JP5585482B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device having a structure that applies a binding force to a plurality of power storage elements.

  When an assembled battery is configured using a plurality of unit cells, the plurality of unit cells may be arranged in one direction and constrained from both ends in the arrangement direction. Here, when the assembled battery is viewed in the arrangement direction of the unit cells, the plurality of unit cells overlap each other.

JP 2008-053019 A JP 2007-109546 A

  The inventor of the present application has found that depending on charging / discharging of the unit cell, only the surface pressure in one part of the unit cell changes more than the surface pressure in the other part. Here, when the surface pressure of the unit cell increases, the unit cell expands, and when the surface pressure of the unit cell decreases, the unit cell contracts. Therefore, if a large change in the surface pressure is suppressed, it is possible to suppress deterioration of the input / output characteristics of the unit cell.

A present invention is a power storage device, the predetermined direction, are arranged side by side in a direction orthogonal to the predetermined direction, and a plurality of storage elements including a reaction region for charge and discharge therein, our Keru plurality of power storage in a predetermined direction And a restraining mechanism that applies a restraining force in a predetermined direction to the plurality of power storage elements from both sides of the element . Here, the two power storage elements adjacent in the predetermined direction are arranged so as to be shifted in the orthogonal direction in a state where a part of the region including one end of the reaction region overlaps with each other in the predetermined direction. In addition, two power storage elements adjacent in the orthogonal direction are arranged with a gap in the orthogonal direction. Two power storage elements adjacent in a predetermined direction can be brought into contact with each other.

  The power storage element includes a power generation element. The power generation element includes a reaction region, and can be configured by winding a laminated body in which a positive electrode plate, a negative electrode plate, and an electrolyte layer are stacked around a predetermined axis. Here, the partial region of the reaction region can be a region including the end of the reaction region in the direction of the predetermined axis.

The width W _E2 of a partial region in the direction of the predetermined axis, the width W _A of the reaction zone in the direction of the predetermined axis preferably satisfies the relationship of formula (I).
14 ≦ W _E2 / W _A × 100 ≦ 27 (I)

  The restraining mechanism can be composed of a pair of end plates and a connecting member. The pair of end plates sandwich a plurality of power storage elements in a predetermined direction. The connecting member extends in a predetermined direction and is connected to the pair of end plates. Here, on the surface of the end plate that faces the power storage element, a protrusion that protrudes toward the power storage element can be provided. The protrusion can be brought into contact with the power storage element at a position where a restraining force is applied to a part of the region.

A pressurizing member that applies a restraining force from the restraining mechanism can be disposed in a partial region of the power storage element . The plurality of power storage elements include a power storage element having a partial region overlapping with the pressure member in a predetermined direction. And a pressurization member and the electrical storage element adjacent to a pressurization member in the orthogonal direction are arrange | positioned at intervals in the orthogonal direction . The pressure member can be brought into contact with a region different from a region in contact with each other among two power storage elements adjacent in a predetermined direction.

  The plurality of power storage elements constituting the power storage device can be configured by a plurality of power storage elements arranged in a predetermined direction and a plurality of power storage elements arranged in a direction orthogonal to the predetermined direction. As the power storage element, a lithium ion secondary battery that is charged or discharged at a rate of 20 C or higher can be used.

  According to the present invention, two power storage elements adjacent in a predetermined direction are arranged so as to be shifted in a direction orthogonal to the predetermined direction in a state where a part of the region including one end of the reaction region overlaps with each other in the predetermined direction. For this reason, if a plurality of energy storage devices arranged in a predetermined direction are constrained using a constraining mechanism, a constraining force is applied to a part of the region in the reaction region. Pressure change can be suppressed.

