JP2012113935A - Power storage element, and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the variation of contact pressure of a power storage element accompanied with charing/discharging.SOLUTION: A power storage element (10) on which a load (F) is applied from the outside, comprises a generating body (14), a case (13) for storing the generating body, and a pressurizing member (144) applying the load on the generating body. In the generating body, a positive electrode plate (141) including a positive electrode active material layer (141b) and a negative electrode plate (142) including a negative electrode active material layer (142b) are laminated while putting an electrolyte layer (143) therebetween. The generating body has a reaction area (A) which is used for charing/discharging, and in which the positive electrode active material layer and the negative electrode active layer oppose to each other. The pressurizing member is attached to the generating body, and applies a load received form the case, on a partial area (P) including an end portion of the reaction area, of the reaction area.

Description

  The present invention relates to a power storage element having a structure for applying a load to a part of a power generator, and a power storage device including a plurality of the 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, a partition plate made of resin is disposed between two unit cells disposed adjacent to each other.

JP 2008-053019 A JP 2007-073317 A Japanese Patent No. 3321835 Japanese Patent No. 3466663

  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 is considered to have expanded, and when the surface pressure of the unit cell decreases, the unit cell is considered to contract.

  In the conventional assembled battery, as described above, a binding force is applied to the unit cell. However, the partition plate is in contact with the entire side surface of the unit cell, and applies a load to the entire side surface of the unit cell. ing. In this configuration, as described above, only the surface pressure in a part of the unit cell greatly changes.

  The present invention is a power storage element to which a load is applied from the outside, and includes a power generation body, a case that houses the power generation body, and a pressure member that applies a load to the power generation body. In the power generator, a positive electrode plate including a positive electrode active material layer and a negative electrode plate including a negative electrode active material layer are stacked with an electrolyte layer interposed therebetween, and used for charging and discharging, and the positive electrode active material layer and the negative electrode active material layer are mutually connected. Has reaction areas facing each other. The pressurizing member is attached to the power generator, and applies the load received from the case to a part of the reaction region including the end of the reaction region.

  The power generator can be 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. In this case, the partial region to which the load is applied can be a region including both ends of the reaction region in the direction of the predetermined axis.

Further, it is preferable that the width W _P of the partial region in the direction of the predetermined axis, the width W _A of the reaction zone in the direction of a predetermined axis wherein the following formula (I).

14 ≦ W _P / W _A × 100 ≦ 27 (I)

  The pressure member can be disposed between the power generation body and the side surface of the case to which a load is applied. Thereby, this load can be given to an electric power generation body via a pressurization member by giving a load to the side of a case. Here, the pressure member can be arranged so as to surround the power generation body.

  An adhesive tape can be used as the pressure member. Only by sticking the adhesive tape, it is possible to apply a load to only a part of the region of the power generator. By winding the laminate, the end of the laminate can be fixed with an adhesive tape when configuring the power generator.

  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. When charging or discharging is performed at a rate of 20 C or higher, the variation in the surface pressure of the power storage element tends to increase. Therefore, the present invention can be applied to a lithium ion secondary battery in which such charging and discharging are performed.

  By using a plurality of power storage elements of the present invention, a power storage device can be configured. Specifically, a plurality of power storage elements can be arranged in a predetermined direction, and a partition plate can be disposed between two power storage elements adjacent in the predetermined direction. In addition, a restraining mechanism that applies restraining force in a predetermined direction to the plurality of power storage elements can be provided. By using the restraining force of the restraining mechanism, the pressing member can apply a load to a partial region of the power generator.

  Here, the partition plate can give a restraining force to the area | region corresponding to a pressurization member among electrical storage elements. Specifically, the partition plate can be brought into contact with only the region corresponding to the pressure member in the power storage element. Thereby, a load can be given to the one part area | region of an electric power generation body using a partition plate and a pressurization member.

  According to the present invention, by applying a load to a partial region in the reaction region, it is possible to suppress a change in surface pressure in the partial region. Thereby, it is possible to suppress variation in the surface pressure depending on the position in the power storage element.

