Battery pack

Abstract

A battery pack (1) of the present application is charged by being connected to a charger (2) and discharged by being connected to a load (3), and includes: a charge / discharge terminal (1a) composed of a positive terminal (B+), a negative terminal (B-), and a temperature terminal (TH); a charge battery (10) that is charged and discharged via the positive terminal (B+) and the negative terminal (B-); a current measuring unit (11) that measures a charge / discharge current (I) of the charge battery (10); a thermistor (12) that is connected to the temperature terminal (TH) and measures a battery temperature (Tbat) of the charge battery (10); a voltage switching unit (14) that intermittently outputs an applied voltage (Va) that operates the thermistor (12) to the temperature terminal (TH); and a control unit (15) that identifies a connection state of the charge / discharge terminal (1a) based on a voltage of the temperature terminal (TH) during an on period and an off period of the applied voltage (Va) and the charge / discharge current (I).

Description

TECHNICAL FIELD

[0001] The present application relates to a battery pack. BACKGROUND

[0002] A battery pack that performs charging by being connected to a charger and discharging by being connected to a load device is known. For example, in Patent Literature 1, a battery pack that includes a temperature terminal in addition to positive and negative terminals that bear the load of charging and discharging is disclosed. Such a three-terminal battery pack is configured so that a thermistor for measuring the battery temperature of an internal charging battery is connected to the electrode terminals. Therefore, in the case of being connected to the electrode terminals of the battery pack, the charger applies a prescribed voltage to the electrode terminals, the battery temperature of the charging battery can be measured based on the change in the resistance value of the thermistor, and charging control corresponding to the battery temperature can be performed.

[0003] Here, a general charger for charging a three-terminal charging battery can be used even for a battery pack that does not have a control section for controlling charging, and thus is only charger-side charging control using the temperature terminal described above, and thus can be used as a general-purpose charger as long as the terminals can be connected to each other.

[0004] In addition, the battery pack disclosed in Patent Literature 1 is provided with a control circuit for controlling the charging state based on the battery voltage and battery temperature, and is configured so that charging control can be managed based on the battery voltage of each battery cell even on the battery pack side.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2010-11698 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, the charger described above is not necessarily in a charging control state when connected to the battery pack, and for example, in the case of being a type that can cyclically recover discharging, it is also possible to be in a control state that discharges the charging battery. In the above-described battery pack, since the state of the connection target cannot be identified even in such a case, for example, there is a possibility that the charging battery cannot be protected in accordance with the control state of the charger. In addition, although the battery pack has the possibility that the electrode terminals are connected not only to the charger but also to the load as described above, in the above-described prior art, since the connected state and the unconnected state of the load cannot be identified, and furthermore, the control state of the load cannot be identified, there is a possibility that the charging battery cannot be protected in accordance with these states.

[0010] Here, in the case where the electrode terminal connecting the charger and the battery pack includes a terminal for communication in addition to the above three terminals, the control sections of both can share the state recognition with each other. However, the battery pack having the electrode terminal of four terminals like this can be charged only with the dedicated charger common in the communication form, and thus, it is not possible to charge with the general charger as described above.

[0011] The present application has been achieved in view of the above-described circumstances, and aims to provide a battery pack capable of recognizing the state of a connection target even if the electrode terminal is three terminals.

[0012] Technical solution for solving the technical problem

[0013] To achieve the above object, the battery pack according to the present application is charged by being connected to a charger and discharged by being connected to a load, and includes: a charge / discharge terminal composed of a pair of power terminals and a temperature terminal; a charge battery which is charged and discharged via the pair of power terminals; a current measuring section which measures the charge / discharge current of the charge battery; a thermistor which is connected to the temperature terminal and measures the battery temperature of the charge battery; a voltage switching section which intermittently outputs an applied voltage for operating the thermistor to the temperature terminal; and a control section which recognizes the connection state of the charge / discharge terminal based on the voltage of the temperature terminal during the on period and the off period of the applied voltage and the charge / discharge current.

