JP6910802B2 - Battery pack protection structure - Google Patents

Description

The present invention relates to a battery pack protection structure capable of protecting the battery pack from impacts and the like.

Recently, electric vehicles using a motor as a driving force source, particularly so-called saddle-type vehicles such as bicycles and motorcycles, have become widespread. In this type of vehicle, the battery pack powers the motor. The battery pack is removed from the vehicle body when the capacity of the battery in the housing is low, and is attached to, for example, a charger electrically connected to a household power source, whereby charging is performed. The fully charged battery pack is attached to the vehicle body, and the battery side terminal and the vehicle body side terminal are electrically connected. With this connection, it becomes possible to supply electric power from the battery in the housing to the motor (see, for example, Patent Document 1).

It is required to increase the capacity of the battery pack in order to cope with the increase in power consumption in the vehicle. As a result of the use of a larger number of batteries for this purpose, the battery pack has become considerably heavy. As recognized from Patent Document 1, the battery pack is attached to the vehicle body or the charger so as to descend from above, but at this time, the user accidentally attaches the battery pack even though the battery pack is being attached. Once released, the battery pack will begin to descent at a high rate. When such a situation occurs, the battery side terminal and the vehicle body side terminal may collide with each other and both may be deformed.

In order to avoid this, it is recalled to provide a cushioning material in the battery pack. For example, Patent Document 2 describes that a cushioning material and a battery are housed in a housing. Further, Patent Document 3 discloses a battery pack in which a shock absorbing member (cushioning material) is provided on the outer bottom surface of the housing.

Japanese Unexamined Patent Publication No. 11-115873 (see particularly FIGS. 2 and 3) JP-A-2010-123583 (see paragraph [0019] and FIG. 2 in particular). Japanese Unexamined Patent Publication No. 2016-38883 (see paragraph [0042] and FIG. 8 in particular).

The present invention has been made in connection with the above-mentioned techniques, and an object of the present invention is to provide a battery pack protection structure capable of more effectively protecting a battery pack.

In order to achieve the above object, the present invention is a battery pack protection structure for protecting a battery pack detachably housed in a casing.
When the battery pack is housed in the casing, a dilatant body that receives a load from the battery pack and exhibits dilatancy behavior before the battery-side connector and the casing-side connector are engaged is provided. do.

The dilatant body becomes relatively hard when an external force is suddenly applied, while it becomes relatively soft when an external force is applied slowly. Therefore, when the pressing force from the battery pack that descends vigorously is applied, the dilatant body becomes hard, and before the battery-side connector abuts on the casing-side connector, the battery pack is received and temporarily stopped. Therefore, it is possible to prevent the battery-side connector from vigorously contacting the casing-side connector, and thus it is possible to prevent both connectors from being deformed or damaged.

When the battery pack is stopped, the weight of the battery pack acts on the dilatant body. That is, the pressing force applied to the dilatant body becomes slow. As a result, the dilatant body becomes soft and is gradually crushed. As a result, the battery pack is slowly lowered, the battery-side connector and the casing-side connector are spontaneously engaged, and both connectors are electrically connected.

With a simple cushioning material, it is difficult to prevent the battery-side connector from vigorously contacting the casing-side connector if the cushioning action is small. On the contrary, if the buffering action is large, it is necessary to push the battery pack further after the battery pack is stopped. On the other hand, since the dilatant body is used in the present invention, it is possible to prevent the battery-side connector or the casing-side connector from being deformed or damaged, and both connectors are easily engaged with each other.

The dilatant body is configured as, for example, a molded body made of a material exhibiting dilatancy behavior. In this case, it is preferable that the dilatant body is a hollow body. As a result, the dilatant body after the battery pack is stopped is easily crushed. Therefore, both connectors are efficiently engaged.

Further, it is preferable to form a communication hole extending from the inner wall to the outer wall and communicating the hollow inside and the outside in the dilatant body. In this case, when the dilatant body is crushed, the gas inside the hollow is discharged to the outside through the communication hole. Therefore, since the dilatant body is crushed more easily, both connectors can be engaged more efficiently.

Alternatively, the dilatant body may be composed of a foam. In this case as well, the dilatant body is easily crushed in the same manner as described above.

Instead of the molded body, a flexible container containing a dilatancy fluid may be used as the dilatant body. In this case as well, it is possible to prevent the battery-side connector or the casing-side connector from being deformed or damaged as in the case of using the molded body, and both connectors can be easily engaged with each other. become.