1 is a top view of a battery stack that is Example 1. FIG. 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 body in Example 1. FIG. 1 is an external view of a power generator in Example 1. FIG. 1 is a front view of a power generator in Example 1. FIG. It is a side view of an electric power generation body when it sees from the direction of arrow D1 of FIG. It is a figure which shows the relationship between the position of an electric power generation body, and the surface pressure of a cell. 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. In Example 1, it is a figure explaining the area | region which winds an adhesive tape. It is a figure which shows the relationship between resistance increase rate and cycle number. It is a figure which shows the relationship of resistance increase rate and cycle number when changing the area | region which gives a load. 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 generator. 6 is an external view of a partition plate and a single battery in Example 2. FIG. 6 is a front view of a power generator in Example 3. FIG. It is a side view of an electric power generation body when it sees from the direction of arrow D2 of FIG. FIG. 6 is a cross-sectional view of a power generator in Example 4. FIG. 25 is a side view of the power generator as viewed from the direction of arrow D3 in FIG. 24. FIG. 25 is a top view of the power generator when viewed from the direction of the arrow D4 in FIG. 24. 10 is a cross-sectional view of a power generator in a modification of Example 4. FIG. FIG. 28 is a top view of the power generator as viewed from the direction of arrow D5 in FIG. 27.

  Examples of the present invention will be described below.

  A battery stack (corresponding to a power storage device) that is Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a top view of the battery stack. In FIG. 1, an X axis and a Y axis are axes orthogonal to each other. In addition, an axis orthogonal to the X axis and the Y axis is a Z axis, and in the present embodiment, the Z axis is an axis corresponding to the vertical direction.

  The battery stack 1 includes a plurality of single cells (corresponding to power storage elements) 10 arranged side by side in the X direction. 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, a plurality of single cells 10 can be used to form a single battery module, and the plurality of battery modules can be arranged in the X direction.

  A partition plate 20 is disposed between two unit cells 10 adjacent in the X direction. The partition plate 20 can be formed of, for example, resin, and the surface that contacts the unit cell 10 is formed as a flat surface. A pair of end plates (a part of the restraining mechanism) 31 are arranged at both ends of the battery stack 1 in the X direction. The end plate 31 can be formed of resin, for example. Both ends of a restraining band (part of the restraining mechanism) 32 extending in the X direction are fixed to the pair of end plates 31.

  In the present embodiment, two restraining bands 32 are disposed on the upper surface of the battery stack 1, and two restraining bands 32 are disposed on the lower surface of the battery stack 1. If the restraining band 32 is fixed to the pair of end plates 31, the restraining force F can be applied to the unit cell 10 and the partition plate 20 sandwiched between the pair of end plates 31. The restraining force F is a force that sandwiches the unit cell 10 and the partition plate 20 in the X direction.

  The plurality of single cells 10 are electrically connected in series by a bus bar 40. Specifically, in two unit cells 10 adjacent in the X direction, the positive terminal 11 of one unit cell 10 and the negative terminal 12 of the other unit cell 10 are electrically connected by a bus bar 40. . Here, the number of unit cells 10 constituting the battery stack 1 can be appropriately set based on the required output of the battery stack 1 and the like.

  The battery stack 1 can constitute a battery pack by being housed in a case. The battery pack can be mounted on a vehicle, for example. If the electric energy output from the battery pack is converted into kinetic energy by a 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, this electric energy can be stored in the battery pack.

  Next, the configuration of the unit cell 10 will be specifically described.

  As shown in FIG. 2, the positive electrode terminal 11 and the negative electrode terminal 12 are disposed on the upper surface of the battery case 13. The battery case 13 can be formed of metal, for example. In this case, the positive electrode terminal 11 and the negative electrode terminal 12 need to be electrically insulated.

  A safety valve 13 a is provided on the upper surface of the battery case 13. The safety valve 13 a is disposed between the positive terminal 11 and the negative terminal 12. The safety valve 13 a is used for discharging gas generated inside the battery case 13 to the outside of the battery case 13. Specifically, when the internal pressure of the battery case 13 rises to a predetermined value (the operating pressure of the safety valve 13a) with the generation of gas, the safety valve 13a changes from the closed state to the open state, so that the outside of the battery case 13 Let the gas out.

