Battery cell stack fixing structure and battery cell stack fixing system

Abstract

To obtain a battery cell stack fixing structure and a battery cell stack fixing system that can change the distance between a pair of support members that support stacked battery cells. [Solution] The battery cell stack fixing structure comprises a case 22 fixed to the vehicle body and a battery cell stack 14 having a plurality of battery cells 12 stacked along the stacking direction. The battery cell stack fixing structure also comprises a pair of support members 16 that are positioned on both sides of the battery cell stack 14 in the stacking direction and engage with the case 22, supporting the battery cell stack 14. Furthermore, the battery cell stack fixing structure comprises a movable structure 26 that supports one of the support members 16 by sandwiching it between itself and the case 22, and slides with the other support member 16, thereby allowing displacement of one support member 16 in the stacking direction relative to the other support member 16.

Description

Technical Field

[0001] The present invention relates to a battery cell laminate fixing structure and a battery cell laminate fixing system.

Background Art

[0002] Patent Document 1 below discloses a battery module that realizes suppression of stress concentration at the fixing portion between the battery module and the support member even when the laminate type cell expands. The battery module described in this document includes a plurality of laminate type cells laminated in the horizontal direction, an intermediate plate provided at an intermediate portion in the stacking direction of the plurality of laminate type cells, and a pair of end plates provided at both end portions in the stacking direction of the plurality of laminate type cells. Further, the battery module includes a pair of restraining members that face each other in a first direction orthogonal to the stacking direction and are connected to the pair of end plates to restrain the plurality of laminate type cells. Each laminate type cell has an electrode tab that extends in a second direction orthogonal to the stacking direction and the first direction. Further, outside the plurality of laminate type cells in the second direction, a cover plate that extends in the stacking direction and covers the electrode tab is provided. This cover plate is connected to at least one of the intermediate plate and the pair of end plates, and the cover plate is provided with fixing portions for fixing the battery module to the support member on one end side and the other end side in the stacking direction rather than the intermediate plate. Thus, in the configuration in which the cover plate is provided outside the plurality of laminate type cells in the second direction orthogonal to the stacking direction, by providing the fixing portion on the cover plate, it is possible to suppress stress concentration due to cell expansion at the fixing portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] Incidentally, from the standpoint of reducing the load associated with the expansion of battery cells such as laminated cells, it is desirable to be able to change the distance between a pair of support members, such as a pair of end plates that support the stacked battery cells, but the configuration described in Patent Document 1 above does not take this into consideration.

[0005] In consideration of the above facts, the present invention aims to provide a battery cell stack fixing structure and a battery cell stack fixing system that can change the distance between a pair of support members that support stacked battery cells. [Means for solving the problem]

[0006] The battery cell stack fixing structure of the first embodiment comprises: a fixing member fixed to the vehicle body; a battery cell stack having a plurality of battery cells stacked along the stacking direction; a pair of support members respectively arranged on both sides of the battery cell stack in the stacking direction and engaged with the fixing member to support the battery cell stack; and a movable structure that supports one of the support members by sandwiching it between itself and the fixing member, and slides with the other support member, thereby allowing displacement of one of the support members in the stacking direction relative to the other support member.

[0007] In the battery cell stack fixing structure of the first embodiment, a pair of support members are engaged with a fixing member. A battery cell stack having multiple battery cells is supported by the pair of support members. Here, the movable structure supports one of the support members by sandwiching it between itself and the fixing member. The movable structure slides with one of the support members, allowing displacement of one support member relative to the other support member in the stacking direction. This makes it possible to change the distance between the pair of support members when a dimensional change occurs in the stacking direction of the battery cell stack.

[0008] A battery cell stack fixing system according to a second embodiment comprises: a fixing member fixed to a vehicle body; a battery cell stack having a plurality of battery cells stacked along the stacking direction; a pair of support members respectively arranged on both sides of the battery cell stack in the stacking direction and engaged with the fixing member, supporting the battery cell stack; an operating unit connected to one of the support members, which, when actuated, displaces one of the support members in the stacking direction relative to the fixing member; and a control unit that operates the operating unit according to the amount of change in the dimensions of the battery cell stack in the stacking direction.

