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 recharging, making them highly convenient and widely 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 can cause the electrolyte to gasify. If a secondary battery expands due to deterioration, there is a risk of electrolyte leakage or fire, so expansion of the secondary battery is monitored. For example, a conventional invention proposes attaching four strain gauges to the roughly 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 measurements of the four attached strain gauges (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-198765 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a need for a method that can more effectively detect the expansion of a secondary battery. The present invention has been made to solve the above-mentioned 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 view of the above-mentioned 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 body, and the housing body is characterized in that the first main surface side of the battery and the second main surface side of the battery have different susceptibility to deformation in response to battery expansion. [Effects 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 explanation of the drawings]

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

[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 monitored (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 rounded, generally cubic shape, and has a configuration in which a cover 3 is placed on a housing 2.

[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 peripheral surface of the lower end portion 211. The lower housing 22 has a groove portion 221A formed along the inner peripheral 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, upper housing 21 has a groove 212A formed along the outer circumferential surface of upper end 212. Cover 3 has a rim 31A formed along the inner circumferential surface of lower end 31. By fitting groove 212A of upper housing 21 into rim 31A of cover 3, upper housing 21 and cover 3 are configured to be detachably engaged with each other. Note that upper housing 21 and cover 3 can be attached and detached with a relatively light force.

[0013] The housing, which is made up of an upper housing 21 and a lower housing 22, contains 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 member), 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. 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 located between the upper housing 21 and the frame 7. In other words, the detection switch 5 is provided on the first main surface 81 side of the battery 8. Furthermore, the terminal 1 is configured such that the frame 7, which constitutes a housing, 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. In this way, the detection switch 5 and the battery 8 do not come into direct contact, and the force applied to the battery 8 due to contact with the detection switch 5 is dispersed by the frame 7. Therefore, excessive pressure is not applied to the battery 8 due to contact with the detection switch 5, and the battery 8 is less likely to be damaged and leak the electrolyte inside. In addition, in the example shown in Figure 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 housed in the battery 8 (see center line L2), but this is not limited to this 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 housed in the battery 8.

[0016] Frame 7, which constitutes the housing, has a protrusion 72 at a position facing detection switch 5 on main surface 71 on the main control board 6 side. Frame 7, which constitutes the housing, also has a recess 73 at a position other than the position facing detection switch 5, specifically, at a position facing electronic components 4 mounted on the frame 7 side of main control board 6. Protrusion 72 and recess 73 are provided to prevent frame 7 from coming into contact with anything other than detection switch 5 (e.g., electronic components 4 mounted on main control board 6) before it comes into contact with detection switch 5 when battery 8 expands. By providing frame 7 with protrusion 72 and recess 73 in this way, electronic components 4, main control board 6, battery 8, etc. can be accommodated at a high density within the housing formed by upper housing 21 and lower housing 22, and the space within the housing formed by upper housing 21 and lower housing 22 can be used effectively.

[0017] Note that, if the frame 7 does not come into contact with anything other than the detection switch 5 (for example, the electronic component 4 mounted on the main control board 6) before it 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 does not have to be one. Furthermore, instead of the concave portion 73, an opening that is slightly larger than the electronic component 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 (for example, the electronic component 4 mounted on the main control board 6) before it comes into contact with the detection switch 5. Furthermore, the detection switch 5 may detect contact with the frame 7 using 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 internal electrolyte expands or gas is generated inside, causing the battery to expand. If the battery expands, the secondary 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 illustrating the center of a battery cell. The battery 8 has a main section 83 that houses a battery cell 83A and a sub-section 84 that houses a control circuit (not shown) and the like. As shown in FIG. 3, in the battery housing structure according to this embodiment, in a plan view from the first main surface 81 side of the battery 8 (a projection surface facing the detection switch 5), the center C1 of the detection switch 5 and the center C2 of the battery cell 83A are offset from each other. In other words, in a plan view 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 do not overlap each other. In the battery housing structure according to this embodiment, the center C2 of the battery cell 83A is located at the intersection of diagonals L3 and L4 of the battery cell 83A. Note that the battery cell 83A according to this embodiment has a rectangular or substantially rectangular shape in a plan view seen from the first main surface 81 side, and therefore 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 does not apply if the shape of the battery cell 83A is different in a plan view seen from the first main surface 81 side. For example, if the shape of the battery cell 83A is irregular (e.g., polygonal) in a plan view seen 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. Furthermore, if two or more battery cells 83A are housed in the battery 8, the intersection of the diagonals of the battery cells 83A or the geometric center of gravity of each battery cell 83A may be set as the center. In this case, there will be two or more centers C2.

[0020] 4 and 5 (the battery cell 83A is not shown in FIGS. 4 and 5) are schematic diagrams illustrating the ease of deformation of the frame 7 and the lower housing 22 that constitute 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 that faces the first main surface 81 of the battery 8 and the lower housing 22 that faces the second main surface 82 of the battery 8 differ in the ease of deformation due to the expansion of the battery 8. Specifically, the frame 7 that faces the first main surface 81 of the battery 8 and the lower housing 22 that faces the second main surface 82 of the battery 8 are structured so that the frame 7 that faces the first main surface 81 of the battery 8 is more likely to deform than the lower housing 22 that faces the second main surface 82 of the battery 8. As shown in FIGS. 4 and 5, when the battery 8 expands, the frame 7 deforms more greatly than the lower housing 22.