  As shown in FIG. 3, the battery case 13 houses a power generator 14. One end of the power generation body 14 in the Y direction is connected to the positive electrode tab 15 a, and the positive electrode tab 15 a is also connected to the positive electrode terminal 11. The positive electrode tab 15a can be connected to the power generation body 14 and the positive electrode terminal 11 by welding or the like. The other end of the power generator 14 in the Y direction is connected to the negative electrode tab 15 b, and the negative electrode tab 15 b is also connected to the negative electrode terminal 12. The negative electrode tab 15b can be connected to the power generation body 14 and the negative electrode terminal 12 by welding or the like.

  As shown in FIG. 4, the power generation body 14 includes a positive electrode plate 141, a negative electrode plate 142, and a separator (corresponding to an electrolyte layer) 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 contains 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 there is a region where 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 there is a region where the current collector plate 142a is exposed. Separator 143 contains an electrolytic solution.

  The positive electrode plate 141, the negative electrode plate 142, and the separator 143 are stacked in the order shown in FIG. 4, and the stacked body is wound in the direction indicated by the arrow R in FIG. In FIG. 5, only the current collector plate 141 a of the positive electrode plate 141 is wound at one end portion of the power generator 14 in the Y direction. As described with reference to FIG. 3, the positive electrode tab 15a is fixed to the current collecting plate 141a. Only the current collecting plate 142a of the negative electrode plate 142 is wound at the other end of the power generation body 14 in the Y direction, and the negative electrode tab 15b is fixed to the current collecting plate 142a.

  E shown in FIG. 5 is an end portion of the laminated body when the above-described laminated body is wound. The position of the end E can be set as appropriate depending on how the laminate is wound. Here, although the binding force F acts on the power generation body 14, if there is an end E as a step in the region of the power generation body 14 to which the load from the partition plate 20 is applied, the load applied to the power generation body 14 is not at the end. The portion E changes as a boundary. If the end portion E is disposed at a position facing the upper surface or the bottom surface of the battery case 13, it is possible to suppress the load from the partition plate 20 from being applied to the end portion E, and the load applied to the power generation body 14 changes with the end portion E as a boundary. Can be prevented. In addition, if the position of the end E does not adversely affect the input / output characteristics of the power generation body 14, the position of the end E can be set as appropriate.

  In this embodiment, as shown in FIGS. 6 and 7, an adhesive tape (corresponding to a pressure member) 144 is wound around the power generation body 14. FIG. 7 is a view when the power generation body 14 is viewed from the direction of the arrow D1 in FIG. As the adhesive tape 144, for example, a film (base material) formed of polypropylene and an acrylic adhesive can be used. The adhesive tape 144 is used to fix the end E of the laminate.

  In this embodiment, as shown in FIG. 7, the both ends 144 a of the adhesive tape 144 are in contact with each other, and the adhesive tape 144 is wound so as to make a round around the outer surface of the power generator 14. The adhesive tape 144 has a thickness T, and a layer of the adhesive tape 144 having a thickness T is formed on the outer periphery of the power generation body 14.

  The adhesive tape 144 of the present embodiment is used not only for fixing the end E of the laminated body of the power generation body 14 but also for applying a load only to a partial region of the power generation body 14. Since the binding force F is applied to the unit cell 10, when the adhesive tape 144 is wound around the power generator 14, the load acting on the area where the adhesive tape 144 is wound is the load acting on the area where the adhesive tape 144 is not wound. Higher than. That is, the load can be increased by an amount corresponding to the thickness T of the adhesive tape 144. By making the load in the area around which the adhesive tape 144 is wound higher than the load in other areas, it is possible to suppress variations in the surface pressure of the unit cell 10 as described below.

  When the inventor of this application measures the surface pressure at a plurality of locations of the unit cell 10 (battery case 13) while performing charging and discharging under different rates, the power generator 14 in the Y direction increases as the rate during charging and discharging increases. It was found that the surface pressure at both ends of the plate changed greatly. The surface pressure of the unit cell 10 is a pressure at which the unit cell 10 expands or contracts in the X direction. If the cell 10 expands, the surface pressure increases, and if the cell 10 contracts, the surface pressure decreases. For example, the surface pressure can be measured by arranging a pressure sensor at a measurement location.