[0009] In the second embodiment of the battery cell stack fixing system, a pair of support members engage with a fixing member. A battery cell stack having multiple battery cells is supported by the pair of support members. Here, the control unit operates an actuation unit in response to a dimensional change in the stacking direction of the battery cell stack. As a result, the actuation unit displaces one of the support members in the stacking direction relative to the fixing member. In this way, in the second embodiment of the battery cell stack fixing system, the distance between the pair of support members can be changed when a dimensional change occurs in the stacking direction of the battery cell stack. [Effects of the Invention]

[0010] The battery cell stack fixing structure and battery cell stack fixing system according to the present invention have the excellent effect of being able to change the distance between a pair of support members that support stacked battery cells. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic plan view showing the battery module of the first embodiment. [Figure 2] This is a schematic side view showing the battery module of the first embodiment. [Figure 3] This is a schematic front view showing the battery module of the first embodiment. [Figure 4] This is a schematic side view showing the battery module of the second embodiment. [Figure 5]This is a block diagram of a battery cell stack fixing system. [Figure 6] This is a flowchart to explain control by the battery ECU. [Modes for carrying out the invention]

[0012] (First Embodiment) A battery module 10 to which the battery cell stack fixing structure according to the first embodiment of the present invention is applied will be described with reference to Figures 1 to 3. Arrows FR shown as appropriate in each figure indicate the front side of the vehicle, arrows UP indicate the upper side of the vehicle, arrows LH indicate the left side in the vehicle width direction (left-right direction), and arrows RH indicate the right side in the vehicle width direction (left-right direction). Furthermore, in the following description, unless otherwise specified, when the front / rear, up / down, and left / right directions are indicated, they refer to the front / rear in the vehicle's front-rear direction, the up / down in the vehicle's up-down direction, and the left / right in the vehicle's left-right direction.

[0013] As shown in Figures 1 and 2, the battery module 10 of this embodiment comprises a battery cell stack 14 having a plurality of battery cells 12, and a pair of support members 16 that support the battery cell stack 14 on both sides in the front-rear direction relative to the battery cell stack 14. In the following description, the support member 16 positioned on the rear side relative to the battery cell stack 14 may be referred to as the first support member 18, and the support member 16 positioned on the front side relative to the battery cell stack 14 may be referred to as the second support member 20.

[0014] The battery cell 12 is, for example, an all-solid-state battery formed in the shape of a rectangular block. Multiple battery cells 12 are stacked along the front-to-back direction, which is the stacking direction, and are connected in a defined manner to form a battery cell stack 14. In this embodiment, two battery cell stacks 14 are arranged side by side in the left-to-right direction.

[0015] The first support member 18 is formed using a metal material as an example, and includes a support plate portion 18A formed in a rectangular plate shape extending along the vertical and horizontal directions with the front-rear direction as the thickness direction, and a fixing plate portion 18B extending rearward from the lower end portion of the support plate portion 18A. The rear portion of the battery cell laminate 14 is fixed to the support plate portion 18A. The fixing plate portion 18B is disposed along the upper surface of a case 22 as a fixing member disposed below the battery module 10. Further, the fixing plate portion 18B is fixed to the case 22 by screwing a plurality of bolts 24 inserted into the fixing plate portion 18B from above into the case 22. Note that the case 22 is fixed to a vehicle body not shown in the drawings.

[0016] The second support member 20 is formed using a metal material as an example, and includes a support plate portion 20A formed in a rectangular plate shape extending along the vertical and horizontal directions with the front-rear direction as the thickness direction, and a pair of engagement plate portions 20B extending forward from the lower end portion of the support plate portion 20A. The front portion of the battery cell laminate 14 is fixed to the support plate portion 20A. The pair of engagement plate portions 20B are arranged at intervals in the left-right direction and are disposed along the upper surface of the case 22. Further, the pair of engagement plate portions 20B are supported by the case 22 via a movable structure portion 26 described later.

[0017] As shown in FIGS. 1, 2, and 3, the movable structure portion 26 is for supporting the second support member 20 so as to be movable along the front-rear direction. The movable structure portion 26 includes a pressing bracket 28, two resin plates 30, three spacers 32, and three bolts 24.

[0018] The pressing bracket 28 is formed in a rectangular plate shape with the vertical direction as the thickness direction using the same metal material as the support member 16. In the present embodiment, the shape of the pressing bracket 28 when viewed from above is a rectangular shape with the left-right direction as the longitudinal direction.

[0019] The two resin plates 30 are each formed of a resin material having a lower sliding resistance than the sliding resistance between metal materials. These two resin plates 30 are each formed in a rectangular plate shape extending in the front-back direction and the left-right direction with the up-down direction as the thickness direction.

[0020] The shape of one of the resin plates 30 when viewed from the up-down direction is formed in a rectangular shape with the left-right direction as the longitudinal direction. Also, one of the resin plates 30 is disposed along the lower surface of the pressing bracket 28.

[0021] The shape of the other resin plate 30 when viewed from the up-down direction is formed in a rectangular shape with the left-right direction as the longitudinal direction. Also, the other resin plate 30 is disposed along the upper surface of the case 22.

[0022] The three spacers 32 are each formed in a rectangular block shape.