The dilatant body may be provided, for example, on the tip surface of the battery pack in the approach direction to the casing. In this case, it is not particularly necessary to provide a dilatant body in the housing body to which the battery pack is attached or the housing of the charger. That is, the dilatant body provided in the battery pack constitutes a battery pack protection structure together with a plurality of types of casings. In short, in this case, it is possible to obtain a battery pack protection structure that can be used for various casings only by providing the battery pack with a dilatant body.

Of course, the dilatant body may be provided at the bottom of the casing (the storage body to which the battery pack is attached, the housing of the charger, etc.).

In the present invention, the battery pack is received by a dilatant body that becomes relatively hard when an external force is suddenly applied and becomes relatively soft when an external force is applied slowly. Therefore, when the battery pack descends vigorously in the casing, the hardened dilatant body receives the battery pack and temporarily stops it before the battery-side connector comes into contact with the casing-side connector. After that, the dilatant body becomes soft and is gradually crushed by the weight of the battery pack. As a result, the battery pack is slowly lowered, the battery-side connector and the casing-side connector are spontaneously engaged, and both connectors are electrically connected.

Therefore, according to the present invention using the dilatant body, it is possible to prevent the battery-side connector or the casing-side connector from being deformed or damaged, and both connectors can be easily engaged with each other.

It is a schematic side view of the electric scooter provided with the battery pack protection structure which concerns on embodiment of this invention. It is a schematic front sectional view of the main part of the battery pack protection structure which concerns on 1st Embodiment. It is a schematic front sectional view of the main part of the battery pack protection structure which concerns on 2nd Embodiment. 4A and 4B are schematic vertical sectional views of a dilatant body having a shape different from that of FIG. 5A to 5C are schematic vertical cross-sectional views of the dilatant body provided with the communication holes. It is the whole schematic vertical sectional view of the dilatant body made of a foam. It is a schematic front sectional view of the main part of the battery pack protection structure which concerns on 3rd Embodiment.

Hereinafter, preferred embodiments of the battery pack protection structure according to the present invention will be given and will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic side view of an electric scooter 10 which is a saddle-type electric motorcycle (vehicle). In the electric scooter 10, a storage chamber 18 for storing the battery pack 16 (see FIG. 2) is formed as an internal space in the seat holding portion 14 holding the seat 12 in which the user is seated. That is, in this case, the seat holding portion 14 which is a part of the vehicle body of the electric scooter 10 serves as a casing for accommodating the battery pack 16. The seat 12 can be rotated by a rotation shaft (not shown) provided on the front side in the traveling direction. The storage chamber 18 is closed by rotating the seat 12 in the direction of being seated on the seat holding portion 14, while the rear end portion of the seat 12 in the traveling direction is rotated in the direction of detaching from the seat holding portion 14. The storage chamber 18 is opened at this time, and the battery pack 16 can be attached or detached. That is, the battery pack 16 is detachably stored in the seat holding portion 14.

The electric scooter 10 further includes a motor 20 as a traveling driving force source arranged in the vicinity of the rear wheels 19. The electric power of the battery pack 16 is supplied to the motor 20.

Next, the battery pack protection structure 30 according to the first embodiment, which is composed of the seat holding portion 14 and the battery pack 16 described above, will be described. In the following, the sheet holding portion 14 is shown schematically in a simplified manner.

As shown in FIG. 2, the battery pack 16 has a housing 32 having a substantially rectangular parallelepiped shape. A large number of batteries (also referred to as "single cells") (also referred to as "single cells") are housed in the housing 32. The electrodes of each battery are electrically connected to a battery-side connector 34 provided on the outer surface of the housing 32 near the front end surface in the approach direction. Here, the battery-side connector 34 is configured by providing a current collecting electrode (not shown) on the stepped portion 35 that is recessed toward the back side of the paper surface.

A vehicle body side connector 36 (casing side connector) is provided on the bottom of the seat holding portion 14 so as to project toward the seat 12. That is, the vehicle body side connector 36 is configured by providing a current collecting electrode (not shown) at the protrusion. As the vehicle body side connector 36 engages with the battery side connector 34, the current collecting electrodes come into contact with each other. As a result, the battery-side connector 34 and the vehicle body-side connector 36 are electrically connected.

Of the four side surfaces of the housing 32, for example, two side surfaces that are in a front-to-back relationship with each other are formed with engagement grooves (not shown). Further, a handle portion 37 gripped by the user is provided on the upper end surface facing the seat 12.

