JP5644315B2 - Connection unit and power storage device - Google Patents

Description

  The present invention relates to a power storage device capable of removing an arbitrary power storage element from a current path in a configuration in which a plurality of power storage elements are electrically connected.

  A plurality of unit cells may be electrically connected in series to form an assembled battery. When using a so-called rectangular unit cell as a unit cell, for example, a plurality of unit cells are arranged in one direction, and two unit cells arranged adjacent to each other are electrically connected in series by a bus bar. Yes.

JP 2004-282799 A Japanese Patent Laid-Open No. 06-140022

  In the assembled battery, the degree of deterioration of the unit cell may vary, and only a specific unit cell may be deteriorated more than other unit cells. Here, it is only necessary to replace the unit cell that has deteriorated, but the work for replacing the unit cell may be troublesome. In particular, when a plurality of unit cells are sandwiched between a pair of end plates, it is necessary to replace the unit cells after removing the end plates, and the unit cell replacement work becomes troublesome.

  On the other hand, it is conceivable to replace the assembled battery including a deteriorated unit cell. However, since this assembled battery includes a unit cell that has not deteriorated, the unit cell cannot be used until the end of its life.

The present invention is a connection unit for electrically connecting a plurality of power storage elements arranged side by side in a predetermined direction, and includes a first energization line, a second energization line, and a conductive member. The first energization line is electrically connected to one of the positive electrode terminal and the negative electrode terminal provided on the same surface of the energy storage device, and is used for charging and discharging the energy storage device. The second energization line can be electrically connected to the other terminal of the positive electrode terminal and the negative electrode terminal, and is used for charging / discharging the storage element. The conductive member is used to electrically connect the other terminal of the positive electrode terminal and the negative electrode terminal to the second energization line. Further, the conductive member can rotate from a position in contact with the other terminal to a position in contact with one terminal, with the shaft portion extending in a predetermined direction as a center.

  A shaft portion of the conductive member can be disposed between the positive electrode terminal and the negative electrode terminal. Further, the conductive member can be provided with an opening through which the other terminal passes. Here, according to the rotation of the conductive member, one terminal can enter the opening. Thereby, an electroconductive member can be connected to a positive electrode terminal or a negative electrode terminal using an opening part.

  The case supporting the first energization line, the second energization line, and the conductive member can be formed of an insulating material. Moreover, the fixing member for engaging with the positive electrode terminal and negative electrode terminal which penetrated the case and fixing the case to the positive electrode terminal and the negative electrode terminal can be used.

  A motor that generates power for rotating the conductive member and a power transmission mechanism that transmits the power of the motor to the conductive member to rotate the conductive member can be provided. Thereby, a conductive member can be rotated by control of a motor.

In the configuration of arranging side by side a plurality of storage elements in a predetermined direction, in a predetermined direction, it can be provided with a restraining mechanism for restraining across the plurality of power storage elements. In a power storage device using a restraining mechanism, any power storage element can be removed from the current path during charge / discharge while the restraining force of the restraining mechanism is still applied to the plurality of power storage elements.

  According to the present invention, when the conductive member is brought into contact with the other terminal (positive electrode terminal or negative electrode terminal), the storage element can be charged and discharged. Further, if the conductive member is rotated and brought into contact with one terminal (negative electrode terminal or positive electrode terminal), the power storage element can be bypassed in the current path during charge / discharge. As described above, charging and discharging of the power storage element can be permitted or prohibited only by rotating the conductive member, and it is not necessary to physically remove the power storage element from the power storage device.

