BATTERY MODULE

A battery module includes a battery cell, a positive electrode lead or negative electrode lead provided in the battery cell, a first conductor electrically connected to the battery cell, at least a portion of the first conductor being functioning as a fuse above the positive electrode lead or the negative electrode lead, and a first base, at least a portion of the first base being located between the positive electrode lead or negative electrode lead, and the fuse.

This application is based on Japanese patent application NO. 2021-159633, filed on Sep. 29, 2021, the content of which is incorporated hereinto by reference.

BACKGROUND

Technical Field

The present invention relates to a battery module.

Related Art

A battery module such as a lithium-ion secondary battery may include a plurality of stacked battery cells. In such a battery module, the plurality of battery cells are electrically connected to each other by positive electrode leads and negative electrode leads drawn from an exterior material of the battery cells. The battery module may include a fuse to suppress the flow of an overcurrent.

Japanese Laid-open Patent Publication No. H11-73871 discloses an example of a fuse. The fuse includes two separated metal plates and solder to connect the two metal plates to each other. A space onto which the solder melted by an overcurrent falls is provided below the solder.

SUMMARY

The fuse may be disposed above leads such as a positive electrode lead and a negative electrode lead of the battery cell. However, in this case, when the fuse is fused, the fused fuse may come into contact with the lead.

An example of an object of the present invention is to prevent the melted fuse from coming into contact with the lead. Other objects of the invention will become apparent from the description of the present specification.

One aspect of the present invention is a battery module. The battery module includes a battery cell, a lead provided in the battery cell, a conductor electrically connected to the battery cell, at least a portion of the conductor being functioning as a fuse above the lead, and a base, at least a portion of the base being located between the lead and the fuse.

According to the above aspect, the melted fuse can be prevented from coming into contact with the lead.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all drawings, similar components are denoted by the similar reference signs, and description thereof will not be repeated.

In the present specification, ordinal numbers such as “first”, “second”, and “third” are added in order to simply distinguish components having similar names unless otherwise specified, and do not mean the particular feature of the component (for example, order or importance).

FIG.1is a perspective view of a battery module50according to an embodiment when viewed from the front.FIG.2is a perspective view of the battery module50according to the embodiment when viewed from the rear.FIG.3is a view with a housing body20detached fromFIG.1.FIG.4is a view with the housing body20detached fromFIG.2.FIG.5is a perspective view of a cell stacked body10according to the embodiment when viewed from the front.

InFIGS.1to5, arrows indicating a first direction X, a second direction Y, and a third direction Z indicate that a direction from the base end toward the tip end of the arrow is a positive direction of a direction indicated by the arrow, and a direction from the tip end to the base end of the arrow is a negative direction of the direction indicated by the arrow. The first direction X indicates one direction parallel to the horizontal direction perpendicular to the vertical direction. Specifically, the first direction X indicates the front-back direction of the battery module50. The positive direction of the first direction X is a direction from the front to the rear of the battery module50. The negative direction of the first direction X is a direction from the rear to the front of the battery module50. The second direction Y indicates a direction perpendicular to the vertical direction and the first direction X. The second direction Y indicates the left-right direction of the battery module50. The positive direction of the second direction Y is a direction from the right to the left of the battery module50when viewed from the front of the battery module50. The negative direction of the second direction Y is a direction from the left to the right of the battery module50when viewed from the front of the battery module50. The third direction Z indicates a direction parallel to the vertical direction. The positive direction of the third direction Z is a direction from the lower side to the upper side of the battery module50. The negative direction of the third direction Z is a direction from the upper side to the lower side of the battery module50.

The relationship of the first direction X, the second direction Y, the third direction Z, the vertical direction, and the horizontal direction is not limited to the above-described example. For example, the battery module50may be disposed so that the first direction X or the second direction Y is parallel to the vertical direction.

Hereinafter, unless otherwise specified, “right” and “left” mean the right and the left when viewed from the front of the battery module50, respectively.

In the present embodiment, the battery module50is mounted on a moving object such as an automobile. However, the use of the battery module50is not limited to this example.

The battery module50includes a cell stacked body10, a housing body20, a first voltage detection device30A, and a second voltage detection device30B. The first voltage detection device30A includes a first fuse device40A. The second voltage detection device30B includes a second fuse device40B. As will be described later with reference toFIG.6, the first fuse device40A includes a fuse electrically connected to a terminal positive electrode lead112T. The second fuse device40B includes a fuse electrically connected to a terminal negative electrode lead114T.

As shown inFIG.5, the cell stacked body10includes a plurality of cell groups100G stacked in the second direction Y. Each cell group100G includes a plurality of battery cells100stacked in the second direction Y. Each battery cell100includes an exterior material102, a positive electrode lead112, and a negative electrode lead114.

In the present embodiment, each cell group100G includes two battery cells100. However, each cell group100G may include three or more battery cells100. In the cell stacked body10, the plurality of cell groups100G may not be connected in series, but the plurality of battery cells100may be connected in series. In other words, the number of battery cells100in the cell group100G may be only one.

Each battery cell100is placed substantially vertically. The battery cell100being placed substantially vertically does not only refer to the battery cell100being placed exactly vertically. The battery cell100being placed substantially vertically may also refer to the battery cell100being inclined diagonally from the third direction Z to the extent that the operation of the battery module50is not hindered.

