Battery pack

Abstract

To provide a battery pack capable of confirming a cut-off state of a current path from the outside.SOLUTION: The present disclosure provides a battery pack including an outer case and a battery module housed in the outer case, wherein the outer case includes a connector electrically connected to the battery module and a heat-sensitive deformation portion positioned on an outer surface of the outer case, the battery module includes a battery and a tab electrically connected to the battery and the connector, the tab includes a fusible portion, and the heat-sensitive deformation portion and the fusible portion are connected to each other in a heat conductive manner.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack. [Background technology]

[0002] Patent Document 1 discloses a bus bar that electrically connects external terminals of different energy storage elements in an energy storage device. The bus bar has a fusible portion that is narrower than other portions. When an overcurrent flows, heat generated in the bus bar is trapped in the fusible portion, and the high temperature causes the fusible portion to melt, thereby interrupting the current path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-029309 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, the inventors of the present application have found that the structure described in Patent Document 1 still has room for improvement in the following respects: In the structure described in Patent Document 1, the fusible part that interrupts the current path is located inside the electricity storage device, so it is not possible to check from the outside whether the current path has been interrupted. As a result, there is a risk that an electricity storage device whose current path has already been interrupted may be mistakenly reused.

[0005] The present disclosure has been made in view of the above-mentioned problems, and a main object of the present disclosure is to provide a battery pack that allows the interruption of a current path to be confirmed from the outside. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have come up with the invention of a battery pack that achieves the above-mentioned main object.

[0007] A battery pack according to an embodiment of the present disclosure includes an outer case and a battery module housed in the outer case, the exterior case includes a connector electrically connected to the battery module and a heat-sensitive deformation portion positioned on an outer surface of the exterior case; the battery module includes a battery and a tab electrically connected to the battery and the connector; the tab comprises a fusible portion; The heat-sensitive deformation portion and the fusible portion are connected to each other so as to be capable of conducting heat. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, a battery pack is provided that allows for external confirmation of the interruption status of a current path. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view showing the appearance of a battery pack according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic side view of the battery pack shown in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the AA cross section of the battery pack shown in FIG. [Figure 4] FIG. 4 is a schematic side view of the battery pack shown in FIG. 1, excluding the outer case. [Figure 5] FIG. 5 is a schematic perspective view of a tab according to one embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic circuit diagram of a battery pack according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic cross-sectional view showing the CC cross section of the battery pack shown in FIG. [Figure 8] FIG. 8 is a schematic enlarged cross-sectional view of part D of the battery pack shown in FIG. [Figure 9] FIG. 9 is a schematic enlarged cross-sectional view showing a state in which the fusible portion is broken. [Figure 10A]FIG. 10A is a schematic enlarged view showing part B of the battery pack shown in FIG. 2 before the fusible portion breaks. [Figure 10B] FIG. 10B is a schematic enlarged view showing part B of the battery pack shown in FIG. 2 after the fusible portion has broken. [Figure 11] FIG. 11 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. [Figure 12A] 12A is a schematic enlarged view showing the state of the heat-sensitive deformation portion before the fusible portion breaks in the battery pack shown in FIG. 11. FIG. [Figure 12B] 12B is a schematic enlarged view showing the state of the heat-sensitive deformation portion after the fusible portion breaks in the battery pack shown in FIG. [Figure 13] FIG. 13 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. [Figure 14] FIG. 14 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. [Figure 15] FIG. 15 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. [Figure 16] FIG. 16 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. [Figure 17] FIG. 17 is a schematic enlarged view showing the state of the heat-sensitive deformation portion after the fusible portion breaks in the battery pack shown in FIG. [Figure 18] FIG. 18 is a schematic enlarged view showing the vicinity of a heat-sensitive deformation portion of a battery pack according to another embodiment. [Figure 19] FIG. 19 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. [Figure 20] FIG. 20 is a schematic enlarged cross-sectional view of a battery pack according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes specific embodiments of the present disclosure. The applicant provides the following description and examples to enable those skilled in the art to fully understand the present disclosure, and it should be noted that these are not intended to limit the subject matter described in the claims. In other words, the present disclosure is not particularly limited to the embodiments described below, and can be implemented with appropriate modifications within the scope of its purpose. For convenience, the present disclosure may be divided into embodiments, etc., in consideration of ease of explanation or understanding of the main points. However, partial substitution and / or combination of the configurations shown in different embodiments, etc. is possible. In describing such embodiments, redundant explanations of substantially identical matters may be omitted, and only differences may be described. In particular, similar actions and effects resulting from similar configurations may not be mentioned in each embodiment.

[0011] The various numerical ranges referred to herein are intended to include the lower and upper numerical limits themselves unless otherwise specified, and the term "about" means that there may be a variation or difference of a few percent, for example, ±10%.

[0012] A battery pack according to an embodiment of the present disclosure will be described below with reference to the drawings. Although the description will be made with reference to the drawings as needed, the contents shown in the drawings are merely shown as schematic examples for the purpose of understanding the present disclosure, and the appearance, dimensional ratios, etc. may differ from the actual product.

[0013] In this specification, the "Z direction" refers to the thickness direction of an object (e.g., a battery pack), and a drawing viewed from the Z direction is a top view. The "Y direction" refers to the height direction of a battery housed in a battery pack, and a drawing viewed from the Y direction is a front view. The "X direction" refers to the direction perpendicular to the Z and Y directions, and a drawing viewed from the X direction is a side view. In other words, the X, Y, and Z directions are intended to be perpendicular to each other. Note that, although the X, Y, and Z directions are shown in the drawings, the direction of the arrows refers to the positive direction (or + direction), and the direction opposite to the arrows refers to the negative direction (or - direction).

[0014] In this specification, "cross-sectional view" corresponds to viewing a cross section cut along a direction perpendicular to the thickness of any surface of the outer case CS, from a direction perpendicular to the extension direction of the cross section. Furthermore, in this specification, "planar view" corresponds to viewing an object from a direction perpendicular to the extension direction of any surface of the outer case CS (i.e., the thickness direction of the surface).

[0015] The present disclosure relates to a configuration of a battery pack that houses a battery module. First, in order to understand the overall structure of the battery pack of the present disclosure, the basic configuration of the battery pack and battery module of the present disclosure will be described below with reference to the drawings.

[0016] [Basic configuration of battery pack] A battery pack BP according to the present disclosure will be described with reference to Figs. 1 to 3. Fig. 1 is a schematic perspective view showing the appearance of a battery pack BP according to one embodiment of the present disclosure. Fig. 2 is a schematic side view of the battery pack BP shown in Fig. 1. Fig. 3 is a schematic cross-sectional view showing the AA cross section of the battery pack BP shown in Fig. 1. Fig. 4 is a schematic side view of the components of the battery pack shown in Fig. 1, excluding the outer case CS, viewed from the -X direction.

