JP4137891B2 - Lithium ion secondary battery monitoring semiconductor device and test method thereof - Google Patents

Description

  The present invention relates to a lithium ion secondary battery monitoring semiconductor device and a test method thereof, and more particularly, to a technique effective when applied to characteristic evaluation of a temperature monitoring function of a lithium ion secondary battery monitoring semiconductor device.

  As a technique studied by the present inventor, for example, the following technique is conceivable in a lithium ion secondary battery monitoring semiconductor device.

  A lithium ion secondary battery (hereinafter simply referred to as “battery”) has a protection circuit built in the battery pack for ensuring safety. This is because a battery has a high risk of expansion, heat generation, and ignition in a state such as overcharge or short circuit between external connection terminals due to its high capacity. For this reason, it is necessary to enhance the protection function.

  That is, when the battery is charged using the charger, the battery voltage increases when the battery is charged with a constant current even after the charging completion state. In such an overcharged state, there is a risk of heat generation and further ignition due to damage to the battery due to an increase in pressure inside the battery, short circuit between electrodes due to deposition of metallic lithium, and the like. In the overcharged state, the battery temperature of the battery continues to rise. Therefore, a temperature monitoring function is required to detect the battery temperature.

  When a temperature monitoring function is included, a circuit that compares a reference voltage that does not depend on temperature and a potential of an element that depends on temperature is used.

As a battery protection circuit having a temperature monitoring function, for example, there is a technique described in Patent Document 1.
JP 2003-173825 A

  By the way, as a result of examination of the technique of the battery monitoring semiconductor device as described above by the present inventors, the following has been clarified.

  For example, when evaluating the characteristics of the temperature monitoring function, it is necessary to measure the “circuit that compares the reference voltage independent of temperature and the potential of the element dependent on temperature” by actually changing the temperature. However, this method is burdensome in terms of time and cost.

  Therefore, an object of the present invention is to provide a function that can directly measure the “temperature-dependent reference voltage” and the “temperature-dependent element potential” in the temperature monitoring function of the battery monitoring semiconductor device, The object is to provide a technique that enables an alternative measurement of the temperature detection function at room temperature.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  In other words, the lithium ion secondary battery monitoring semiconductor device according to the present invention includes a first voltage source having temperature dependency, a second voltage source having no temperature dependency, and one input serving as the first voltage source. A temperature detection comparator connected to the second voltage source at the other input, a first switch connected to the first voltage source at one terminal, and the first switch connected to the first voltage source at one terminal. A second switch connected to the second voltage source, one input connected to the detection terminal, and the other input connected to the other terminal of the first switch and the other terminal of the second switch. And a test comparator.

  According to another aspect of the present invention, there is provided a test method for a lithium ion secondary battery monitoring semiconductor device, wherein the lithium ion secondary battery monitoring semiconductor device is used to short-circuit one of the first switch and the second switch. And changing the potential of the detection terminal to detect the potential of the first voltage source or the second voltage source based on the potential fluctuation of the output of the test comparator. .

  Further, the test method for a lithium ion secondary battery monitoring semiconductor device according to the present invention uses the lithium ion secondary battery monitoring semiconductor device to short-circuit the first switch at an arbitrary temperature, and to detect the detection terminal. The potential is changed, the potential of the first voltage source is detected based on the potential fluctuation of the output of the test comparator, and the detection result and the set temperature obtained from the temperature characteristics of the first voltage source are detected. The first voltage source is compared with a set value of the potential of the first voltage source, and the first voltage source is adjusted based on the comparison result.

  Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  In the characteristic evaluation of the temperature monitoring function of the battery monitoring semiconductor device, it is not necessary to change the temperature, and the temperature monitoring function can be measured by measuring the electric characteristics at room temperature, thereby reducing the test cost and the test time.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a diagram showing the overall configuration of a battery monitoring semiconductor device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of the battery monitoring semiconductor device of this embodiment, and FIG. 3 is the temperature of FIG. FIG. 4 is a circuit diagram showing another configuration example of the temperature detection circuit of FIG. 2.