1 is an external view of a single cell in Example 1. FIG. 2 is a diagram showing an internal structure of a single cell in Example 1. FIG. It is an expanded view of the electric power generation element in Example 1. FIG. 1 is an external view of a power generation element in Embodiment 1. FIG. 1 is a top view of a battery pack that is Embodiment 1. FIG. 1 is an external view of a part of a battery pack that is Embodiment 1. FIG. FIG. 3 is a diagram illustrating a part of the battery pack assembling method according to the first embodiment. 6 is a top view of a part of a battery pack that is a modification of Example 1. FIG. In Example 1, it is a figure explaining the reaction area | region and the restraint area | region. It is a figure which shows the surface pressure of the cell in charge of rate 1C. It is a figure which shows the surface pressure of the cell in charge of rate 12C. It is a figure which shows the surface pressure of the cell in charge of rate 20C. It is a figure which shows the surface pressure of the cell in charge of rate 32C. It is a figure which shows the surface pressure of the cell in the discharge of rate 1C. It is a figure which shows the surface pressure of the cell in the discharge of rate 12C. It is a figure which shows the surface pressure of the cell in the discharge of rate 20C. It is a figure which shows the surface pressure of the cell in the discharge of rate 32C. It is a figure which shows the relationship between resistance increase rate and cycle number. It is a figure which shows the relationship between resistance increase rate and the number of cycles in the case of changing the size of the first constrained region. It is a figure which shows the relationship between resistance increase rate and the number of cycles in the case of changing the size of the power generation element.

  Examples of the present invention will be described below.

  A single cell (corresponding to a storage element) which is Example 1 will be described. FIG. 1 is a perspective view of a unit cell, and FIG. 2 is a diagram showing an internal structure of the unit cell. 1 and 2, the X axis, the Y axis, and the Z axis are axes orthogonal to each other. The relationship among the X axis, the Y axis, and the Z axis is the same in other drawings.

  As the unit cell 1, 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. The unit cell 1 includes a battery case 10 and a power generation element 14 accommodated in the battery case 10. The battery case 10 is made of metal and has a case body 10a and a lid 10b. The case main body 10a has an opening for incorporating the power generation element 14, and the lid 10b closes the opening of the case main body 10a. Thereby, the inside of the battery case 10 is hermetically sealed. The lid 10b and the case main body 10a can be fixed by welding, for example.

  The positive electrode terminal 11 and the negative electrode terminal 12 are fixed to the lid 10b. The positive electrode terminal 11 is connected to the power generation element 14 via the positive electrode tab 15a, and the negative electrode terminal 12 is connected to the power generation element 14 via the negative electrode tab 15b. Further, a valve 13 is provided on the lid 10b. The valve 13 is used to discharge gas to the outside of the battery case 10 when gas is generated inside the battery case 10. Specifically, when the internal pressure of the battery case 10 reaches the operating pressure of the valve 13 as the gas is generated, the valve 13 changes from a closed state to an open state, thereby discharging the gas to the outside of the battery case 10. Let

  FIG. 3 is a development view of the power generation element 14. The power generation element 14 includes a positive electrode plate 141, a negative electrode plate 142, and a separator 143. The positive electrode plate 141 includes a current collector plate 141a and a positive electrode active material layer 141b formed on the surface of the current collector plate 141a. The positive electrode active material layer 141b includes a positive electrode active material, a conductive agent, a binder, and the like. The positive electrode active material layer 141b is formed in a partial region of the current collector plate 141a, and the other region of the current collector plate 141a is exposed. The negative electrode plate 142 includes a current collector plate 142a and a negative electrode active material layer 142b formed on the surface of the current collector plate 142a. The negative electrode active material layer 142b includes a negative electrode active material, a conductive agent, a binder, and the like. The negative electrode active material layer 142b is formed in a partial region of the current collector plate 142a, and the other region of the current collector plate 142a is exposed. Separator 143 contains an electrolytic solution.

  The power generation element 14 is configured by laminating the positive electrode plate 141, the negative electrode plate 142, and the separator 143 in the order shown in FIG. 3, and winding this laminate in the direction indicated by the arrow R in FIG. The portion of the laminate that has been wound can be fixed using a tape. In FIG. 3, only the current collecting plate 141 a of the positive electrode plate 141 is wound at one end of the power generation element 14 in the Y direction. As described with reference to FIG. 2, the positive electrode tab 15a is fixed to the current collecting plate 141a. At the other end of the power generation element 14 in the Y direction, only the current collecting plate 142a of the negative electrode plate 142 is wound, and the negative electrode tab 15b is fixed to the current collecting plate 142a.