[0023] The first spacer 32 is disposed between the central portion in the left-right direction of the pressing bracket 28 and the case 22 and between the central portions in the left-right direction of the two resin plates 30. Also, the first spacer 32 is disposed between the pair of engaging plate portions 20B of the second support member 20.

[0024] The second spacer 32 is disposed between the left end portion of the pressing bracket 28 and the case 22 and between the left end portions of the two resin plates 30. Also, the second spacer 32 is disposed on the left side with respect to the left engaging plate portion 20B of the second support member 20.

[0025] The third spacer 32 is disposed between the right end portion of the pressing bracket 28 and the case 22 and between the right end portions of the two resin plates 30. Also, the third spacer 32 is disposed on the right side with respect to the right engaging plate portion 20B of the second support member 20.

[0026] Then, three bolts 24 are inserted from above into the retaining bracket 28, the two resin plates 30, and the three spacers 32, and the three bolts 24 are screwed into the case 22. As a result, the pair of engaging plate portions 20B of the second support member 20 are sandwiched between the retaining bracket 28 and the case 22 via the two resin plates 30. In this way, the second support member 20 is supported by the case 22.

[0027] In the embodiment described above, as the charge rate (hereinafter referred to as "SOC (State of Charge)") of the multiple battery cells 12 increases, the battery cell stack 14 expands in the front-rear direction, and the second support member 20 is pressed forward by the battery cell stack 14. When the force pressing the second support member 20 forward by the battery cell stack 14 exceeds the frictional force between the pair of engaging plate portions 20B of the second support member 20 and the two resin plates 30, the pair of engaging plate portions 20B of the second support member 20 and the two resin plates 30 slide against each other, causing the second support member 20 to move forward relative to the first support member 18.

[0028] In response to this, as the SOC of the multiple battery cells 12 decreases, the battery cell stack 14 contracts in the front-rear direction, and the second support member 20 is pulled towards the rear by the battery cell stack 14. When the force pulling the second support member 20 towards the rear by the battery cell stack 14 exceeds the frictional force between the pair of engaging plate portions 20B of the second support member 20 and the two resin plates 30, the pair of engaging plate portions 20B of the second support member 20 and the two resin plates 30 slide against each other, causing the second support member 20 to move towards the rear relative to the first support member 18.

[0029] Thus, in this embodiment, when the dimensions of the battery cell stack 14 change in the front-to-back direction, the distance between the pair of support members 16 (the distance between the first support member 18 and the second support member 20) can be changed. This makes it possible to reduce the load on each component (the pair of support members 16, each bolt 24, etc.) that occurs as a result of the dimensions of the battery cell stack 14 changing in the front-to-back direction.

[0030] Furthermore, in this embodiment, the pair of engaging plate portions 20B of the second support member 20 are sandwiched between the retaining bracket 28 and the case 22 via two resin plates 30. This makes it possible to suppress vertical vibration of the front side of the battery module 10 relative to the case 22.

[0031] (Second Embodiment) A battery cell stack fixing system 34 according to the second embodiment of the present invention will be described with reference to Figures 4 to 6. In this embodiment, members and parts corresponding to the members and parts constituting the battery cell stack fixing structure according to the first embodiment are denoted by the same reference numerals as the members and parts constituting the battery cell stack fixing structure according to the first embodiment, and their descriptions may be omitted.

[0032] As shown in Figures 4 and 5, the battery cell stack fixing system 34 of this embodiment is configured to include a battery module 10, a motor 36 as an operating unit connected to the battery module 10, and a battery ECU 38 as a control unit electrically connected to the motor 36 and the battery module 10.

[0033] As shown in Figure 4, the motor 36 has a rotation axis 36A with the front-rear direction as its axial direction. This motor 36 is fixed to the case 22 on the front side relative to the second support member 20. The motor 36 and the second support member 20 are connected via a coupling mechanism 40.

[0034] The connecting mechanism 40 includes a connecting bracket 42 to which the second support member 20 is fixed, and a guide member 44 that supports the connecting bracket 42 so that it can slide in the front-rear direction while fixed to the case 22. The connecting mechanism 40 also includes a first threaded portion 46 fixed to the connecting bracket 42, and a second threaded portion 48 provided on the rotation shaft 36A of the motor 36 and screwed into the first threaded portion 46. One of the first threaded portion 46 and the second threaded portion 48 is, for example, a nut. The other of the first threaded portion 46 and the second threaded portion 48 is, for example, a trapezoidal screw. As the rotation of the rotation shaft 36A of the motor 36 occurs, the second threaded portion 48 rotates, causing the first threaded portion 46, which is screwed into the second threaded portion 48, to be displaced in the front-rear direction together with the connecting bracket 42.