[0017] The battery pack BP may include an outer case CS and a battery module BM housed in the outer case CS (see FIGS. 1 and 3). The battery module BM will be described in detail below.

[0018] The outer case CS may have a box-like shape that defines a storage space for accommodating the battery module BM. The outer case CS can also be understood as an outer casing that surrounds the battery module BM, and may also be referred to as a pack outer casing, etc. For example, the outer case CS may be located on the terminal side of the batteries accommodated in the battery pack, and may have a box-like shape with two opposing end faces CS1 and a side face CS2 that connects the two end faces CS1. Such an outer case CS may, for example, define a storage space by combining two or more case members.

[0019] The outer case CS may be provided with a connector CN that is electrically connected to the battery module BM. The connector CN can function as a terminal for extracting power from the battery module BM. The connector CN may be provided on the outer surface CSa of the outer case CS. In the exemplary battery pack BP shown in FIG. 1, the connector CN is provided on the side surface CS2 of the outer case CS, but the location of the connector CN is not limited to this. For example, the connector CN may be located on the end surface CS1 of the outer case CS.

[0020] [Basic configuration of battery module] The battery module BM of the present disclosure will be described with reference to FIGS.

[0021] The battery module BM of the present disclosure may mainly include a battery CB, a battery holder HD, a tab 3, and a control board SB. Each component will be described in detail below.

[0022] -battery- The battery CB is intended to be a chemical battery that converts mainly chemical energy into DC power through a chemical reaction. The battery CB used in the battery module BM shown in Figures 3 and 4 is a cylindrical battery with a cylindrical axis in the ±Y direction, but the shape of the battery is not particularly limited. For example, a battery CB having a shape other than a cylindrical shape (e.g., an elliptical cylinder, a rectangular column, a polygonal column, etc.) may also be used.

[0023] The battery module BM of the present disclosure may include two or more batteries CB. The batteries CB may be arranged adjacent to each other. For example, in the embodiment shown in FIG. 3, five batteries CB may be arranged in a row adjacent to each other in the X direction, and arranged in a matrix with two rows stacked in the +Z direction (a total of ten batteries CB may be included). For example, as shown in FIG. 3, the batteries CB may be arranged in a staggered manner so that the batteries CB in each row are staggered when viewed from the Y direction. Note that the number of batteries and the row stacking arrangement are not limited to those shown in FIG. 3.

[0024] -Battery holder- The battery holder HD may function as a member that holds and / or fixes the battery CB within the storage space of the outer case CS. For example, as shown in FIG. 2, the battery holder HD may be provided on the +Z and -Z sides of the battery CB. In other words, the battery holder HD may fit into the battery CB so as to sandwich it from both sides in the ±Z directions, restricting movement of the battery CB within the outer case CS. The number of battery holders HD is not particularly limited, and the battery holder HD may be composed of two or more members.

[0025] For example, as shown in FIG. 2, three types of battery holders HD1 to HD3 may be used, positioned between multiple batteries CB and between the batteries CB and other components. Specifically, the battery pack BP may include a first battery holder HD1 positioned between the batteries CB and the control board SB, a second battery holder HD2 extending along the side of the outer case CS on the -Z direction and positioned between the outer case CS and the batteries CB, and a third battery holder HD3 positioned between rows of batteries CB. The first battery holder HD1 and the second battery holder HD2 may be positioned to fill the gap between the batteries CB and the control board SB or between the batteries CB and the outer case CS. For example, the first battery holder HD1 and the second battery holder HD2 may have side surfaces that curve along the outer periphery of the batteries CB, allowing them to come into contact with the batteries CB. This may limit movement of the batteries CB in the ±X directions within the outer case CS.

[0026] More specifically, the first battery holder HD1 maintains an appropriate distance between the exterior case CS and the battery CB, and contributes to maintaining the positions of the control board SB and the battery CB within the exterior case CS, while the second battery holder HD2 contributes to maintaining the distance between the exterior case CS and the battery CB.

[0027] The third battery holder HD3 may be disposed between adjacent rows of batteries CB. The third battery holder HD3 may have a shape that conforms to the side shape of the batteries CB so as to fit into the gaps between the rows of batteries CB. Such a third battery holder HD3 may appropriately maintain the spacing between the batteries CB. For example, as shown in FIG. 3, the battery pack BP may have multiple third battery holders HD3. The multiple third battery holders HD3 may have the same shape, or some of the third battery holders HD3 may have different shapes, such as a shape with a recessed portion, as shown in FIG. 3, as shown in FIG. 3. Alternatively, the third battery holder HD3 may be formed as a single, integrally molded member.

[0028] The provision of the battery holder HD as described above can appropriately maintain the position of the batteries CB within the outer case CS (e.g., the spacing between the batteries CB). This can prevent damage to the battery pack BP due to unintended movement of the batteries CB. For example, a metal plate, which is typically used as the material for the tabs 3, can effectively prevent deformation of the tabs 3 due to buckling caused by movement of the batteries CB, and separation of the tabs 3 from the batteries CB.

[0029] The shape of the battery holder HD is not particularly limited as long as it can maintain the battery CB in the above-described position. For example, the battery holder HD may be a single member made of one component, and the battery CB may be held and / or fixed by inserting the battery CB from the +Y or -Y direction. Furthermore, the direction in which the battery holder HD sandwiches the battery CB is not limited to the ±Z direction, and the battery holder HD may be configured to sandwich the battery CB from both the ±Y directions.

[0030] At least a portion of the positive terminal PT and the negative terminal NT of the battery CB may be exposed from the battery holder HD. The positive terminal PT and the negative terminal NT that are not covered by the battery holder HD may be electrically connected to the tab 3. In other words, the tab 3 may be electrically connected to the battery CB in the area that is not covered by the battery holder HD.

[0031] -tab- As shown in Fig. 3, the tab 3 may electrically connect the positive electrode terminals PT and / or the negative electrode terminals NT of adjacent batteries CB. The tab 3 is electrically conductive. In this specification, "electrically conductive" means a material having a volume resistivity of 10 5 For example, as shown in Fig. 3, two adjacent batteries CB located in different rows may be electrically connected in series by electrically connecting the positive terminal PT of one battery CB with the negative terminal NT of the other battery CB.

[0032] The tab 3 can function as an electrical connection member that electrically connects the batteries CB and / or the batteries CB and a control board SB (described later). Such tab 3 includes a fusible portion 32 that can be melted when an overcurrent flows. Specifically, the fusible portion 32 can be broken by melting due to Joule heat generated when an overcurrent flows. Such a fusible portion 32 can function as a so-called fuse that cuts off an electric circuit by melting when an overcurrent flows through the electric circuit. The fusible portion 32 can also be called, for example, a fuse, a fusible link, a thermal melting portion, an overcurrent interrupting portion, or a fusible portion.