As shown inFIGS.3and4, a plurality of adhesive members104are disposed on the upper surface of the cell stacked body10. Each adhesive member104is, for example, a cured body of liquid resin. In the present embodiment, the plurality of adhesive members104are regularly arranged. Specifically, the plurality of adhesive members104extend parallel to the second direction Y and are arranged in parallel to the first direction X. An insulating sheet (not shown) is disposed above the plurality of adhesive members104. A sixth cover member260, which will be described later, is disposed above the insulating sheet (not shown). The layout of the adhesive members104is not limited to the layout according to the present embodiment. For example, the adhesive member104may be provided over the entire upper surface of the cell stacked body10. Alternatively, the plurality of adhesive members104may be irregularly arranged, or may be arranged in accordance with a rule different from the rules shown inFIGS.3and4. Adhesive members are also arranged on the lower surface of the cell stacked body10in a manner similar to the upper surface of the cell stacked body10.

The exterior material102houses a positive electrode, a negative electrode, and a separator (not shown) together with an electrolytic solution (not shown). In one example, the positive electrode, the negative electrode, and the separator are stacked in the exterior material102in the second direction Y. Alternatively, the positive electrode, the negative electrode, and the separator may be wound in the exterior material102.

The positive electrode lead112is drawn from one of the front end and the rear end of the exterior material102substantially in the horizontal direction. The positive electrode lead112is electrically connected to the positive electrode in the exterior material102. In one example, the positive electrode lead112is made of metal such as aluminum. The positive electrode lead112being drawn substantially in the horizontal direction does not only refer to the positive electrode lead112being drawn strictly in the horizontal direction. The positive electrode lead112being drawn substantially in the horizontal direction may also refer to the positive electrode lead112being drawn in a direction shifted from the horizontal direction to the extent that the operation of the battery module50is not hindered.

The negative electrode lead114is drawn from the other of the front end and the rear end of the exterior material102substantially in the horizontal direction. The negative electrode lead114is electrically connected to the negative electrode in the exterior material102. In one example, the negative electrode lead114is made of metal, such as copper, which is different from the metal forming the positive electrode lead112. The negative electrode lead114being drawn substantially in the horizontal direction does not only refer to the negative electrode lead114being drawn strictly in the horizontal direction. The negative electrode lead114being drawn substantially in the horizontal direction may also refer to the negative electrode lead114being drawn in a direction shifted from the horizontal direction to the extent that the operation of the battery module50is not hindered.

When each cell group100G includes a plurality of battery cells100, the plurality of battery cells100are connected in parallel. Specifically, the plurality of battery cells100in each cell group100G are stacked in the second direction Y. The positive electrode leads112of the plurality of battery cells100in each cell group100G are bundled in the second direction Y and connected to each other. The negative electrode leads114of the plurality of battery cells100in each cell group100G are bundled in the second direction Y and connected to each other. Adjacent battery cells100may be stacked through an adhesive member. Examples of the adhesive member include a double-sided tape and a member that cures liquid resin.

The plurality of cell groups100G are connected in series via the lead portion110. The lead portion110includes a plurality of positive electrode leads112of one cell group100G of the cell groups100G adjacent to each other in the second direction Y and a plurality of negative electrode leads114of the other cell group100G of the cell groups100G adjacent to each other in the second direction Y. The plurality of positive electrode leads112and the negative electrode leads114in the lead portion110are bonded to each other by bonding methods such as laser welding, ultrasonic bonding, resistance welding, and adhesion. When the material of the positive electrode lead112is different from the material of the negative electrode lead114, laser welding is preferable among the above bonding methods from the viewpoint of high bonding reliability and reduction in the number of components. The lead portion110is folded back between the cell groups100G adjacent to each other in the second direction Y. Thus, a plurality of lead portions110are arranged in the second direction Y in front of the cell stacked body10. A plurality of lead portions110are arranged in the second direction Y in the rear of the cell stacked body10.

In the present embodiment, as shown inFIG.3, a plurality of negative electrode leads114are located in front of the plurality of positive electrode leads112at bonding portions of the plurality of positive electrode leads112and the plurality of negative electrode leads114in each lead portion110located in front of the cell stacked body10. As shown inFIG.4, the plurality of positive electrode leads112are located in rear of the plurality of negative electrode leads114at bonding portions of the plurality of positive electrode leads112and the plurality of negative electrode leads114in each lead portion110located in rear of the cell stacked body10. When the plurality of positive electrode leads112are located in front of the plurality of negative electrode leads114in front of the cell stacked body10, the material of a first tip end portion314A described later is preferably the same as the material of the positive electrode lead112.

In the present embodiment, as shown inFIG.3, the plurality of positive electrode leads112in the cell group100G at one end of the plurality of cell groups100G connected in series are located on the right front side of the cell stacked body10. If necessary, the plurality of positive electrode leads112in the cell group100G at one end of the plurality of cell groups100G connected in series are referred to as terminal positive electrode leads112T below. As shown inFIG.4, the plurality of negative electrode leads114in the cell group100G at the other end of the plurality of cell groups100G connected in series are located on the left rear side of the cell stacked body10. If necessary, the plurality of negative electrode leads114in the cell group100G at the other end of the plurality of cell groups100G connected in series are referred to as terminal negative electrode leads1141below.

The structure of the cell stacked body10is not limited to the structure according to the present embodiment. For example, the terminal negative electrode lead114T may be located on the left front side of the cell stacked body10instead of the left rear side. In this example, both the terminal positive electrode lead112T and the terminal negative electrode lead114T are located on the front side. Whether the terminal negative electrode lead114T is located on the left front side or the left rear side of the cell stacked body10can be adjusted by the number of cell groups100G stacked in the second direction Y.