FIG. 8 is a diagram illustrating the relationship between the position of the power generation body 14 and the amount of change in surface pressure. A region A (corresponding to a reaction region) A shown in FIG. 8 is a region where the positive electrode plate 141 (positive electrode active material layer 141b), the separator 143, and the negative electrode plate 142 (negative electrode active material layer 142b) overlap each other. 10 is a region used for charging and discharging. In this embodiment, as shown in FIG. 8, 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 area A, corresponding to the width of the positive electrode active material layer 141b ing.

  9 to 12 show the surface pressure of the unit cell 10 when charging is performed while changing the rate. 9 to 12, the vertical axis indicates the surface pressure of the unit cell 10, and the horizontal axis indicates the position of the power generator 14 in the Y direction. 9 to 12, a dotted line indicates a surface pressure before starting charging (surface pressure at 0 second), and a solid line indicates a surface pressure after 10 seconds from starting charging.

  FIG. 9 shows changes in surface pressure when charging is performed at a rate of 1C, and FIG. 10 shows changes in surface pressure when charging is performed at a rate of 12C. Further, FIG. 11 shows a change in surface pressure when charging is performed at 20C, and FIG. 12 shows a change in surface pressure when charging is performed at 32C. As shown in FIGS. 9 to 12, the surface pressure at both ends of region A becomes higher than the other regions in region A as the rate during charging increases. When the rate at the time of charging is 20C or more, the variation in surface pressure tends to increase.

  FIG. 13 to FIG. 16 show the surface pressure of the unit cell 10 when discharging is performed while changing the rate. 13 to 16, the vertical axis represents the surface pressure of the unit cell 10, and the horizontal axis represents the position of the power generator 14 in the Y direction. 13 to 16, the dotted line indicates the surface pressure before starting the discharge (surface pressure at 0 second), and the solid line indicates the surface pressure after 10 seconds from the start of discharge.

  FIG. 13 shows the change in surface pressure when discharging at a rate of 1C, and FIG. 14 shows the change in surface pressure when discharging at a rate of 12C. FIG. 15 shows a change in surface pressure when discharging is performed at a rate of 20C, and FIG. 16 shows a change in surface pressure when discharging is performed at a rate of 32C. As shown in FIGS. 13 to 16, the surface pressure at both ends of the region A is lower than the other regions in the region A as the discharge rate increases. When the discharge rate is 20C or more, the variation in surface pressure tends to increase.

  In this embodiment, by using the adhesive tape 144, changes in the surface pressure generated at both ends of the region A are suppressed. That is, by applying a restraining force F to both ends of the region A, the deformation and expansion (contraction or contraction) of both ends of the region A due to charge / discharge are suppressed. By suppressing the power generation body 14 from being easily deformed, variation in deterioration within the power generation body 14 can be suppressed.

Here, the area | region which gives a load to the electric power generation body 14 is demonstrated using FIG. The area to which the load is applied is determined by the position where the adhesive tape 144 is wound and the width of the adhesive tape 144. In FIG. 17, W _A indicates the width of the region A (the length in the Y direction). Further, W _P indicates a width of a region P giving the load (length in the Y direction), the width W _P, the length relative to the ends of the region A. Width _{W A} and width _{W P} preferably satisfies the following equation (1).

14 ≦ W _P / W _A × 100 ≦ 27 (1)

If determines the width W _A, it is possible to identify the width W _P based on the equation (1). Region P of the width W _P is one in which the amount of change in surface pressure identifying a region larger than the other regions. If the area | region P which gives a load can be specified, the width | variety of the adhesive tape 144 and the position which sticks the adhesive tape 144 can be specified. And if a load is given with respect to the area | region P, it can suppress that the surface pressure of only a part of electric power generation body 14 changes a lot.

  Here, the load can be applied not only to the region P but also to at least one of the regions H1 and H2 (see FIG. 17) located outside the region A in the power generation body 14. The region H1 is a region where the current collecting plate 141a of the positive electrode plate 141 is wound, and the region H2 is a region where the current collecting plate 142a of the negative electrode plate 142 is wound.

In the above formula (1), the width W _A, the lower limit value relationship W _P (14) is smaller than, the region giving the load may be insufficient. The width W _A, the relationship between W _P, the upper limit of the above formula (1) (27) greater than, also will give a load to the area change amount of the surface pressure is small.