[0033] The fusible portion 32 may be provided at any location on the tabs 3 that constitute the electrical circuit of the battery pack BP. For example, the fusible portion 32 may be provided on a tab that electrically connects multiple batteries CB. Alternatively, as shown in FIG. 4 and other figures, the fusible portion 32 may be provided on a tab that connects the batteries CB and the control board SB. Specifically, the fusible portion 32 may be located between a first tab 34 electrically connected to the batteries CB and a second tab 36 electrically connected to the control board SB, and may electrically connect the first tab 34 and the second tab 36 to each other. In other words, the first tab 34 and the second tab 36 may be electrically connected via the fusible portion 32. In this structure, when the fusible portion 32 melts, the electrical connection between the control board SB and the batteries CB is interrupted.

[0034] The material and shape of the fusible portion 32 are not particularly limited as long as it can be melted by an overcurrent. For example, the fusible portion 32 may be made of a low-melting-point material that melts when heated by an overcurrent. The fusible portion 32 may be made of a material different from that of the other portions (e.g., the first tab 34 and the second tab 36) and may be electrically connected to the other portions using various fastening means such as crimping.

[0035] Alternatively, the fusible portion 32 may have a structure that has a higher electrical resistance than portions of the tab 3 other than the fusible portion 32, thereby locally increasing the amount of heat generated when an overcurrent flows. FIG. 5 is a partial enlarged view that schematically illustrates the fusible portion of an exemplary tab 3. For example, as shown in FIG. 5, the width dimension of the tab 3 may be locally reduced at the fusible portion 32, thereby locally increasing the electrical resistance at the fusible portion 32. Such a fusible portion 32 may be made of the same material as the tab 3. For example, the tab 3 and the fusible portion 32 may be integrally formed.

[0036] -Control board- In FIG. 3 showing an example, the control board SB may be disposed on the outer surface of the battery holder HD. The control board SB may be electrically connected to the tab 3. The control board SB may be electrically connected to the battery CB via the tab 3. As a result, the control board SB may receive power from the battery CB via the tab 3 connected to the control board SB. The control board SB may also control the power output from the battery CB via the tab 3.

[0037] The battery pack BP may include additional components. For example, as shown in Figures 3 and 4, an insulating member INS may be disposed between the battery CB and the tab 3 to prevent a short circuit between the battery CB and the tab 3.

[0038] [Features of the battery pack disclosed herein] The battery pack of the present disclosure is characterized by having a structure that allows the fusion state of the fusible portion 32 to be determined from outside the outer case CS. Details of this feature will be described below with reference to the drawings.

[0039] As shown in FIG. 2, the exterior case CS has a heat-sensitive deformable portion 10 on its outer surface CSa. In this specification, the term "heat-sensitive deformable portion" simply refers to a portion configured to be deformable in response to temperature. More specifically, the heat-sensitive deformable portion 10 is a portion configured to be deformable by application of heat to such an extent that the presence or absence of deformation can be visually determined. In other words, the heat-sensitive deformable portion 10 is a portion that can be deformed to such an extent that the difference between the shape before and after application of heat can be visually determined. The manner of deformation is not particularly limited as long as it is visually identifiable, but examples include deformation due to partial melting, expansion, contraction, fracture, and / or melting. Such heat-sensitive deformable portion 10 can also be referred to as a thermally deformable portion, a heat-responsive shape-changing portion, a heat-responsive shape-changing portion, or the like.

[0040] The heat-sensitive deformation portion 10 is thermally conductively connected to the fusible portion 32 of the tab 3 housed in the outer case CS. "Connected thermally conductively" is not limited to a direct connection, but also includes a connection via any thermally conductive member. In other words, the battery pack BP of the present disclosure may be configured so that heat generated in the fusible portion 32 can propagate to the heat-sensitive deformation portion 10. This configuration can also be interpreted as the heat-sensitive deformation portion 10 being thermally connected to the fusible portion 32. This structure allows the heat-sensitive deformation portion 10 to change shape in response to the heat generated in the fusible portion 32.

[0041] As described above, the fusible portion 32 melts due to Joule heat generated by an abnormal overcurrent. The heat generated at this time propagates to the heat-sensitive deformation portion 10 located on the outer surface CSa of the outer case CS, allowing the heat-sensitive deformation portion 10 to deform. The heat-sensitive deformation portion 10 is configured to be deformable in response to heat propagated from the fusible portion 32 when it reaches a temperature at which the fusible portion 32 melts due to an overcurrent (hereinafter simply referred to as the "fusing temperature"). Simply put, when the fusible portion 32 of the tab 3 reaches its fusing temperature, a change in shape occurs in the heat-sensitive deformation portion 10 of the outer case CS. More specifically, the heat-sensitive deformation portion 10 becomes deformable when the fusible portion 32 reaches its fusing temperature and the temperature rises to a predetermined temperature due to the heat propagated from the fusible portion 32. On the other hand, the heat-sensitive deformation portion 10 does not deform when the temperature of the fusible portion 32 is below its fusing temperature.

[0042] According to the configuration of the present disclosure, the heat-sensitive deformable portion 10 can function as an indicator of the melting state of the fusible portion 32. An operator can determine whether the melting temperature of the fusible portion 32 has been reached by checking whether there is a change in the shape of the heat-sensitive deformable portion 10 on the outer surface CSa of the outer case CS. In other words, it becomes possible to check the melting state of the fusible portion 32 inside the outer case CS from outside the outer case CS.

[0043] According to the present disclosure, the fusion state of the fusible portion 32 can be determined indirectly from the outside without the need for direct visual inspection, such as by installing an opening such as a window in the outer case CS or by disassembling the battery pack BP. This makes it possible to determine the fusion state of the fusible portion 32 without exposing the battery module BM housed in the outer case CS to the outside. Therefore, when checking the fusion state of the fusible portion 32, it is possible to effectively prevent foreign matter such as moisture and / or dust from entering the battery module BM.

[0044] The configuration of the battery pack of the present disclosure can also be advantageous when multiple fusible portions 32 are included. For example, one possible way to check the fused state of the fusible portions 32 is to check their continuity. However, when a battery pack includes multiple fusible portions 32, it is difficult to determine from the outside which fusible portion 32 has fused.

[0045] In particular, when the battery module BM has a parallel circuit in which multiple sets of batteries CB are connected in parallel, at least one fusible part 32 may be incorporated for each of the battery CB sets. FIG. 6 shows a schematic circuit diagram of an exemplary battery pack BP having a parallel circuit. As shown in the figure, the battery pack BP may include two battery sets CBs and CBsA each consisting of multiple batteries CB. The positive electrode PE of the battery set CBs may be connected to the positive electrode PE of the battery set CBsA and may be led to the external positive terminal PTE of the connector CN (see FIG. 1). Similarly, the negative electrode NE of the battery set CBs may be connected to the negative electrode NE of the battery set CBsA and may be led to the external negative terminal NTE of the connector CN. In this way, the battery sets CBs and CBsA may be connected in parallel. A fusible part 32, 32A may be inserted into each of the two battery sets CBs and CBsA. The outer case CS may include a plurality of heat-sensitive deformable portions 10, 10A connected to each of the fusible portions 32, 32A in a heat-conductive manner (see FIG. 3). Specifically, the outer case CS may include a heat-sensitive deformable portion 10 connected to the fusible portion 32 in a heat-conductive manner, and a heat-sensitive deformable portion 10A connected to the fusible portion 32A in a heat-conductive manner.