The storage chamber 18 is formed as a space having a substantially quadrangular prism shape so as to correspond to the shape of the battery pack 16. Therefore, the battery pack 16 is prevented from swinging inside the storage chamber 18. On the other hand, an engaging convex portion (not shown) is projected on the inner wall of the storage chamber 18. When the engaging groove engages with the engaging convex portion, the battery pack 16 slides along the engaging convex portion. That is, the engaging groove and the engaging convex portion play a role of preventing the battery pack 16 from being displaced when the battery pack 16 is attached and detached, and guiding the battery pack 16.

Insertion holes 38 are formed through the four corners at the bottom of the storage chamber 18. The legs 42 of the dilatant body 40 are inserted into each insertion hole 38. That is, in the first embodiment, four dilatant bodies 40 are provided at the bottom of the storage chamber 18 (seat holding portion 14 as a casing), and two of them are shown in FIG. Further, a step portion 43 that functions as a stopper is provided at the bottom of the storage chamber 18.

The dilatant body 40 has a retaining portion 44 which is connected to the leg portion 42 and has a larger diameter than the insertion hole 38, and a main body portion 46 exposed in the storage chamber 18. Since the retaining portion 44 functions as a stopper, the leg portion 42 is prevented from being separated from the insertion hole 38. Further, the flat top surface of the main body 46 is located higher than the vehicle body side connector 36. In other words, the upper end surface of the dilatant body 40 is closer to the seat 12 than the upper end surface of the vehicle body side connector 36.

The dilatant body 40 is made of a material exhibiting dilatancy behavior. Here, the dilatancy behavior is known as an event in which the viscosity increases as the shear rate increases. Specifically, it is defined as a property in which the fluidity decreases and becomes a solid state when an external force is rapidly applied, while it exhibits sufficient fluidity and becomes a liquid state when the external force is applied slowly. When the dilatant body 40 is a molded body, the dilatant body 40 becomes hard when a sudden external force is applied, and becomes soft when a slow external force is applied.

Therefore, when the retaining portion 44 of the dilatant body 40 is pushed into the insertion hole 38 from the inside of the storage chamber 18, the retaining portion 44 is deformed. After that, the retaining portion 44 exposed from the insertion hole 38 on the outside of the seat holding portion 14 returns to its original shape. Therefore, it is possible to pass the retaining portion 44 having a diameter larger than that of the insertion hole 38 through the insertion hole 38.

Preferable examples of the material exhibiting dilatancy behavior include polyurethane described in JP-A-5-320305, silicone polymer described in JP-A-2007-516303, and the like. That is, the dilatant body 40 in the first embodiment is a molded body made of such a material.

The battery pack protection structure 30 according to the first embodiment is basically configured as described above, and the effects thereof will be described next.

When inserting the battery pack 16 into the storage chamber 18, the user first grips and conveys the handle portion 37 of the battery pack 16, and then pushes the engaging convex portion formed on the inner wall of the storage chamber 18 into the battery pack 16. Pass through the engagement groove formed on the side surface of. After that, the gripped battery pack 16 may be lowered toward the bottom of the storage chamber 18. During this process, if the handle 37 is released from the user's grip for some reason, the battery pack 16 begins to vigorously descend to the bottom of the storage chamber 18.

Here, the upper end surface of the dilatant body 40 (main body portion 46) is located higher than the upper end surface of the vehicle body side connector 36 as described above. Therefore, the bottom surface of the battery pack 16 comes into contact with the upper end surface of the dilatant body 40 (main body 46) before the battery side connector 34 of the descending battery pack 16 comes into contact with the vehicle body side connector 36. Since the battery pack 16 is in a state of being accelerated by gravity, a sudden pressing force is applied to the dilatant body 40 at the time of contact.

Therefore, the dilatant body 40 has reduced fluidity and becomes a relatively hard elastic body. Therefore, the dilatant body 40 firmly receives the lowered battery pack 16 and stops it. The deformation of the dilatant body 40 at this time is extremely slight because the dilatant body 40 is relatively hard. Therefore, it is effectively prevented that the battery-side connector 34 comes into contact with the vehicle body-side connector 36.

After the main body 46 of the dilatant body 40 receives and stops the battery pack 16, the dilatant body 40 is pressed by the weight of the battery pack 16. That is, a slow external force acts on the dilatant body 40. Therefore, the dilatant body 40 becomes relatively soft and gradually deforms. In other words, the dilatant body 40 is gradually crushed toward the bottom of the storage chamber 18.