1 is an external view of a part of a battery pack that is Embodiment 1. FIG. In Example 1, it is an external view of a cell and a connection unit. 3 is an external view of a part of a connection unit in Embodiment 1. FIG. 1 is a cross-sectional view of a battery pack that is Example 1. FIG. 1 is a top view of a battery pack that is Embodiment 1. FIG. It is a figure which shows the circuit structure equivalent to the battery pack before performing a bypass process. It is a figure which shows the circuit structure equivalent to the battery pack after performing a bypass process. It is the schematic which shows the drive mechanism which rotates a bus-bar. It is a circuit diagram which shows the system configuration | structure in the vehicle by which the battery pack which is Example 1 is mounted. It is a flowchart which shows the deterioration determination of a cell in the vehicle by which the battery pack is mounted. In the modification of Example 1, it is a flowchart which shows the deterioration determination of a cell, and a bypass process. It is a flowchart which shows charging / discharging control of a battery pack in the vehicle by which a battery pack is mounted. It is the schematic which shows the structure of the connection unit which is Example 2 (reference example) .

  Examples of the present invention will be described below.

  A battery pack (corresponding to a power storage device) that is Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is an external view showing a partial configuration of the battery pack. The X-axis, Y-axis, and Z-axis shown in FIG. 1 are axes that are orthogonal to each other. In this embodiment, the Z-axis is an axis that corresponds to the vertical direction.

  The battery pack 100 includes a plurality of single cells (corresponding to power storage elements) 10 arranged side by side in the X direction. A partition plate 101 is disposed between two unit cells 10 adjacent in the X direction. The partition plate 101 can be formed of an insulating material such as resin. The partition plate 101 holds one unit cell 10 out of the two unit cells 10 sandwiching the partition plate 101, and has a protrusion (not shown) on the surface facing the other unit cell 10. Note that, at one end of the battery pack 100 in the X direction, the unit cell 10 is sandwiched between a partition plate 101 and an end plate 102 described later.

  A space can be formed between the unit cell 10 and the partition plate 101 when the protruding portion of the partition plate 101 contacts the unit cell 10. This space is a space where a heat exchange medium for adjusting the temperature of the unit cell 10 moves. As the heat exchange medium, a gas such as air or a liquid can be used. In the case of using a liquid, for example, an insulating liquid (for example, fluorinate) can be accommodated together with the battery pack 100 in a sealed case.

  When the unit cell 10 generates heat due to charging / discharging or the like, the temperature rise of the unit cell 10 can be suppressed by bringing the cooling heat exchange medium into contact with the unit cell 10 using the space. In addition, when the unit cell 10 is excessively cooled, the temperature reduction of the unit cell 10 can be suppressed by bringing the heating exchange medium into contact with the unit cell 10 using the space. .

  A pair of end plates (a part of the restraining mechanism) 102 are disposed at both ends of the battery pack 100 in the X direction. The end plate 102 can be formed of resin, for example. Both ends of a restraining band (a part of the restraining mechanism) extending in the X direction are fixed to the pair of end plates 102. A restraining force can be applied to the unit cell 10 using the restraining band and the end plate 102. The restraining force is a force that sandwiches the unit cell 10 in the X direction, and can suppress the expansion of the unit cell 10.

  The unit cell 10 includes a battery case and a power generation element housed in the battery case. The power generation element is an element that can be charged and discharged, and can be composed of a positive electrode element, a negative electrode element, and a separator (including an electrolytic solution) disposed between the positive electrode element and the negative electrode element. In the positive electrode element, a layer containing a positive electrode active material is formed on the surface of a current collector plate. In the negative electrode element, a layer containing a negative electrode active material is formed on the surface of a current collector plate.

  As the unit cell 10, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor (capacitor) can be used instead of the secondary battery. In the present embodiment, the plurality of single cells 10 are arranged in the X direction, but the present invention is not limited to this. For example, one battery module can be configured using a plurality of single cells 10 and the plurality of battery modules can be arranged in the X direction.

  A positive terminal (also referred to as an electrode terminal) 11 and a negative terminal (also referred to as an electrode terminal) 12 are provided on the upper surface of the unit cell 10. The positive electrode terminal 11 is electrically connected to the positive electrode element of the power generation element, and the negative electrode terminal 12 is electrically connected to the negative electrode element of the power generation element. The plurality of single cells 10 are electrically connected in series by the connection unit.