In the present embodiment, as shown inFIG.3, the front surface of the bonding portion of the positive electrode lead112and the negative electrode lead114in each lead portion110located in front of the cell stacked body10is substantially parallel to the direction perpendicular to the first direction X. The front surface of the bonding portion being substantially parallel to the direction perpendicular to the first direction X does not only refer to the front surface of the bonding portion being exactly parallel to the direction perpendicular to the first direction X. The front surface of the bonding portion being substantially parallel to the direction perpendicular to the first direction X may also refer to the front surface of the bonding portion being slightly deforming from a state of being parallel to the direction perpendicular to the first direction X to the extent that the function of the lead portion110is not hindered. In the present embodiment, a first voltage detection portion310A, which will be described later, can be easily bonded to the front surface of the lead portion110as compared with a case where the front surface of the bonding portion is curved. In another example different from the present embodiment, the front surface of the bonding portion described above may be curved.

In the present embodiment, as shown inFIG.4, the rear surface of the bonding portion of the positive electrode lead112and the negative electrode lead114in each lead portion110located in rear of the cell stacked body10is substantially parallel to the direction perpendicular to the first direction X in a manner similar to the front surface of the bonding portion of the positive electrode lead112and the negative electrode lead114in each lead portion110located in front of the cell stacked body10.

The housing body20houses the cell stacked body10, the first voltage detection device30A, and the second voltage detection device30B. The housing body20includes a first cover member210, a second cover member220, a third cover member230, a fourth cover member240, a fifth cover member250, and a sixth cover member260. In the present embodiment, the first cover member210, the second cover member220, the third cover member230, the fourth cover member240, the fifth cover member250, and the sixth cover member260is made of metal containing aluminum as a main component. However, the materials forming the first cover member210, the second cover member220, the third cover member230, the fourth cover member240, the fifth cover member250, and the sixth cover member260are not limited to this example.

The first cover member210covers the front side of the cell stacked body10and the first voltage detection device30A. The second cover member220covers the rear side of the cell stacked body10and the second voltage detection device30B. The third cover member230covers the right side of the cell stacked body10. The fourth cover member240covers the left side of the cell stacked body10. The fifth cover member250covers the lower side of the cell stacked body10. The sixth cover member260covers the upper side of the cell stacked body10.

As shown inFIGS.1and2, a “+” mark is attached to the right front side of the upper surface of the sixth cover member260. A “−” mark is attached to the left rear side of the upper surface of the sixth cover member260. The “+” mark indicates that the terminal positive electrode lead112T shown inFIG.3is located at the position to which the “+” mark is attached. The “−” mark indicates that the terminal negative electrode lead114T shown inFIG.4is located at the position to which the “−” mark is attached. Thus, a user of the battery module50can determine, from the “+” mark and the “−” mark, the position of the terminal positive electrode lead112T and the position of the terminal negative electrode lead114T even when the cell stacked body10is hardly visible from the outside of the housing body20.

The first voltage detection device30A includes a first holding body300A, a plurality of first voltage detection portions310A, a plurality of first voltage detection lines320A, and a first connector330A.

The first holding body300A is provided in front of the cell stacked body10. The first holding body300A is an insulator. Examples of the insulator include polypropylene-based resin or resin having a hardness and an insulating property equal to or higher than a hardness and an insulating property of the polypropylene-based resin. The first holding body300A is attached to the housing body20by mechanical bonding such as a snap fit and a screw.

Each first voltage detection portion310A includes a first base end portion312A, a first tip end portion314A, and a first connection portion316A.

The first base end portion312A is movably supported in the first direction X along a first support shaft318A provided at the first holding body300A. Thus, each first voltage detection portion310A is held by the first holding body300A. The first support shaft318A penetrates in the first direction X a through-hole provided in the first base end portion312A. The diameter of the front end portion of the first support shaft318A in the direction perpendicular to the first direction X is larger than the diameter of the through-hole of the first base end portion312A in the direction perpendicular to the first direction X. Thus, the first base end portion312A is suppressed from escaping from the first support shaft318A toward the front of the first support shaft318A.

In the present embodiment, when viewed from the front of the cell stacked body10, the first tip end portion314A is offset from the first base end portion312A in the horizontal direction and the vertical direction. Specifically, when viewed from the front of the cell stacked body10, the first tip end portion314A is located on the lower right side of the first base end portion312A. As a result, a gap from which a portion of the front surface of the lead portion110is exposed toward the front is provided on the right side of the first base end portion312A and on the upper side of the first tip end portion314A. Accordingly, at least a portion of the bonding portion such as a laser welding portion between the positive electrode lead112and the negative electrode lead114can be provided in a region of the lead portion110overlapping the gap in the first direction X. That is, it is necessary that the bonding portion of the lead portion110does not overlap the first tip end portion314A in the first direction X. Accordingly, in the present embodiment, the length of the bonding portion of the lead portion110in the vertical direction can be increased as compared with, for example, a case where the first tip end portion314A is located on the right side of the first base end portion312A without offset downward from the first base end portion312A. Thus, in the present embodiment, the connection between the positive electrode lead112and the negative electrode lead114in the lead portion110can be improved as compared with the above-described case.

In the present embodiment, the first tip end portion314A is offset from the first base end portion312A to the side on which the lead portion110is located. Accordingly, in the present embodiment, as compared with a case where the position of the first base end portion312A in the first direction X and the position of the first tip end portion314A in the first direction X are aligned in the first direction X, the first tip end portion314A can be easily close to the lead portion110, and the first tip end portion314A can be easily connected to the lead portion110. In the present embodiment, a movable range of the first base end portion312A in the first direction X can be increased as compared with the above-described case.