With this crushing, the battery pack 16 slowly descends, in other words, gradually descends. Finally, the battery pack 16 comes into contact with the step portion 43 to prevent further descent, and the battery side connector 34 and the vehicle body side connector 36 engage with each other, and the battery constituting the battery pack 16 is transferred to the vehicle body. It becomes possible to supply electric power. The descending speed of the battery pack 16 is slow after coming into contact with the dilatant body 40. Therefore, it is possible to prevent the battery-side connector 34 and the vehicle body-side connector 36 from being deformed or damaged.

When a cushioning material having a large elasticity is used, the cushioning material is greatly elastically deformed when the battery pack 16 comes into contact with the battery pack 16, so that the reduction of the lowering speed of the battery pack 16 becomes insufficient, and the battery side connector 34 becomes the vehicle body side connector. There is a concern that it cannot be sufficiently avoided to come into contact with 36 vigorously. Further, when a cushioning material having a relatively large rigidity is used, the lowering speed of the battery pack 16 can be sufficiently reduced, but the battery pack 16 is stopped before the battery side connector 34 engages with the vehicle body side connector 36. Therefore, it is necessary for the user to press the battery pack 16 in order to engage the battery side connector 34 and the vehicle body side connector 36, which is complicated.

On the other hand, in the first embodiment, a dilatant body 40 that behaves as a hard body immediately after the battery pack 16 comes into contact with the battery pack 16 and then acts as a soft body is used. Therefore, it is possible to prevent the battery-side connector 34 from vigorously contacting the vehicle body-side connector 36, and it is also possible to spontaneously engage the battery-side connector 34 and the vehicle body-side connector 36. That is, it is not necessary for the user to press the battery pack 16, and the work of attaching the battery pack 16 to the electric scooter 10 is simplified accordingly.

After that, if the seat 12 is rotated to close the storage chamber 18, the user can run the electric scooter 10 across the seat 12. During traveling, the battery pack 16 supplies electric power to, for example, the motor 20 which is the traveling driving force source of the electric scooter 10 and electrical equipment such as headlights. Along with this, the capacity of the battery is reduced and charging is required.

At this time, the user may rotate the seat 12 to open the storage chamber 18, grip the handle portion 37, and pull the battery pack 16 out of the storage chamber 18. Even when the handle portion 37 is released from the grip of the user during this process, the dilatant body 40 performs the same function as described above. As a result, it is effectively prevented that the battery-side connector 34 and the vehicle body-side connector 36 come into contact with each other.

As the battery pack 16 is removed from the storage chamber 18, the dilatant body 40 is released from being pressed by the battery pack 16. The dilatant body 40 then returns to its shape before being pressed by the battery pack 16.

Next, the user inserts the battery pack 16 into the outlet of the charger. It is also preferable to provide the dilatant body 40 at the bottom of the outlet of the charger. In this configuration, the battery pack 16 and the housing of the charger form a battery pack protection structure. That is, in this case, the casing is the housing of the charger, and the casing-side connector is the charger-side connector.

Then, when the handle portion 37 is released from the grip of the user while the battery pack 16 is being inserted into the insertion port of the charger, the battery side connector 34 and the charger side connector are momentum by the dilatant body 40 in the same manner as described above. Good contact is prevented. Further, after that, the battery side connector 34 and the charger side connector are spontaneously engaged with each other.

When the dilatant body 40 does not exhibit sufficient dilatancy behavior or is damaged, the dilatant body 40 may be replaced with a new one. At this time, the retaining portion 44 may be appropriately deformed and passed through the insertion hole 38.

Next, the battery pack protection structure 50 according to the second embodiment shown in FIG. 3 will be described. In addition, in order to facilitate understanding, basically the same reference numerals are given to the same components as those shown in FIG.

In this case, the dilatant body 52 is provided at the four corners of the bottom surface of the battery pack 16 (the tip surface in the approaching direction to the storage chamber 18), for example, by sticking. In FIG. 3, two of them are shown. In the second embodiment, the dilatant body 52 is a hollow body, and the opening thereof is closed by the bottom surface of the battery pack 16.

The height of the dilatant body 52 is larger than the protruding height of the vehicle body side connector 36. Therefore, when the battery pack 16 descends in the storage chamber 18, the flat lower end surface of the dilatant body 52 hits the inner bottom surface of the storage chamber 18 before the battery side connector 34 engages with the vehicle body side connector 36. Contact.