  A region (referred to as a reaction region) A shown in FIG. 2 and FIG. 4 is a region where the positive electrode active material layer 141b and the negative electrode active material layer 142b overlap each other, and a chemical reaction occurs when the unit cell 1 is charged and discharged. This is the area to be performed.

  Next, a battery pack (corresponding to a power storage device) according to the present embodiment will be described with reference to FIGS. FIG. 5 is a top view of the battery pack 100, and FIG. 6 is a perspective view showing a part of the battery pack 100. The battery pack shown in FIGS. 5 and 6 can be housed in a case (not shown).

  The battery pack 100 has a plurality of single cells 1. The number of the single cells 1 can be appropriately set based on the required output of the battery pack 100. The battery pack 100 can be mounted on a vehicle, for example. If the electric energy output from the battery pack 100 is converted into kinetic energy by the motor / generator, the vehicle can be driven using this kinetic energy. Further, if kinetic energy generated during braking of the vehicle is converted into electric energy by a motor / generator, the electric energy can be stored in the battery pack 100.

  The plurality of single cells 1 are arranged in the X direction and the Y direction. Two unit cells 1 adjacent in the X direction are arranged so as to be shifted in the Y direction, and are in contact with each other in a partial region of the unit cell 1. A space S is formed in a region where the two unit cells 1 are not in contact with each other. The space S can be used as a moving space for air used to adjust the temperature of the unit cell 1.

  When the unit cell 1 is generating heat, the cooling air is allowed to flow through the space S, so that heat exchange is performed between the cooling air and the unit cell 1, thereby suppressing an increase in the temperature of the unit cell 1. it can. When the unit cell 1 is excessively cooled, heat is exchanged between the heating air and the unit cell 1 by flowing warming air through the space S, and the temperature of the unit cell 1 is reduced. Can be suppressed.

  The plurality of single cells 1 constituting the battery pack 100 are electrically connected in series by a plurality of bus bars 50. The bus bar 50 is fixed to the positive terminal 11 of one unit cell 1 and the negative terminal 12 of the other unit cell 1 out of two unit cells 1 electrically connected in series.

  The plurality of bus bars 50 can be fixed to a holder made of an insulating material (for example, resin). Thereby, the several bus bar 50 can be handled collectively. In the present embodiment, the bus bar 50 is disposed as shown in FIG. 5, but the present invention is not limited to this. That is, if the plurality of single cells 1 can be electrically connected in series, the arrangement of the bus bars 50 can be set as appropriate.

  A pair of end plates (part of a restraining mechanism) 20 are disposed at both ends of the battery pack 100 in the X direction. The end plate 20 can be formed of resin, for example. The end plate 20 has a plurality of protrusions 21 on the surface facing the unit cell 1. The protrusion 21 protrudes in the X direction.

  Both ends 31 of a restraining band (corresponding to a connecting member) 30 extending in the X direction are fixed to the pair of end plates 20. Both ends 31 of the restraining band 30 are bent along the end plate 20 and are fixed to the end plate 20 using, for example, bolts or rivets.

  In the present embodiment, the pair of restraint bands 30 are disposed at both ends of the battery pack 100 in the Y direction, but the number of restraint bands 30 and the positions at which the restraint bands 30 are disposed can be appropriately set. Further, the shape of the restraining band 30 can be set as appropriate. The shape of the restraining band 30 includes a shape in a cross section orthogonal to the longitudinal direction of the restraining band 30. The restraint band 30 only needs to be connected to the pair of end plates 20.

  If the restraining band 30 is fixed to the pair of end plates 20, the restraining force F can be applied to the plurality of single cells 1 sandwiched between the pair of end plates 20. The restraining force F is a force that sandwiches the plurality of single cells 1 in the X direction.

  A plurality of spacers 40 are disposed at both ends of the battery pack 100 in the Y direction. The spacer 40 is sandwiched between two unit cells 1 in the X direction, or is sandwiched between the unit cells 1 and the end plate 20 in the X direction. The spacer 40 can be formed of resin, for example.