[0014] Technical effects

[0015] According to the present application, it is possible to provide a battery pack capable of recognizing the state of a connection target even if the electrode terminal is three terminals. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a configuration view showing the brief configuration of the battery pack.

[0017] Figure 2 is a view schematically showing the voltage range of the temperature measuring circuit.

[0018] Figure 3 is a timing chart schematically showing the relationship between the voltage of the temperature measuring circuit corresponding to the on / off period of the measuring switch and the temperature measuring period.

[0019] Figure 4 is a view showing the connection mode of the battery pack and the load.

[0020] Figure 5is a flowchart showing a control step of state recognition performed by the control section of the battery pack. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of the present application will be described in detail with reference to the drawings. Note that the present application is not limited to the following description, and can be implemented with any modifications within the scope of the gist thereof. Also, the drawings used in the description of the embodiment schematically show structural components, and sometimes parts are emphasized, enlarged, reduced, or omitted, etc. for the purpose of deepening understanding, rather than correctly showing the scale, shape, etc. of the structural components.

[0022] Figure 1 is a structural diagram showing a brief structure of the battery pack 1. As the main structure, the battery pack 1 includes a charge-discharge terminal la, a charge battery 10, a current measuring section 11, a thermistor 12, a regulator 13, a voltage switching section 14, and a control section 15. Also, the battery pack 1 is charged by being connected to a charger 2 which is a general-purpose charger, and is discharged by being connected to a load 3 described later, thereby supplying electric power to the load 3.

[0023] The charge-discharge terminal la is constituted by a positive terminal B+, a negative terminal B-, and a temperature terminal TH, and charges and discharges the battery pack 1 via a pair of power terminals constituted by the positive terminal B+ and the negative terminal B-. Also, the temperature terminal TH is connected to the thermistor 12 described later, and a prescribed application voltage Va (generally 5 V) is input from the charger 2, thereby becoming a voltage corresponding to the battery temperature Tbat of the charge battery 10, whereby the charger 2 recognizes the battery temperature Tbat.

[0024] Here, the charger 2 is a general-purpose charger having a charge port 2a connectable to the charge-discharge terminal la. The charge port 2a is constituted by a positive terminal B+, a negative terminal B-, and a temperature terminal TH, like the battery pack 1. The charger 2 measures the battery temperature Tbat of the charge battery 10 inside the battery pack 1 based on the control of an internal charge control section 2b, and outputs an application voltage Va formed by stepping down an internal power source Vreg using a resistor Rc inside the charger from the temperature terminal TH. Thus, the charger 2 can charge the charge battery 10 via the positive terminal B+ and the negative terminal B- while monitoring the battery temperature Tbat.

[0025] The charge battery 10 is constituted by, for example, a nickel-hydrogen battery or a lithium-ion battery, and in the present embodiment, is constituted by a group battery in which a plurality of battery cells are connected in series. The charge battery 10 is constituted so that the positive and negative electrodes are in conduction with the positive terminal B+ and the negative terminal B- of the charge-discharge terminal la, respectively.

[0026] Here, the positive electrode of the secondary battery 10 is provided with a charging path and a discharging path in this embodiment. The charging path is provided with a charging current Ic from the positive electrode terminal B+ via a charging switch SWc, a first diode Dl, and a first fuse Fl. The discharging path is provided with a discharging current Id to the positive electrode terminal B+ via the first fuse Fl, a second diode D2, and a discharging switch SWd. The charging switch SWc and the discharging switch SWd are, for example, N-channel MOSFETs (Metal-Oxide Semiconductor Field-Effect Transistors), and the gates thereof are controlled by the control section 15 described later, so that the charging and discharging can be stopped as needed.

