Battery housing structure

Abstract

To provide a battery housing structure capable of more effectively detecting expansion of a battery.SOLUTION: A battery housing structure has a housing body of a battery. The housing body has different ease of deformation with respect to expansion of the battery between on a first major surface side of the battery and on a second major surface side of the battery.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery housing structure. [Background technology]

[0002] Secondary batteries such as lithium-ion batteries can be used repeatedly by charging, making them highly convenient and therefore used in a wide range of fields, including vehicles, communications, industry, construction, renewable energy, and mobile devices. However, secondary batteries can expand due to the deterioration of the materials used inside them, which causes the electrolyte to gasify and expand. If a secondary battery expands due to deterioration, there is a risk of electrolyte leakage or fire, so the expansion of the secondary battery is detected. For example, a conventional invention proposes attaching four strain gauges to the approximately rectangular main surface of a lithium-ion battery to detect the pressure on the battery surface, and detecting the expansion of the lithium-ion battery based on the measurement values ​​of the four attached strain gauges (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-198765 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a need for a more effective method for detecting the expansion of a secondary battery. The present invention has been made to solve the above problems, and has an object to provide a battery housing structure that can more effectively detect battery expansion.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a battery housing structure that can more effectively detect battery expansion. [Means for solving the problem]

[0006] In order to solve the above problems, the battery housing structure of the present invention has a battery housing, and the housing is characterized in that the ease of deformation due to battery expansion differs between a first main surface side of the battery and a second main surface side of the battery. Effect of the Invention

[0007] According to the present invention, it is possible to provide a battery housing structure that can more effectively detect battery expansion. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of a terminal according to an embodiment. [Diagram 2] 2 is a cross-sectional view of the terminal according to the embodiment taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is a schematic plan view for explaining the center of a battery cell. [Figure 4] 11A and 11B are schematic diagrams for explaining the ease of deformation of a battery container. [Diagram 5] 11A and 11B are schematic diagrams for explaining the ease of deformation of a battery container. [Figure 6] 11A and 11B are diagrams illustrating another example of a battery housing structure. [Figure 7] 11A and 11B are diagrams illustrating another example of a battery housing structure. [Figure 8] 11A and 11B are diagrams illustrating another example of a battery housing structure. [Figure 9] 11A and 11B are diagrams illustrating another example of a battery housing structure. [Figure 10] FIG. 11 is an enlarged cross-sectional view of a portion of another example of a battery housing structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment] Hereinafter, a battery (secondary battery) housing structure according to an embodiment will be described with reference to the drawings. The battery housing structure according to the embodiment is a battery housing structure for a terminal carried by a person being watched (e.g., a child) and used in a so-called monitoring system. In the following description, an example in which the battery housing structure is applied to a terminal used in a monitoring system will be described, but the battery housing structure can be applied to any device that houses a battery.

[0010] As shown in FIG. 1, the terminal 1 has a generally rounded cubic shape and has a configuration in which a case 2 is covered with a cover 3.

[0011] 2, the housing 2 is composed of an upper housing 21 and a lower housing 22 (second member). The upper housing 21 has a rim portion 211A formed along the outer circumferential surface of the lower end portion 211. The lower housing 22 has a groove portion 221A formed along the inner circumferential surface of the upper end portion 221. The rim portion 211A of the upper housing 21 and the groove portion 221A of the lower housing 22 are fitted together, whereby the upper housing 21 and the lower housing 22 are detachably engaged with each other.

[0012] Additionally, the upper housing 21 has a groove 212A formed along the outer circumferential surface of the upper end 212. The cover 3 has a rim 31A formed along the inner circumferential surface of the lower end 31. The groove 212A of the upper housing 21 and the rim 31A of the cover 3 are fitted together, so that the upper housing 21 and the cover 3 are removably engaged. The upper housing 21 and the cover 3 can be attached and detached with a relatively light force.

[0013] The housing consisting of upper housing 21 and lower housing 22 houses a main control board 6 (printed circuit board) on which various electronic components 4 such as semiconductor chips, capacitors, resistors, and detection switches 5 are mounted, a frame 7 (first component), a battery 8 (secondary battery), and the like.

[0014] The frame 7 is fixed to the lower housing 22 with screws (not shown) or the like, and the frame 7 and the lower housing 22 form a housing that houses the battery 8. Note that in this embodiment, the frame 7 is fixed to the lower housing 22 with screws or the like, but the fixing method is not important.