  A restraining force F acts on a portion where the protruding portion 21 of the end plate 20 and the unit cell 1 are in contact with each other. In addition, the restraining force F acts on a portion where the spacer 40 and the unit cell 1 are in contact with each other and a portion where the two unit cells 1 are in contact with each other. In the present embodiment, as shown in FIG. 6, the restraining force F acts only on a partial area (referred to as a restraining area) E <b> 1 of each unit cell 1. As shown in FIG. 6, two constraining areas E <b> 1 are provided on the side surface of the unit cell 1 that forms the YZ plane. A method for determining the constrained area E1 will be described later.

  Next, a method for manufacturing the battery pack 100 will be briefly described with reference to FIG. FIG. 7 is a diagram showing a jig 200 for arranging a plurality of single cells 1 at predetermined positions.

  The jig 200 has a plurality of first stoppers 201 and second stoppers 202. The second stoppers 202 are provided at both ends of the jig 200 in the Y direction and extend in the X direction. The 1st stopper 201 and the 2nd stopper 202 are used in order to position the cell 1 and the spacer 40 in the position shown in FIG. The unit cell 1 and the spacer 40 can be arranged in a space formed between the first stopper 201 and the second stopper 202. By using the first stopper 201 and the second stopper 202, the unit cell 1 and the spacer 40 can be easily positioned.

  After positioning the plurality of single cells 1 and the plurality of spacers 40, the pair of end plates 20 are disposed and the restraining band 30 is fixed to the pair of end plates 20. Further, if a plurality of bus bars 50 are connected to a plurality of single cells 1, the battery pack 100 can be assembled.

  In this embodiment, as shown in FIGS. 5 and 6, one spacer 40 is disposed between two unit cells 1, but this is not a limitation. For example, the spacer 41 shown in FIG. 8 can be used. The spacer 41 has a plurality of protrusions 41a. As shown in FIG. 8, the protrusion 41 a is sandwiched between the two unit cells 1 or between the unit cell 1 and the end plate 20.

  In this embodiment, the cells 1 are arranged not only in the X direction but also in the Y direction, but this is not restrictive. Specifically, the plurality of single cells 1 may be simply arranged in the X direction. Also in this case, the two unit cells 1 adjacent in the X direction are in contact with each other in a part of the restraint region E1. Each unit cell 1 is in contact with the spacer 40.

  Next, the restraining region E1 that gives the restraining force F to the unit cell 1 will be specifically described.

  When the inventor of this application measures the surface pressure at a plurality of locations of the unit cell 1 while performing charging and discharging under different conditions, the surface pressure at both ends of the power generation element 14 in the Y direction increases as the rate during charging and discharging increases. Was found to change significantly. The surface pressure of the unit cell 1 is a pressure when the unit cell 1 (power generation element 14) expands or contracts. If the cell 1 expands, the surface pressure increases, and if the cell 1 contracts, the surface pressure decreases. For example, the surface pressure can be measured by arranging a pressure sensor at a measurement location.

FIG. 9 is a diagram illustrating the positional relationship between the positive electrode plate 141, the negative electrode plate 142, and the separator 143. The reaction region A, the positive electrode active material layer 141b and the negative electrode active material layer 142b is a region overlapping each other across the separator 143, the width of the reaction zone A in the Y direction is W _A. In this embodiment, with respect to the length of the Y-direction, since the positive electrode active material layer 141b is made shortest, the width W _A of the reaction zone A corresponds to the width of the positive electrode active material layer 141b. The restraint area E1 includes a first restraint area E2 and a second restraint area E3.

  10 to 13 show the surface pressure of the unit cell 1 when charging is performed while changing the rate. 10 to 13, the vertical axis represents the surface pressure of the unit cell 1, and the horizontal axis represents the position of the power generation element 14 in the Y direction. One end of the horizontal axis corresponds to one end side of the power generation element 14 in the Y direction, and the other end of the horizontal axis corresponds to the other end side of the power generation element 14 in the Y direction. 10 to 13, the dotted line indicates the surface pressure (surface pressure at 0 second) of the unit cell 1 before starting charging, and the solid line indicates the unit cell 1 after 10 seconds have elapsed after starting charging. The surface pressure is shown.

