JP2019114415A - Battery pack - Google Patents

Abstract

To provide a battery pack capable of detecting an overspecified drop to which an impact exceeding a predetermined allowable impact range may be applied and performing predetermined processing when the overspecified drop is detected.SOLUTION: A battery pack includes a secondary battery cell, a gravity sensor capable of detecting gravity, a detection circuit that detects a falling state by using an output signal of the gravity sensor, and a control circuit that controls the charge/discharge current of the secondary battery cell on the basis of the output signal of the detection circuit, and the detection circuit includes a function of measuring a fall time in which the battery pack is in a drop state, and the control circuit determines that there is an overspecified drop when the fall time continues for a prescribed time or more.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a battery pack incorporating a secondary battery cell.

  A lithium ion secondary battery is known as an example of the non-aqueous electrolyte secondary battery. Lithium ion secondary batteries are lightweight and have high capacity, and are widely used as power sources for portable electronic devices. The non-aqueous electrolyte secondary battery is connected to the control circuit to constitute a battery pack. The battery pack includes one or more battery cells composed of non-aqueous electrolyte secondary batteries and a control circuit.

  The battery cell is covered by an outer package. When the battery cell receives a physical impact, a crack or the like may occur in the outer package, and the non-aqueous electrolyte may leak from the battery cell. If the non-aqueous electrolyte leaks, the battery can not be properly charged and discharged.

  Most of the causes of the physical impact of the battery cells are due to the falling of the battery pack. For example, in the case where the battery pack is connected to a smart phone or a notebook computer and used as a portable power source, etc., dropping the battery pack from a desk onto a hard floor etc. exceeds the shock tolerance specified as the specification of the battery pack. Shocks may occur. For this reason, it is preferable to provide the battery pack with a function of detecting an out-of-specification drop that may be subject to an impact exceeding a predetermined impact allowable range. Furthermore, it is desirable that the battery pack be made to operate in response to a failure that occurs in the battery pack when an out-of-specification drop is detected.

  2. Description of the Related Art Conventionally, as a device capable of detecting a drop of a device or the like, for example, Patent Document 1 discloses a storage battery provided with a circuit breaker that cuts off current in response to an impact applied to a vehicle storage battery. Further, Patent Document 2 discloses a battery incorporating a shock sensitive shut-off device, which assumes a battery mounted on an electric vehicle and cuts off current in response to a shock applied due to a collision of the electric vehicle or the like. There is. Further, Patent Document 3 discloses a lithium battery system that detects an impact with an acceleration sensor and counts the number of times the impact is applied, or cuts off a current when an impact is detected. Further, Patent Document 4 discloses a battery abnormality detection system which detects a deflection of a battery generated by vibration and shuts off a circuit connected to the battery when the deflection exceeds a predetermined value.

Japanese Patent Application Laid-Open No. 49-067127 Unexamined-Japanese-Patent No. 04-188573 Japanese Patent Application Laid-Open No. 11-040205 JP 2012-146447 A

  However, in the inventions of Patent Documents 1 to 3, although the detection of an impact is described, a configuration for determining an out-of-specification drop of the device is not disclosed, and it is performed in response to an out-of-specification drop No protective action is disclosed. Moreover, although the invention of Patent Document 4 can detect the deflection of the battery, it does not disclose a configuration or the like corresponding to falling outside the specified range.

  The present invention has been made in view of the above-described situation, and it detects an overrun drop that may be subject to an impact exceeding a predefined shock tolerance, and detects a overrun drop. To provide a battery pack capable of performing the processing of

  In order to solve the above problems, the battery pack of the present invention includes a secondary battery cell, a gravity sensor capable of detecting gravity, a detection circuit for detecting a falling state using an output signal of the gravity sensor, and the detection And a control circuit for controlling the charge / discharge current of the secondary battery cell based on an output signal of the circuit, wherein the detection circuit measures a falling time during which the battery pack is in a falling state. The control circuit is characterized in that the control circuit determines that there is an out-of-specification drop when the drop time lasts for a prescribed time or more.

  Further, in the present invention, it is preferable that the detection circuit determines that it is in the falling state when the gravity detected by the gravity sensor reaches a predetermined threshold.

  Further, in the present invention, it is preferable that the battery pack further includes an external display function, and the control circuit uses the external display function to display a warning when it is determined that the outside of the specified drop has occurred.

  Further, in the present invention, the battery pack further includes an external communication function, and the control circuit determines that the battery pack has the determination result using the external communication function when it is determined that the falling outside the predetermined range has occurred. It is preferable to notify the connected device.