[0015] The detection switch 5 is a switch that detects contact with the frame 7, and is mounted on the frame 7 side of the main control board 6 that is present between the upper housing 21 and the frame 7. That is, the detection switch 5 is provided on the first main surface 81 side of the battery 8. The terminal 1 is configured such that the frame 7 that constitutes the container is interposed between the first main surface 81 of the battery 8 and the detection switch 5 so that the first main surface 81 of the battery 8 and the detection switch 5 do not come into direct contact with each other. In this way, the detection switch 5 and the battery 8 do not come into direct contact with each other, and the force applied to the battery 8 due to contact with the detection switch 5 is dispersed by the frame 7. For this reason, excessive pressure is not applied to the battery 8 due to contact with the detection switch 5, and the structure is such that the exterior of the battery 8 is not easily damaged and the electrolyte inside is not easily leaked. In addition, in the example shown in FIG. 2, the center of the detection switch 5 (see center line L1) is located at a position offset from the center of the battery cell 83A contained in the battery 8 (see center line L2), but this is not limited to the above as long as the detection switch 5 can be mounted on the main control board 6 so that the center of the detection switch 5 is located at a position corresponding to the center of the battery cell 83A contained in the battery 8.

[0016] The frame 7 constituting the housing is provided with a protrusion 72 at a position facing the detection switch 5 on the main surface 71 on the main control board 6 side. The frame 7 constituting the housing is provided with a recess 73 at a position other than the position facing the detection switch 5, specifically, at a position facing the electronic component 4 mounted on the frame 7 side of the main control board 6. The protrusion 72 and the recess 73 are provided to prevent the frame 7 from contacting anything other than the detection switch 5 (for example, the electronic component 4 mounted on the main control board 6) before the frame 7 contacts the detection switch 5 when the battery 8 expands. In this way, by providing the protrusion 72 and the recess 73 on the frame 7, the electronic components 4, the main control board 6, the battery 8, etc. can be densely accommodated in the housing formed by the upper housing 21 and the lower housing 22, and the space in the housing formed by the upper housing 21 and the lower housing 22 can be effectively used.

[0017] In addition, if the frame 7 does not come into contact with anything other than the detection switch 5 (e.g., electronic components 4 mounted on the main control board 6) before the frame 7 comes into contact with the detection switch 5 when the battery 8 expands, it is not necessary to provide at least one of the convex portion 72 and the concave portion 73 on the frame 7. Also, the number of concave portions 73 provided on the frame 7 may not be one. Also, instead of the concave portion 73, an opening one size larger than the electronic components 4 mounted on the frame 7 side of the main control board 6 may be provided to prevent the frame 7 from coming into contact with anything other than the detection switch 5 (e.g., electronic components 4 mounted on the main control board 6) before the frame 7 comes into contact with the detection switch 5. Also, the detection switch 5 may detect contact with the frame 7 by any method as long as it can detect contact with the frame 7.

[0018] The battery 8 in this embodiment is a secondary battery such as a lithium ion battery. When a secondary battery is repeatedly charged and discharged, the electrolyte inside the battery expands or gas is generated inside the battery, causing the battery to expand. If the battery expands, the battery deteriorates and becomes unusable. In this embodiment, the detection switch 5 is configured to detect such a malfunction of the battery 8.

[0019] FIG. 3 is a schematic plan view for explaining the center of the battery cell. The battery 8 has a main part 83 in which the battery cell 83A is accommodated, and a sub part 84 in which a control circuit (not shown) and the like are accommodated. As shown in FIG. 3, in the battery accommodation structure according to this embodiment, in a plan view (projection surface facing the detection switch 5) seen from the first main surface 81 side of the battery 8, the center C1 of the detection switch 5 and the center C2 of the battery cell 83A are in positions that are offset from each other. In other words, in a plan view seen from the first main surface 81 side of the battery 8, the center C1 of the detection switch 5 and the center C2 of the battery cell 83A are in positions that do not overlap each other. In the battery accommodation structure according to this embodiment, the center C2 of the battery cell 83A is the intersection of the diagonals L3 and L4 of the battery cell 83A. In addition, since the battery cell 83A according to this embodiment is rectangular or approximately rectangular in plan view from the first main surface 81 side, the intersection of the diagonals L3 and L4 of the battery cell 83A is set as the center C2 of the battery cell 83A. However, this is not limited to the case where the shape of the battery cell 83A is different in plan view from the first main surface 81 side. For example, if the shape of the battery cell 83A is irregular (e.g., polygonal) in plan view from the first main surface 81 side, the geometric center of gravity of the battery cell 83A may be set as the center of the battery 8. In addition, if two or more battery cells 83A are housed in the battery 8, the intersection of the diagonals or the geometric center of gravity of each battery cell 83A may be set as the center. In this case, there are two or more centers C2.