[0027] In addition, the negative electrode of the secondary battery 10 is connected to the negative electrode terminal B- via the current measuring section 11 in this embodiment. The current measuring section 11 is composed of a first resistor Rl and an operational amplifier OP, and the charging and discharging current I is measured by the operational amplifier OP based on the voltage drop in the first resistor Rl accompanying the charging and discharging current I of the secondary battery 10. In addition, the measured value of the charging and discharging current I differs in sign depending on the direction of the current, so that the charging current Ic and the discharging current Id are discriminated depending on whether the charging direction or the discharging direction.

[0028] One end of the thermistor 12 is connected to the temperature terminal TH, and the other end is grounded, and is disposed adjacent to the secondary battery 10. The resistance value of the thermistor 12 changes depending on the battery temperature Tbat of the secondary battery 10 when a prescribed applied voltage Va is input to one end, so that the battery temperature Tbat of the secondary battery 10 can be represented by the voltage at one end at that time. In this embodiment, the conductive line in which the voltage becomes common to the temperature terminal TH and the thermistor 12 is represented as a temperature measuring line L T .

[0029] The regulator 13 is an internal power source that forms the power required for the control operation of the battery pack 1. More specifically, the regulator 13 steps down the input voltage Vin input from the charger 2 or the secondary battery 10 via a third diode D3 and a second fuse F2, and outputs a prescribed output voltage Vout to the portion requiring power in the battery pack 1. In this embodiment, the regulator 13 supplies the output voltage Vout to the voltage switching section 14 and the control section 15. Here, the regulator 13 can be a so-called linear regulator, or can be a switching regulator.

[0030] The voltage switching section 14 is composed of a series connection of a second resistor R2 and a measurement switch SWm, and outputs the voltage formed by the output voltage Vout of the regulator 13 to the above-described temperature measuring line L TThe switch SWm used for measurement is, for example, an N-channel MOSFET. Its drain is connected to the regulator 13 via a second resistor R2, and its source is connected to the temperature measurement circuit L. T The gate is connected to the control unit 15, which will be described later.

[0031] Here, the voltage switching unit 14 sets the resistance value of the second resistor R2 so that the same voltage as the applied voltage Va used to operate the thermistor 12 can be output to the temperature measuring circuit L. T The applied voltage Va is intermittently output to the thermistor 12 based on the on / off control from the control unit 15.

[0032] The control unit 15 is, for example, composed of a known microcomputer control circuit, which monitors the state of the rechargeable battery 10, such as the battery temperature Tbat and the state of charge (SOC), and identifies whether the charging and discharging terminal 1a is connected, as will be described later. Based on the situation, it performs charging and discharging control of the rechargeable battery 10, and manages the battery pack 1 as a whole in a unified manner.

[0033] In addition, the control unit 15 includes a power input terminal Vcc and a pulse output terminal P. OUT Temperature measurement terminal TH IN Current measuring terminal I IN and grounding terminal. Therefore, the control unit 15 operates by providing the output voltage Vout of the regulator 13 to the power input terminal Vcc, and utilizes the pulse output terminal P. OUT To control the gate of the measuring switch SWm, and based on the temperature measuring terminal TH IN and current measuring terminal I IN The input voltage is used to calculate the battery temperature Tbat and the charging / discharging current I.

[0034] Figure 2 This is a schematic representation of the temperature measuring circuit L. T A diagram showing the voltage range. Control unit 15 connects to the temperature measurement terminal TH. IN The battery temperature Tbat of the rechargeable battery 10 corresponding to the voltage is calculated. However, due to limitations such as the number of bits in the microcomputer control circuit, the control unit 15 can only calculate the temperature of the rechargeable battery 10, even if the voltage is, for example, lower than... Figure 2 The voltage V1 or a voltage higher than V6 is input to the temperature measuring terminal TH. IN It also cannot identify the voltage, and directly measures the voltages as V1 and V6 respectively. That is, the control unit 15 can read the temperature measurement circuit L within the range of voltage V1 to voltage V6. T The voltage.