[0021] Here, any method can 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, thereby making the frame 7 more easily deformable than the lower housing 22. Alternatively, 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. Alternatively, 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, that improves the rigidity of the lower housing 22. Alternatively, 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 made up of the lower housing 22 and the frame 7, and the housing has different susceptibility to deformation in response to expansion of the battery 8 on the side of the first main surface 81 of the battery 8 and on the side of the second main surface 82 of the battery 8. For example, by providing the detection switch 5 for detecting expansion of the battery 8 on the side of the first main surface 81 of the battery 8 and configuring the housing so that the side of the first main surface 81 of the battery 8 is more susceptible to deformation than the side of the second main surface 82 of the battery 8, the expansion of the battery 8 can be guided toward the detection switch 5, 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 the housing 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. This prevents the detection switch 5 from coming into direct contact with the battery 8, 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, causing the internal electrolyte to leak.

[0024] Furthermore, 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 its center coincides with the 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 its center is offset from the center of the battery cell 83A, expansion of the battery 8 can be effectively detected.

[0025] Furthermore, in the battery housing structure according to this embodiment, frame 7 (first member) constituting the housing is provided with a convex portion 72 at a position facing detection switch 5. Furthermore, in the battery housing structure according to this embodiment, frame 7 (first member) constituting the housing is provided with a concave portion 73 in at least a portion other than the position facing detection switch 5. By providing at least one of convex portion 72 and concave portion 73 on frame 7 in this manner, when battery 8 expands, it is possible to prevent frame 7 from coming into contact with anything other than detection switch 5 (for example, electronic components 4 mounted on main control board 6, etc.) before it comes into contact with detection switch 5. Furthermore, electronic components 4, main control board 6, battery 8, etc. can be densely housed within the housing formed by upper housing 21 and lower housing 22, and the space within the housing formed by upper housing 21 and lower housing 22 can be used effectively. 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 (for example, 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 made up of 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 using 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, for example, by using a material in the frame 7 that is more easily deformed than the lower housing 22, expansion of the battery 8 can be guided toward the detection switch 5, and expansion of the battery 8 can be effectively detected.

[0027] Furthermore, 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 used effectively.

[0028] [Modification 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, but the frame 7 may be in a state where it is not fixed or locked 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 will expand 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 will expand most, so that the expansion of the battery 8 can be detected in the same way as if the detection switch 5 were provided so that its center was positioned facing the center of the battery cell 83A.

[0029] Furthermore, a part of the frame 7 may be fixed or locked to the lower housing 22, in other words, the frame 7 may be cantilevered. 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 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 positioned 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] Furthermore, a cutout, opening, or slit (hereinafter referred to as a cutout 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 cutout 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 this does not necessarily have to be U-shaped. It is preferable that the cutout or the like 74 provided in the frame 7 be provided in at least two directions in the predetermined area facing the detection switch 5. By providing the cutouts 74 etc. in the frame 7 in this way, even if the frame 7 is not in a floating state, the area 75 surrounded by the cutouts 74 etc. is more likely to be displaced by pressure from the battery cell 83A side than the area other than the area 75 of the frame 7, so that the area 75 surrounded by the cutouts 74 of the frame 7 follows the expansion of the center of the battery cell 83A which expands most, as shown in Fig. 9. Therefore, even if the detection switch 5 cannot be provided in a position opposite the center of the battery cell 83A, the area 75 surrounded by the cutouts 74 of the frame 7 follows the expansion of the center of the battery cell 83A which expands 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 positioned opposite 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, not 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, and it is possible to detect the expansion of the battery 8 in the same way as if the detection switch 5 were provided in 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 cutouts 74 or the like 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 cutouts 74 of the frame 7 follows the expansion of the center of the battery cell 83A, which expands most, and therefore it is possible to detect the expansion of the battery 8 in the same way as when the detection switch 5 is provided so that the center of the detection switch 5 is positioned facing the center of the battery cell 83A.

[0033] Furthermore, in the battery housing structure according to the modified example of this embodiment, the cutouts 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 cutouts 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] Furthermore, in the battery housing structure according to this embodiment, when the battery 8 expands, the frame 7 is provided with a protrusion 72 to prevent the frame 7 from coming into contact with anything other than the detection switch 5 (for example, electronic components 4 mounted on the main control board 6) before the frame 7 comes into contact with the detection switch 5. However, as shown in Fig. 10, instead of providing the protrusion 72 on the frame 7, 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 a protrusion 72, and the switch portion 52 of the detection switch 5 may be extended.

[0035] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereby. In other words, the present invention can be carried out 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 housing 22: Lower housing (second member) 31: Bottom end 31A: Rim section 51: Base part 52: Switch section 71: Main surface 72: Convex part 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 that houses the battery; a contact-type detection switch that detects the expansion of the battery; The container is The ease of deformation of the first surface side of the battery and the ease of deformation of the second surface side of the battery are different from each other, the detection switch is provided on a substrate on which devices other than the detection switch are mounted, and is provided on a first surface side of the battery at a position shifted from the center of a battery cell accommodated in the battery; A battery housing structure characterized by:

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 first member and a second member provided on a second surface side of the battery, The first member is not fixed or locked to the second member.

3. The battery housing structure according to claim 2.

4. The container is the first member and a second member provided on a second surface side of the battery, a structure in which a part of the first member is fixed or locked to the second member, The detection switch is the first member is provided at a position opposite to the side where the first member is fixed or engaged with the second member from the center of a battery cell housed in the battery; 3. The battery storage structure according to claim 2.

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

3. The battery housing structure according to claim 2.

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

2. The battery housing structure according to claim 1.

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