  First, an example of the configuration of the battery monitoring semiconductor device according to the present embodiment will be described with reference to FIG. The battery monitoring semiconductor device according to the present embodiment is, for example, a battery monitoring IC 101, and includes FETs (Field Effect Transistors) 102 and 103, resistors 104, 105, and 106 as additional circuits. A pack 108 is configured.

  The positive (+) electrode of the battery 107 is connected to the Pack (+) terminal of the battery pack 108, and is connected to the VCC terminal of the battery monitoring IC 101 via the resistor 104.

  The negative (−) electrode of the battery 107 is connected to the source electrode of the FET 102 and the GND terminal of the battery monitoring IC 101.

  The drain electrode of the FET 102 is connected to the drain electrode of the FET 103, and the gate electrode of the FET 102 is connected to the DCH terminal of the battery monitoring IC 101.

  The source electrode of the FET 103 is connected to the Pack (−) terminal of the battery pack 108, is connected to the IDT terminal of the battery monitoring IC 101 via the resistor 105, and the gate electrode of the FET 103 is connected to the CHG of the battery monitoring IC 101 via the resistor 106. Connected to the terminal.

  A charger or a load 109 is connected between the Pack (+) terminal and the Pack (−) terminal of the battery pack 108.

  The VCC terminal of the battery monitoring IC 101 is a positive power supply terminal, and GND is a negative power supply terminal.

  The IDT terminal (detection terminal) is an overcurrent voltage detection input, a charge overcurrent detection input, and a negative (−) pole side power supply terminal of the CHG output. The discharge current increases and the input voltage of the IDT terminal becomes the overcurrent detection voltage. When (V5) or the short-circuit current detection voltage (V6) is exceeded, the DCH output becomes low level (GND), and then, when the input voltage becomes V5 or less, the overcurrent state is restored.

  The DCH terminal is a drive signal output of the external FET 102 for interrupting the discharge circuit, and becomes high level (VCC) when the voltage of the battery 107 is normal, and becomes low level (GND) when an overdischarge state or an overcurrent state is detected. .

  The CHG terminal is a drive signal output of the external FET 103 for interrupting the charging circuit, and is high level (VCC) when the voltage of the battery 107 is normal, and low level (IDT) when an overcharged state or an excessive charger voltage is detected. become.

  Next, an example of the internal configuration of the battery monitoring IC 101 will be described with reference to FIG. The battery monitoring IC 101 according to the present embodiment includes, for example, a temperature detection circuit 201, a control circuit 202, a drive circuit 203, a reference voltage generation circuit 204, an upper limit voltage detection circuit 205, a lower limit voltage detection circuit 206, an oscillator 207, a counter 208, a charge Voltage detector circuit 209, discharge current detector circuit 210, and the like.

  In the temperature detection circuit 201, the IDT 211 is input from the IDT terminal, the control signal 212 is input from the control circuit 202, the temperature detection signal 213 is output to the control circuit 202, and the test signal 214 is output to the drive circuit 203. Further, the test signal 214 (charge circuit cutoff element drive signal or discharge circuit cutoff element drive signal) is connected to the CHG terminal or DCH terminal via the drive circuit 203.

  In normal operation, when the battery monitoring IC 101 exceeds the set temperature, the temperature detection signal 213 of the temperature detection circuit 201 changes, and the control circuit 202 is connected to the DCH terminal or the CHG terminal via the drive circuit 203, for example. The FETs 102 and 103 are turned off and the timer time setting is changed.

  At the time of testing, a control signal 212 is output from the control circuit 202 to the temperature detection circuit 201, a predetermined voltage is swept and applied to the IDT 211, a change in the test signal 214 is monitored via the drive circuit 203, and the temperature detection circuit 201 Characteristic evaluation is performed.