  In FIG. 18, the rate of increase in resistance when the load is applied to the entire surface of the power generation body 14 (overall constraint), and the load is applied to a part (region P) of the power generation body 14 as in this embodiment. It shows the resistance increase rate (both ends restraint) when given. The resistance increase rate is a value indicating the relationship between the resistance value of the single cell 10 in the initial state and the resistance value of the single cell 10 after charging and discharging, and is a value indicating the increase rate of the resistance value. It can be seen that the unit cell 10 deteriorates as the resistance increase rate increases. 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. The number of cycles shown on the horizontal axis in FIG. 18 is the number of times when charging / discharging for a predetermined time is one cycle.

  As shown in FIG. 18, in this embodiment (both ends restraint), an increase in the resistance increase rate can be suppressed and deterioration of the unit cell 10 can be restrained compared to the conventional case (overall restraint).

  The graph shown in FIG. 19 shows the change in the resistance increase rate when the width of the region to which the load is applied (the length in the Y direction) is changed. 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.

  The graph G11 shows a change in the resistance increase rate when a load is applied to the entire power generation body 14, in other words, a change in the resistance increase rate when the adhesive tape 144 is omitted. Graph G12 shows a change in resistance increase rate when a load is applied to a part of region A using adhesive tape 144. In the test of the graph G12, a load is applied to the power generation body 14 under the condition of the following formula (2).

W _P / W _A × 100 = 35 (2)

  Graph G13 shows a change in resistance increase rate when a load is applied to a part of region A using adhesive tape 144. In the test of the graph G13, a load is applied to the power generation body 14 under the condition of the following formula (3).

W _P / W _A × 100 = 20 (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 body 14) of the width W _A. The vertical axis in 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 a load is applied to the entire power generator 14, in other words, changes in the resistance increase rate when the adhesive tape 144 is omitted. In the test of the graph G21, the power generation body 14 having the reference size region A is used. The reference size is the same size as the region A of the power generation body 14 used in the test described in FIG. In the graph G22, the size of the region A is 1.4 times the reference size. In the graph G23, the size of the region A is 1.65 times the reference size.

  Graphs G24, G25, and G26 indicate changes in the resistance increase rate when the binding force F is applied to a part of the region A using the adhesive tape 144 under the condition of the following formula (4).

W _P / W _A × 100 = 20 (4)

  In the graph G24, the size of the area A is set as a reference size. In the graph G25, the size of the region A is 1.4 times the reference size, and in the graph G26, the size of the 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. Further, the timing at which the resistance increase rate increases as the size of the region A increases. In other words, as the size of the region A increases, the number of cycles until the predetermined resistance increase rate is increased.

  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. Even if the sizes of the regions A are different, the change in the resistance increasing rate shows the same behavior. As can be seen from the test results shown in FIG. 20, if the ratio between the area A and the area P to which the load is applied satisfies a predetermined condition (the above formula (1)), the resistance increase rate increases even if the size of the area A changes. Can be suppressed.

  The load applied to the region P of the power generation body 14 can be set based on the thickness T of the adhesive tape 144. When using the adhesive tape 144 with a large thickness T, as shown in FIG. 7, the adhesive tape 144 may be simply wound around the outer surface of the power generator 14. Moreover, when using the adhesive tape 144 with a small thickness T, a desired load can be generated by overlapping and winding the adhesive tape 144.

  In the present embodiment, as shown in FIG. 7, both end portions 144a of the adhesive tape 144 are brought into contact with each other, but this is not restrictive. That is, the area | region of the both ends side of the adhesive tape 144 may mutually overlap. In this case, the region where the adhesive tape 144 overlaps is preferably at a position facing the upper surface or the lower surface of the battery case 13.

  Moreover, although the adhesive tape 144 is used in the present Example, it is not restricted to this. For example, a tape that does not have adhesiveness can be used. In this case, after winding the tape around the power generation body 14, both ends of the tape can be fixed with an adhesive or the like. Even with such a configuration, the end E of the stacked body of the power generation body 14 can be fixed and a load can be applied to the region P of the power generation body 14. In addition, a ring-shaped elastic body can be prepared, and this elastic body can be disposed in the region P of the power generation body 14. It is preferable to fix the elastic body to the region P so that the elastic body does not deviate from the region P. As the elastic material, for example, EPDM (ethylene-propylene-diene rubber) can be used. Even if a ring-shaped elastic body is used, the same effect as in the present embodiment can be obtained.