[0035] The battery ECU 38 controls the rotation of the motor 36's rotation shaft 36A based on information from various sensors installed in the battery module 10. For example, the battery ECU 38 acquires SOC information from the battery cell 12 and controls the rotation of the motor 36's rotation shaft 36A.

[0036] More specifically, as shown in Figure 6 (see also Figures 4 and 5), in step S1, the battery ECU 38 measures the State of Charge (SOC) of the battery cells 12 and acquires SOC information. Next, in step S2, the battery ECU 38 checks and determines whether the SOC has increased or decreased based on the SOC information acquired in step S1. If a positive determination is made in step S2, that is, if it is determined that the SOC has increased in step S2, the battery ECU 38 calculates the amount of expansion of each battery cell 12 corresponding to the increase in SOC in step S3. Next, in step S4, the battery ECU 38 calculates the amount of expansion of all battery cells 12 based on the amount of expansion of each battery cell 12 calculated in step S3. Next, in step S5, the battery ECU 38 calculates the amount of increase in the front-rear dimension of the battery cell stack 14 based on the amount of expansion of all battery cells 12 calculated in step S4. That is, it calculates the amount of forward stroke of the second support member 20 relative to the first support member 18. Next, in step S6, the battery ECU 38 calculates the amount of rotation of the motor 36's rotation shaft 36A to one side based on the stroke amount calculated in step S5. Then, in step S7, the battery ECU 38 rotates the motor 36's rotation shaft 36A to one side by the amount of rotation calculated in step S6, and terminates the process. As a result, the second screw portion 48 rotates to one side, causing the first screw portion 46, which is screwed with the second screw portion 48, to be displaced forward together with the connecting bracket 42. As a result, the connecting bracket 42 moves forward relative to the first support member 18 together with the second support member 20.

[0037] In contrast, if a negative judgment is made in step S2, that is, if it is determined in step S2 that the SOC is decreasing, the battery ECU 38 calculates the amount of contraction of each battery cell 12 corresponding to the amount of decrease in SOC in step S8. Next, in step S9, the battery ECU 38 calculates the amount of contraction of all battery cells 12 based on the amount of contraction of each battery cell 12 calculated in step S8. Next, in step S10, the battery ECU 38 calculates the amount of decrease in the front-rear dimension of the battery cell stack 14 based on the amount of contraction of all battery cells 12 calculated in step S9. That is, it calculates the amount of stroke of the second support member 20 toward the rearward side relative to the first support member 18. Next, in step S11, the battery ECU 38 calculates the amount of rotation of the motor 36's rotating shaft 36A toward the other side based on the amount of stroke calculated in step S10. Next, in step S12, the battery ECU 38 rotates the motor 36's rotating shaft 36A toward the other side by the amount of rotation calculated in step S11, and terminates the process. As a result, the second threaded portion 48 rotates to the other side, causing the first threaded portion 46, which is screwed into the second threaded portion 48, to be displaced rearward together with the connecting bracket 42. This causes the connecting bracket 42 to move rearward relative to the first support member 18 together with the second support member 20.

[0038] Thus, in this embodiment, when the dimensions of the battery cell stack 14 change in the front-to-back direction, the distance between the pair of support members 16 (the distance between the first support member 18 and the second support member 20) can be changed. This makes it possible to reduce the load on each component (the pair of support members 16, each bolt 24, etc.) that occurs as a result of the dimensions of the battery cell stack 14 changing in the front-to-back direction.

[0039] Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above, and can be implemented in various other ways without departing from the spirit of the invention. [Explanation of Symbols]

[0040] 12 battery cells 14. Battery cell stack 16 Support member 22 Case (fixing component) 26 Movable structure 34. Battery cell stack fixing system 36. Motor (operating part) 38 Battery ECU (Control Unit)

Claims

1. A fixing member that is fixed to the vehicle body, A battery cell stack having multiple battery cells stacked along the stacking direction, A pair of support members are arranged on both sides of the stacking direction with respect to the battery cell stack and are engaged with the fixing member, and support the battery cell stack. A movable structure that supports one of the support members by sandwiching it between the fixed member and the other support member, and allows displacement of one of the support members in the stacking direction relative to the other support member by sliding with the other support member, A battery cell stack fixing structure equipped with the following features.

2. A fixing member that is fixed to the vehicle body, A battery cell stack having multiple battery cells stacked along the stacking direction, A pair of support members are arranged on both sides of the stacking direction with respect to the battery cell stack and are engaged with the fixing member, and support the battery cell stack. An operating part connected to one of the support members, which, when operated, displaces one of the support members in the stacking direction relative to the other support member, A control unit that operates the operating unit according to the amount of change in the dimensions of the battery cell stack in the stacking direction, A battery cell stack fixing system equipped with the following features.

Images