Therefore, also in the second embodiment, when the handle portion 37 is released from the user's grip while the user attaches or detaches the battery pack 16, and the battery pack 16 vigorously descends in the storage chamber 18. The dilatant body 52 first behaves as a hard body, and after the battery pack 16 comes into contact with it, it behaves as a soft body. Therefore, as in the first embodiment, the battery-side connector 34 is prevented from vigorously contacting the vehicle body-side connector 36, and the battery-side connector 34 and the vehicle body-side connector 36 are prevented from being lowered after the battery pack 16 is stopped. Spontaneously engage and the two are electrically connected.

Since the dilatant body 52 is a hollow body, the dilatant body 52 is crushed relatively quickly after receiving the battery pack 16. Therefore, the time until the battery-side connector 34 and the vehicle body-side connector 36 engage with each other is shortened.

Further, according to the second embodiment, since the dilatant body 52 is provided on the outer surface of the battery pack 16, a vast work space is secured as compared with the first embodiment in which the dilatant body 40 is provided at the bottom of the storage chamber 18. .. Therefore, the work of providing the dilatant body 52 becomes easy.

In addition, since the dilatant body 52 is provided on the outer surface of the battery pack 16, the battery pack protection structure including the dilatant body 52 together with the seat holding portion 14 (vehicle body) and the battery pack protection formed together with the charger are provided. It can also be used as a structure. Therefore, it is not particularly necessary to provide the dilatant body 52 at the bottom of the storage chamber 18 or the insertion port of the charger. Therefore, the number of dilatant bodies 52 can be reduced, and the work of providing the dilatant bodies 52 becomes easier accordingly.

In both the first embodiment and the second embodiment, the dilatant body is not particularly limited to the shape (conical trapezoidal shape) shown in FIGS. 2 and 3. As an example, a battery pack 16 provided on the bottom surface of the battery pack 16 as in the second embodiment may be a dilatant body 54 having a stepwise smaller diameter as shown in FIG. 4A, or as shown in FIG. 4B. It may be a hemispherical dilatant body 56.

Here, it is preferable that the atmosphere can be derived from the hollow interior of the dilatant bodies 52, 54, 56. For this purpose, as shown in FIGS. 5A to 5C, a communication hole 58 that extends from the inner wall to the outer wall and communicates between the hollow inside and the outside may be formed. In this case, after the dilatant bodies 52, 54, and 56 receive the battery pack 16, they are crushed more quickly. Therefore, the battery-side connector 34 and the vehicle body-side connector 36 are efficiently engaged with each other.

Alternatively, as shown in FIG. 6, a dilatant body 60 made of a foam may be used. Even in this case, since the dilatant body 60 is quickly crushed after receiving the battery pack 16, the battery-side connector 34 and the vehicle body-side connector 36 can be efficiently engaged with each other.

Next, the battery pack protection structure 70 according to the third embodiment shown in FIG. 7 will be described. The same components as those shown in FIGS. 2 and 3 are basically designated by the same reference numerals.

In the third embodiment, the dilatant body 72 is positioned and fixed to the four corners of the bottom of the storage chamber 18. In this case, the dilatant body 72 is formed by accommodating the dilatancy fluid 76 in the hollow rubber ring 74. That is, the rubber ring 74 is an accommodating body and exhibits flexibility based on the fact that the material is rubber.

The dilatancy fluid 76 includes a suspension in which polymer particles such as vinyl chloride, styrene-acrylonitrile copolymer, polystyrene, and polyvinyltoluene are suspended in an appropriate solvent, dimethylpolysiloxane resin, and dimethylpoly crosslinked with boron. Examples thereof include silicone-based polymers such as siloxane resin. The suspension of polymer particles is a liquid, for example, the above-mentioned suspension of silicone-based polymer has a low viscosity and exhibits fluidity when a sudden external force is not applied. That is, when it is allowed to stand, it flows so as to disperse.

In this case, a flat plate-shaped cushioning plate 78 is provided near the bottom of the storage chamber 18. A shaft portion 80 is joined to the lower end surface of the cushioning plate 78, and the shaft portion 80 is passed through an inner hole 82 and an insertion hole 38 of the rubber ring 74. Further, a retaining portion 84 is provided at the tip of the shaft portion 80. The rubber ring 74 is positioned by passing the shaft portion 80 through the inner hole 82 of the rubber ring 74, and the cushioning plate 78 is positioned and prevented from coming off by the retaining portion 84. The shaft portion 80 is slidable with respect to the insertion hole 38.