  Next, the configuration of the connection unit will be described. A connection unit 20 shown in FIG. 2 is arranged on the upper surface of the battery pack 100 shown in FIG. FIG. 2 shows an appearance of a part of the connection unit 20. The connection unit 20 is fixed to the positive electrode terminal 11 and the negative electrode terminal 12 of the unit cell 10 by nuts (corresponding to fixing members) 30a and 30b. On the outer peripheral surfaces of the positive electrode terminal 11 and the negative electrode terminal 12, thread grooves that engage with the nuts 30a and 30b are formed.

  A safety valve 14 is provided on the upper surface of the battery case 13, and the safety valve 14 is used to release gas generated inside the battery case 13 to the outside of the battery case 13. The safety valve 14 can be a so-called destructive or reset valve. The destructive safety valve 14 is a valve that irreversibly changes from a closed state to an open state. The return-type safety valve 14 is a valve that reversibly changes between a closed state and an open state.

  The connection unit 20 is arranged at a position away from the safety valve 14. Here, as shown in FIG. 4, the partition plate 101 protrudes above the upper surface of the battery case 13, and the connection unit 20 comes into contact with the upper end portion of the partition plate 101. Thereby, a space S is formed between the connection unit 20 and the safety valve 14, and it is possible to secure a movement path for the gas discharged from the safety valve 14.

  The connection unit 20 has a case 21 made of an insulating material such as resin. As shown in FIG. 3, wiring 41 is fixed to the bottom surface 21 a of the case 21, and the wiring 41 is arranged along the bottom surface 21 a of the case 21. Openings 21 b and 21 c for allowing the positive electrode terminal 11 and the negative electrode terminal 12 to penetrate are formed on the bottom surface 21 a of the case 21.

  One end 41 a of the wiring 41 is in contact with the negative electrode terminal 12 that penetrates the bottom surface 21 a of the case 21. One end 41 a of the wiring 41 is formed in a ring shape, and is disposed along the outer periphery of the negative electrode terminal 12. A nut 30 a and a washer 31 a are fixed to the negative electrode terminal 12. Thereby, the electrical connection between the one end 41a of the wiring 41 and the negative electrode terminal 12 can be ensured. Here, in FIG. 3, the wiring 41 having one end 41a corresponds to the first energization line of the present invention.

  A voltage detection line 51 a is attached to the washer 31 a, and the voltage detection line 51 a is connected to the voltage detection circuit 52. The voltage detection circuit 52 detects the voltage of the unit cell 10, and the detection voltage is used to control charging / discharging of the unit cell 10.

  The wiring 41 is used to electrically connect two unit cells 10 adjacent in the X direction in series. FIG. 3 shows only one end 41 a of the wiring 41 connected to the negative electrode terminal 12, but the other end 41 b of this wiring 41 has the structure shown in FIG. 3 with respect to the positive electrode terminal 11 of another unit cell 10. Are connected by the same structure.

  The other end 41 b of the wiring 41 is connected to the fastening bracket 42. The fastening bracket 42 is fixed to the bottom surface 21a of the case 21 by two bolts 43a and 43b, and holds down the rotating shaft 44a of the bus bar (conductive member) 44. The bolt 43 a is also used to connect the fastening fitting 42 and the other end 41 b of the wiring 41. The bus bar 44 is electrically connected to the wiring 41 through the fastening fitting 42. Here, in FIG. 3, the wiring 41 having the other end 41b corresponds to the second energization line of the present invention.

  The positioning fitting 45 is used for positioning the rotation shaft 44a of the bus bar 44, and is fixed to the bottom surface 21a of the case 21 by a bolt 43c. When the fastening fitting 42 and the positioning fitting 45 hold both ends of the rotating shaft 44a, the bus bar 44 can rotate in the direction indicated by the arrow D around the rotating shaft 44a. The bus bar 44 has a plate portion 44b in which an opening 44c is formed.