[0020] 4 and 5 (the battery cell 83A is omitted in FIGS. 4 and 5) are schematic diagrams for explaining the ease of deformation of the frame 7 and the lower housing 22 constituting the housing for the battery 8. FIG. 4 is a schematic cross-sectional view of the housing before the battery 8 expands. FIG. 5 is a schematic cross-sectional view of the housing after the battery 8 expands. In the terminal 1 of this embodiment, the frame 7 on the first main surface 81 side of the battery 8 and the lower housing 22 on the second main surface 82 side of the battery 8 have different degrees of deformation due to the expansion of the battery 8. Specifically, the frame 7 on the first main surface 81 side of the battery 8 and the lower housing 22 constituting the housing for the battery 8 are structured such that the frame 7 on the first main surface 81 side of the battery 8 is more easily deformed than the lower housing 22 on the second main surface 82 side of the battery 8, and as shown in FIGS. 4 and 5, when the battery 8 expands, the frame 7 is deformed more than the lower housing 22.

[0021] Here, any method may be used to make the frame 7 more easily deformable than the lower housing 22. For example, the frame 7 and the lower housing 22 may be made of different materials, so that the frame 7 is more easily deformable than the lower housing 22. For example, the frame 7 may be made more easily deformable than the lower housing 22 by changing the thickness T1 of the frame 7 and the thickness T2 of the lower housing 22. For example, the frame 7 may be made more easily deformable than the lower housing 22 by adopting a structure between the frame 7 and the lower housing 22, such as a honeycomb structure, which improves the rigidity of the lower housing 22. For example, the frame 7 may be made more easily deformable than the lower housing 22 by changing at least two or more of the material, thickness, and structure of the frame 7 and the lower housing 22.

[0022] As described above, the battery housing structure according to this embodiment has a battery housing constituted by the lower housing 22 and the frame 7, and the housing has different susceptibility to deformation in response to expansion of the battery 8 between the first main surface 81 side of the battery 8 and the second main surface 82 side of the battery 8. For example, a detection switch 5 for detecting expansion of the battery 8 is provided on the first main surface 81 side of the battery 8, and the housing is structured so that the first main surface 81 side of the battery 8 is more susceptible to deformation than the second main surface 82 side of the battery 8, whereby the expansion of the battery 8 can be guided to the detection switch 5 side, and the expansion of the battery 8 can be effectively detected.

[0023] Furthermore, in the battery housing structure according to this embodiment, a frame 7 (first member) constituting a housing body is interposed between a first main surface 81 of the battery 8 and the detection switch 5 so that the first main surface 81 of the battery 8 and the detection switch 5 do not come into direct contact with each other. Therefore, the detection switch 5 and the battery 8 do not come into direct contact with each other, and the force applied to the battery 8 due to contact with the detection switch 5 is dispersed by the frame 7. As a result, excessive pressure is not applied to the battery 8 due to contact with the detection switch 5, and the structure is such that the exterior of the battery 8 is not easily damaged and the electrolyte inside is not easily leaked.

[0024] Moreover, in the battery housing structure according to this embodiment, the detection switch 5 is provided at a position offset from the center of the battery cell 83A housed in the battery 8. Because electronic components 4 other than the detection switch 5 are mounted on the main control board 6 on which the detection switch 5 is mounted, it is difficult to provide the detection switch 5 so that the center of the detection switch 5 coincides with a position corresponding to the center of the battery cell 83A that swells most when the battery 8 expands; however, in the battery housing structure according to this embodiment, even if the detection switch 5 is provided on the main control board 6 so that the center of the detection switch 5 is located at a position offset from the center of the battery cell 83A, the expansion of the battery 8 can be effectively detected.

[0025] In the battery housing structure according to the present embodiment, the frame 7 (first member) constituting the housing is provided with a convex portion 72 at a position facing the detection switch 5. In the battery housing structure according to the present embodiment, the frame 7 (first member) constituting the housing is provided with a concave portion 73 at least in a part other than the position facing the detection switch 5. By providing at least one of the convex portion 72 and the concave portion 73 on the frame 7 in this manner, it is possible to prevent the frame 7 from coming into contact with anything other than the detection switch 5 (for example, the electronic component 4 mounted on the main control board 6) before the frame 7 comes into contact with the detection switch 5 when the battery 8 expands. In addition, the electronic components 4, the main control board 6, the battery 8, etc. can be densely housed in the housing formed by the upper housing 21 and the lower housing 22, and the space in the housing formed by the upper housing 21 and the lower housing 22 can be effectively used. As described above, instead of the recess 73, an opening that is slightly larger in plan view than the electronic components 4 mounted on the frame 7 side of the main control board 6 may be provided to prevent the frame 7 from coming into contact with anything other than the detection switch 5 (such as the electronic components 4 mounted on the main control board 6) before it comes into contact with the detection switch 5.