The first connection portion316A protrudes downward from the first base end portion312A. One end of the first voltage detection line320A is connected to the first connection portion316A. The first connection portion316A may be integrated with the first base end portion312A, for example. As shown inFIG.6, which will be described later, in the present embodiment, the first connection portion316A includes two first barrels316aA that crimp one end of the first voltage detection line320A. The two first barrels316aA are arranged in the vertical direction. One end of the first voltage detection line320A enters into the internal space of the two first barrels316aA substantially parallel to the vertical direction from the lower sides of the two first barrels316aA and is crimped by the two first barrels316aA. As a result, the one end of the first voltage detection line320A is fixed to the first connection portion316A. However, a method of fixing the one end of the first voltage detection line320A to the first connection portion316A is not limited to the method according to the present embodiment. For example, the number of the first barrels316aA provided at each first connection portion316A may be only one. One end of the first voltage detection line320A may be soldered to the first connection portion316A.

The shape of the first voltage detection portion310A is not limited to the shape according to the present embodiment as long as the first tip end portion314A does not overlap the bonding portion between the positive electrode lead112and the negative electrode lead114in the lead portion110in the first direction X. For example, the gap may not be provided on the right side of the first base end portion312A and on the upper side of the first tip end portion314A when viewed from the front of the cell stacked body10. The position of the first base end portion312A in the first direction X and the position of the first tip end portion314A in the first direction X may be aligned in the first direction X.

Each of the plurality of first voltage detection portions310A is connected to each of the plurality of lead portions110in front of the cell stacked body10. Specifically, each first tip end portion314A is bonded to each lead portion110in front of the cell stacked body10by a bonding method such as laser welding. In the present embodiment, the rear surface of the first tip end portion314A is bonded to the front surface of the bonding portion of the positive electrode lead112and the negative electrode lead114in the lead portion110. The first tip end portion314A is preferably made of the same material as the portion of the lead portion110in contact with the first tip end portion314A. In the present embodiment, the first tip end portion314A is in contact with the negative electrode lead114. In this example, the first tip end portion314A can be easily bonded to the negative electrode lead114as compared with a case where the first tip end portion314A is made of a material different from the material of the negative electrode lead114. In another example, the first tip end portion314A may be made of a material different from the portion of the lead portion110in contact with the first tip end portion314A.

Each of the plurality of first voltage detection lines320A electrically connects each of the plurality of first voltage detection portions310A to the first connector330A. As described above, one end of each first voltage detection line320A is connected to the first connection portion316A. The other end of each first voltage detection line320A is connected to the first connector330A. In the present embodiment, a portion of each first voltage detection line320A is drawn from the first connection portion316A to a space below a first frame340A through a notch350A provided in the first frame340A described later. The notch350A is provided at a corner of the first frame340A between a second edge portion344A and a third edge portion346A, which will be described later. The other portion of each first voltage detection line320A passes through a space between adjacent first frames340A in a region offset from the center of the first holding body300A to the right side, and then is drawn from a space below a plurality of first frames340A to the first connector330A located above the plurality of first frames340A. The position of the first voltage detection portion310A, the routing of the first voltage detection lines320A, the position of the notch350A, and the position of the first connector330A are not limited to the examples according to the present embodiment.

In the present embodiment, at least a portion of a region of the first voltage detection line320A located between the first connection portion316A and the notch350A has flexibility. When the first base end portion312A is moved along the first support shaft318A in the first direction X, the first voltage detection line320A may come into contact with the first holding body300A or the first frame340A in the vicinity of the notch350A. Even in such a case, at least the above portion of the first voltage detection line320A is bent such that the first base end portion312A can be moved along the first support shaft318A in the first direction X.

The first holding body300A has a plurality of first frames340A. The first frame340A is an insulator. Examples of the insulator include polypropylene-based resin or resin having a hardness and an insulating property equal to or higher than a hardness and an insulating property of the polypropylene-based resin. Each of the plurality of first frames340A surrounds each of the plurality of lead portions110and each of the plurality of first voltage detection portions310A. Thus, the first frame340A can protect the lead portion110and the first voltage detection portion310A from an external impact. Each first frame340A may not be located in the entire region surrounding each lead portion110and each first voltage detection portion310A. Each first frame340A may be located in at least a portion of a region surrounding each lead portion110and each first voltage detection portion310A. The first holding body300A may be formed with a single member, or may be formed with a plurality of members combined with each other.

Each first frame340A has a first edge portion342A, a second edge portion344A, a third edge portion346A and a fourth edge portion348A. The first edge portion342A extends in the vertical direction on the right side of the lead portion110and the first voltage detection portion310A surrounded by the first frame340A. The second edge portion344A extends in the vertical direction on the left side of the lead portion110and the first voltage detection portion310A surrounded by the first frame340A. The third edge portion346A extends in the left-right direction on the lower side of the lead portion110and the first voltage detection portion310A surrounded by the first frame340A. The fourth edge portion348A extends in the left-right direction on the upper side of the lead portion110and the first voltage detection portion310A surrounded by the first frame340A.

The shape of the first frame340A is not limited to the shape according to the present embodiment. For example, the first frame340A may not have one of the first edge portion342A and the second edge portion344A. The first frame340A may not have at least one of the third edge portion346A and the fourth edge portion348A.

In the present embodiment, at least a portion of an insulator forming each first frame340A is located between the first voltage detection portion310A surrounded by each first frame340A and a lead portion110different from the lead portion110connected to the first voltage detection portion310A. Thus, in the present embodiment, the electrical insulation can be secured between the first voltage detection portion310A surrounded by each first frame340A and the lead portion110different from the lead portion110connected to the first voltage detection portion310A.