  FIG. 10 shows changes in surface pressure when charging is performed at a rate of 1C, and FIG. 11 shows changes in surface pressure when charging is performed at a rate of 12C. FIG. 12 shows changes in surface pressure when charging is performed at a rate of 20C, and FIG. 13 shows changes in surface pressure when charging is performed at a rate of 32C. As shown in FIGS. 10 to 13, as the charging rate increases, the surface pressure at both ends of the reaction region A (corresponding to the first constraining region E2) becomes higher than the other regions of the reaction region A. . As can be seen from the surface pressure distribution shown in FIGS. 10 to 13, when the rate during charging is 20 C or more, the variation in surface pressure tends to increase.

  14 to 17 show the surface pressure of the unit cell 1 when discharging is performed while changing the rate. 14 to 17, the vertical axis represents the surface pressure of the unit cell 1, and the horizontal axis represents the position of the power generation element 14 in the Y direction. 14 to 17, the dotted line indicates the surface pressure (surface pressure at 0 second) of the unit cell 1 before starting the discharge, and the solid line indicates the unit pressure after 10 seconds have elapsed from the start of discharge. The surface pressure of the battery 1 is shown.

  FIG. 14 shows changes in surface pressure when discharging is performed at a rate of 1C, and FIG. 15 shows changes in surface pressure when discharging is performed at a rate of 12C. FIG. 16 shows a change in surface pressure when discharging is performed at a rate of 20C, and FIG. 17 shows a change in surface pressure when discharging is performed at a rate of 32C. As shown in FIGS. 14 to 17, the surface pressure at both ends of the reaction region A (corresponding to the first constraining region E2) is lower than the other regions of the reaction region A as the discharge rate increases. ing. As can be seen from the surface pressure distribution shown in FIGS. 14 to 17, when the rate during discharge is 20 C or more, the variation in surface pressure tends to increase.

  In the present embodiment, the two unit cells 1 adjacent in the X direction are shifted in the Y direction, and the partial regions of the unit cells 1 are brought into contact with each other, whereby the constraint region E1 (particularly, the first constraint region E2) is brought into contact. The restraint force F is applied to suppress the deformation (expansion and contraction) of the first restraint region E2 due to charge / discharge. By suppressing the power generation element 14 from being partially deformed, variation in deterioration inside the power generation element 14 can be suppressed.

  The first constrained region E2 can be determined based on the following equation (1).

14 ≦ W _E2 / W _A × 100 ≦ 27 (1)
Here, _{W A} is the width of the reaction zone A (the length of the _{Y-direction), W E2} indicates a width of the first restraining region E2 (length in the Y direction) (see FIG. 9). The width W _E2 is a length based on both ends of the reaction region A.

If determines the width W _A, it is possible to determine the width W _E2 based on the equation (1). The first restraint region E2 specifies a region where the amount of change in the surface pressure is larger than the other regions of the reaction region A.

In the above formula (1), if the relationship between the widths W _A and W _E2 is smaller than the lower limit value (W _E2 / W _A = 14), there is a possibility that the region where the restraining force F is applied becomes insufficient. That is, an insufficient region is generated with respect to suppressing expansion and contraction of the power generation element 14. Further, if the relationship between the widths W _A and W _E2 is larger than the upper limit value (W _E2 / W _A = 27) of the above equation (1), the restraining force F is also given to the region where the change amount of the surface pressure is small. become.

  FIG. 18 is a diagram showing the relationship between the resistance increase rate of the unit cell 1 in this example and the resistance increase rate of the unit cell as a comparative example. The vertical axis in FIG. 18 indicates the resistance increase rate, and the horizontal axis indicates the number of cycles. The resistance increase rate is a value indicating the relationship between the resistance value of the single cell 1 in the initial state (during manufacture) and the resistance value of the single cell 1 after charging and discharging, and is a value indicating the increase rate of the resistance value. It can be seen that the unit cell 1 deteriorates as the resistance increase rate increases. The number of cycles is the number of times charging / discharging for a predetermined time is repeated, and charging / discharging for a predetermined time is performed once in one cycle.

