JP6960085B2 - Batteries - Google Patents

Description

The present invention relates to an assembled battery having a battery stack in which a plurality of rechargeable and dischargeable cells are electrically connected.

In recent years, secondary batteries such as lithium-ion secondary batteries have been used as portable power sources for personal computers, mobile terminals, etc., and vehicle drive power sources for electric vehicles (EV), hybrid vehicles (HV), plug-in hybrid vehicles (PHV), etc. It is preferably used in.

In a vehicle drive power supply application, a secondary battery is generally used in the form of an assembled battery formed by connecting a plurality of single batteries (battery cells) in order to increase the output. In the assembled battery, a restraining load is applied in the direction perpendicular to the electrode surface in the cell to prevent the position of the cell from shifting due to vibration or impact when the vehicle is running, and to secure the battery characteristics and battery life. There is a need to. For example, Patent Document 1 describes a battery stack in which a plurality of cells are arranged in a predetermined direction, a pair of end plates arranged at both ends of the battery stack, and a pair of side plates connecting the pair of end plates. And, an assembled battery including a plurality of fastening members for fastening an end plate and a side plate and applying a restraining load between the pair of end plates is disclosed.

Japanese Unexamined Patent Publication No. 2011-175743

By the way, in each cell in the battery stack, the cell may expand in the arrangement direction during charging and discharging. As a result, a load is applied from the battery stack to the end plate. Here, the pair of end plates are fastened to the pair of side plates by a plurality of fastening members. Then, when a load is applied from the battery stack to the end plate, bending stress is generated in the fastening member in addition to tensile stress. Due to such bending stress, the fastening force between the pair of end plates and the pair of side plates may decrease. Even if a load is applied from the battery stack to the end plate, it is necessary to securely fasten the pair of end plates and the side plates with the fastening member and apply a restraining load to the battery stack with the pair of end plates.

The present invention has been made in view of this point, and an object of the present invention is to provide an assembled battery in which an end plate and a side plate are firmly fastened even when a load is applied from the battery stack to the end plate. And.

The assembled battery according to the present invention includes a battery stack in which a plurality of rechargeable and dischargeable single batteries are electrically connected and arranged in a predetermined direction, and a pair arranged at both ends of the battery stack in the predetermined direction. The end plate and the battery stack are arranged in between, and the pair of side plates connecting the pair of end plates and the end plate and the side plate are fastened to each other, and a restraining load is applied between the pair of end plates. The plurality of fastening members are provided with, and the plurality of fastening members for fastening one end plate of the pair of end plates and one side plate of the pair of side plates are the first. A plurality of first fastening members arranged in one direction, and the first fastening member arranged in the first direction and arranged on the battery stack side of the plurality of first fastening members and with respect to the plurality of first fastening members. Includes a plurality of second fastening members that are biased in the direction of.

According to the assembled battery according to the present invention, one end plate and one side plate are fastened to each other by a plurality of first fastening members and a plurality of second fastening members. Here, the first fastening members are arranged in the first direction, the second fastening members are arranged in the first direction, are arranged on the battery stack side from the first fastening member, and are arranged in the first direction with respect to the first fastening member. It is biased to. As a result, the fastening between the end plate and the side plate is performed in a wider range as compared with the case where all the fastening members are arranged in the first direction, and the fastening portion of the end plate and the side plate is bent. The rigidity can be improved. According to the assembled battery according to the present invention, the bending rigidity of the fastening portion between the end plate and the side plate can be increased without increasing the number of fastening members.

It is a perspective view which shows typically the assembled battery which concerns on one Embodiment. It is a graph which shows the relationship between the restraint load and the maximum bolt stress. It is a perspective view which shows typically the assembled battery which concerns on another embodiment.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The present invention can be carried out based on the contents disclosed in the present specification and common general technical knowledge in the art. It should be noted that each drawing is drawn schematically and does not necessarily reflect the actual product. In addition, each drawing shows only one example, and each drawing does not limit the present invention unless otherwise specified.

<First Embodiment>
FIG. 1 is a perspective view schematically showing the structure of the assembled battery 100 according to the present embodiment. As shown in FIG. 1, the assembled battery 100 includes a battery stack 20 having a plurality of cell cells 10, a pair of end plates 30A and 30B, a pair of side plates 40A and 40B, and a plurality of fastening members 50. ing.

The battery stack 20 is configured by arranging a plurality of rechargeable and dischargeable single batteries 10 in a predetermined direction (in the direction of arrow X in FIG. 1) in a state of being electrically connected. The cell 10 is electrically connected in series or in parallel. A member other than the cell 10 (for example, a cooling plate or the like) may be interposed between the plurality of cell 10.