[0046] If an abnormal current flows through a battery module BM in such a parallel circuit, when one of the multiple fusible parts 32 melts, the applied voltage to the circuit may temporarily drop, potentially preventing the other fusible parts 32 from blowing. In other words, the battery module BM may contain battery CB sets whose fusible parts 32 have melted and battery CB sets whose fusible parts 32 have not melted. In such a battery module BM, the electrical circuit is not completely interrupted, so it is not possible to determine the melted state of the fusible parts 32 based on the presence or absence of continuity. When such a battery module BM is used normally, the number of parallel-connected batteries CBs required for parallel connection may not be secured, and an overcurrent greater than that expected by the design may flow through the remaining battery CB sets whose circuits remain.

[0047] According to the present disclosure, by providing a plurality of heat-sensitive deformable portions 10 connected to each of the plurality of fusible portions 32 in a manner that allows thermal conduction, the fused state of each of the plurality of fusible portions 32 can be visually confirmed from the outside of the outer case CS. In other words, it is possible to confirm from the outside of the battery pack BP which of the plurality of fusible portions 32 has fused, and whether or not there are any fusible portions 32 that have not fused. In this way, by clearly indicating from the outside whether or not a fusible portion 32 has fused, it is possible to prevent continued use of a battery pack BP in which a fault has occurred.

[0048] 7 is a cross-sectional view schematically showing the CC cross section of the heat-sensitive deformation unit 10 shown in FIG. 3. The BB cross section is a cross section taken along the thickness direction T of the surface of the outer case CS on which the heat-sensitive deformation unit 10 is located (hereinafter simply referred to as the "thickness direction T of the outer case CS"). As shown in the figure, the heat-sensitive deformation unit 10 and the fusible unit 32 may be arranged opposite each other in the thickness direction T of the outer case CS. For example, the heat-sensitive deformation unit 10 and the fusible unit 32 may be positioned coaxially in the thickness direction T of the outer case CS. In this specification, "positioned coaxially" means that the heat-sensitive deformation unit 10 and the fusible unit 32 are positioned so that they at least partially overlap when viewed in the thickness direction T of the outer case CS.

[0049] According to this structure, the heat-sensitive deformation portion 10 is disposed on the outer surface CSa of the exterior case CS at a position corresponding to the location of the fusible portion 32. This shortens the distance between the heat-sensitive deformation portion 10 and the fusible portion 32, allowing heat from the fusible portion 32 to be more efficiently transmitted to the heat-sensitive deformation portion 10. This allows the heat-sensitive deformation portion 10 to more efficiently reflect the fusion state of the fusible portion 32.

[0050] Furthermore, by arranging the heat-sensitive deformable portions 10 in positions corresponding to the fusible portions 32 inside the outer case CS, an operator can ascertain the positions of the fusible portions 32 from outside the outer case CS. This structure is particularly useful when the battery module BM includes multiple fusible portions 32. For example, multiple heat-sensitive deformable portions 10 may be arranged in positions corresponding to the multiple fusible portions 32. By visually checking each heat-sensitive deformable portion 10 from outside the outer case CS, an operator can easily confirm which position of the fusible portion 32 has fused. In other words, according to the present disclosure, the position of the fused fusible portion 32 can be visually confirmed from outside the outer case CS.

[0051] The fusible portion 32 may be in contact with the inner surface CSb of the outer case CS at a position facing the heat-sensitive deformation portion 10. In other words, the outer case CS may have the heat-sensitive deformation portion 10 on the outer surface CSa, while being in contact with the fusible portion 32 on the inner surface CSb facing the heat-sensitive deformation portion 10. This allows the distance of heat transfer from the fusible portion 32 to the heat-sensitive deformation portion 10 to be substantially the same as the thickness of the outer case CS. This allows for more efficient heat transfer from the fusible portion 32 to the heat-sensitive deformation portion 10, improving the thermal responsiveness of the heat-sensitive deformation portion 10 to a temperature increase in the fusible portion 32.

[0052] The heat-sensitive deformation portion 10 may be formed from a material that is deformable in response to temperature. Preferably, the heat-sensitive deformation portion 10 may be molded integrally with the outer case CS. The material of such an outer case CS may be, for example, a thermoplastic resin material (e.g., plastic) or a metal material. Examples of resin materials include polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polycarbonate ABS (PCABS), polybutylene terephthalate (PBT), polyethylene, nylon, modified polyphenylene ether (m-PPE), and polyamide (PA). Examples of metal materials include aluminum.

[0053] When the heat-sensitive deformation portion 10 is molded integrally with the outer case CS, it is more preferable that the material of the outer case CS be a thermoplastic resin material. Generally, thermoplastic resin materials have lower thermal conductivity than metals. Therefore, if the outer case CS is made of a thermoplastic resin material, the heat transferred from the fusible portion 32 to the heat-sensitive deformation portion 10 is less likely to diffuse throughout the entire outer case CS, allowing localized deformation in the heat-sensitive deformation portion 10 due to thermal response. This allows the heat-sensitive deformation portion 10 to more clearly indicate the heat generation state of the fusible portion 32 (i.e., the fracture state of the fusible portion 32).

[0054] 8 is a schematic partial enlarged view of portion C of the battery pack BP shown in FIG. 7. As shown in the figure, the heat-sensitive deformable portion 10 may have a recess 15 formed by partially reducing the thickness of the outer case CS. In other words, the heat-sensitive deformable portion 10 may be formed by the presence of a recess 15 formed by partially reducing the thickness of the outer case CS on the outer surface CSa of the outer case CS. This shape allows the heat-sensitive deformable portion 10 to change shape at the recess 15 due to heat transmitted from the fusible portion 32. In other words, according to the battery pack of the present disclosure, the fusion state of the fusible portion 32 can be determined from the change in shape of the recess 15 formed in the heat-sensitive deformable portion 10.

[0055] The manner in which the recess 15 changes shape differs depending on the shape of the recess 15 before the shape change (i.e., before the fusible portion 32 is melted). For example, the manner in which the shape of the heat-sensitive deformable portion 10 changes may differ between a heat-sensitive deformable portion 10 that includes a plurality of minute recesses 15 as shown in Fig. 8 and a heat-sensitive deformable portion 10 that includes recesses 15 formed by the entire heat-sensitive deformable portion 10 being depressed as shown in Fig. 16. Below, we will first explain the manner in which the heat-sensitive deformable portion 10 includes a plurality of minute recesses 15.