  Further, in the present invention, it is preferable that the battery pack further includes a non-volatile memory, and the control circuit records the occurrence history of the non-specified drop in the non-volatile memory.

  Further, in the present invention, it is preferable that the control circuit stops charging of the battery pack and allows discharge from the battery pack when it is determined that the out-of-specification drop has occurred.

  Further, in the present invention, preferably, the control circuit stops charging and discharging the battery pack when it is determined that the out-of-specification drop has occurred.

  Further, in the present invention, the battery pack further includes an abnormality detection unit, and the control circuit determines that the abnormality detection unit is in the state of the secondary battery cell within a predetermined time after determining that the outside of the regulation falls. When an abnormality is detected, it is preferable to stop charging and discharging of the battery pack.

  According to the present invention, a battery pack capable of performing predetermined processing upon detection of falling outside the specified range where a shock exceeding the predetermined allowable shock range may be applied and detection of falling outside the specified range is performed. It becomes possible to offer.

It is a perspective view of a battery pack concerning this embodiment. It is a perspective view of a battery pack concerning this embodiment. It is the model which showed typically the circuit part of the battery pack concerning this embodiment, and the structure of the periphery of it. It is the flowchart which showed the operation | movement at the time of the excess fall of the battery pack of this invention in steps.

  Hereinafter, a battery pack according to an embodiment of the present invention will be described with reference to the drawings. Each embodiment shown below is concretely described in order to understand the meaning of the invention better, and does not limit the present invention unless otherwise specified. Further, in the drawings used in the following description, for the sake of easy understanding of the features of the present invention, the main parts may be enlarged for convenience, and the dimensional ratio of each component may be the same as the actual one. Not necessarily.

  In the following description, falling outside the regulation (dropping outside the regulation) means, for example, the possibility that an impact exceeding the impact resistance performance (impact tolerance range) specified in the specifications of the battery pack as a product is applied to the battery pack Indicates a falling phenomenon of the battery pack. The conditions for such nonstandard drop depend on the drop height, the colliding part, the material of the drop collision surface, and the like.

FIG. 1 is a schematic perspective view of a battery pack according to the present embodiment. Moreover, FIG. 2 is a cross-sectional schematic diagram of the battery pack concerning this embodiment.
As shown in FIGS. 1 and 2, the battery pack 100 according to the present embodiment includes battery cells 10, 10,..., A circuit unit 20, a gravity sensor 30, and a housing 40 for housing these. In FIG. 1, the housing 40 is illustrated by a dotted line in order to illustrate the internal structure.

(Battery cell)
The battery cell 10 is composed of a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery is preferably a lithium ion secondary battery using lithium ion as a carrier. Battery cell 10 includes a positive electrode, a negative electrode, a separator, and an exterior body. The positive electrode and the negative electrode are disposed opposite to each other with the separator interposed therebetween. The exterior body covers the positive electrode, the negative electrode and the separator except for the positive electrode terminal 11 connected to the positive electrode and the negative electrode terminal 12 connected to the negative electrode.

  The positive electrode is a plate-like (film-like) positive electrode collector provided with a positive electrode active material layer. The negative electrode is a plate-like (film-like) negative electrode current collector provided with a negative electrode active material layer. The positive electrode active material layer and the negative electrode active material layer are impregnated with an electrolytic solution. The positive electrode and the negative electrode exchange ions via this electrolytic solution.

  The electrolytic solution is a non-aqueous electrolytic solution (hereinafter referred to as a non-aqueous electrolytic solution). In the non-aqueous electrolyte, an electrolyte is dissolved in a non-aqueous solvent. As the non-aqueous solvent, an organic carbonate solvent is preferable. The organic carbonate solvent is preferably at least one of cyclic carbonate and linear carbonate. The ratio of cyclic carbonate to linear carbonate is preferably 1: 9 to 1: 1 by volume.

  As cyclic carbonate, what can solvate electrolyte can be used. For example, ethylene carbonate, propylene carbonate and butylene carbonate can be used.

Chain carbonates can reduce the viscosity of cyclic carbonates. For example, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate can be mentioned.
In addition, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane and the like may be mixed and used.

  As the electrolyte, metal salts such as lithium salts and magnesium salts can be used. The electrolyte is particularly preferably a metal salt containing a fluorine atom, such as lithium hexafluorophosphate (LiPF6) or lithium tetrafluoroborate (LiBF4).