The cell 10 is preferably an all-solid-state battery, and more preferably an all-solid-state lithium secondary battery. All-solid-state batteries typically include a positive electrode, a negative electrode, and a solid electrolyte. When the cell 10 is an all-solid-state battery, the stacking directions of the positive electrode, the negative electrode, and the solid electrolyte are the same as the predetermined direction X. The cell 10 may be a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. When the cell 10 is a non-aqueous electrolyte secondary battery, the stacking directions of the positive electrode, the negative electrode, and the separator are the same as the predetermined direction X. Therefore, a restraining load is applied in the direction perpendicular to the electrode surface in the cell 10. Further, the cell 10 may be a fuel cell, a nickel-metal hydride battery or other secondary battery.

In the present specification, the "secondary battery" generally refers to a power storage device capable of being repeatedly charged and discharged, and is a term including a so-called storage battery and a power storage element such as an electric double layer capacitor.

The pair of end plates 30A and 30B are arranged at both ends of the battery stack 20 in a predetermined direction X. That is, the end plate 30A is arranged at one end of the battery stack 20 in the predetermined direction X, and the end plate 30B is arranged at the other end of the battery stack 20 in the predetermined direction X. The end plates 30A and 30B receive the fastening force of the fastening member 50 and the reaction force (load) from the battery stack 20. Therefore, the end plates 30A and 30B are made of a material and a shape that can withstand these forces. The end plates 30A and 30B may be made of metal or resin, and may be made of carbon steel, for example. The end plates 30A and 30B are formed in a plate shape. The battery stack 20 and the pair of end plates 30A and 30B may be in direct contact with each other, or may be indirectly in contact with each other by arranging another member between them.

The battery stack 20 is arranged between the pair of side plates 40A and 40B. The side plates 40A and 40B are separated from the battery stack 20. The side plate 40A and the side plate 40B face each other via the battery stack 20. The side plates 40A and 40B connect a pair of end plates 30A and 30B, respectively. That is, the side plate 40A connects the end portion 30AK of the end plate 30A on one side in the arrow Z direction of FIG. 1 and the end portion 30BK of the end plate 30B on the one side in the arrow Z direction of FIG. The side plate 40B connects the other end 30AL of the end plate 30A in the arrow Z direction of FIG. 1 and the other end 30BL of the end plate 30B in the arrow Z direction of FIG. The side plate 40A is connected to a plate-shaped first portion 40AX and one end of the first portion 40AX in the direction of arrow X in FIG. 1, and is thicker than the first portion 40AX and is an end plate. A second portion 40AY connected to 30A and a second portion 40AX connected to the other end of the first portion 40AX in the direction of arrow X in FIG. 1, having a thickness thicker than that of the first portion 40AX and being connected to the end plate 30B. It has three portions 40AZ and. The side plate 40B is connected to a plate-shaped first portion 40BX and one end of the first portion 40BX in the direction of arrow X in FIG. 1, and is thicker than the first portion 40BX and is an end plate. A second portion 40BY connected to 30A and a second portion 40BX connected to the other end of the first portion 40BX in the direction of arrow X in FIG. 1 and having a thickness thicker than that of the first portion 40BX and connected to the end plate 30B. It has three portions 40 BZ and. The side plates 40A and 40B are made of the same material as the end plates 30A and 30B, but may be made of different materials.

The fastening member 50 connects the end plate 30A and the side plate 40A, the end plate 30A and the side plate 40B, the end plate 30B and the side plate 40A, the end plate 30B and the side plate 40B, respectively. In the example shown in FIG. 1, the fastening member 50 connecting the end plate 30B and the side plate 40A, and the end plate 30B and the side plate 40B is not shown. The fastening member 50 applies a restraining load between the pair of end plates 30A and 30B.

The fastening member 50 includes a plurality of first fastening members 51 and a plurality of second fastening members 52. The first fastening member 51 and the second fastening member 52 connect the end plate 30A and the side plate 40A, the end plate 30A and the side plate 40B, the end plate 30B and the side plate 40A, and the end plate 30B and the side plate 40B, respectively. .. The first fastening member 51 is arranged so as to be arranged in the Y direction of the arrow in FIG. The second fastening member 52 is arranged so as to be arranged in the Y direction of the arrow in FIG. The second fastening member 52 is arranged on the battery stack 20 side of the first fastening member 51. In the present embodiment, the second fastening member 52 is arranged so as to overlap a part of the first fastening member 51 in the direction of arrow Z. The second fastening member 52 may be arranged at a position that does not overlap with the first fastening member 51 in the direction of arrow Z. The second fastening member 52 is biased with respect to the first fastening member 51. That is, the second fastening member 52 is arranged at a position that does not overlap with the first fastening member 51 in the Y direction of the arrow. In the present embodiment, the second fastening member 52, the first fastening member 51, the second fastening member 52, the first fastening member 51, the second fastening member 52, and the second fastening member 52 are directed from one side to the other side in the Y direction. The member 52, the first fastening member 51, the second fastening member 52, the first fastening member 51, and the second fastening member 52 are arranged in this order. Arrangement of the first fastening member 51 and the second fastening member 52 that connect the end plate 30A and the side plate 40A, and the arrangement of the first fastening member 51 and the second fastening member 52 that connect the end plate 30A and the side plate 40B. Is symmetrical with respect to the arrow Z direction. In the present embodiment, the number of the first fastening members 51 used when fastening the end plate 30A and the side plate 40A is 4, and the number of the second fastening members 52 is 6, but the number is not limited to this.