[0056] 8, the outer surface CSa of the outer case CS may have a textured area with a plurality of minute depressions 15 formed at least in the heat-sensitive deformation portion 10. In other words, the heat-sensitive deformation portion 10 may be textured. This can also be interpreted as the outer surface CSa of the outer case CS having a minutely uneven surface with fine irregularities in the heat-sensitive deformation portion 10.

[0057] In this specification, "grain" refers to a shape having a repeating pattern of fine irregularities on the outer surface CSa. The repeating pattern of irregularities does not necessarily have to be regular, and may be a shape including a plurality of irregular irregularities. The grained region refers to a region where a graining process has been applied, and may also be referred to as a finely irregular region, a finely irregular region, an embossed region, or the like. In Figure 8, the irregularities of the grained region are schematically illustrated for ease of understanding, but may differ from the actual irregularity dimensions. In the following figures, to make the figures easier to understand, the grained region is hatched and the irregular shape may not be illustrated.

[0058] In the textured area, light incident on the textured area is diffused, resulting in a difference in gloss between the textured area and the non-textured area, which can be visually distinguished from the textured area by the gloss difference.

[0059] The average height of the irregularities in the textured region may be, for example, 3 μm or more. By having the average height within the above range, it becomes possible to appropriately distinguish the difference in gloss between the textured region and the non-textured region. The upper limit of the average height is not particularly limited, but may be, for example, 100 μm or less. The average height is a value measured using a stylus-type surface roughness measuring device conforming to JIS B 0651:2001, according to the method specified in JIS B 0601:2001.

[0060] FIG. 9 is a partially enlarged view of the battery pack BP shown in FIG. 8 after the fusible portion 32 has melted. FIGS. 10A and 10B are partially enlarged views of the heat-sensitive deformable portion 10 shown in FIG. 8, taken from the outside of the outer case CS. FIG. 10A shows the state before the fusible portion 32 melts, and FIG. 10B shows the state after the fusible portion 32 melts. As shown, in the textured region of the heat-sensitive deformable portion 10, the heat from the fusible portion 32 changes the shape of the irregularities that form the textured region. This change in shape changes the gloss of the textured region. For example, the heat transmitted from the fusible portion 32 can smooth the irregularities of the textured region. Here, "smoothing the irregularities" does not simply mean that the irregularities are reduced, but also includes smoothing the outer contour shape of the convex portions that make up the irregularities. Specifically, the change in shape of the heat-sensitive deformable portion 10 includes not only a reduction in the average height of the irregularities in the textured region, but also a reduction in the curvature of the tips of the convex portions included in the textured region.

[0061] Due to such changes in the shape of the unevenness, the gloss of the heat-sensitive deformable portion 10 changes before and after the fusion of the fusible portion 32. For example, by reducing the unevenness in the textured region and making it more smoothly flat, scattering of light incident on the heat-sensitive deformable portion 10 from outside the battery pack BP is suppressed, resulting in a glossier appearance compared to before the shape change. Alternatively, by reducing the curvature of the corners located on the tip side of the convex portion (e.g., the tip of the convex portion), the convex portion becomes more rounded, suppressing scattering of light incident on the heat-sensitive deformable portion 10. This results in a glossier appearance compared to before the shape change. Such changes in gloss of the heat-sensitive deformable portion 10 make it possible to determine the fusion state of the fusible portion 32. To make such determinations based on gloss differences easier, it is preferable that the textured region include convex portions with sharp (e.g., large curvature) corners so that the change in gloss due to deformation of the convex portions becomes more apparent.

[0062] When the thermally deformable portion 10 has a textured region, the amount of heat propagating from the fusible portion 32 may vary within the region of the thermally deformable portion 10. This difference in heat amount may result in differences in the shape change of the unevenness of the textured region, which may cause gloss unevenness in the thermally deformable portion 10. For example, the thermally deformable portion 10 may be configured so that when the fusible portion 32 reaches its melting temperature, a predetermined degree of gloss difference occurs due to the heat propagated to the thermally deformable portion 10. In other words, an operator may be able to determine whether the heated fusible portion 32 has melted by checking the degree of gloss unevenness in the thermally deformable portion 10.

[0063] For example, the heat-sensitive deformable portion 10 may be configured so that when the fusible portion 32 reaches its melting temperature, the area where the gloss changes in the heat-sensitive deformable portion 10 exceeds a certain area. With this configuration, it is possible to determine that the fusible portion 32 has melted when the area where the gloss changes in the heat-sensitive deformable portion 10 exceeds a certain range. Specifically, as shown in FIGS. 10A and 10B , the heat-sensitive deformable portion 10 may have a first region 14 and a second region 16, both of which may be uniformly textured. For example, the central region of the heat-sensitive deformable portion 10 may be the first region 14, and the region surrounding the first region 14 may be the second region 16. The heat-sensitive deformable portion 10 may be configured so that when the fusible portion 32 reaches its melting temperature, at least the entire first region 14 changes shape to exhibit a gloss different from that of the second region 16. This makes it easier to determine the shape change in the heat-sensitive deformable portion 10.

[0064] In this configuration, a mark such as a line indicating the position of the outer edge of the first region 14 may be provided on the outer edge of the first region 14 so that the range of the first region 14 can be visually recognized for determining the fusion state of the fusible portion 32. The mark may be formed by any method, such as printing such as silk screen printing, or laser marking.

[0065] 10A and 10B show the heat-sensitive deformation unit 10 as being substantially circular when viewed in the thickness direction T of the outer case CS, but the shape of the heat-sensitive deformation unit 10 is not limited to being substantially circular. For example, the heat-sensitive deformation unit 10 may have any of an oval, an ellipse, a polygonal shape such as a triangle or a rectangle, or an irregular shape when viewed in the thickness direction T of the outer case CS.

[0066] Fig. 11 is an enlarged cross-sectional view schematically illustrating the periphery of the heat-sensitive deformation portion 10 of a battery pack BP according to another embodiment different from that of Fig. 8. As shown in the figure, the outer surface CSa of the exterior case CS may also be textured in an area CSa1 other than the heat-sensitive deformation portion 10. For example, the entire outer surface CSa excluding the heat-sensitive deformation portion 10 may be textured.

[0067] 11, the heat-sensitive deformation portion 10 may be textured, while the area adjacent to the heat-sensitive deformation portion may not be textured. In other words, the outer surface CSa of the outer case CS may include a non-textured area CSa2 adjacent to the textured area of ​​the heat-sensitive deformation portion 10. The outer surface CSa of the outer case CS may be textured over the entire surface except for the non-textured area CSa2. In other words, the non-textured area CSa2 may be the only area of ​​the outer case CS that is not textured.

[0068] The non-textured area CSa2 is an area with gentler unevenness than the textured area, and does not necessarily have to be a smooth surface without any unevenness. For example, the density of unevenness (e.g., the number of convex portions per unit area (peak density Spd)) may be lower than that of the textured area, making it possible to appropriately distinguish the difference in gloss between the textured area and the non-textured area.