  The opening 44 c comes into contact with the positive electrode terminal 11 penetrating the opening 21 b of the case 21. That is, the positive electrode terminal 11 penetrates the opening 21 b of the case 21 and penetrates the opening 44 c of the bus bar 44. In this state, the nut 30 b and the washer 31 b are fixed to the positive terminal 11. Thereby, the positive electrode terminal 11 is electrically connected to the wiring 41 via the bus bar 44. A voltage detection line 51 b is attached to the washer 31 b, and the voltage detection line 51 b is connected to the voltage detection circuit 52. The voltage detection circuit 52 can detect the voltage between the terminals of the unit cell 10 via the voltage detection lines 51a and 51b.

  The structure shown in FIG. 3 is provided for each unit cell 10. As shown in FIG. 5, if all the bus bars 44 are brought into contact with the corresponding positive terminals 11, all the unit cells 10 arranged in the X direction can be electrically connected in series.

  In this embodiment, all the unit cells 10 are electrically connected in series, but the present invention is not limited to this. A plurality of unit cells 10 electrically connected in parallel may be included. In the present embodiment, the one end 41a of the wiring 41 is connected to the negative terminal 12, and the bus bar 44 is connected to the positive terminal 11. However, the present invention is not limited to this. Specifically, one end 41 a of the wiring 41 can be connected to the positive terminal 11 and the bus bar 44 can be connected to the negative terminal 12.

  When the nut 30b and the washer 31b are removed from the positive electrode terminal 11, the bus bar 44 can be rotated around the rotation shaft 44a. Here, if the pressing of the rotating shaft 44a by the fastening fitting 42 or the positioning fitting 45 is loosened, the bus bar 44 can be easily rotated. When the bus bar 44 is rotated in the direction of the arrow D <b> 1 in FIG. 4, the bus bar 44 can be connected to the negative electrode terminal 12. That is, the negative terminal 12 passes through the opening 44 c of the bus bar 44.

  The bus bar 44 can be fixed to the negative electrode terminal 12 by attaching the nut 30a and the washer 31a to the negative electrode terminal 12 penetrating the opening 44c of the bus bar 44. The nut 30b and the washer 31b are attached to the positive electrode terminal 11 from which the bus bar 44 is removed. In this embodiment, the opening 44c is formed in the bus bar 44, but the present invention is not limited to this. That is, it is only necessary that the bus bar 44 can be connected to the electrode terminals 11 and 12. For example, a notch portion along the outer periphery of the electrode terminals 11 and 12 can be formed in the bus bar 44.

  When the bus bar 44 is connected to the negative electrode terminal 12, the unit cell 10 corresponding to the bus bar 44 can be removed from the current path for charging and discharging. In this embodiment, this process is referred to as a bypass process. The bypassed cell 10 is not used for charging / discharging the battery pack 100. Thereby, in the state which has arrange | positioned the arbitrary cell 10 in the battery pack 100, this cell 10 can be removed from an electrical circuit.

  On the other hand, when the nuts 30a and 30b and the washers 31a and 31b are removed from all the electrode terminals 11 and 12, all the unit cells 10 and the connection units 20 can be separated. Here, if all the bus bars 44 are connected to the negative electrode terminal 12, the connection unit 20 can be removed in a state where all the electric cells 10 are disconnected from each other. Thereby, the safety | security when disassembling the used battery pack 100 can be improved.

  As shown in FIGS. 4 and 5, two restraint bands 61 are arranged on the upper surface of the battery pack 100, and each restraint band 61 extends in the X direction. Both end portions 61 a of the restraining band 61 are fixed to the end plate 102 by bolts 63. The two restraining bands 61 are arranged at positions sandwiching the connection unit 20 in the Y direction.

  On the other hand, two restraint bands 62 are arranged on the bottom surface of the battery pack 100, and each restraint band 62 extends in the X direction. Both end portions 62a of the restraining band 62 are fixed to the end plate 102 by bolts. The positions where the restraining bands 61 and 62 are arranged are not limited to the positions shown in FIGS. 4 and 5. It is only necessary that both ends of the restraining bands 61 and 62 are connected to the pair of end plates 102 to generate the restraining force of the unit cell 10.