A passage hole 86 is formed substantially in the center of the buffer plate 78. The vehicle body side connector 36 is located at a position facing the passage hole 86. Further, at the bottom of the storage chamber 18, a step portion 43 that functions as a stopper is provided below the cushioning plate 78.

In the third embodiment, when the handle portion 37 is released from the user's grip while the user attaches or detaches the battery pack 16, and the battery pack 16 vigorously descends in the storage chamber 18, the battery-side connector Prior to the 34 coming into contact with the vehicle body side connector 36, the bottom surface of the battery pack 16 vigorously comes into contact with the upper end surface of the cushioning plate 78. As a result, a sudden external force is applied to the dilatant body 72. For this reason, the dilatancy fluid 76 housed in the rubber ring 74 loses its fluidity substantially and behaves as a solid. That is, the dilatant body 72 becomes relatively hard.

Therefore, the battery pack 16 is temporarily stopped. As a result, the external force applied to the dilatant body 72 becomes slow, so that the dilatancy fluid 76 exhibits fluidity and behaves as a liquid. As a result, the dilatant body 72 becomes relatively soft.

After that, the dilatant body 72 is gradually crushed by the weight of the battery pack 16, and the buffer plate 78 is gradually lowered. At this time, the shaft portion 80 slides in the insertion hole 38, while the vehicle body side connector 36 relatively rises in the passage hole 86. Finally, the cushioning plate 78 abuts on the step portion 43 to prevent further descent, and the battery-side connector 34 and the vehicle body-side connector 36 that has passed through the passage hole 86 and is exposed from the passage hole 86. Engage with each other.

As described above, in the battery pack protection structure 70 using the dilatant body 72 configured by accommodating the dilatancy fluid 76 in the flexible container, the same phenomenon as the battery pack protection structures 30 and 50 occurs. .. As a result, it is possible to prevent the battery-side connector 34 or the vehicle body-side connector 36 from being deformed or damaged.

The present invention is not particularly limited to the first to third embodiments described above, and various modifications can be made without departing from the gist of the present invention.

For example, the battery pack 16 is not limited to the one mounted on the vehicle body, and may be used for other purposes. As the casing, various casings can be applied according to the intended use.

Further, in the third embodiment, it is not particularly necessary to provide the cushioning plate 78, and it may be omitted.

10 ... Electric scooter 14 ... Seat holder 16 ... Battery pack 18 ... Storage chamber 20 ... Motor 30, 50, 70 ... Battery pack protection structure 34 ... Battery side connector 36 ... Body side connector 40, 52, 54, 56, 60, 72 ... Dilatant body 43 ... Step 58 ... Communication hole 74 ... Rubber ring 76 ... Dilatancy fluid 78 ... Buffer plate 86 ... Passing hole

Claims (8)

It is a battery pack protection structure to protect the battery pack that is detachably stored in the casing.
A shock absorber provided in the battery pack, or a shock absorber whose lower end abuts on the inner bottom surface of the casing before the battery-side connector and the casing-side connector engage when the battery pack is housed in the casing. Provided in the casing and provided with a shock absorber whose upper end abuts against the bottom surface of the battery pack when the battery pack is housed in the casing, before the battery-side connector and the casing-side connector engage. ,
The buffer body, when said battery pack is housed in the casing, the battery pack protection structure, characterized in Rukoto such a dilatant material showing a dilatant behavior by receiving a pressing force from the battery pack. The battery pack protection structure according to claim 1 , wherein the dilatant body is made of a molded body. The battery pack protection structure according to claim 2 , wherein the dilatant body is a hollow body. The protection structure according to claim 3 , wherein the dilatant body is formed with a communication hole extending from the inner wall to the outer wall to communicate the hollow inside and the outside. The battery pack protection structure according to claim 2 , wherein the dilatant body is a foam. The protection structure according to claim 1 , wherein the dilatant body has a dilatancy fluid and an accommodating body containing the dilatancy fluid and exhibiting flexibility. The protection structure according to any one of claims 1 to 6 , wherein the buffer is provided on the front end surface of the battery pack in the approach direction to the casing. The battery pack protection structure according to any one of claims 1 to 6 , wherein the shock absorber is provided at the bottom of the casing.

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