  In the comparative example, the restraint force F is applied to the entire power generation element 14, in other words, the reaction region A and the second restraint region E3 described with reference to FIG. In this embodiment, the restraining force F is applied only to the restraining region E1. The graph shown in FIG. 18 shows the result of repeated charge and discharge at a rate of 25 C under a temperature condition of 25 ° C.

  As shown in FIG. 18, in this embodiment, it is possible to suppress an increase in the resistance increase rate and suppress deterioration of the unit cell 1 as compared with the comparative example.

  The graph shown in FIG. 19 shows the change in the resistance increase rate when the width (the length in the Y direction) of the first constraining region E2 is changed. Similarly to FIG. 18, the vertical axis in FIG. 19 indicates the resistance increase rate, and the horizontal axis indicates the number of cycles. The data shown in FIG. 19 has shown the measurement result when charging / discharging is repeated at the rate 32C.

  A graph G11 shows a change in the resistance increase rate when the restraint force F is applied to the entire power generation element 14 (the reaction region A and the second restraint region E3). Graphs G12 and G13 show changes in the resistance increase rate when the restraining force F is applied to the restraining region E1. In the test of the graph G12, the constraint region E1 (first constraint region E2) is set so as to satisfy the condition of the following equation (2), and in the test of the graph G13, the condition of the following equation (3) is satisfied. A restraint area E1 (first restraint area E2) is set. In the graphs G11 to G13, the sizes of the reaction region A and the second restraint region E2 in the power generation element 14 are the same.

W _E2 / W _A × 100 = 35 (2)
W _E2 / W _A × 100 = 27 (3)

  As shown in FIG. 19, in the graphs G11 and G12, the resistance increase rate increases as the number of cycles increases. On the other hand, in the graph G13, the resistance increase rate does not increase even if the number of cycles increases.

The graph shown in FIG. 20 shows a change in the resistance increase rate of changing the size (in other words, the size of the power generating element 14) of the width W _A. As in FIG. 18, the vertical axis of FIG. 20 indicates the resistance increase rate, and the horizontal axis indicates the number of cycles. The data shown in FIG. 20 has shown the measurement result when charging / discharging is repeated at the rate 32C.

  Graphs G21, G22, and G23 show changes in the resistance increase rate when the restraining force F is applied to the entire power generation element 14 (reaction region A and second restraint region E3). In the test of the graph G21, the power generation element 14 having the reaction area A of the reference size is used. The reference size is the same size as the reaction region A of the power generation element 14 used in the test described in FIG. In the graph G22, the size of the reaction region A is 1.4 times the reference size. In the graph G23, the size of the reaction region A is 1.65 times the reference size.

  Graphs G24, G25, and G26 show changes in the resistance increase rate when the restraining force F is applied to the restraining region E1 under the condition of the following formula (4).

W _E2 / W _A × 100 = 27 (4)

  In the graph G24, the size of the reaction region A is set as a reference size. In the graph G25, the size of the reaction region A is 1.4 times the reference size, and in the graph G26, the size of the reaction region A is 1.65 times the reference size.

  As shown in FIG. 20, in the graphs G21, G22, and G23, the resistance increase rate increases as the number of cycles increases. On the other hand, in the graphs G24, G25, and G26, the resistance increase rate does not change even when the number of cycles increases. Further, in the graphs G24, G25, and G26, even when the size of the reaction region A is different, the change in the resistance increase rate shows the same behavior. As can be seen from the test results shown in FIG. 20, if the ratio of the reaction region A and the first constraining region E2 satisfies a predetermined condition (the above formula (1)), the resistance increase rate can be increased even if the size of the reaction region A changes. The rise can be suppressed.