As described above, according to the assembled battery 100 of the present embodiment, the pair of end plates 30A and 30B and the pair of side plates 40A and 40B are mutually connected by the plurality of first fastening members 51 and the plurality of second fastening members 52. It has been concluded. Here, the first fastening member 51 is arranged in the Y direction of the arrow, the second fastening member 52 is arranged in the Y direction of the arrow, is arranged on the battery stack 20 side of the first fastening member 51, and has an arrow with respect to the first fastening member 51. It is biased in the Y direction. As a result, the end plates 30A and 30B and the side plates 40A and 40B can be fastened in a wider range than in the case where all the fastening members 50 are arranged on the same straight line in the arrow Y direction. The bending rigidity of the joint between the end plates 30A and 30B and the side plates 40A and 40B can be improved. That is, in the assembled battery 100, the bending rigidity of the fastening portion between the end plates 30A and 30B and the side plates 40A and 40B can be increased without increasing the number of fastening members 50.

FIG. 2 is a graph showing the relationship between the maximum stress applied to the fastening member 50 and the restraining load applied to the battery stack 20. When a load is applied to the end plates 30A and 30B from the battery stack 20 due to the expansion of the cell 10, a force is applied in the direction of separating the end plates 30A and 30B from the side plates 40A and 40B. That is, a relatively large load is applied to the fastening member 50. When a predetermined load or more is applied to the fastening member 50, the end plates 30A and 30B and the side plates 40A and 40B are released, and the load applied to the fastening member 50 increases. Therefore, it may be disadvantageous to secure the strength of the fastening member 50. In the example shown in FIG. 2, the point where the inclination changes indicates the restraining load at which the end plates 30A and 30B and the side plates 40A and 40B have started to be released. As shown in FIG. 2, when the fastening members 50 are arranged in a row, the end plates 30A and 30B and the side plates 40A and 40B start to separate at the position of the point P in FIG. On the other hand, when the fastening members 50 are arranged in a staggered pattern as in the present embodiment, the end plates 30A and 30B and the side plates 40A and 40B have started to be separated from each other at the position of the point Q in FIG. In this way, when the fastening members 50 are arranged in a staggered pattern, the release of the end plates 30A and 30B and the side plates 40A and 40B can be suppressed up to a higher restraining load.

<Second Embodiment>
FIG. 3 is a perspective view schematically showing the structure of the assembled battery 100 according to the present embodiment. In the present embodiment, the second fastening member 52, the first fastening member 51, the first fastening member 51, the first fastening member 51, the second fastening member 52, and the second fastening member 52 are directed from one side to the other side in the Y direction. The member 52, the first fastening member 51, the first fastening member 51, the first fastening member 51, and the second fastening member 52 are arranged in this order. In the present embodiment, the number of the first fastening members 51 used when fastening the end plate 30A and the side plate 40A is 6, and the number of the second fastening members 52 is 4, but the present invention is not limited thereto.

The assembled battery 100 of the present embodiment is suitable as a power source for driving a vehicle such as a hybrid vehicle or an electric vehicle.

Although the present invention has been described in detail above, the above-described embodiments and examples are merely examples, and the inventions disclosed herein include various modifications and modifications of the above-mentioned specific examples.

10 Single battery 20 Battery stack 30A, 30B End plate 40A, 40B Side plate 50 Fastening member 51 First fastening member 52 Second fastening member 100 assembled battery

Claims (1)

A battery stack in which multiple chargeable and dischargeable cells are electrically connected and arranged in a predetermined direction,
A pair of end plates arranged at both ends of the battery stack in the predetermined direction,
A pair of side plates with the battery stack arranged in between and connecting the pair of end plates, respectively.
A plurality of fastening members for fastening the end plate and the side plate and applying a restraining load between the pair of end plates are provided.
The plurality of fastening members for fastening one end plate of the pair of end plates and one side plate of the pair of side plates are the plurality of first fastening members arranged in the first direction. , A plurality of second fastenings arranged in the first direction, arranged on the battery stack side from the plurality of first fastening members, and biased in the first direction with respect to the plurality of first fastening members. Assembled battery, including components.

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