[0026] Furthermore, in the battery housing structure according to this embodiment, the housing constituted by the lower housing 22 and the frame 7 is constructed with different materials on the side of the first main surface 81 of the battery 8 and the side of the second main surface 82 of the battery 8. In this way, by making the side of the first main surface 81 of the battery 8 and the side of the second main surface 82 of the battery 8 out of different materials, for example, by making the frame 7 out of a material that is more easily deformed than the lower housing 22, it is possible to guide the expansion of the battery 8 towards the detection switch 5, and it is possible to effectively detect the expansion of the battery 8.

[0027] Moreover, in the battery housing structure according to this embodiment, the detection switch 5 is provided on the main control board 6 on which electronic components 4 (devices) other than the detection switch 5 are mounted. By providing the detection switch 5 on the main control board 6 on which electronic components 4 other than the detection switch 5 are mounted in this way, the increase in cost due to the provision of the detection switch 5 is suppressed, and the space within the housing formed by the upper housing 21 and the lower housing 22 can be effectively utilized.

[0028] [Modifications of the embodiment] Modifications of the embodiment will be described below with reference to FIGS. 6 to 10 (note that the battery cell 83A is not shown in FIGS. 6 to 9). In the above embodiment, the frame 7 is fixed to the lower housing 22. However, the frame 7 may be in a state where it is not fixed or engaged anywhere on the lower housing 22, in other words, the frame 7 may be in a floating state. In this case, the frame 7 will rise up in response to the expansion of the battery 8, but as shown in Fig. 6, the portion of the frame 7 other than the portion facing the center of the battery cell 83A housed in the battery 8 (the peripheral portion) will follow the expansion of the center of the battery cell 83A which expands the most. Therefore, even if the detection switch 5 cannot be provided in a position facing the center of the battery cell 83A, the peripheral portion of the frame 7 will follow the expansion of the center of the battery cell 83A which expands the most, so that the expansion of the battery 8 can be detected in the same way as if the detection switch 5 was provided so that the center of the detection switch 5 is located in a position facing the center of the battery cell 83A.

[0029] Furthermore, a portion of the frame 7 may be fixed or engaged with the lower housing 22, in other words, the frame 7 may be in a cantilevered state. In this case, the side of the frame 7 opposite to the side fixed or locked to the lower housing 22 (the left side when facing the drawing in the example shown in FIG. 7) follows the expansion of the battery 8, causing the frame 7 to rise. At this time, as shown in FIG. 7, the side of the frame 7 that is not fixed or locked to the lower housing 22 follows the expansion of the center of the battery cell 83A that expands the most. Therefore, even if the detection switch 5 cannot be provided in a position facing the center of the battery cell 83A, the side of the frame 7 that is not fixed or locked to the lower housing 22 follows the expansion of the center of the battery cell 83A that expands the most, so that the expansion of the battery 8 can be detected in the same way as when the detection switch 5 is provided so that the center of the detection switch 5 is located in a position facing the center of the battery cell 83A. Regarding the position at which the frame 7 is fixed or engaged to the lower housing 22, it is preferable to fix or engage the end of the frame 7 to the lower housing 22 at a position opposite the center of the detection switch 5, with the center of the battery cell 83A as the symmetrical point, when viewed in a plan view from the first main surface 81 side of the battery 8.

[0030] Also, a cut hole, opening or slit (hereinafter referred to as a cut hole or the like 74) may be provided in at least a part of the frame 7 constituting the housing other than a predetermined area facing the center of the battery cell 83A housed in the battery 8. In the example shown in Fig. 8, the cut hole or the like 74 provided in the frame 7 is U-shaped so as to surround the detection switch 5 in a plan view, but it is not necessarily required to be U-shaped. The cut holes or the like 74 provided in the frame 7 are preferably provided in at least two directions of the predetermined area facing the detection switch 5. By providing the cut holes 74 in the frame 7 in this manner, even if the frame 7 is not in a floating state, the region 75 surrounded by the cut holes 74 is more likely to be displaced by pressure from the battery cell 83A side than the region other than the region 75 of the frame 7, so that the region 75 surrounded by the cut holes 74 of the frame 7 follows the expansion of the center of the battery cell 83A that expands the most, as shown in Fig. 9. Therefore, even if the detection switch 5 cannot be provided in a position facing the center of the battery cell 83A, the region 75 surrounded by the cut holes 74 of the frame 7 follows the expansion of the center of the battery cell 83A that expands the most, so that the expansion of the battery 8 can be detected in the same way as when the detection switch 5 is provided so that its center is located in a position facing the center of the battery cell 83A.