  6 and 7 are diagrams showing a circuit configuration equivalent to a part of the battery pack 100. FIG. FIG. 6 shows a state in which the bus bar 44 is connected to the positive electrode terminal 11, and shows a circuit configuration when the bypass process of the unit cell 10 is not performed. In the state shown in FIG. 6, all the unit cells 10 are electrically connected in series, and all the unit cells 10 are charged / discharged. The arrows shown in FIG. 6 indicate the direction in which current flows during charging. The voltage detection circuit 52 can detect the voltage of each unit cell 10.

  When the bus bar 44 corresponding to each unit cell 10 is rotated and connected to the negative electrode terminal 12, the circuit configuration shown in FIG. 7 is obtained. In the state shown in FIG. 7, the cell 10 is bypassed, and no charge / discharge current flows through the cell 10. The voltage of each cell 10 detected by the voltage detection circuit 52 is zero [V].

  The bus bar 44 can also be automatically rotated by a drive mechanism including a motor. FIG. 8 is a schematic view showing a mechanism for driving the bus bar 44, and this mechanism can be provided in the connection unit 20. The motor 71 serves as a drive source for rotating the bus bar 44. A worm gear (a part of the power transmission mechanism) 72 is attached to the output shaft of the motor 71, and the worm gear 72 rotates in the direction of arrow M in response to power from the motor 71. The worm gear 72 meshes with a worm wheel (part of the power transmission mechanism) 73, and the worm wheel 73 is fixed to the rotation shaft 44 a of the bus bar 44. As the worm wheel 73 rotates by receiving the driving force from the motor 71, the bus bar 44 rotates in the direction of arrow D.

  By controlling the driving of the motor 71, the bus bar 44 can be rotated from the position in contact with the positive terminal 11 to the position in contact with the negative terminal 12. Here, when the nuts 30a and 30b and the washers 31a and 31b are used, it is necessary to remove the nuts 30a and 30b and the washers 31a and 31b from the electrode terminals 11 and 12 before the bus bar 44 is rotated. On the other hand, the bus bar 44 can be brought into contact with the electrode terminals 11 and 12 using the holding torque of the motor 71. In this case, the nuts 30a and 30b and the washers 31a and 31b can be omitted.

  The battery pack 100 of the present embodiment can be mounted on a vehicle. Such vehicles include hybrid vehicles and electric vehicles. A hybrid vehicle is a vehicle including a fuel cell or an engine in addition to the battery pack 100 as a power source for running the vehicle. An electric vehicle is a vehicle that uses only the battery pack 100 as a power source of the vehicle.

  FIG. 9 shows a circuit configuration of the hybrid vehicle. Battery pack 100 is connected to booster circuit 202 via relays 201a and 201b. The booster circuit 202 increases the output voltage from the battery pack 100 and supplies it to the inverter 203. The inverter 203 converts output power (DC power) from the booster circuit 202 into AC power and supplies the AC power to the motor (three-phase AC motor) 204. By transmitting the kinetic energy generated by the motor 204 to the wheels 205, the vehicle can be driven.

  When the vehicle is decelerated or stopped, the motor 204 converts kinetic energy generated during braking of the vehicle into electric energy (AC power) and supplies the electric energy to the inverter 203. The inverter 203 converts AC power from the motor 204 into DC power and supplies it to the booster circuit 202. The booster circuit 202 reduces the output voltage from the inverter 203 and supplies it to the battery pack 100.

  The kinetic energy generated by the engine 206 is used to drive the wheels 205. The motor 204 converts the kinetic energy generated by the engine 206 into electric energy and supplies the electric energy to the battery pack 100. In the configuration shown in FIG. 9, the booster circuit 202 can be omitted. If the AC motor 204 is not used, the inverter 203 can be omitted.