  In the present embodiment, three battery cells 10 are connected in series. As a result, a current having a potential difference (voltage) that is three times the electromotive force of one battery cell 10 is output. The housing 40 is formed with an input / output outlet 50 for extracting power from the battery cell 10 via the circuit unit 20 and charging the battery cell 10.

(Gravity sensor)
The gravity sensor 30 is fixed to, for example, the inner surface of the housing 40 and is electrically connected to a detection circuit 22 described later. The gravity sensor 30 is an acceleration sensor, and examples thereof include a vibration method, an optical method, and a semiconductor method. In the present embodiment, a semiconductor-type acceleration sensor that does not require time for maintenance such as adjustment and repair is used as the gravity sensor 30.

  Examples of the acceleration detection method of the semiconductor type acceleration sensor include an electrostatic capacitance detection method, a piezoresistive method, a heat detection method, and the like. In the electrostatic capacitance detection method, a minute movable part supported by a beam structure is slightly curved due to gravity change such as falling, and detected as a change in electrostatic capacitance.

In the piezoresistive method, an annular thin diaphragm is formed by a silicon semiconductor manufacturing technology, and a weight is supported by the diaphragm to detect an acceleration, for example, a displacement due to a change in gravity by a piezoresistive element.
In the heat detection method, thermal convection is generated in a case by a heater or the like, and it is detected that thermal convection changes due to acceleration by thermal resistance.

  Such a gravity sensor 30 outputs an output signal V1 of the gravity sensor 30 indicating the acceleration in the vertical direction applied to the battery pack 100 toward a detection circuit 22 (see FIG. 3) described later.

(Housing)
The housing 40 accommodates the battery cells 10, 10 ... and the circuit unit 20. A case 40 shown in FIG. 1 stores three stacked battery cells 10, 10,. The number of battery cells 10, 10,... Stored in the housing 40 is not limited to this case, and may be one or two or four or more.

  Although the material which comprises the housing | casing 40 does not matter in particular, it is preferable to have insulation. The flow of current through the housing 40 can be avoided.

(Circuit section)
FIG. 3 is a schematic view schematically showing a circuit portion of the battery pack according to the present embodiment and the periphery thereof.
The circuit unit 20 includes a control circuit 21, a detection circuit 22 connected to the control circuit 21, a charge / discharge circuit 23, an external communication circuit 24, an external display circuit 25, and a non-volatile memory 26.

  The detection circuit 22 is constituted of, for example, an integrated circuit chip or the like, measures the falling time when the battery pack 100 is in a falling state, and outputs the falling time toward the control circuit 21 as an output signal V2 of the detection circuit 22. Specifically, when the gravity detected by the gravity sensor 30 reaches a predetermined threshold value, the detection circuit 22 determines that the state is falling.

For example, among the output signal V1 of the gravity sensor 30, the acceleration in the vertical direction is equal to or higher than the gravity acceleration (9.8 m / s ² ), that is, a state in which the gravity is almost 0 is stored in the detection circuit 22 in advance as a threshold. . When the output signal V1 of the gravity sensor 30 is equal to or greater than this threshold value, the detection circuit 22 determines that the battery pack 100 is in the dropped state. Then, when it is determined that the battery pack 100 is in the falling state, the detection circuit 22 measures the duration of the falling state, and sets the measured value as the falling time of the battery pack 100. The detection circuit 22 outputs the falling time toward the control circuit 21 as an output signal V2 of the detection circuit 22.

  The control circuit 21 includes, for example, a CPU, a memory chip, and the like, and determines that the battery pack 100 has dropped outside the specified range when the drop time of the battery pack 100 continues for the specified time or longer, and performs safety processing (described later) for the battery pack 100.

  Specifically, the control circuit 21 refers to the specified time (threshold value) related to the drop recorded in advance in the non-volatile memory 26. When the output signal V2 of the detection circuit 22 is input, the control circuit 21 compares the value of the output signal V2, that is, the falling time of the battery pack 100 with the specified time related to the falling. Then, the control circuit 21 determines that there is an out-of-specification drop when the fall time exceeds the prescribed time.

When the acceleration in the vertical direction of the battery pack 100 changes from a zero state to a gravitational acceleration (9.8 m / s ² ) which is a free fall state, the battery pack 100 is, for example, in a free fall state from the desktop toward the floor surface. It shows. From the falling time at this time, it is possible to calculate the falling height and know the large impact applied to the battery pack 100. The specified time recorded in advance in the non-volatile memory 26 described above is, for example, the lower limit value of the drop height for causing the battery pack 100 to have an impact larger than the range of impact resistance in the specification of the battery pack 100. The equivalent fall time may be taken.