[0031] As described above, in the battery housing structure according to the modified example of this embodiment, the frame 7 (first member) constituting the housing is in a floating state without being fixed or locked. Therefore, the peripheral portion of the frame 7 follows the expansion of the center of the battery cell 83A, which expands the most, so that the expansion of the battery 8 can be detected in the same way as when the detection switch 5 is provided at a position facing the center of the battery cell 83A.

[0032] Furthermore, in the battery housing structure according to the modified example of this embodiment, the frame 7 (first member) constituting the housing has cut holes 74 or the like provided in at least a part other than a predetermined area facing the center of the battery cell 83A housed in the battery 8. Therefore, the area 75 surrounded by the cut holes 74 of the frame 7 follows the expansion of the center of the battery cell 83A which expands the most, so that the expansion of the battery 8 can be detected in the same way as when the detection switch 5 is provided so that the center of the detection switch 5 is located at a position facing the center of the battery cell 83A.

[0033] In the battery housing structure according to the modified example of this embodiment, the cut holes 74 provided in the frame 7 (first member) are provided in at least two directions in a predetermined area facing the detection switch 5. By providing the cut holes 74 in at least two directions in a predetermined area facing the detection switch 5, it is possible to more reliably follow the expansion of the center of the battery cell 83A.

[0034] In the battery housing structure according to this embodiment, the frame 7 is provided with a protrusion 72 to prevent the frame 7 from contacting anything other than the detection switch 5 (such as the electronic component 4 mounted on the main control board 6) before the frame 7 comes into contact with the detection switch 5 when the battery 8 expands, but as shown in Fig. 10, the frame 7 may not be provided with the protrusion 72, and a rod-shaped switch portion 52 may be provided on the base portion 51 to extend the detection switch 5 (for example, a tactile switch may be used). Alternatively, the frame 7 may be provided with the protrusion 72, and the switch portion 52 of the detection switch 5 may be extended.

[0035] In addition, the above-mentioned embodiments are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited thereby. In other words, the present invention can be implemented in various forms without departing from the gist or main characteristics thereof. [Explanation of symbols]

[0036] 1: Terminal 2: Housing 3: Cover 4: Electronic components 5: Detection switch 6: Main control board 7: Frame (first member) 8: Battery (secondary battery) 21: Upper case 22: Lower housing (second member) 31: Bottom end 31A: Rim section 51: Base part 52: Switch section 71: Main surface 72: Convex 73: Recess 74: Cut holes etc. 75 :Area 81: First main surface 82: Second main surface 83: Main section 83A: Battery cell 84: Sub-section 211: Bottom end 211A: Rim section 212: Upper end 212A:Groove 221: Upper end 221A:Groove T1: Thickness T2: Thickness

Claims

1. Battery and A housing for housing the battery; A contact-type detection switch for detecting the expansion of the battery, The container is The ease of deformation of a first surface side of the battery is different from the ease of deformation of a second surface side of the battery, The detection switch is provided on a first surface side of the battery at a position offset from the center of a battery cell accommodated in the battery. A battery housing structure characterized by the above.

2. a first member constituting the housing is interposed between the first surface of the battery and the detection switch so that the first surface of the battery and the detection switch do not come into direct contact with each other; 2. The battery housing structure according to claim 1 .

3. The container is The battery includes the first member and a second member provided on a second surface side of the battery, The first member is not fixed or engaged with the second member.

3. The battery housing structure according to claim 2.

4. The container is The battery includes the first member and a second member provided on a second surface side of the battery, A part of the first member is fixed or engaged with the second member.

3. The battery housing structure according to claim 2.

5. The detection switch is The first member is provided at a position opposite to a side where the first member is fixed or engaged to the second member from a center of a battery cell accommodated in the battery.

5. The battery storage structure according to claim 4.

6. The first member is A protrusion is provided at a position facing the detection switch.

3. The battery housing structure according to claim 2.

7. The detection switch is The detection switch is provided on a substrate on which devices other than the detection switch are mounted.

2. The battery housing structure according to claim 1 .

8. The second surface side of the battery of the housing is The detection switch and the substrate are configured by at least a part of a housing that accommodates the detection switch and the substrate.

8. The battery housing structure according to claim 7.

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