  Next, an example of the internal configuration of the temperature detection circuit 201 and an example of a test method will be described with reference to FIG. The temperature detection circuit 201 according to the present embodiment includes, for example, a first voltage source (Vt) 301 having a temperature dependency, a second voltage source (Vref) 302 having no temperature dependency, and one input of a first voltage source (Vref) 302 having a first input. A temperature detecting comparator 303 having one input connected to the second voltage source 302 and a first switch 304 having one terminal connected to the first voltage source 301. A second switch 305 having one terminal connected to the second voltage source 302, one input connected to an IDT (detection terminal) 211, and the other input being the other terminal of the first switch 304. And a test comparator 306 connected to the other terminal of the second switch 305, etc., and the output (temperature detection signal 213) of the temperature detection comparator 303 is connected to the control circuit 202, and the test comparison Out of vessel 306 (Test signal 214) is connected to the drive circuit 203.

  The first voltage source (Vt) 301 has a potential that varies with temperature, and utilizes a junction diode, a gate-source voltage of a field effect transistor (such as a MOS transistor), or the like.

  The temperature detection circuit 201 detects the temperature based on the potential fluctuation of the output (temperature detection signal 213) of the temperature detection comparator 303 during normal operation, and the control circuit 202 performs the above-described processing. At this time, the first switch 304 and the second switch 305 are turned off by the control signal 212 from the control circuit 202.

  At the time of the test, one of the first switch 304 and the second switch 305 is short-circuited by the control signal 212 from the control circuit 202, the potential of the IDT 211 is changed, and the output of the test comparator 306 (test The potential of the first voltage source 301 or the second voltage source 302 is detected based on the potential fluctuation of the signal 214). When adjusting (trimming) the first voltage source 301, the first switch 304 is short-circuited at an arbitrary temperature (preferably normal temperature), and the potential of the IDT 211 (detection terminal) is changed to perform testing. The potential of the first voltage source 301 is detected based on the potential fluctuation of the output of the comparator 306, and the detection result of the first voltage source 301 at a set temperature obtained from the detection result and the temperature characteristics of the first voltage source 301. The first voltage source 301 is adjusted based on the comparison result with the set value of the potential.

  FIG. 4 shows another example of the internal configuration of the temperature detection circuit 201. The temperature detection circuit 201 according to this example has a function equivalent to that of the first voltage source (Vt) 301 of FIG. 3, which is constituted by a temperature-dependent resistor (Rt) 401 and a constant current source 402. Other configurations and operations are the same as those of the temperature detection circuit 201 of FIG.

  Therefore, according to the battery monitoring semiconductor device and the test method thereof according to the present embodiment, the “reference voltage independent of temperature” and the “potential of the element dependent on temperature” can be directly measured from the outside. A measurement equivalent to the changed measurement can be performed at an arbitrary temperature or room temperature.

  Although the invention made by the present inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the scope of the invention. Needless to say.

  For example, although the lithium ion secondary battery has been described in the above embodiment, the present invention is not limited to this, and can be applied to other secondary batteries (rechargeable batteries).

  The present invention is applicable to a lithium ion secondary battery monitoring IC, a charging control IC, and the like.

It is a figure which shows the whole structure of the battery monitoring semiconductor device by one embodiment of this invention. In the battery monitoring semiconductor device by one embodiment of this invention, it is a block diagram which shows an internal structure. FIG. 3 is a circuit diagram illustrating a configuration example of a temperature detection circuit in FIG. 2. FIG. 3 is a circuit diagram showing another configuration example of the temperature detection circuit of FIG. 2.