  A battery stack that is Embodiment 2 of the present invention will be described. Here, the same reference numerals are used for members having the same functions as those described in the first embodiment. In Example 1, the surface of the partition plate 20 facing the unit cell 10 is configured as a flat surface, but in this example, the surface of the partition plate 20 facing the unit cell 10 is configured as an uneven surface. Yes. Hereinafter, differences from the first embodiment will be mainly described.

  FIG. 21 is a diagram showing the partition plate 20 in the present embodiment. The partition plate 20 has a first region 21 and a second region 22 on one surface facing the unit cell 10. The other surface of the partition plate 20 is a flat surface. The first region 21 protrudes in the X direction from the second region 22 and comes into contact with the unit cell 10. Further, when the first region 21 is in contact with the unit cell 10, the second region 22 is separated from the unit cell 10.

  The first region 21 contacts the region of the battery case 13 corresponding to the region P of the power generator 14. That is, when the first region 21 is in contact with the battery case 13, the load from the first region 21 acts on the region P of the power generation body 14 via the battery case 13. If the power generation body 14 is positioned inside the battery case 13, a load can be applied only to the region P of the power generation body 14 even from the outside of the battery case 13.

  Since the second region 22 is separated from the unit cell 10, a space is formed between the second region 22 and the unit cell 10. This space can be used as a movement path of a heat exchange medium used for temperature adjustment of the unit cell 10. For example, air can be used as the heat exchange medium. When the cell 10 is generating heat, the temperature increase of the cell 10 can be suppressed by bringing the cooling heat exchange medium into contact with the cell 10. Further, when the unit cell 10 is excessively cooled, the unit cell 10 can be warmed by bringing the heating heat exchange medium into contact with the unit cell 10. Thus, by adjusting the temperature of the cell 10, it is possible to suppress the deterioration of the input / output characteristics of the cell 10.

  According to the present embodiment, a load can be applied to the region P of the power generation body 14 by using the adhesive tape 144 and the partition plate 20 (first region 21). Thereby, the same effect as Example 1 can be acquired.

  In the present embodiment, only the first region 21 of the partition plate 20 is brought into contact with the unit cell 10, but this is not restrictive. Specifically, the first region 21 and the second region 22 can be brought into contact with the unit cell 10. Here, since the first region 21 protrudes in the X direction from the second region 22, the load received from the first region 21 is larger than the load received from the second region 22. Thereby, it is possible to apply a larger load to the region P of the power generation body 14 than other regions.

  In this embodiment, one partition plate 20 is used to apply a load to the two regions P of the power generation body 14, but this is not a limitation. For example, two partition plates are prepared and a load is applied to one region P of the power generation body 14 using one partition plate, and a load is applied to the other region P of the power generation body 14 using the other partition plate. Can be given.

  In the present embodiment, the first region 21 of the partition plate 20 is configured with a flat surface, and the entire surface of the first region 21 is in contact with the battery case 13, but is not limited thereto. For example, in the first region 21 of the partition plate 20, a plurality of ribs can be formed, or protrusions such as a columnar shape can be formed. In this case, a part of the first region 21 contacts the battery case 13. The plurality of ribs can be arranged side by side in the Y direction or the Z direction. Even in a configuration in which a part of the first region 21 is in contact with the battery case 13, a load can be applied to the region P of the power generation body 14.

  A battery stack that is Embodiment 3 of the present invention will be described. Here, the same reference numerals are used for members having the same functions as those described in the first embodiment. In Example 1 (see FIG. 7), the adhesive tape 144 is wound so as to surround the power generation body 14, but in this example, the adhesive tape 144 is attached only to a part of the power generation body 14. Hereinafter, differences from the first embodiment will be mainly described.