  The voltage detection circuit 52 detects the voltage of each cell 10 and outputs the detection result to a battery ECU (Electronic Control Unit) 210. Current sensor 208 detects a current value at the time of charging / discharging and outputs the detection result to battery ECU 210. Temperature sensor 209 detects the temperature of battery pack 100 and outputs the detection result to battery ECU 210. Battery ECU 210 determines the state of unit cell 10 based on the outputs of voltage detection circuit 52, current sensor 208, and temperature sensor 209. Examples of the state of the unit cell 10 include a state of charge (SOC) and a deterioration state.

  An HV-ECU (Hybrid Vehicle Electronic Control Unit) 211 communicates with the battery ECU 210 to control charging / discharging of the battery pack 100. The HV-ECU 211 controls operations of the booster circuit 202, the inverter 203, and the engine 206. The display unit 212 receives specific control information from the HV-ECU 211 and displays specific information. As the display unit 212, for example, a display used in a navigation system mounted on a vehicle or a display for displaying a traveling speed of the vehicle can be used.

  The control operation of the battery pack 100 will be described with reference to FIG. The process shown in FIG. 10 is performed by the HV-ECU 211.

  In step S101, the HV-ECU 211 determines whether or not the ignition switch has been turned on. If the ignition switch is turned on, the HV-ECU 211 performs the process of step S102. In step S <b> 102, the HV-ECU 211 causes the vehicle to travel while controlling charging / discharging of the battery pack 100. For example, charging / discharging control of the battery pack 100 can be performed so that the power during charging / discharging does not exceed a preset threshold value. Further, the charge / discharge control of the battery pack 100 can be performed so that the voltage of the battery pack 100 falls within the range of the upper limit voltage and the lower limit voltage.

  While charging / discharging the battery pack 100, the battery ECU 210 monitors the voltage and temperature of the unit cell 10 based on the outputs of the voltage detection circuit 52 and the temperature sensor 209 (S103). In step S <b> 104, the HV-ECU 211 determines whether there is a deteriorated unit cell 10 based on the monitoring result of the battery ECU 210.

  The deterioration state of the cell 10 can be determined based on the voltage value or temperature of the cell 10, for example. Specifically, when the voltage value of the unit cell 10 is lower than the lower limit voltage used in the charge / discharge control, it can be determined that the unit cell 10 is in a deteriorated state. Moreover, the deterioration value of the cell 10 is calculated, and when the deterioration value reaches the threshold value, it can be determined that the cell 10 is in the deterioration state. The deterioration value is a value specified by the internal resistance of the unit cell 10. For example, the resistance value of the unit cell 10 can be used as the deterioration value, or the ratio between the resistance value of the unit cell 10 in the initial state and the current resistance value of the unit cell 10 can be used as the deterioration value. Here, the deterioration value can be corrected based on the temperature of the battery pack 100.

  Various proposals have been made for the estimation method of the degradation state, and these estimation methods can also be applied to this embodiment. In the present embodiment, it suffices if the unit cell 10 to be bypassed can be specified. And the determination conditions of whether the cell 10 is a deterioration state can be set suitably.

  In step S <b> 105, the HV-ECU 211 causes the display unit 212 to display information related to the deteriorated unit cell 10. The information displayed on the display unit 212 may be information indicating that the specific unit cell 10 is in a deteriorated state. For example, characters, symbols, and the like can be used. Further, not only the display unit 211 can display information on the unit cell 10 in a deteriorated state, but also other users can be used to notify the user or the like. As other means, for example, voice can be used.

  If the user or the like is notified of information related to the degraded unit cell 10, the bypass process of the unit cell 10 can be performed by operating the bus bar 44 corresponding to the degraded unit cell 10.