  The non-volatile memory 26 is constituted by, for example, a flash memory, and records (stores) a history of occurrence of falling outside the regulation. Specifically, when the control circuit 21 determines that there is an out-of-specification drop, for example, information on the time when the drop occurred (or a value obtained by converting this into a drop height), a drop occurs. It records fall information such as information on the date and time of the operation, and information on safety processing (described later) performed by the control circuit 21 thereafter. Moreover, it is preferable that the non-volatile memory 26 memorize | stores the regulation time (threshold value) which concerns on the fall mentioned above. The drop information recorded in the non-volatile memory 26 can be externally referred to, for example, via the external communication circuit (external communication function) 24.

  The charge / discharge circuit 23 includes, for example, an integrated circuit chip, a switching element, and the like, and is electrically connected between the battery cells 10, 10,... The charge / discharge circuit 23 performs control to charge the battery cells 10, 10,... By the power input from the input / output outlet 50, and power from the battery cells 10, 10,. Supply (discharge) control.

  Further, the charge and discharge circuit 23 can open and close (on and off) the charge circuit and the discharge circuit independently based on the discharge shutoff signal and the charge shutoff signal output from the control circuit 21. Specifically, when the control circuit 21 determines that there is an out-of-specification drop, as one of safety processing, the switch of the charging circuit constituting the charge / discharge circuit 23 is opened to charge the battery cells 10, 10. Stop it. When the control circuit 21 determines that there is an out-of-specification drop, the switch of the discharge circuit constituting the charge / discharge circuit 23 is opened as one of the safety processing to stop the discharge of the battery cells 10, 10.

  The external communication circuit (external communication function) 24 includes, for example, a wired LAN chip, a wireless LAN chip, etc., and controls the external device M (for example, a notebook computer) to which power is supplied by the battery pack 100. Make a notification. Specifically, when the control circuit 21 determines that the battery pack 100 has dropped out of the regulation, the charge / discharge circuit 23 is provided to the external device M connected to the battery pack 100 as one of safety processing. Notify that it has shut off the discharge.

  The external device M that has received such a notification, for example, the notebook computer, can recognize that the power supply has been stopped due to the battery pack 100 falling outside the specified range, and thus performs an operation such as automatically saving data of the program being executed. It can be done. In addition, when the external device M includes a display monitor, when the external communication circuit 24 notifies that the discharge has been interrupted, the power supply interruption may be displayed on the display monitor. The external communication circuit (external communication function) 24 may use another communication method such as Bluetooth (registered trademark) besides the wired LAN and the wireless LAN, and the communication method is limited. It is not a thing.

  In addition, when a personal computer or the like is connected to the external communication circuit (external communication function) 24, drop information recorded in the non-volatile memory 26 can be referred to via the control circuit 21.

  The external display circuit (external display function) 25 includes, for example, a monitor output chip and a monitor connection port, and can connect the display monitor D. The control circuit 21 determines that the battery pack 100 has fallen outside the specified range, and when the charge / discharge circuit 23 is subjected to discharge interruption or charge interruption, it is connected via the external display circuit 25 as one of safety processing. The display monitor D is made to display a warning such as discharge cutoff execution or charge cutoff execution.

  A configuration is also preferable in which the battery pack 100 itself has a warning display function by providing a small LED panel on the outer surface of the housing 40 of the battery pack 100 and displaying a warning on the LED panel.

  Further, battery pack 100 does not have to include all of external communication circuit 24, external display circuit 25, and nonvolatile memory 26, and may have one or two of these configurations, and in particular, these configurations. You do not have to

The operation of the above-described battery pack of the present invention at the time of an out-of-specification drop will be described with reference to FIGS.
FIG. 4 is a flow chart showing stepwise the operation of the battery pack of the present invention at the time of extraordinarily falling.
In the following description, for example, a notebook personal computer (external device) and the battery pack of the present invention for supplying power to the notebook personal computer are placed on a desk and used, and the battery pack is accidentally floored during use. Assume the case of dropping on the surface.

  The battery pack 100 supplies power from the charge / discharge circuit 23 to the notebook computer (external device) via the input / output outlet 50. Further, in the battery pack 100, the acceleration in the vertical direction is constantly monitored by the detection circuit 22 (S0).