[0035] Additionally, the control unit 15 has a temperature measurement circuit LT If the voltage is within the readable region, the temperature corresponding to that voltage is calculated, but if... Figure 2 If the calculated temperature falls within the range of voltages V1 to V2 or V5 to V6, and this range cannot be assumed to be the temperature of the rechargeable battery 10, then the battery temperature Tbat is determined to be in an uncalcifiable range. That is, the control unit 15 can determine this within the temperature measurement circuit L. T The battery temperature Tbat is calculated when the voltage is within the range of voltage V2 to voltage V5. Furthermore, in this embodiment, even if the battery temperature Tbat is abnormally hot, the control unit 15 determines that the actual temperature of the rechargeable battery 10 is within the calculateable range simply by measuring the actual temperature.

[0036] In addition, the control unit 15 has a temperature measurement circuit L T If the voltage is included in the temperature calculation range, and the calculated temperature is appropriate as the operating temperature of the rechargeable battery 10, it is judged to be within the normal temperature range.

[0037] In addition, according to the temperature measurement circuit L T The correspondence between voltage and battery temperature Tbat is such that the readable range mentioned above can also be consistent with the calculable temperature range (V1=V2, V5=V6). In this case, if the temperature measuring circuit L... T If the voltage is within the calculable temperature range, then the lower limit value, i.e., voltage V2 (=V1), or the upper limit value, i.e., voltage V5 (=V6), is input to the temperature measuring terminal TH. IN .

[0038] Next, the timing of the temperature measurement performed by the control unit 15 will be explained. Figure 3 This schematically represents the temperature measuring circuit L corresponding to the on / off period of the measuring switch SWm. T A timing diagram showing the relationship between voltage and temperature measurement periods. Here, regarding the measurement switch SWm, which is repeatedly controlled to be on / off, the first period (term1) and the third period (term3) are the on-time periods, and the second period (term2) and the fourth period (term4) are the off-time periods. Additionally, the temperature measurement circuit L... T The voltage is set to be at least within the calculable temperature range.

[0039] In addition, Figure 3 In the process, the control unit 15 calculates the battery temperature Tbat three times during each of the on and off periods of the measuring switch SWm. However, the control interval of the measuring switch SWm and the timing of the battery temperature Tbat calculation are not limited to... Figure 3For example, as for the measurement with the switch SWm, the on period can be set to 50 ms and the off period can be set to 950 ms, and as for the measurement of the battery temperature Tbat, the following operation period can be set: the on period is set to 50 ms and the off period is set to 225 ms.

[0040] In a case where the charge-discharge terminal la of the battery pack 1 is connected to the charge port 2a of the charger 2, the voltage of the temperature measurement line L T is stably input via the temperature terminal TH, and thus, as shown in (A), the voltage Vbat corresponding to the battery temperature Tbat is stabilized. Figure 3

[0041] Therefore, as shown in (B), the battery temperature Tbat can be measured based on the voltage of the temperature measurement line L T regardless of whether the measurement with the switch SWm is the on period or the off period. Figure 3

[0042] On the other hand, in a case where the charger 2 is not connected to the battery pack 1, the voltage of the temperature measurement line L T is as shown in (C): 0 V, which is a voltage value deviating from the temperature computable range, is indicated in the off period of the measurement with the switch SWm, that is, the second period term2 and the fourth period term4, and the voltage Vbat is indicated in the on period, that is, the first period term1 and the third period term3. Figure 3

[0043] Therefore, as shown in (D), the battery temperature Tbat cannot be measured based on the voltage of the temperature measurement line L T in the off period of the measurement with the switch SWm. Figure 3 That is, the control section 15 can identify whether the charger 2 is connected to the battery pack 1 or not, in accordance with whether the battery temperature Tbat can be computed based on the voltage of the temperature measurement line L T in the period when the measurement with the switch SWm is off.