[0069] 12A and 12B are partial enlarged views of the heat-sensitive deformable portion 10 shown in FIG. 11 , taken from the outside of the outer case CS. FIG. 12A shows the state before the fusible portion 32 is fused, and FIG. 12B shows the state after the fusible portion 32 is fused. As shown in FIG. 12A , the non-textured region CSa2, which is not textured, may be positioned in a band shape along the outer edge 11 of the heat-sensitive deformable portion 10 so as to surround the heat-sensitive deformable portion 10. In other words, a circular non-textured region CSa2 may exist around the heat-sensitive deformable portion 10. In this structure, the outer surface CSa of the outer case CS may be textured on both the inside and outside of the non-textured region CSa2.

[0070] In this battery pack BP, the heat-sensitive deformable portion 10, including the textured region, and the non-textured region CSa2 are adjacent to each other. When the fusible portion 32 melts due to an overcurrent, heat generated in the fusible portion 32 propagates to the heat-sensitive deformable portion 10. The heat propagates to change the shape of the texture of the heat-sensitive deformable portion 10, smoothing the unevenness. This reduces the difference in gloss between the heat-sensitive deformable portion 10 and the non-textured region CSa2 adjacent to the textured region (see FIG. 12B ). In this battery pack BP, the non-textured region CSa2 can function as a reference for determining changes in gloss due to changes in the shape of the heat-sensitive deformable portion 10. For example, the heat-sensitive deformable portion 10 may be configured to change its shape due to the heat propagated from the fusible portion 32 when it reaches a temperature at which the fusible portion 32 melts, resulting in a gloss equivalent to that of the non-textured region CSa2. This allows the worker to appropriately determine the blown state of the fusible portion 32 by checking the difference in gloss between the heat-sensitive deformable portion 10 and the non-textured region CSa2.

[0071] As shown in FIG. 8 , the tab 3 including the fusible portion 32 may include a convex portion 30 that protrudes toward the outer case CS in a cross-sectional view. The fusible portion 32 may be located at the top of the convex portion 30. In other words, the tab 3 may include a convex portion 30 that protrudes toward the outer case CS. This allows the tab 3 to fuse at the top of the convex portion 30 when an overcurrent flows. For example, the convex portion 30 may be formed by bending or curving the first tab 34 and the second tab 36, located on either side of the fusible portion 32, toward the outer case CS on the fusible portion 32 side. The convex portion 30 may position the fusible portion 32 closer to the outer case CS than the first tab 34 and the second tab 36. This allows heat generated in the fusible portion 32 to be more efficiently transmitted to the heat-sensitive deformation portion 10.

[0072] Such a convex portion 30 may be elastically deformable in the thickness direction T of the outer case CS. Such a convex portion 30 may be sandwiched between the outer case CS and the battery CB in an elastically compressed state inside the outer case CS. The elastically compressed convex portion 30 can exert a biasing force between the outer case CS and the battery CB. Specifically, when the convex portion 30 is housed in the outer case CS in an elastically compressed state, the fusible portion 32 located at the top of the convex portion 30 can be biased toward the outer case CS. This structure allows the fusible portion 32 to be pressed against the outer case CS. This allows heat generated in the fusible portion 32 to be more efficiently transmitted to the heat-sensitive deformation portion 10 located in the outer case CS.

[0073] 8, the convex portion 30 may be elastically deformable by having a stepped shape that bends in stages toward the outer case CS. That is, the convex portion 30 may be formed by bending the first tab 34 and the second tab 36 in a crank shape on both sides of the fusible portion 32. This bent shape allows the convex portion 30 to be elastically deformable inside the outer case CS in the thickness direction T of the outer case CS.

[0074] Next, modified examples of the battery pack BP will be described with reference to Figures 13 to 19. In describing the modified battery pack BP, the description of points common to the above description will be omitted as appropriate. In other words, the following description will focus on points that are different from the above description.

[0075] [Variation 1] 13 is an enlarged cross-sectional view schematically showing the periphery of the heat-sensitive deformation portion 10 of the battery pack BP of Modification 1. As shown in the figure, the outer case CS may have a recessed region 12 in the area where the heat-sensitive deformation portion 10 is provided, where the inner surface CSb of the outer case CS is relatively recessed. In other words, the outer case CS may have the heat-sensitive deformation portion 10 on the outer surface CSa, while having the recessed region 12 on the inner surface CSb facing the heat-sensitive deformation portion 10, thereby relatively reducing the thickness. The inner surface CSb may be recessed in the area where the heat-sensitive deformation portion 10 is provided, thereby locally reducing the thickness of the outer case CS.

[0076] In the battery pack BP of the present disclosure, from the viewpoint of improving the thermal responsiveness of the heat-sensitive deformation portion 10 to heat propagated from the fusible portion 32, it is preferable that the thermal conductivity from the fusible portion 32 to the heat-sensitive deformation portion 10 be higher. The structure including the recessed region 12 described above reduces the thickness of the outer case CS, thereby shortening the distance between the heat-sensitive deformation portion 10 located on the outer surface CSa of the outer case CS and the fusible portion 32 located inside the outer case CS. This allows the heat generated in the fusible portion 32 to be efficiently propagated to the heat-sensitive deformation portion 10. The fusion state of the fusible portion 32 can be clearly reflected by the heat-sensitive deformation portion 10.

[0077] [Variation 2] 14 and 15 are enlarged cross-sectional views schematically showing the periphery of the thermally deformable portion 10 of the battery pack BP of Modification 2. As shown in the figures, the battery pack BP may further include a heat transfer portion 50 located between the thermally deformable portion 10 and the fusible portion 32. The heat transfer portion 50 is capable of transferring heat to both the thermally deformable portion 10 and the fusible portion 32. The thermally deformable portion 10 and the fusible portion 32 may be connected to each other via the heat transfer portion 50 so that heat can be conducted therebetween.

[0078] The heat transfer unit 50 may be located inside the outer case CS. Therefore, the heat transfer unit 50 may be sandwiched between the outer case CS and the battery module BM so as to be located between the thermally deformable unit 10 and the fusible unit 32. Such a heat transfer unit 50 may be understood as an intervening member having thermal conductivity, and may also be referred to as a heat transfer intervening member. Such a heat transfer unit 50 may function as a heat collecting member from the viewpoint of efficiently transferring heat generated in the fusible unit 32 to the thermally deformable unit 10.

[0079] By providing the heat transfer section 50, the heat generated in the fusible section 32 is indirectly transferred to the heat-sensitive deformation section 10 via the heat transfer section 50. In this way, by arranging the heat transfer section 50 between the fusible section 32 and the heat-sensitive deformation section 10, a heat transfer path can be formed from the fusible section 32 to the heat-sensitive deformation section 10. This allows the heat generated in the fusible section 32 to be transferred more efficiently to the heat-sensitive deformation section 10, improving the thermal responsiveness of the heat-sensitive deformation section 10.