  For example, when the battery pack 100 supplying power to a notebook computer (external device) falls from a fixed height position, the gravity sensor 30 fixed inside the housing 40 of the battery pack 100 is, for example, in the vertical direction The acceleration is detected, and an output signal V1 which is a value of the acceleration in the vertical direction is output to the detection circuit 22 (S1).

When the output signal V1 of the gravity sensor 30 is input, the detection circuit 22 compares the value of the output signal V1 with a predetermined threshold (S2). The threshold is set, for example, to gravitational acceleration (9.8 m / s ² ). Then, when the output signal V1 of the gravity sensor 30, that is, the value of the acceleration in the vertical direction becomes equal to or more than the gravity acceleration (9.8 m / s ² ) which is a threshold, the detection circuit 22 determines that the battery pack 100 is in a dropped state. to decide.

  The detection circuit 22 measures the time during which the output signal V1 exceeds the threshold value, that is, the falling time of the battery pack 100 (S3). Then, the detection circuit 22 outputs an output signal V2 indicating the value of the falling time of the battery pack 100 to the control circuit 21 (S4).

  When the control circuit 21 receives the output signal V2 from the detection circuit 22, the control circuit 21 refers to the specified time (threshold value) related to the drop recorded in the non-volatile memory 26. Then, the value of the output signal V2, that is, the falling time of the battery pack 100, is compared with the specified time relating to the falling (S5). Then, the control circuit 21 determines that there is an out-of-specification drop when the fall time exceeds the prescribed time.

  If the control circuit 21 determines that the battery pack 100 is dropped outside the specified range, the control circuit 21 outputs a discharge shutoff signal or a charge shutoff signal to the charge / discharge circuit 23 (S6). The charge / discharge circuit 23 turns off the charge circuit or the discharge circuit when the discharge shutoff signal or the charge shutoff signal is input from the control circuit 21. Thus, the power supply from the battery pack 100 to the notebook computer (external device) is stopped (S7).

  In addition, when the control circuit 21 determines that the battery pack 100 is dropped outside the regulation, the control circuit 21 records (stores) the drop information in the non-volatile memory 26 (S8).

  Further, when the control circuit 21 determines that the battery pack 100 has dropped out of the regulation, the external communication circuit (external communication function) 24 notifies the notebook computer of discharge interruption or charge interruption (S9). The notebook computer that has received the notification from the external communication circuit 24 can recognize that the power supply has been stopped due to the battery pack 100 falling out of the regulation, so that, for example, data saving of the program being executed is automatically performed. The operation can be performed and the operation of the laptop can be safely ended.

  In addition, when the control circuit 21 determines that the battery pack 100 has dropped outside the specified range, the control monitor 21 displays a warning such as discharge cutoff execution or charge cutoff execution on the display monitor D connected to the external display circuit (external display function) 25. (S10).

  As described above, according to the present invention, the acceleration of the battery pack 100 in the vertical direction is measured by the gravity sensor 30, the falling state is detected by the control circuit 21, and the time during which the falling state is measured is measured by the control circuit 21. This makes it possible to detect an out-of-specification drop that may be subject to an impact exceeding a predefined impact tolerance.

  Then, if the battery pack 100 falls out of the regulation, the control circuit 21 shuts off the discharge and charge of the battery cell 10, so that the discharge and charge are continued in a state where the battery pack 100 is damaged, for example There is no concern and the safety of the battery pack 100 can be further enhanced.

  In addition, when the battery pack 100 falls outside the specified range, the external device is safely stopped by notifying the external device connected to the battery pack 100 via the external communication circuit (external communication function) 24. It becomes possible.

Next, another operation example of the above-described operation when the battery pack falls outside the prescribed range will be described.
In the operation example shown in FIG. 4, when the control circuit 21 determines that the battery pack 100 has dropped outside the specified range, the control circuit 21 is configured to interrupt the discharge and charge of the battery cell 10 via the charge / discharge circuit 23. If, as another configuration example, the control circuit 21 determines that the battery pack 100 has fallen outside the specified range, only the charge of the battery cell 10 is interrupted via the charge / discharge circuit 23, and the discharge is permitted. good.

  For example, as the external device connecting the battery pack 100, such a configuration cuts off the power supply unexpectedly when the battery pack 100 falls out of the regulation, such as a moving object or various devices worn by a person. It can be preferably applied as a configuration of a battery pack for devices that are not desirable.