  Here, as described with reference to FIG. 8, in the configuration in which the bus bar 44 can be rotated by controlling the driving of the motor 71, the process shown in FIG. 11 is performed instead of the process shown in FIG. be able to. The process shown in FIG. 11 is performed by the HV-ECU 211. The same processes as those described in FIG. 10 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In step S105, information related to the deteriorated unit cell 10 is displayed on the display unit 212. Then, in step S106, it is determined whether or not to perform bypass processing on the deteriorated unit cell 10. Specifically, the HV-ECU 211 causes the display unit 212 to display selection information indicating whether to perform bypass processing. Then, the user can input information on whether to perform bypass processing. For example, the display unit 212 can be configured with a touch panel, and information regarding whether to perform bypass processing can be input. The HV-ECU 211 receives information input from the user and determines whether to perform bypass processing.

  When the bypass process is performed, the process proceeds to step S107, and when the bypass process is not performed, this process is terminated. In step S107, the HV-ECU 211 rotates the bus bar 44 corresponding to the unit cell 10 in the deteriorated state using the power source. For example, a motor 71 can be used as the power source. By rotating the bus bar 44, the unit cell 10 in a degraded state can be removed from the current path for charging and discharging.

  In step S108, the HV-ECU 211 determines whether or not the bypass process has ended normally. Specifically, the HV-ECU 211 confirms the voltage of the unit cell 10 that has undergone the bypass process based on the output of the voltage detection circuit 52. If the voltage of the unit cell 10 is 0 [V], the HV-ECU 211 determines that the bypass process has ended normally. On the other hand, if the voltage of the unit cell 10 is not 0 [V], the HV-ECU 211 determines that the bypass process has not ended normally.

  When the bypass process is normally completed, this process is terminated. When the bypass process is not normally terminated, the process proceeds to step S109. In step S109, the HV-ECU 211 causes the display unit 212 to display that an error has been displayed in the bypass process. Thereby, it is possible to notify the user that an error has occurred in the bypass process, and the user can check the bypass process. Here, the operator can check the bypass process by visual observation. Further, by controlling the driving of the motor 71, it is possible to check whether or not the bypass process has been normally completed by performing the bypass process again after temporarily returning the bus bar 44 to the original position.

  Next, the process after performing the bypass process of the cell 10 will be described with reference to FIG. The process shown in FIG. 12 is executed by the HV-ECU 211.

  In step S201, the HV-ECU 211 determines whether or not the ignition switch is turned on. If the ignition switch is turned on, the HV-ECU 211 performs the process of step S202. In step S <b> 202, the HV-ECU 211 determines whether there is a unit cell 10 for which bypass processing has been performed. About the cell 10 which performed the bypass process, since a voltage value becomes 0 [V], what is necessary is just to discriminate | determine whether the cell 10 whose voltage value is 0 [V] exists.

  If there is no unit cell 10 that has undergone the bypass process, this process ends. As described with reference to FIG. 10, the vehicle can be driven while controlling charging / discharging of the battery pack 100. On the other hand, if there is a cell 10 that has undergone the bypass process, the process proceeds to step S203. In step S203, the HV-ECU 211 determines whether or not the total number of the single cells 10 that have undergone the bypass process is greater than a predetermined number. The predetermined number is a value set in advance based on the output required by the system shown in FIG. 9, and can be stored in the memory. Since the output of the battery pack 100 decreases as the number of unit cells 10 to be bypassed increases, the predetermined number can be set in consideration of the relationship with the required output of the system.

  If the total number of bypassed cells 10 is greater than the predetermined number, in step S204, the HV-ECU 211 determines that the battery pack 100 needs to be replaced. At this time, the HV-ECU 211 can cause the display unit 212 to display information indicating that the battery pack 100 needs to be replaced. Information indicating that the battery pack 100 needs to be replaced can be notified to a user or the like using voice or the like. When it is determined that the battery pack 100 needs to be replaced, the HV-ECU 211 prohibits charging / discharging of the battery pack 100.

  When the total number of bypassed cells 10 is less than the predetermined number, the HV-ECU 211 changes control parameters used for charging / discharging the battery pack 100 in step S205. Examples of the control parameter include an upper limit voltage / lower limit voltage used in charge / discharge control of the unit cell 10 and an upper limit value of input / output of the unit cell 10. As an example of changing the control parameter, the range of the upper limit voltage and the lower limit voltage can be narrowed as the number of bypassed cells 10 increases. For example, the upper limit voltage can be reduced as the number of bypassed cells 10 increases. On the other hand, as the number of bypassed cells 10 increases, the input / output upper limit value of the cells 10 can be reduced.