  22 is a diagram when the power generation body 14 of the present embodiment is viewed from the X direction, and FIG. 23 is a diagram when the power generation body 14 is viewed from the direction of the arrow D2 in FIG. In this embodiment, the adhesive tape 144 is attached to the surface of the power generator 14 that faces the side surface of the battery case 13. The side surface of the battery case 13 is a side surface orthogonal to the X direction and is a surface in contact with the partition plate 20.

  The adhesive tape 144 fixes the end E of the laminated body of the power generator 14. The adhesive tape 144 is affixed to the region P of the power generator 14. The definition of the region P is the same as that in the first embodiment. If the thickness T of the adhesive tape 144 has a desired thickness, only one adhesive tape 144 needs to be attached to the power generator 14. Further, if the thickness T of the adhesive tape 144 is thinner than a desired thickness, a plurality of adhesive tapes 144 can be stacked and pasted. Here, the desired thickness is a thickness that can apply a load to the region P of the power generation body 14.

  In this embodiment, as shown in FIG. 23, the adhesive tape 144 is affixed to both side surfaces of the power generation body 14 in the X direction, but this is not restrictive. Specifically, the adhesive tape 144 can be attached to only one surface (the surface on which the end portion E is located) of both side surfaces of the power generation body 14 in the X direction. The end E can be fixed and a load can be applied only to the region P of the power generator 14 by simply attaching the adhesive tape 144 to one surface of the power generator 14.

  In the present embodiment, all of the surface of the adhesive tape 144 that comes into contact with the power generation body 14 has adhesiveness, but is not limited thereto. For example, even when a non-adhesive tape is used, the same effects as in the present embodiment can be obtained only by fixing both end portions in the longitudinal direction of the tape to the power generator 14. For example, an adhesive may be used to fix the power generation body 14 to the non-adhesive tape.

  A battery stack that is Embodiment 4 of the present invention will be described. Here, the same reference numerals are used for members having the same functions as those described in the first embodiment. In Examples 1 to 3, the power generation body 14 is configured by winding a laminate of the positive electrode plate 141, the negative electrode plate 142, and the separator 143. On the other hand, in the present embodiment, the power generator 14 uses a configuration in which the positive electrode plate 141, the separator 143, and the negative electrode plate 142 are simply stacked. Hereinafter, differences from the first to third embodiments will be mainly described.

  FIG. 24 is a cross-sectional view of the power generation body 14 in the present embodiment. 25 is a side view of the power generation body 14 when viewed from the direction of the arrow D3 in FIG. 24, and FIG. 26 is a top view of the power generation body 14 when viewed from the direction of the arrow D4 in FIG. The power generation body 14 of the present embodiment can be covered with a case made of, for example, a laminate film.

  The power generator 14 includes a plurality of bipolar electrodes 145 and separators 143. The plurality of bipolar electrodes 145 are stacked with the separator 143 interposed therebetween. The bipolar electrode 145 includes a current collector plate 145a, a positive electrode active material layer 145b formed on one surface of the current collector plate 145a, and a negative electrode active material layer 145c formed on the other surface of the current collector plate 145a. . A positive electrode tab 146 a is provided on the upper surface of the power generation body 14, and a negative electrode tab 146 b is provided on the lower surface of the power generation body 14. Note that a solid electrolyte (corresponding to an electrolyte layer) can be used instead of the separator 143 containing an electrolytic solution.

  As shown in FIG. 25, an adhesive tape 144 is wound around the outer surface of the power generation body 14. Specifically, the adhesive tape 144 is wound around the end of the power generation body 14 on the side where the positive electrode tab 146a and the negative electrode tab 146b are drawn. The position where the adhesive tape 144 is wound is the same as that described in the first embodiment. In this embodiment, a plurality of bipolar electrodes 145 are stacked, and the stacked region corresponds to the region A described in the first embodiment. And the position where the adhesive tape 144 is wound can be specified with the region A as a reference.

  According to the present embodiment, if a force for sandwiching the power generation body 14 is applied in the stacking direction of the power generation bodies 14, the load on the power generation body 14 where the adhesive tape 144 is wound is larger than the other portions. Can be given. Thereby, similarly to Example 1, the variation in the surface pressure of the power generation body 14 can be suppressed.