[0044] In addition, the control section 15 confirms whether the battery temperature Tbat can be computed based on the voltage of the temperature measurement line L T in the period when the measurement with the switch SWm is on, and in a case where the computed battery temperature Tbat deviates from the temperature computable range, it can be identified that there is a measurement abnormality at the thermistor 12. This can occur in a case where the thermistor 12 itself has failed or the thermistor 12 has been detached from the battery 10, and the like.

[0045]

[0046] ​​​​Next, a case where the load 3 is connected to the battery pack 1 will be described. Figure 4 is a schematic view showing the connection mode of the battery pack 1 and the load 3. The structure of the battery pack 1 is the same as that of the battery pack 1 shown in Figure 1 , and therefore, detailed description thereof will be omitted here.

[0047] The load 3 has a power supply port 3a connectable to the charge-discharge terminal la of the battery pack 1, and the positive terminal B+ and the negative terminal B- provided to the power supply port 3a are connected to the positive terminal B+ and the negative terminal B- of the charge-discharge terminal la, respectively, so that the load 3 can receive the power supply from the battery pack 1. Further, since the load 3 does not recognize the battery temperature Tbat of the charge battery 10, the temperature terminal TH is not provided to the power supply port 3a.

[0048] More specifically, in a case where the power supply port 3a is connected to the charge-discharge terminal la, the load 3 is driven by the power supplied from the charge battery 10 of the battery pack 1 via the discharge path described above. In addition, in a case where the load 3 can be driven in regeneration, the load 3 outputs the regenerative power between the positive terminal B+ and the negative terminal B-, so that the load 3 can supply the regenerative power to the battery pack 1 via the charge path described above to charge the charge battery 10.

[0049] That is, the battery pack 1 has a state where the charger 2 is connected, a state where the load 3 is connected, and a state where nothing is connected, and in a case where the charger 2 or the load 3 is connected, the battery pack 1 also has a state where the charge current Ic is supplied and a state where the discharge current Id is supplied, and therefore, there is a need to recognize these states and perform control appropriate to each state. Hereinafter, a control step of recognizing the state of the battery pack 1 will be described.

[0050] Figure 5 is a flowchart showing a control step of state recognition performed by the control section 15 of the battery pack 1. The control section 15 is started by supplying power to the power input terminal Vcc, performs standard charge-discharge control of the charge battery 10, and starts the control step shown in Figure 5 , thereby performing state recognition related to the charge-discharge terminal la, and performing appropriate charge-discharge control according to the recognized state. Further, the control section 15, in the course of performing the control step, in a case where various abnormal operations are recognized, for example, in a case where the battery temperature Tbat of the charge battery 10 is outside the normal temperature range and is within the temperature calculation range, prohibits the charge-discharge of the charge battery 10 and terminates the control step, and for example, can notify the user of an error state.

[0051] The control section 15 first supplies the power from the pulse output terminal P OUTThe control signal is used to start the on / off control of the switch SWm to measure the continuity (step S1). Thus, the voltage switching unit 14 intermittently sends a signal to the temperature measuring circuit L. T The applied voltage Va is 5V.

[0052] In addition, the control unit 15 utilizes the temperature measurement terminal TH IN Let's begin Figure 3 The temperature measurement circuit L described in the document T Voltage measurement (step S2). That is, the control unit 15 starts voltage measurement in step S2, so that it always attempts to calculate the battery temperature Tbat of the rechargeable battery 10 in subsequent processing during startup.

[0053] Then, the control unit 15 uses the voltage switching unit 14 to transmit power to the temperature measuring line L. T The output applied voltage Va is the voltage at the temperature terminal TH during the conduction period, i.e., the temperature measuring circuit L. T The voltage is used to determine whether the battery temperature Tbat can be calculated (step S3). Figure 3 The first period (term 1) and the third period (term 3) in the middle.

