcharge testing circuit 16 goes out the overcharge of lithium ion battery 12 from the voltage detecting of terminal 15a, 15c, and detection signal is supplied to logical circuit 19.Overdischarge testing circuit 17 goes out the overdischarge of lithium ion battery 12 from the voltage detecting of terminal 15a, 15c, and detection signal is supplied to logical circuit 19.The electric current that overcurrent sensing circuit 18 goes out to flow into resistance R12 from the voltage detecting of terminal 15c, 15f is excessive overcurrent, and detection signal is supplied to logical circuit 19.
Protection IC15 connects the tie point A of thermistor R13 and resistance R14 at terminal 15b, in one end of terminal 15f contact resistance R12, the other end of resistance R12 connects outside terminal 14.DOUT lead-out terminal 15d is connected to the grid of MOS transistor M11 by protection IC15, COUT lead-out terminal 15e is connected to the grid of MOS transistor M12.
In protection IC15, terminal 15b is connected to the non-inverting input of comparison circuit 21.Terminal 15c is connected to the negative pole of the source of stable pressure 20 such as voltage stabilizing didoe (Zener diode), and the positive pole of source of stable pressure 20 is connected to the reverse input end of comparison circuit 21.
As shown in Figure 2, because thermistor R13 is the NTC thermistor with negative temperature coefficient, therefore along with the rising of temperature makes resistance value step-down, cause the voltage rise of tie point A.
Comparison circuit 21 has hysteresis characteristic, by comparing the voltage of constant voltage V1 and the tie point A produced at source of stable pressure 20, when the voltage height of tie point A, exports high signal.That is, when the detected temperatures of thermistor R13 exceedes predetermined temperature (such as, about 70 DEG C) corresponding to constant voltage V1, comparison circuit 21 exports high signal as high temperature detection signal.
The high temperature detection signal that comparison circuit 21 exports is supplied to not sensitive time initialization circuit 22.When the high signal of high temperature detection signal hold time exceed predetermined value (such as 0.5sec) time, high high temperature detection signal is not supplied to logical circuit 19 by sensitive time initialization circuit 22.
Logical circuit 19 receives the detection signal of overcharge testing circuit 16, overdischarge testing circuit 17, overcurrent sensing circuit 18 respectively, also receives the high temperature detection signal that not sensitive time initialization circuit 22 exports simultaneously.
When logical circuit 19 detects overcharge detection signal by overcharge testing circuit 16, the output of the COUT of terminal 15e is made to be low (low), to disconnect the connection of MOS transistor M12; When logical circuit 19 detects overdischarge detection signal by overdischarge testing circuit 17, the output of the DOUT of terminal 15d is made to be low (low), to disconnect the connection of MOS transistor M11; When logical circuit 19 detects over-current detection signal by overcurrent sensing circuit 18, the output of the DOUT of terminal 15d is made to be low (low), to disconnect the connection of MOS transistor M11.
When high temperature detection signal is high, logical circuit 19 makes the output of the COUT of terminal 15e be low, to disconnect the connection of MOS transistor M12.Accordingly, correctly can detect the temperature of lithium ion battery 12, and when lithium ion battery 12 reaches a high temperature, charging can be stopped protecting battery.
Because thermistor R13 uses NTC thermistor, and NTC thermistor as shown in Figure 2, and resistance value close to linear change, therefore can detect temperature relative to temperature accurately.Further, due in battery case 10, thermistor R13 is disposed near lithium ion battery 12, therefore can detect the temperature of lithium ion battery 12 accurately.At this, because the resistance value of PTC thermistor sharply increases when exceeding a certain temperature, therefore can not detected temperatures accurately.
But, in battery case 10, because the series circuit forming the thermistor R13 and resistance R14 that carry out the temperature sensing circuit of temperature detection is connected in parallel in lithium ion battery 12, therefore form a closed circuit by lithium ion battery 12, thermistor R13, resistance R14.
Therefore, in battery case 10, even if overdischarge detected and disconnect the connection of MOS transistor M11, lithium ion battery 12 also can discharge at this closed circuit.Therefore, even if be in over-discharge state, battery case 10 may produce the situation of being discharged further by lithium ion battery 12.The following describes after detecting overdischarge, prevent the content of electric discharge further.
(embodiment)
Fig. 3 is the block diagram of the embodiment representing battery case of the present invention.In the drawings, the symbol that identical with Fig. 1 portion markings is identical.
The protection IC15A that the battery case 10A of the present embodiment has, the basis with the protection IC of each terminal illustrated in reference example also has terminal 15g.Further, IC15A is protected to have the MOS transistor M13 as switch element be connected between terminal 15g and terminal c.The grid of MOS transistor M13 receives the output signal exported from logical circuit 19.The MOS transistor M13 of the present embodiment have employed the n channel MOS transistor identical with MOS transistor M11, M12.