  If a map indicating the correspondence between the total number of bypassed cells 10 and the control parameters is prepared in advance, the control parameters can be specified according to the total number of bypassed cells 10. This map can be stored in memory. Note that control parameters corresponding to the total number of bypassed cells 10 can be obtained by calculation. By changing the control parameter in accordance with the total number of bypassed cells 10, charge / discharge control suitable for the number of cells 10 used for charging / discharging can be performed.

Battery pack is a real施例2 (reference example) will be described with reference to FIG. Here, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the first embodiment, the rotation shaft 44a of the bus bar 44 extends in the X direction. In this embodiment (reference example) , the rotation shaft 44a of the bus bar 44 extends in the Z direction. Thereby, the plate part 44b of the bus bar 44 rotates around the Z axis. When the bypass process of the unit cell 10 is not performed, the plate portion 44 b of the bus bar 44 is in contact with the outer peripheral surface of the positive electrode terminal 11. On the other hand, when performing bypass processing of the unit cell 10, the plate portion 44 b can be brought into contact with the outer peripheral surface of the negative electrode terminal 12 by rotating the bus bar 44 in the direction of arrow D 2 .

DESCRIPTION OF SYMBOLS 100: Battery pack (electric storage apparatus) 101: Partition plate 102: End plate (a part of restraint mechanism) 10: Single battery (electric storage element)
11: Positive terminal 12: Negative terminal 13: Battery case 14: Safety valve 20: Connection unit 21: Case 21a: Bottom surface 30a, 30b: Nut (fixing member)
31a, 31b: Washer 41: Wiring (first energization line and second energization line)
42: Fastening brackets 43a to 43c: Bolt 44: Bus bar (conductive member) 44a: Rotating shaft 44b: Plate portion 44c: Opening portion 45: Positioning bracket 61, 62: Restraint band (part of restraint mechanism)
71: Motor 72: Worm gear (part of the power transmission mechanism)
73: Worm wheel (part of the power transmission mechanism)

Claims (8)

A connection unit for electrically connecting a plurality of power storage elements arranged side by side in a predetermined direction ,
A first energization line that is electrically connected to one of the positive electrode terminal and the negative electrode terminal provided on the same surface of the power storage element and is used for charging and discharging the power storage element;
A second energization line that is electrically connectable to the other of the positive electrode terminal and the negative electrode terminal, and is used for charging and discharging the power storage element;
A conductive member for electrically connecting the other terminal and the second energization line;
The connection unit, wherein the conductive member is rotatable about a shaft portion extending in the predetermined direction from a position in contact with the other terminal to a position in contact with the one terminal.   The connection unit according to claim 1, wherein the shaft portion is disposed between the positive terminal and the negative terminal.   3. The conductive member has an opening through which the other terminal penetrates, and the one terminal enters the opening according to the rotation of the conductive member. The connection unit described in 1.   4. The connection unit according to claim 1, further comprising a case formed of an insulating material that supports the first energization line, the second energization line, and the conductive member. 5.   5. The connection unit according to claim 4, further comprising: a fixing member that engages with the positive terminal and the negative terminal penetrating the case and fixes the case to the positive terminal and the negative terminal. A motor for generating power for rotating the conductive member;
A power transmission mechanism for transmitting the power of the motor to the conductive member and rotating the conductive member;
The connection unit according to claim 1, wherein the connection unit is provided. A connection unit according to any one of claims 1 to 6,
A plurality of power storage elements that are electrically connected by the connection unit and arranged in a predetermined direction ; and
A power storage device comprising: The power storage device according to claim 7, further comprising a restraining mechanism that restrains the plurality of power storage elements in the predetermined direction.

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