Explanation of symbols

101 Battery monitoring IC
102,103 FET
104, 105, 106 Resistor 107 Battery 108 Battery pack 109 Charger or load 201 Temperature detection circuit 202 Control circuit 203 Drive circuit 204 Reference voltage generation circuit 205 Upper limit voltage detection circuit 206 Lower limit voltage detection circuit 207 Oscillator 208 Counter 209 Charger voltage detection Circuit 210 Discharge current detection circuit 211 IDT
212 Control signal 213 Temperature detection signal 214 Test signal 301 First voltage source (Vt)
302 Second voltage source (Vref)
303 Temperature Detection Comparator 304 First Switch 305 Second Switch 306 Test Comparator 401 Resistance (Rt)
402 Constant current source

Claims (5)

A monitoring semiconductor device used in a battery pack including a lithium ion secondary battery,
The monitoring semiconductor device includes at least a power supply terminal connected to the lithium ion secondary battery, an output terminal, a detection terminal, a control circuit, and a temperature detection circuit,
The temperature detection circuit includes a first voltage source having temperature dependence, a second voltage source having no temperature dependence, and a first comparator, and one input of the first comparator has the first voltage source. 1 is connected to the first voltage source, the other input is connected to the second voltage source, and the output is connected to the control circuit. During normal operation, the temperature is based on the potential fluctuation of the output of the first comparator. Is configured to be detected,
The monitoring semiconductor device further includes a second comparator, the second comparator is one input connected to the detection terminal, the other input is the first voltage source via a first switch, Each of which is connected to the second voltage source via a second switch, and the output of the second comparator is connected to the output terminal;
During the test, the first switch and the output terminal of the potential variation at the output of the second comparator when changing the potential of the detecting terminal in a state of being short-circuited one of the second switches detecting from said first voltage source or the lithium ion secondary to the potential of the second voltage source, characterized in that it is detected battery monitoring semiconductor device based on the potential fluctuation. In the lithium ion secondary battery monitoring semiconductor device according to claim 1,
The lithium ion secondary battery monitoring semiconductor device, wherein the first voltage source uses any one of a junction diode, a field effect transistor, and a resistor. A monitoring semiconductor device used in a battery pack including a lithium ion secondary battery,
The monitoring semiconductor device includes first and second power supply terminals connected to the lithium ion secondary battery, a first output terminal for outputting a drive signal to a discharge circuit cutoff field effect transistor, and a charging circuit cutoff circuit A second output terminal for outputting a drive signal to the field effect transistor, an input terminal, a control circuit, and a temperature detection circuit;
The temperature detection circuit includes a first voltage source having temperature dependence, a second voltage source having no temperature dependence, and a first comparator, and one input of the first comparator is the first voltage source. The other input is connected to the second voltage source and the output is connected to the control circuit, respectively. The temperature is controlled based on the potential fluctuation of the output of the first comparator during normal operation. Configured to be detected,
The monitoring semiconductor device further includes a second comparator, wherein one input is connected to the input terminal, and the other input is connected to the first voltage source via a first switch. The output is connected to the second voltage source through the switch of 2, and the output to the first or second output terminal, respectively.
At the time of a test, potential fluctuations in the output of the second comparator when one of the first switch and the second switch is short-circuited to change the potential of the input terminal are the first and second A lithium ion secondary battery monitoring semiconductor device, characterized in that a potential of the first voltage source or the second voltage source is detected based on the potential fluctuation and detected from any one of output terminals. In the lithium ion secondary battery monitoring semiconductor device according to claim 3,
The lithium ion secondary battery monitoring semiconductor device, wherein opening and closing of the first and second switches is controlled by the control circuit. In the lithium ion secondary battery monitoring semiconductor device according to claim 1,
At any temperature, detecting the potential of said first voltage source based on a potential fluctuation at the output of the second comparator when changing the potential of the detecting terminal in a state of being short-circuited the first switch Then, the detection result is compared with the set value of the potential of the first voltage source at the set temperature obtained from the temperature characteristic of the first voltage source, and the first voltage source is based on the comparison result. A test method for a lithium ion secondary battery monitoring semiconductor device, characterized in that:

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