  As a modification of the present embodiment, a unit cell 1 in which the power generation element 14 is covered with a laminate film can be used. Even in the case of the unit cell 1 using a laminate film, the unit cell 1 can be arranged in the same manner as in this example. Here, the power generation element 14 disposed inside the unit cell 1 is configured by laminating a positive electrode plate 141, a separator 143, and a negative electrode plate 142. The power generation element 14 includes a positive electrode terminal and a negative electrode terminal. Connected. The positive electrode terminal and the negative electrode terminal protrude outside the unit cell 1 in a state of being sandwiched between laminate films.

  In the unit cell 1 using a laminate film, the power generation element 14 has a configuration in which a positive electrode plate 141, a separator 143, and a negative electrode plate 142 are simply laminated. Therefore, in order to suppress changes in surface pressure (expansion and contraction) and to prevent the electrolyte from leaking outside the power generation element 14, it is preferable to apply a restraining force F to the entire outer edge of the power generation element. . The restraining force F acts in the stacking direction of the positive electrode plate 141, the separator 143, and the negative electrode plate 142, and the outer edge of the power generating element 14 is the surface of the power generating element 14 in a plane orthogonal to the direction in which the restraining force F acts. It is an end. The region to which the restraining force F is applied can be determined by the same method as in this embodiment.

100: Battery pack (power storage device) 1: Single battery (power storage element)
DESCRIPTION OF SYMBOLS 10: Battery case 10a: Case main body 10b: Cover 11: Positive electrode terminal 12: Negative electrode terminal 13: Valve 14: Electric power generation element 15a: Positive electrode tab 15b: Negative electrode tab 141: Positive electrode plate 141a: Current collecting plate 141b: Positive electrode active material layer 142 : Negative electrode plate 142a: current collector plate 142b: negative electrode active material layer 143: separator (electrolyte layer)
20: End plate 21: Protruding part 30: Restraint band (connection member) 40: Spacer (pressure member)
50: Bus bar 200: Jig 201: First stopper 202: Second stopper A: Reaction area E1: Restraint area E2: First restraint area E3: Second restraint area

Claims (8)

A plurality of power storage elements that are arranged side by side in a predetermined direction and in an orthogonal direction orthogonal to the predetermined direction and include a reaction region that performs charging and discharging,
From both sides of your Keru said plurality of power storage devices in the predetermined direction, anda restraint mechanism for applying a restraining force in the predetermined direction to said plurality of power storage devices,
The two power storage elements adjacent in the predetermined direction are arranged so as to be shifted in the orthogonal direction in a state where a part of the region including one end of the reaction region overlaps with the predetermined direction ,
The two power storage elements adjacent in the orthogonal direction are arranged with an interval in the orthogonal direction .   The power storage device according to claim 1, wherein the two power storage elements adjacent in the predetermined direction are in contact with each other. The power storage element is configured by winding a laminate in which a positive electrode plate, a negative electrode plate, and an electrolyte layer are laminated around a predetermined axis, and includes a power generation element including the reaction region,
The power storage device according to claim 1, wherein the partial region is a region including an end portion of the reaction region in a direction of the predetermined axis. The width WE2 of the partial region in the direction of the predetermined axis and the width WA of the reaction region in the direction of the predetermined axis have the relationship of the following formula (I):
14 ≦ WE2 / WA × 100 ≦ 27 (I)
The power storage device according to claim 3. The restraint mechanism is
A pair of end plates sandwiching the plurality of power storage elements in the predetermined direction;
A connecting member extending in the predetermined direction and connected to the pair of end plates;
The power storage device according to any one of claims 1 to 4, wherein the power storage device is provided. The end plate has a protrusion that protrudes toward the power storage element on the surface facing the power storage element;
The power storage device according to claim 5, wherein the protrusion is in contact with the power storage element at a position where a binding force is applied to the partial region. With respect to the partial region of the storage element, and have a pressing member to provide the restraining force from the restraining mechanism,
The plurality of power storage elements include the power storage element having the partial region overlapping the pressure member in the predetermined direction,
The pressure member and the power storage element adjacent to the pressure member in the orthogonal direction are arranged at an interval in the orthogonal direction. The power storage device described in 1. The electric storage element, the electric storage device according to any one of claims 1 to 7, characterized in that charging or discharging at a rate greater than 20C is a lithium ion secondary battery is performed.

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