Next, another embodiment of the battery pack of the present invention will be described.
As another embodiment of the battery pack of the present invention, in addition to the configuration of the battery pack 100 shown in FIGS. 1 to 3 described above, abnormality detection means can be further provided. As the abnormality detection means, for example, when the control circuit 21 determines that the current value or voltage value detected by the sensor for detecting the current or voltage of the battery cell 10 exceeds a predetermined threshold (abnormal voltage, abnormality The structure of interrupting the discharge and charge of the battery cell 10 through the charge / discharge circuit 23 is exemplified as the current).

  Further, as the abnormality detection means, for example, a liquid leakage sensor is provided in the case 40 of the battery pack 100, and when liquid leakage is detected from the battery cell 10, discharge of the battery cell 10 via the charge / discharge circuit 23 And a configuration for interrupting charging respectively.

  Further, as the abnormality detection means, for example, the battery cell 10 is provided with an expansion detection sensor, and when the expansion of the battery cell 10 is detected, the discharge and charge of the battery cell 10 are interrupted through the charge / discharge circuit 23 respectively. Configuration can be mentioned.

  Further, as the abnormality detection means, for example, the battery cell 10 is provided with a temperature sensor, and when the control circuit 21 determines that the temperature detected by this temperature sensor exceeds a predetermined threshold (temperature abnormality), The structure which interrupts | blocks discharge and charge of the battery cell 10 via the charging / discharging circuit 23, respectively is mentioned.

  The above-mentioned abnormality detection means discharges the battery cell 10 when the abnormality detection means detects an abnormality of the battery cell 10 within a predetermined time after the control circuit 21 determines that the battery pack 100 is dropped outside the specified range. Shut off the charge respectively. As a result, the discharge and charge of the battery cell 10 are also caused by the current abnormality, the voltage abnormality, the battery cell leakage, the battery cell expansion, and the battery cell abnormal temperature rise caused by the out-of-specification drop of the battery pack 100. Therefore, the safety of the battery pack 100 can be further enhanced.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

For example, since the falling motion in the air strictly receives air resistance, the air resistance is inversely proportional to the density of the falling object, proportional to the lower surface area and velocity, shape, rotation, and air flow when falling The threshold value of the acceleration in the vertical direction may be finely adjusted from the gravitational acceleration (9.8 m / s ² ) in consideration of the difference.

DESCRIPTION OF SYMBOLS 10 ... Battery cell 20 ... Circuit part 21 ... Control circuit 22 ... Detection circuit 23 ... Charge / discharge circuit 24 ... External communication circuit 25 ... External display circuit 26 ... Nonvolatile memory 30 ... Gravity sensor 40 ... Housing | casing 100 ... Battery pack

Claims (8)

A secondary battery cell, a gravity sensor capable of detecting gravity, a detection circuit for detecting a falling state using an output signal of the gravity sensor, and charging / discharging of the secondary battery cell based on an output signal of the detection circuit A control circuit for controlling a current;
The detection circuit includes a function of measuring the falling time of the battery pack in the falling state,
A battery pack characterized in that the control circuit determines that there is an out-of-specification drop when the drop time lasts for a specified time or more.   The battery pack according to claim 1, wherein the detection circuit determines that the battery pack is in a falling state when the gravity detected by the gravity sensor reaches a predetermined threshold. The battery pack further includes an external display function.
The battery pack according to claim 1 or 2, wherein the control circuit displays a warning using the external display function when determining that the out-of-specification drop has occurred. The battery pack further comprises an external communication function,
4. The apparatus according to claim 1, wherein said control circuit, when judging that said out-of-specification fall has occurred, notifies said judgment result to an apparatus to which said battery pack is connected, using said external communication function. The battery pack according to any one of the items. The battery pack further comprises a non-volatile memory,
The battery pack according to any one of claims 1 to 4, wherein the control circuit records the occurrence history of the non-specified drop in the non-volatile memory.   The said control circuit will stop the charge with respect to the said battery pack, and will allow discharge from the said battery pack, if it judges that there existed the said non-specified drop, The discharge from the said battery pack is permitted, Battery pack.   The battery pack according to any one of claims 1 to 5, wherein the control circuit stops charging and discharging the battery pack when it is determined that the out-of-specification drop has occurred. The battery pack further comprises abnormality detection means.
The control circuit is characterized by stopping charging and discharging of the battery pack when the abnormality detecting means detects an abnormal state of the secondary battery cell within a predetermined time after determining that the falling outside the prescribed range has occurred. The battery pack according to any one of claims 3 to 5.

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