Specifically, at least a portion of an insulator forming the first edge portion342A except the first frame340A located at the rightmost end is located between the first voltage detection portion310A located on the left side of the first edge portion342A and the lead portion110located on the right side of the first edge portion342A. Thus, as compared with a case where the first edge portion342A is not provided, the electrical insulation can be secured between the first voltage detection portion310A located on the left side of the first edge portion342A and the lead portion110located on the right side of the first edge portion342A.

At least a portion of an insulator forming the second edge portion344A except the first frame340A located at the leftmost end is located between the first voltage detection portion310A located on the right side of the second edge portion344A and the lead portion110located on the left side of the second edge portion344A. Thus, as compared with a case where the second edge portion344A is not provided, the electrical insulation can be secured between the first voltage detection portion310A located on the right side of the second edge portion344A and the lead portion110located on the left side of the second edge portion344A.

In the present embodiment, at least a portion of an insulator forming each first frame340A is located between different lead portions110. Specifically, at least a portion of an insulator forming each first frame340A is located between the lead portions110adjacent to each other. Thus, the electrical insulation can be secured between the different lead portions110as compared with a case where at least the portion of an insulator forming each first frame340A is not located between the different lead portions110.

Specifically, at least a portion of an insulator forming the first edge portion342A except the first frame340A located at the rightmost end is located between the lead portion110located on the left side of the first edge portion342A and the lead portion110located on the right side of the first edge portion342A. Thus, as compared with a case where the first edge portion342A is not provided, the electrical insulation can be secured between the lead portion110located on the left side of the first edge portion342A and the lead portion110located on the right side of the first edge portion342A.

At least a portion of the insulator forming the second edge portion344A except the first frame340A located at the leftmost end is located between the lead portion110located on the right side of the second edge portion344A and the lead portion110located on the left side of the second edge portion344A. Thus, as compared with a case where the second edge portion344A is not provided, the electrical insulation can be secured between the lead portion110located on the right side of the second edge portion344A and the lead portion110located on the left side of the second edge portion344A.

An insulating protrusion portion that protrudes toward the positive direction side of the first direction X may be provided on the surface of the first frame340A on the positive direction side of the first direction X. At least a portion of the protrusion portion is located between the lead portions110adjacent to each other in the second direction Y. For example, the protrusion portion is provided on the positive direction side of the first direction X of the first edge portion342A of the left first frame340A of the first frames340A adjacent to each other in the second direction Y, and is provided on the positive direction side of the first direction X of the second edge portion344A of the right first frame340A of the first frames340A adjacent to each other in the second direction Y. In this example, when the lead portions110adjacent to each other in the second direction Y are displaced in the second direction Y due to a factor such as an impact from the outside, the lead portions110hit the protrusion portion. This can suppress collision between the lead portions110adjacent to each other in the second direction Y. The length of the protrusion portion is not particularly limited, but may be, for example, a length for suppressing the collision between the lead portions110adjacent to each other in the second direction Y. The position at which the protrusion portion is provided is not limited to the above-described example.

In the present embodiment, at least a portion of the insulator forming each first frame340A is located between at least one lead portion110and at least a conductive portion of the housing body20. Accordingly, in the present embodiment, the electrical insulation can be secured between at least one lead portion110and at least a conductive portion of the housing body20.

Specifically, at least a portion of the third edge portion346A is located below the lead portion110surrounded by each first frame340A. In the present embodiment, the front end portion of the fifth cover member250is located below the lower end portion of the lead portion110. When the fifth cover member250has conductivity and the lower end portion of the lead portion110is in contact with the front end portion of the fifth cover member250, the lead portion110and the fifth cover member250may be short-circuited. On the other hand, in the present embodiment, at least a portion of an insulator forming the third edge portion346A is located between the lower end portion of the lead portion110and the front end portion of the fifth cover member250. This can suppress an occurrence of a short circuit between the lead portion110and the fifth cover member250as compared with a case where the third edge portion346A is not provided.

In the above-described example, it has been described that the third edge portion346A secures the electrical insulation between the lower end portion of the lead portion110and the front end portion of the fifth cover member250. However, securing the electrical insulation between the lead portion110and the housing body20by the first frame340A is not limited to the above-described example. For example, the fourth edge portion348A can secure the electrical insulation between the upper end portion of the lead portion110and the front end portion of the sixth cover member260. The first edge portion342A of the first frame340A located at the rightmost end of the plurality of first frame340A can secure the electrical insulation between the right end portion of the lead portion110located at the rightmost end of the plurality of lead portions110and the front end portion of the third cover member230. The second edge portion344A of the first frame340A located at the leftmost end of the plurality of first frame340A can secure the electrical insulation between the left end portion of the lead portion110located at the leftmost end of the plurality of lead portions110and the front end portion of the fourth cover member240.

In the present embodiment, the second edge portion344A of the first frame340A surrounding the right lead portion110of the lead portions110adjacent to each other in the second direction Y and the first edge portion342A of the first frame340A surrounding the left lead portion110of the lead portions110adjacent to each other in the second direction Y are located between the lead portions110adjacent to each other in the second direction Y. Thus, a distance in the second direction Y between the lead portions110adjacent to each other in the second direction Y is required to be larger than a distance in the second direction Y between the above-described second edge portion344A and the above-described first edge portion342A located between the lead portions110adjacent to each other in the second direction Y. The distance in the second direction Y between the lead portions110adjacent to each other in the second direction Y increases as the number of battery cells100in the cell group100G increases. Accordingly, as compared with a case where the number of battery cells100in the cell group100G is only one, the distance in the second direction Y between the lead portions110adjacent to each other in the second direction Y is more easily increased when the number of battery cells100in the cell group100G is plural.