In the present embodiment, one end of resistance R14 is connected to A, and the other end is connected to terminal 15g, and resistance R14 is connected to the negative pole of lithium ion battery 12 by MOS transistor M13.Therefore, in the present embodiment, closed circuit is formed by lithium ion battery 12, thermistor R13, resistance R14, MOS transistor M13.
In the present embodiment, when receiving overdischarge detection signal from overdischarge circuit 17, logical circuit 19 makes the DOUT of terminal 15d export as low, to disconnect the connection of MOS transistor M11, the electric discharge from lithium ion battery 12 to load is stopped.The low signal being fed to terminal 15d is fed to the grid of MOS transistor M13 by logical circuit 19, closes MOS transistor M13 and disconnects.In the present embodiment, MOS transistor M11 and MOS transistor M13 is preferably disconnected simultaneously.
When MOS transistor M13 is disconnected connection, in battery case 10A, the closed circuit be made up of lithium ion battery 12, thermistor R13, resistance R14, MOS transistor M13 is disconnected, thus the electric discharge from lithium ion battery 12 to closed circuit is stopped.Therefore, overdischarge can be made in battery case 10A after lithium ion battery 12 electric discharge stop.
As mentioned above, according to the battery case 10a of the present embodiment, the thermistor R13 of temperature sensing circuit and the series circuit of resistance R14 is formed even if having, by arranging MOS transistor M13 between this series circuit and the negative pole of lithium ion battery 12, the further electric discharge after also can making overdischarge stops.Therefore, according to the battery case 10A of the present embodiment, the temperature protection of lithium ion battery 12 can be carried out accurately, and the electric discharge of lithium ion battery 12 after can making overdischarge to be detected stops.
In the present embodiment; MOS transistor M13 is arranged in protection IC15A; but be not limited thereto, MOS transistor M13 also can be arranged on the outside of protection IC15A, as long as be arranged on the position that can disconnect the closed circuit be made up of thermistor R13, resistance R14, lithium ion battery 12.
Describe the present invention based on embodiment above, but the present invention is not limited to the content shown in above-described embodiment.When being no more than inventive concept, can various change be carried out, suitable change can be carried out according to application state.
Claims (3)
1. a battery case; comprise by detecting the overcharge of secondary cell, overdischarge, overcurrent and control the open/close protective circuit of first and second switch element; first and second switch element described is arranged on described secondary cell and load or the distribution between described secondary cell and charging device; the feature of described battery case is to have:
Have the series circuit of thermistor and resistance, described series circuit is arranged near described secondary cell, and is connected in parallel with described secondary cell;
Be arranged on the comparison circuit in described protective circuit, described comparison circuit is used for the voltage of the tie point of more described thermistor and resistance and corresponds to the reference voltage of predetermined temperature; And
The 3rd switch element between the negative pole being arranged on described resistance and described secondary cell,
When the overdischarge of described secondary cell being detected, described protective circuit closes described first switch element and described three switch elements.
2. battery case according to claim 1, is characterized in that, the described first to the 3rd switch element is n channel MOS transistor.
3. battery case according to claim 1 and 2, is characterized in that, described thermistor is the NTC thermistor with negative temperature coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810169639.7A CN101728841B (en) | 2008-10-13 | 2008-10-13 | Battery case |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810169639.7A CN101728841B (en) | 2008-10-13 | 2008-10-13 | Battery case |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101728841A CN101728841A (en) | 2010-06-09 |
| CN101728841B true CN101728841B (en) | 2015-03-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200810169639.7A Active CN101728841B (en) | 2008-10-13 | 2008-10-13 | Battery case |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104242253A (en) * | 2014-09-30 | 2014-12-24 | 成都闰世科技有限公司 | Lithium battery protection based on-board PTC (positive temperature coefficient) protection circuit |
| CN106300279B (en) * | 2015-05-12 | 2018-09-18 | 高达能源科技股份有限公司 | Circuit is protected for the forced charge after secondary cell overdischarge |
| CN105978064B (en) * | 2016-05-09 | 2018-10-16 | 深圳珈伟光伏照明股份有限公司 | A kind of self-locking battery, which is crossed, puts overcharge protection circuit and lamps and lanterns |
| CN113839433A (en) * | 2020-06-24 | 2021-12-24 | 北京小米移动软件有限公司 | Charge and discharge protection circuit and protection method, battery protection board and electronic equipment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1118916C (en) * | 1999-10-18 | 2003-08-20 | 神基科技股份有限公司 | Charge control device and method |
| CN1533006A (en) * | 2003-03-18 | 2004-09-29 | 阳 魏 | Battery discharge protective regulating circuit |
| JP4135676B2 (en) * | 2004-04-28 | 2008-08-20 | ミツミ電機株式会社 | Battery protection device, battery protection system using the same, and battery protection method |
| JP2006280060A (en) * | 2005-03-28 | 2006-10-12 | Matsushita Electric Works Ltd | Charger |
| JP4415131B2 (en) * | 2005-10-31 | 2010-02-17 | ミツミ電機株式会社 | Battery protection device and battery protection circuit |
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| CN101728841A (en) | 2010-06-09 |
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