[0054] At this time, even when the temperature measuring line L is being measured... T If the battery temperature Tbat cannot be calculated during the conduction period of the applied voltage Va ("No" in step S3), the control unit 15 determines that the thermistor 12 is malfunctioning (step S4), stops the charge / discharge control, and terminates the control step. On the other hand, if the battery temperature Tbat can be calculated during the conduction period of the applied voltage Va ("Yes" in step S3), the control unit 15 assumes that there is no malfunction in the temperature measurement of the thermistor 12 and continues the control step.

[0055] Next, the control unit 15 uses the applied voltage Va from the voltage switching unit 14 to measure the voltage of the temperature terminal TH during the disconnection period, i.e., the temperature measuring line L. T The voltage is used to determine whether the battery temperature Tbat can be calculated (step S5). Figure 3 The second period (term 2) and the fourth period (term 4) in the text.

[0056] At this time, if the battery temperature Tbat can be calculated (yes in step S5), the control unit 15 can determine that the applied voltage Va is applied to the temperature measuring circuit L from the charger 2 via the temperature terminal TH. T That is, the control unit 15 identifies the connection status of the charger 2 based on the condition that it can calculate the battery temperature Tbat based on the voltage of the temperature terminal TH during the disconnection period of the applied voltage Va from the voltage switching unit 14.

[0057] Then, the control section 15 determines the direction of the charge-discharge current I based on the voltage input from the current measurement terminal I IN the charge-discharge current I is the charging current Ic (YES in step S6), it is possible to identify the case where the charger 2 is in the connected state and the charger 2 is in the charging control state (step S7).

[0058] In addition, in the case where the charge-discharge current I is the discharging current Id (NO in step S6), the control section 15 can identify the case where the charger 2 is in the connected state and the charger 2 is in the cycle-repair discharging control state (step S8). That is, even in the case where the charger 2 has the function of cycle-repair discharging, the control section 15 can identify the cycle-repair discharging control state.

[0059] On the other hand, in the case where it is determined that NO in step S5, the control section 15 at least determines that the charger 2 is not connected, and then determines whether the charge-discharge current I is the discharging current Id based on the voltage input from the current measurement terminal I IN

[0060] Then, in the case where it is determined that the charge-discharge current I is the discharging current Id (YES in step S9), the control section 15 can identify the case where the load 3 is in the connected state and the load 3 is in the power loss state (step S10).

[0061] On the contrary, in the case where it is determined that the charge-discharge current I is not the discharging current Id (NO in step S9), the control section 15 determines whether the charge-discharge current I is the charging current Ic (step Sll). At this time, in the case where it is determined that the charge-discharge current I is the charging current Ic (YES in step Sll), the control section 15 can identify the case where the load 3 is in the connected state and the load 3 is in the regeneration control state (step S12).

[0062] In addition, in the case where it is determined that NO in step Sll, the control section 15 can identify the case where, since the charge-discharge current I is not measured, it is the state where neither the charger 2 nor the load 3 is connected (step S13). That is, the control section 15 can identify the connected state of the charger 2 with the condition that the battery temperature Tbat cannot be calculated from the voltage of the temperature terminal TH at the time of the off period of the applied voltage Va from the voltage switching section 14 and the charge-discharge current I is measured.

[0063] Further, the control section 15 returns to step S3 after identifying each connected state and the control state of the connection target, and repeats the above procedure, so that the state identification can be continued as long as it is not abnormally stopped in the startup. ​

[0064] Therefore, the control section 15 can manage the charge and discharge of the secondary battery 10 even on the side of the battery pack 1 that can grasp the state of the secondary battery 10 in more detail, not only relying on the charge control of the charger 2 or the control state of the connection target such as the power demand from the load 3.

[0065] More specifically, for example, in a case where the connection state is that of the charger 2 and the charger 2 is in the charge control state (step S7), the control section 15 monitors the charge current Ic, and in a case where the charge current Ic rises to exceed a prescribed upper limit value of the charge current, controls the charge switch SWc to be open.