Similar to the first voltage detection device30A, the second voltage detection device30B includes a second holding body300B, a plurality of second voltage detection portions310B, a plurality of second voltage detection lines320B, and a second connector330B.

The second holding body300B is provided in rear of the cell stacked body10. Each of the plurality of second voltage detection portions310B is connected to each of the plurality of lead portions110in rear of the cell stacked body10. In the present embodiment, the surface of each second voltage detection portion310B on the negative direction side of the first direction X is bonded to the surface of the bonding portion of the positive electrode lead112and the negative electrode lead114in the lead portion110on the positive direction side of the first direction X. Each of the plurality of second voltage detection lines320B electrically connects each of the plurality of second voltage detection portions310B to the second connector330B. A plurality of second frames340B are provided at the second holding body300B. Similar to the plurality of first frames340A, each of the plurality of second frames340B surrounds each of the plurality of lead portions110provided in rear of the cell stacked body10and each of the plurality of second voltage detection portions310B.

FIG.6is an enlarged view of a position of the first voltage detection device30A according to the embodiment at which the first fuse device40A is provided.

The first fuse device40A includes a first base302A, a first conductor400A, a first fixture432A, a second fixture434A, and a first wiring440A.

The first base302A includes the right end portion of the first holding body300A. In the present embodiment, the first base302A includes two first frames340A at the rightmost end of the plurality of first frames340A.

The first conductor400A is provided at the first base302A. The first conductor400A is made of, for example, metal. The first conductor400A functions as a bus bar electrically connected to the terminal positive electrode lead112T.

The first conductor400A includes a plurality of extension bodies extending in different directions. At least a portion of at least one of the plurality of extension bodies is held by the first base302A.

Specifically, the first conductor400A includes a first extension body410A extending in the horizontal direction and a second extension body420A extending in the vertical direction. The second extension body420A extends downward from the right end portion of the first extension body410A. The first extension body410A and the second extension body420A are integrally formed. The first conductor400A may be formed by bonding, for example, metal for the first extension body410A and metal for the second extension body420A. However, a method of forming the first conductor400A is not limited to this example. The shape of the first conductor400A is not limited to the shape according to the present embodiment. For example, the first conductor400A may not include the second extension body420A.

The first extension body410A includes a first wide portion412A, a narrow portion414A, and a second wide portion416A. The left end of the narrow portion414A is connected to the right end of the first wide portion412A. The right end of the narrow portion414A is connected to the left end of the second wide portion416A.

The first wide portion412A functions as a terminal to electrically connect to another battery module (not shown). A fastening hole450A is provided at the left end portion of the first wide portion412A. For example, a fixture (not shown) for fixing a bus bar (not shown) that is electrically connected to another battery module is fixed to the fastening hole450A. In the present embodiment, the peripheral portion of the fastening hole450A of the first wide portion412A is located higher than the narrow portion414A. However, the peripheral portion of the fastening hole450A of the first wide portion412A may be located at the same height as the narrow portion414A.

The narrow portion414A functions as a fuse. The width of the narrow portion414A in the first direction X is narrower than both of the width of the first wide portion412A in the first direction X and the width of the second wide portion416A in the first direction X. Accordingly, the cross-sectional area of the narrow portion414A perpendicular to the second direction Y is smaller than any of the cross-sectional area of the first wide portion412A perpendicular to the second direction Y and the cross-sectional area of the second wide portion416A perpendicular to the second direction Y. Thus, when an overcurrent flows through the first conductor400A, the narrow portion414A is more easily to melt than the first wide portion412A and the second wide portion416A are.

In the present embodiment, the narrow portion414A is attached to the first holding body300A. Thus, the first voltage detection portion310A and the fuse can be provided in a spatially efficient manner as compared with a case where the structure for holding the fuse is provided separately from the first holding body300A.

Additionally, in the present embodiment, the size of the battery module50can be reduced as compared with a case where a tubular fuse tube is used as the fuse. Specifically, when a tubular fuse is used, the larger the energy of the battery module50, the larger the size of the tubular fuse. Accordingly, in the battery module50having relatively high energy, a space for providing the tubular fuse becomes relatively large. On the other hand, when a portion of the first conductor400A functions as the fuse, the space for providing the fuse can be reduced as compared with a case where the tubular fuse is used.

In the present embodiment, the narrow portion414A extends in the same direction as an extension direction of the first wide portion412A. That is, the first wide portion412A and the narrow portion414A extend in the second direction Y. When the narrow portion414A is provided at the second extension body420A and extends in a direction perpendicular to the extension direction of the first wide portion412A, it may be difficult to bond the narrow portion414A provided at the second extension body420A to the terminal positive electrode lead112T. On the other hand, in the present embodiment, it is not necessary to provide the narrow portion414A at the second extension body420A. Thus, in the present embodiment, the length of the bonding portion in the third direction Z between the second extension body420A and the terminal positive electrode lead112T can be increased as compared with the above-described case. In the present embodiment, the length of the narrow portion414A in the second direction Y can be easily adjusted as compared with the above-described case. Furthermore, in the present embodiment, the narrow portion414A and the terminal positive electrode lead112T can be spaced farther apart than in the above-described case. Thus, in the present embodiment, an influence on the terminal positive electrode lead112T by heat generated from the narrow portion414A can be suppressed as compared with the above-described case.