  On the other hand, a load can be applied to the region K1 surrounded by the dotted line in FIG. That is, the adhesive tape 144 can be attached to the region K1. As a result, even when a load is applied to the power generation body 14, it is possible to prevent the electrolyte present in the power generation body 14 from leaking outside the power generation body 14. Based on the viewpoint of preventing leakage of the electrolyte, the position and size of the region K1 can be set as appropriate.

  27 and 28 show a power generation body 14 that is a modification of the present embodiment. 27 is a cross-sectional view of the power generation body 14, and FIG. 28 is a top view of the power generation body 14 when viewed from the direction of the arrow D5 in FIG. In this modification, the direction in which the positive electrode tab 146a and the negative electrode tab 146b are pulled out is changed as compared with the present embodiment. Specifically, in this modification, the positive electrode tab 146a and the negative electrode tab 146b are pulled out in the same direction.

  The adhesive tape 144 is wound around the end of the power generation body 14 on the side from which the positive electrode tab 146a and the negative electrode tab 146b are drawn. The position where the adhesive tape 144 is wound is the same as in this embodiment. On the other hand, in order to prevent the electrolyte from leaking outside the power generation body 14, a load can be applied to the region K2 surrounded by the dotted line in FIG. That is, the adhesive tape 144 can be affixed also to the area K2. The position and size of the region K2 can be set as appropriate.

  Also in the present embodiment, the method of attaching the adhesive tape 144 can be appropriately set as described in the first embodiment. Further, as described in the first embodiment, a tape that does not have adhesiveness can be used, or a ring-shaped elastic body can be used.

1: Battery stack (power storage device) 10: Single battery (power storage element)
11: positive electrode terminal 12: negative electrode terminal 13: battery case 13a: safety valve 14: power generator 141: positive electrode plate 141a: current collector plate 141b: positive electrode active material layer 142: negative electrode plate 142a: current collector plate 142b: negative electrode active material layer 143 : Separator 144: Adhesive tape (pressure member) 145: Bipolar electrode 145a: Current collector 145b: Positive electrode active material layer 145c: Negative electrode active material layer 146a: Positive electrode tab 146b: Negative electrode tab 15a: Positive electrode tab 15b: Negative electrode tab 20: Partition plate 31: End plate (part of restraint mechanism) 32: Restraint band (part of restraint mechanism)
40: Bus bar

Claims (10)

A storage element to which a load is applied from the outside,
A positive electrode plate including a positive electrode active material layer and a negative electrode plate including a negative electrode active material layer are stacked with an electrolyte layer interposed therebetween, and is used for charging and discharging, and the positive electrode active material layer and the negative electrode active material layer face each other. A power generator having a region;
A case for housing the power generator;
A pressure member that is attached to the power generation body and that applies the load received from the case to a part of the reaction region including an end of the reaction region;
A power storage element comprising: The power generator is configured by winding a laminate in which the positive electrode plate, the negative electrode plate, and the electrolyte layer are laminated around a predetermined axis,
The power storage element according to claim 1, wherein the partial region is a region including both ends of the reaction region in a direction of the predetermined axis. Wherein a width W _P of the partial region in the direction of the predetermined axis, the width W _A of the reaction region in the direction of the predetermined axis wherein the following formula (I), the
14 ≦ W _P / W _A × 100 ≦ 27 (I)
The electrical storage element according to claim 2, wherein   The power storage element according to any one of claims 1 to 3, wherein the pressure member is disposed between the power generation body and a side surface of the case to which the load is applied.   The power storage element according to claim 1, wherein the pressurizing member surrounds the power generator.   The power storage element according to claim 1, wherein the pressure member is an adhesive tape.   The power storage element according to claim 2, wherein the pressure member is an adhesive tape that fixes an end of the laminate.   The power storage element according to any one of claims 1 to 7, wherein the power storage element is a lithium ion secondary battery that is charged or discharged at a rate of 20 C or more. The electricity storage device according to any one of claims 1 to 8,
A restraining mechanism for imparting a restraining force in the predetermined direction to the plurality of power storage elements arranged side by side in a predetermined direction;
A partition plate disposed between the two power storage elements adjacent in the predetermined direction;
A power storage device comprising: The power storage device according to claim 9, wherein the partition plate applies the binding force to a region corresponding to the pressure member in the power storage element.

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