[0066] In addition, for example, in a case where the connection state is that of the charger 2 and the charger 2 is in the cycle repair discharge control state (step S8), the control section 15 monitors the battery voltage of the secondary battery 10, and in a case where the battery voltage falls to be lower than a prescribed over-discharge threshold value, controls the discharge switch SWd to be open.

[0067] Further, for example, in a case where the connection state is that of the load 3 and the load 3 is in the power loss state (step S10), the control section 15 monitors the discharge current Id, and in a case where the discharge current Id rises to exceed a prescribed upper limit value of the discharge current, controls the discharge switch SWd to be open.

[0068] Then, for example, in a case where the connection state is that of the load 3 and the load 3 is in the regeneration control state (step S12), the control section 15 monitors the battery voltage of the secondary battery 10, and in a case where the battery voltage rises to exceed a prescribed over-charge threshold value, controls the charge switch SWc to be open.

[0069] In addition, for example, in a case where neither the charger 2 nor the load 3 is connected (step S13), in a case where the state where the charge and discharge current I is 0 continues for a prescribed period, the control section 15 can shift to a sleep state to suppress the standby power.

[0070] As described above, the battery pack 1 intermittently outputs the application voltage Va that operates the thermistor 12 to the temperature terminal TH, and based on the voltage of the temperature terminal TH during the on period and the off period of the application voltage Va, and the charge and discharge current I, recognizes the connection state of the charge and discharge terminal la. Therefore, even if the charge and discharge terminal la is a three-terminal, the battery pack 1 can recognize the state of the connection target.

[0071] <Embodiment of the Invention>

[0072] A battery pack of a first aspect of the present application includes a charge / discharge terminal composed of a pair of power supply terminals and a temperature terminal, a charge battery that is charged and discharged via the pair of power supply terminals, a current measuring section that measures a charge / discharge current of the charge battery, a thermistor that is connected to the temperature terminal and measures a battery temperature of the charge battery, a voltage switching section that intermittently outputs an applied voltage that operates the thermistor to the temperature terminal, and a control section that identifies a connection state of the charge / discharge terminal based on a voltage of the temperature terminal during an on period and an off period of the applied voltage and the charge / discharge current, and the battery pack is charged by being connected to a charger and discharged by being connected to a load.

[0073] A battery pack of a second aspect of the present application includes the control section of the first aspect of the present application, and the control section identifies connection of the charger with a condition that the battery temperature is calculated from the voltage of the temperature terminal during the off period of the applied voltage.

[0074] A battery pack of a third aspect of the present application includes the control section of the second aspect of the present application, and the control section identifies that the charger is in a charge control state with a condition that a direction of the charge / discharge current is a charge direction when the connection of the charger is identified.

[0075] A battery pack of a fourth aspect of the present application includes the control section of the second aspect of the present application, and the control section identifies that the charger is in a cycle repair discharge control state with a condition that the direction of the charge / discharge current is a discharge direction when the connection of the charger is identified.

[0076] A battery pack of a fifth aspect of the present application includes the control section of any one of the first to fourth aspects of the present application, and the control section identifies connection of the load with a condition that the temperature of the charge battery cannot be calculated from the voltage of the temperature terminal during the off period of the applied voltage and the charge / discharge current is measured.

[0077] A battery pack of a sixth aspect of the present application includes the control section of the fifth aspect of the present application, and the control section identifies that the load is in a power loss state with a condition that the direction of the charge / discharge current is a discharge direction when the connection of the load is identified.

[0078] A battery pack of a seventh aspect of the present application includes the control section of the fifth aspect of the present application, and the control section identifies that the load is in a regeneration control state with a condition that the direction of the charge / discharge current is a charge direction when the connection of the load is identified.