A first space402A defining the narrow portion414A is provided in front of the narrow portion414A of the first extension body410A. In the present embodiment, the first space402A is formed by punching with press processing the front portion of a portion functioning as the narrow portion414A of a conductor forming the first extension body410A.

A space defining the narrow portion414A is not provided in rear of the narrow portion414A of the first extension body410A. However, a method of forming the narrow portion414A is not limited to the method according to the present embodiment. For example, the first space402A may be provided in rear of the narrow portion414A. Alternatively, the first space402A may be provided both in front and rear of the narrow portion414A. The first space402A may be formed by a through-hole that penetrates the first extension body410A in the vertical direction. In this case, portions of the first extension body410A on both sides of the first space402A in the first direction X become narrow portions414A that function as fuses.

When the narrow portion414A is formed by press processing, the space defining the narrow portion414A is preferably provided on only one of both sides of the first extension body410A in the first direction X as in the present embodiment. In this case, it is not necessary to punch out with press processing the rear portion of the portion forming the narrow portion414A in the conductor forming the first extension body410A. The present embodiment is compared with a case where both the front portion and the rear portion of the portion forming the narrow portion414A in the conductor forming the first extension body410A are punched out with press processing. In the above-described case, it is necessary to simultaneously or separately punch out the front portion and the rear portion of the portion forming the narrow portion414A. Thus, the mechanical load applied to the narrow portion414A narrowest in the first extension body410A during press processing increases as compared with the present embodiment. Accordingly, in the above-described case, as compared with the present embodiment, it is necessary to widen the width of the narrow portion414A in the first direction X from the viewpoint of suppressing the breakage of the narrow portion414A. On the other hand, in the present embodiment, as compared to the above-described case, it is possible to reduce the width of the narrow portion414A in the first direction X and to increase the degree of freedom in dimensions of the narrow portion414A.

The method of forming the narrow portion414A is not limited to press processing. The narrow portion414A may be formed by, for example, laser processing. When the narrow portion414A is formed by laser processing, the space defining the narrow portion414A may be provided on only one of both sides of the first extension body410A in the first direction X, or may be provided on both sides of the first extension body410A in the first direction X.

A second space304A is provided below the narrow portion414A. The second space304A is defined by a recess provided on the upper surface of the first base302A on which the first extension body410A is placed. In the present embodiment, when an overcurrent flows through the first conductor400A and the narrow portion414A melts, the melted narrow portion414A can fall toward the second space304A. Thus, according to the present embodiment, the accuracy of fusing of the narrow portion414A can be improved as compared with a case where the lower surface of the narrow portion414A is in contact with the upper surface of the first base302A.

The height of the second space304A in the third direction Z, that is, the depth of the recess of the first base302A in the third direction Z may be, for example, greater than the thickness of the narrow portion414A in the third direction Z. In this case, the narrow portion414A can be easily fused as compared with a case where the height of the second space304A in the third direction Z is equal to or less than the thickness of the narrow portion414A in the third direction Z. However, the height of the second space304A in the third direction Z may be equal to or less than the thickness of the narrow portion414A in the third direction Z.

In the present embodiment, at least a portion of the narrow portion414A is located above at least one of the positive electrode lead112and the negative electrode lead114. At least a portion of the first base302A is located between at least one of the positive electrode lead112and the negative electrode lead114, and at least a portion of the narrow portion414A, in the third direction Z. Specifically, a portion defining the bottom of the recess in the first base302A is located between at least one of the positive electrode lead112and the negative electrode lead114, and at least a portion of the narrow portion414A, in the third direction Z. Thus, the melted narrow portion414A can be prevented from coming into contact with the positive electrode lead112or the negative electrode lead114located below the narrow portion414A.

The portion of the first base302A located above at least one of the positive electrode lead112and the negative electrode lead114may have heat resistance. For example, a heat-resistant layer may be provided on the bottom surface of the recess of the first base302A. The heat-resistant layer may be metal or a ceramic type or vitreous inorganic material and the like. By providing the heat-resistant layer, the melted narrow portion414A can be more reliably prevented from melting the main body portion of the first base302A and coming into contact with the positive electrode lead112, the negative electrode lead114, or the first wiring440A.

The first wide portion412A is fixed to the first base302A by the first fixture432A. In the present embodiment, the first fixture432A is a screw that penetrates the first wide portion412A in the vertical direction and is inserted into a portion of the first base302A located below the first wide portion412A. The first wide portion412A is provided with a through-hole into which a shaft portion of the first fixture432A can be inserted in the vertical direction. The first fixture432A may be a fixture other than a screw, such as a vis, a bolt, or the like.

The second wide portion416A is fixed to the first base302A by the second fixture434A. In the present embodiment, the second fixture434A is a screw that penetrates the second wide portion416A in the vertical direction and is inserted into a portion of the first base302A located below the second wide portion416A. The second wide portion416A is provided with a through-hole into which a shaft portion of the second fixture434A can be inserted in the vertical direction. The second fixture434A may be a fixture other than a screw, such as a vis, a bolt, or the like.

In the present embodiment, the fixture such as the first fixture432A and the second fixture434A is removable from the first conductor400A. Thus, when, for example, the narrow portion414A is fused, and thus the first conductor400A needs to be replaced, the first conductor400A can be replaced with a new first conductor400A by detaching the fixture such as the first fixture432A and the second fixture434A.

The method of fixing the first conductor400A to the first base302A is not limited to the above-described example. For example, at least a portion of the first conductor400A may be bonded to at least a portion of the first base302A via mechanical bonding such as snap fit.