[0080] The heat transfer unit 50 has a first main surface 50a and a second main surface 50b that face each other. As shown in FIG. 14 , the first main surface 50a of the heat transfer unit 50 may be in contact with a region of the inner surface CSb of the outer case CS that faces the heat-sensitive deformation unit 10. In other words, the heat transfer unit 50 is disposed opposite the heat-sensitive deformation unit 10 in the thickness direction T of the outer case CS, and the first main surface 50a may be in contact with the inner surface CSb of the outer case CS. Meanwhile, the second main surface 50b of the heat transfer unit 50 may be in contact with the fusible unit 32. With this structure, the heat transfer unit 50 may be in contact with both the outer case CS and the fusible unit 32. This allows heat generated in the fusible unit 32 to be efficiently propagated to the heat-sensitive deformation unit 10 located on the outer surface CSa side of the outer case CS.

[0081] Furthermore, by using the heat transfer unit 50, the heat generated in the fusible portion 32 can be locally propagated to the heat-sensitive deformation portion 10 of the outer case CS. For example, even if the tab 3 extends substantially parallel to the inner surface of the outer case CS across the first tab 34, the fusible portion 32, and the second tab 36 as shown in Fig. 15, the heat transfer unit 50 intervening between the outer case CS and the fusible portion 32 can prevent the heat generated in the fusible portion 32 from propagating to areas of the outer case CS other than the heat-sensitive deformation portion 10 (for example, area CSa1). This can prevent unintended deformation of the outer case in areas other than the heat-sensitive deformation portion 10.

[0082] [Variation 3] Fig. 16 is an enlarged cross-sectional view schematically showing the periphery of the heat-sensitive deformable portion 10 of the battery pack BP of Modification 3. Fig. 17 is an enlarged cross-sectional view schematically showing the state of the battery pack BP shown in Fig. 16 after the fusible portion 32 has melted. As shown in the figure, the heat-sensitive deformable portion 10 may be configured to cleave due to heat propagated from the fusible portion 32 when the temperature reaches the melting temperature of the fusible portion 32.

[0083] For example, as shown in FIG. 16, the battery pack BP may include a recess 15 formed by the entire heat-sensitive deformable portion 10 being recessed. The recess 15 may locally reduce the thickness of the outer case CS at the heat-sensitive deformable portion 10. The heat-sensitive deformable portion 10 may be ruptured at the recess 15 by heat propagated from the fusible portion 32 (see FIG. 17). Therefore, the recess 15 of the heat-sensitive deformable portion 10 (see FIG. 16) may be designed so that the heat-sensitive deformable portion 10 can be ruptured when the temperature reaches a temperature at which the fusible portion 32 melts. With this structure, an operator can determine whether the fusible portion 32 has melted by checking whether the heat-sensitive deformable portion 10 has ruptured.

[0084] Furthermore, when a cleavable heat-sensitive deformation unit 10 is provided, a separate member such as a heat transfer unit 50 may be disposed on the inside of the exterior case CS facing the heat-sensitive deformation unit 10. Any holes made in the exterior case CS by cleaving the heat-sensitive deformation unit 10 may be blocked by this member. This makes it possible to prevent moisture and / or foreign matter from entering the interior of the exterior case CS even after the heat-sensitive deformation unit 10 is cleaved, thereby protecting the battery module BM housed in the exterior case CS.

[0085] Furthermore, an operator may be able to determine that the thermally deformable portion 10 has cleaved by checking whether components such as the heat transfer portion 50 located on the inside of the outer case CS are exposed through a hole formed by the cleavage of the thermally deformable portion 10. From the viewpoint of making it easier for an operator to visually determine whether or not the thermally deformable portion 10 has cleaved (i.e., whether or not the heat transfer portion 50, etc., is exposed), the components such as the heat transfer portion 50 and the outer surface CSa of the outer case CS may be colored in different hues.

[0086] In this way, if the thermally deformable portion 10 is cleaved by heat propagated from the fusible portion 32, the heat transfer portion 50 can function to seal the cleaved portion (see FIG. 17). Furthermore, by positioning the heat transfer portion 50 between the outer case CS and the fusible portion 32, the outer case CS can be protected from the end of the fusible portion 32 that has fused. For example, even if the shape of the thermally deformable portion 10 does not change when the fusible portion 32 is fused, the tip of the fusible portion 32 may come into contact with the outer case CS, potentially causing the outer case CS to unintentionally cleave. The structure including the heat transfer portion 50 shown in FIG. 16 prevents contact between the outer case CS and the fusible portion 32, thereby minimizing damage to the outer case CS caused by the fusible portion 32.

[0087] The heat transfer unit 50 may be formed from a thermally conductive material. Preferably, the heat transfer unit 50 is capable of transferring heat so that the thermally deformable unit 10 changes shape when the fusible portion 32 reaches its melting temperature, but is also selected from a material with appropriate heat capacity and thermal resistance so that the thermally deformable unit 10 does not change shape when the fusible portion 32 is below its melting temperature. For example, the heat transfer unit 50 may be formed from various materials, such as metal, ceramic, a metal-ceramic composite material, an inorganic material, or a thermally conductive resin. While merely illustrative, the heat transfer unit 50 may have a thermal resistance of 1900°C / W or less. Furthermore, if it is important to adequately protect the exterior case CS from the melted fusible portion 32, it is more preferable that the heat transfer unit 50 be formed from a material with better heat resistance than the exterior case CS.

[0088] FIG. 18 is a partially enlarged view of the thermally deformable portion 10 from the outside of the outer case CS. In the figure, the positions of the heat transfer portion 50 and the tab 3 inside the outer case CS are indicated by dashed lines. The shape of the heat transfer portion 50 in a plan view is not particularly limited and may be any of a generally polygonal shape, such as a generally circular, elliptical, or rectangular shape, or an irregular shape. As shown in FIG. 18, the heat transfer portion 50 may have larger outer dimensions than the fusible portion 32 when viewed in the thickness direction T of the outer case CS. For example, if the heat transfer portion 50 and the fusible portion 32 each have a rectangular shape, the length and width of the heat transfer portion 50 may be larger than the length and width of the fusible portion 32.

[0089] Specifically, as viewed in the thickness direction T of the outer case CS, the outer edge 51 of the fusible portion 32 may be located on the inner periphery of the outer edge 33 of the heat transfer portion 50. In other words, as viewed in the thickness direction T of the outer case CS, the heat transfer portion 50 may extend to the outer periphery of the fusible portion 32. As viewed in the thickness direction T of the outer case CS, the fusible portion 32 may be arranged to overlap with the heat transfer portion 50 over the entire area of ​​the fusible portion 32. This allows heat generated in the fusible portion 32 to be suitably transferred to the heat-sensitive deformation portion 10 via the heat transfer portion 50. Furthermore, even after the fusible portion 32 has blown, the heat transfer portion 50 remains between the fusible portion 32 and the outer case CS over the entire area, thereby suitably protecting the outer case CS.