[0079] The battery pack of the eighth aspect of the present application, in any of the above-mentioned first to seventh aspects of the present application, the control section recognizes the case where the charging / discharging terminal is not connected, with the condition that the battery temperature cannot be calculated from the voltage of the temperature terminal during the off period of the applied voltage and that the charging / discharging current is not measured.

[0080] The battery pack of the ninth aspect of the present application, in any of the above-mentioned first to eighth aspects of the present application, the control section recognizes the measurement abnormality of the thermistor, with the condition that the battery temperature cannot be calculated from the voltage of the temperature terminal during the on period of the applied voltage.

[0081] The battery pack of the tenth aspect of the present application, in any of the above-mentioned first to ninth aspects of the present application, the control section prohibits the charging / discharging of the secondary battery, with the condition that the battery temperature calculated from the voltage of the temperature terminal during the on period of the applied voltage is not within a prescribed normal temperature range.

[0082] Explanation of Reference Numerals

[0083] 1 Battery pack

[0084] 2 Charger

[0085] 3 Load

[0086] 10 Secondary battery

[0087] 11 Current measuring section

[0088] 12 Thermistor

[0089] 13 Regulator

[0090] 14 Voltage switching section

[0091] 15 Control section

[0092] 1a Charging / discharging terminal

[0093] B+ Positive terminal

[0094] B- Negative terminal

[0095] TH Temperature terminal

[0096] L T Temperature measurement line

Claims

1. A battery pack, which is charged by connection to a charger and discharged by connection to a load, characterized in that, comprises: a charge / discharge terminal composed of a pair of power supply terminals and a temperature terminal; a charge battery that is charged and discharged via the pair of power supply terminals; a current measuring section that measures a charge / discharge current of the charge battery; a thermistor that is connected to the temperature terminal and measures a battery temperature of the charge battery; a voltage switching section that intermittently outputs, to the temperature terminal, an applied voltage that operates the thermistor; and a control section that identifies a connection state of the charge / discharge terminal based on a voltage of the temperature terminal during an on period and an off period of the applied voltage and the charge / discharge current.

2. The battery pack according to claim 1, wherein the control section identifies the connection of the charger with a condition that the battery temperature is calculated from the voltage of the temperature terminal during the off period of the applied voltage.

3. The battery pack according to claim 2, wherein the control section identifies a case where the charger is in a charge control state with a condition that a direction of the charge / discharge current is a charge direction, in a case where the connection of the charger is identified.

4. The battery pack according to claim 2, wherein the control section identifies a case where the charger is in a cycle repair discharge control state with a condition that the direction of the charge / discharge current is a discharge direction, in a case where the connection of the charger is identified.

5. The battery pack according to claim 1 or 2, wherein the control section identifies the connection of the load with a condition that the battery temperature cannot be calculated from the voltage of the temperature terminal during the off period of the applied voltage and the charge / discharge current is measured.

6. The battery pack according to claim 5, wherein the control section identifies a case where the load is in a power loss state with a condition that the direction of the charge / discharge current is a discharge direction, in a case where the connection of the load is identified.

7. The battery pack according to claim 5, wherein the control section identifies a case where the load is in a regeneration control state with a condition that the direction of the charge / discharge current is a charge direction, in a case where the connection of the load is identified.

8. The battery pack according to claim 1 or 2, wherein the control section identifies a case where the charge / discharge terminal is not connected with a condition that the battery temperature cannot be calculated from the voltage of the temperature terminal during the off period of the applied voltage and the charge / discharge current is not measured.

9. The battery pack according to claim 1 or 2, wherein the control section identifies a measurement abnormality of the thermistor with a condition that the battery temperature cannot be calculated from the voltage of the temperature terminal during the on period of the applied voltage.

10. The battery pack according to claim 1 or 2, wherein ​ The control section prohibits charge and discharge of the secondary battery when the battery temperature calculated from the voltage of the temperature terminal during the on period of the applied voltage is not within a prescribed normal temperature range.

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