In the present embodiment, both the first wide portion412A and the second wide portion416A are fixed to the first base302A by the first fixture432A and the second fixture434A. In this case, a force to break the narrow portion414A can be suppressed from being applied to the narrow portion414A, as compared with a case where at least one of the first wide portion412A and the second wide portion416A is not fixed to the first base302A. The force to break the narrow portion414A is generated, for example, when a bus bar (not shown) is attached to the first wide portion412A in order to electrically connect the battery module50to another battery module (not shown), and a fixture (not shown) is fixed to the fastening hole450A. This is because the fastening hole450A and the narrow portion414A are located in substantially the same plane perpendicular to the third direction Z.

The first fixture432A and the second fixture434A are preferably arranged at positions close to the narrow portion414A. For example, the first fixture432A and the second fixture434A are preferably provided at positions facing each other through the first space402A.

In the present embodiment, at least a portion of the first wiring440A passes through the first space402A. In this case, the first wiring440A can be routed in a spatially efficient manner as compared with a case where the first wiring440A passes through a region different from the first space402A.

In the present embodiment, at least a portion of the first wiring440A passes through a portion offset in the horizontal direction from a portion of the first base302A located below the narrow portion414A. In the present embodiment, a through-hole that passes through the first wiring440A is provided on the bottom surface of the recess defining the second space304A in the first base302A. The through-hole is located on the negative direction side of the first direction X from a region directly below the narrow portion414A. Accordingly, the narrow portion414A melted and fallen into the second space304A can be less likely to come into contact with the first wiring440A.

The first wiring440A has one end connected to the second wide portion416A and the other end connected to the first connector330A shown inFIG.3. A portion of the first wiring440A is drawn downward from one end of the first wiring440A connected to the second wide portion416A, and passes through the first space402A and the second space304A. Another portion of the first wiring440A passes through the portion of the first base302A located below the second space304A, and a region between the two rightmost first frames340A. Then, the other portion of the first wiring440A is drawn to the space below the plurality of first frames340A. Still another portion of the first wiring440A passes through the space between adjacent first frames340A in the region offset from the center of the first holding body300A to the right side, and then is drawn from the space below a plurality of first frames340A to the first connector330A located above the plurality of first frames340A. The routing of the first wiring440A is not limited to the example according to the present embodiment.

In the present embodiment, one end of the first wiring440A connected to the second wide portion416A is fixed to the second wide portion416A by the second fixture434A. In the present embodiment, the first wiring440A is easily attached and detached when the narrow portion414A is fused, as compared with a case where the one end of the first wiring440A is fixed to the second wide portion416A by, for example, solder. A connection component such as a crimp terminal may be provided at the one end of the first wiring440A. In this case, the connection component is fixed by the second fixture434A, so that the one end of the first wiring440A can be fixed to the second wide portion416A. However, the method of connecting the one end of the first wiring440A to the second wide portion416A is not limited to this example.

In the present embodiment, the second fixture434A fixes both the second wide portion416A and one end of the first wiring440A connected to the second wide portion416A, to the first base302A. In this case, the number of components can be reduced as compared to a case where a fixture to fix the second wide portion416A to the first base302A and a fixture to fix the one end of the first wiring440A to the first base302A are separately provided. In another example different from the present embodiment, the fixture to fix the second wide portion416A to the first base302A and the fixture to fix the one end of the first wiring440A to the first base302A may be provided separately.

The portion of the second wide portion416A at which the second fixture434A is provided functions as the voltage detection portion that detects the voltage of the terminal positive electrode lead112T. That is, the terminal positive electrode lead112T is a voltage detection target of the portion of the second wide portion416A at which the second fixture434A is provided. The first wiring440A functions as the voltage detection line electrically connected to the voltage detection portion. In the present embodiment, one end of the first wiring440A fixed by the second fixture434A is electrically connected to the second wide portion416A. In this case, as compared to a case where the first wiring440A is electrically connected to the first wide portion412A, the voltage of the terminal positive electrode lead112T can be detected with less influence of the voltage drop in the narrow portion414A, thereby to more accurately detect the voltage of the terminal positive electrode lead112T.

InFIGS.3and6, the second extension body420A is electrically connected to the terminal positive electrode lead112T. In the present embodiment, the right side surface of the second extension body420A and the left side surface of the terminal positive electrode lead112T are bonded to each other by a bonding method such as laser welding. The second extension body420A may not be provided. When the second extension body420A is not provided, the terminal positive electrode lead112T and the first extension body410A can be also electrically connected via an L-shaped bus bar (not shown).

At least a portion of the second extension body420A is held by at least a portion of the first base302A. In the present embodiment, the upper end of the first extension body410A is held by both side surfaces of the through-hole of the first base302A in the second direction Y through which the upper end of the first extension body410A penetrates. The lower end of the second extension body420A is held by both side surfaces of a hole of the first base302A in the second direction Y into which the lower end of the second extension body420A is inserted. The present embodiment is preferable because application of a force to rotate the narrow portion414A in the direction perpendicular to the vertical direction can be suppressed as compared with a case where the second extension body420A is not held by the first base302A. Thus, the breakage of the narrow portion414A can be further suppressed as compared with a case where the second extension body420A is not held by the first base302A.

Hitherto, the embodiment of the present invention has been described above with reference to the drawings, but these are examples of the present invention, and various configurations other than the above description can be adopted.

For example, the first fuse device40A according to the embodiment is electrically connected to the battery cell100. However, the first fuse device40A may be electrically connected to an electronic equipment different from the battery cell100. The same applies to the second fuse device40B.