[0090] Furthermore, when viewed in the thickness direction T of the outer case CS, the outer edge 51 of the heat-sensitive deformation unit 10 may be located on the inner circumferential side of the outer edge 11 of the heat transfer unit 50. In other words, when viewed in the thickness direction T of the outer case CS, the heat transfer unit 50 may extend to the outer circumferential side of the heat-sensitive deformation unit 10. When viewed in the thickness direction T of the outer case CS, the heat-sensitive deformation unit 10 may be arranged so as to overlap with the heat transfer unit 50 over the entire area of ​​the heat-sensitive deformation unit 10. This allows the heat transfer unit 50 to suitably seal the hole formed by the cleavage, even if the outer case CS is torn due to deformation of the heat-sensitive deformation unit 10.

[0091] [Variation 4] 19 is an enlarged cross-sectional view schematically illustrating the periphery of the thermally deformable portion 10 of the battery pack BP of Modification 4. As shown in the figure, the outer case CS may have a recessed region 12 on the inner surface CSb, and a heat transfer portion 50 may be disposed inside the recessed region 12. With this structure, the recessed region 12 reduces the thickness of the outer case CS. Therefore, it becomes possible to efficiently transfer heat from the fusible portion 32 to the thermally deformable portion 10 while protecting the outer case CS with the heat transfer portion 50.

[0092] [Variation 5] 20 is an enlarged cross-sectional view schematically illustrating the periphery of the heat-sensitive deformation portion 10 of the battery pack BP of Modification 5. As shown in the figure, the heat transfer portion 50 may be positioned on the inner surface CSb of the outer case CS and may be integrated with the outer case CS. For example, the heat transfer portion 50 and the outer case CS may be integrally molded. Therefore, the outer case CS may have a protrusion that protrudes from the inner surface CSb toward the battery module BM, and this protrusion may function as the heat transfer portion 50. The fusible portion 32 may be in contact with the top surface 50b of the convex heat transfer portion 50 that protrudes from the inner surface CSb of the outer case CS.

[0093] Because the heat transfer section 50 is integrally molded, the thickness of the outer case CS increases locally in the area including the heat-sensitive deformation section 10. This increases the strength of the outer case CS in the heat-sensitive deformation section 10, making it possible to prevent unintended damage to the outer case due to excessive shape change caused by heat propagated from the fusible section 32.

[0094] Although the embodiments of the present disclosure have been described above, they are merely exemplary examples. The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined by the claims. The technical scope of the present disclosure also includes all modifications within the meaning and scope of the claims.

[0095] The above-described effects are merely exemplary, and the present disclosure is not limited to the above, and additional effects may also be provided.

[0096] It should be noted that the embodiment of the present disclosure as described above includes the following preferred aspects. <1> A battery pack comprising an outer case and a battery module housed in the outer case, the exterior case includes a connector electrically connected to the battery module and a heat-sensitive deformation portion positioned on an outer surface of the exterior case; the battery module includes a battery and a tab electrically connected to the battery and the connector; the tab comprises a fusible portion; The heat-sensitive deformation portion and the fusible portion are connected to each other so as to be capable of thermal conduction. <2> the heat-sensitive deformation portion is disposed opposite the fusible portion in the thickness direction of the exterior case; <1> The battery pack according to claim 1. <3> the heat-sensitive deformation portion includes a recess formed by partially reducing the thickness of the exterior case; <1> or <2> The battery pack according to claim 1. <4> The heat-sensitive deformation portion includes a grained area. <1> ~ <3> 1. The battery pack according to claim 1, <5> the outer case further includes a non-textured area adjacent to the textured area of ​​the heat-sensitive deformation portion on the outer surface thereof. <4> The battery pack according to claim 1. <6> the outer case has a recessed area in which the inner surface of the outer case is relatively recessed in a region having the heat-sensitive deformation portion; <1> ~ <5> 1. The battery pack according to claim 1, <7> When viewed in cross section, the tab has a convex portion that protrudes toward the outer case, The fusible portion is located at the top of the convex portion. <1> ~ <6> 1. The battery pack according to claim 1, <8> The convex portion is elastically deformable in the thickness direction of the outer case, the convex portion is sandwiched between the battery and the exterior case in an elastically compressed state; <7> The battery pack according to claim 1. <9> the fusible portion is in contact with the inner surface of the outer case at a position facing the heat-sensitive deformation portion; <1> ~ <8> 1. The battery pack according to claim 1, <10> a heat transfer section located between the heat-sensitive deformation section and the fusible section; the heat-sensitive deformation portion and the fusible portion are connected to each other via the heat transfer portion so as to be capable of transferring heat therebetween; <1> ~ <9> 1. The battery pack according to claim 1, <11> the heat transfer portion has a first main surface and a second main surface facing each other, the first main surface is in contact with a region of the inner surface of the exterior case that faces the heat-sensitive deformation portion, The second main surface is in contact with the fusible portion. <10> The battery pack according to claim 1. <12> When viewed in a thickness direction of the exterior case, an outer edge of the heat transfer portion is located outside an outer edge of the fusible portion. <10> or <11> The battery pack according to claim 1. <13> The exterior case is made of a resin material. <1> ~ <12> 1. The battery pack according to claim 1, [Industrial Applicability]

[0097] The present disclosure can be suitably used as a battery pack that allows the interruption status of a current path to be confirmed from the outside. [Explanation of symbols]

[0098] 10: Heat-sensitive deformation part 11: Outer edge of the heat-sensitive deformation part 12: Concave area 14:First area 15: Recess 16:Second area 3: Tab 30:Convex shaped part 32: Fusible part 33: Outer edge of fusible part 34: First tab 36: Second tab 50: Heat transfer section 50a: First main surface 50b: 2nd principal surface 51: Outer edge of heat transfer section BM: Battery module BP: Battery pack CB:Battery CN: Connector CS: Outer case CS1: End face CS2: Side CSa:Outer surface CSb:Inner surface HD: Battery holder NT: Negative terminal PT: Positive terminal

Claims

1. A battery pack comprising an outer case and a battery module housed in the outer case, the exterior case includes a connector electrically connected to the battery module and a heat-sensitive deformation portion positioned on an outer surface of the exterior case; the battery module includes a battery and a tab electrically connected to the battery and the connector; the tab comprises a fusible portion; The heat-sensitive deformation portion and the fusible portion are connected to each other so as to be capable of thermal conduction.

2. The battery pack according to claim 1 , wherein the heat-sensitive deformation portion is disposed opposite the fusible portion in the thickness direction of the exterior case.

3. The battery pack according to claim 1 , wherein the heat-sensitive deformation portion includes a recess formed by partially reducing the thickness of the exterior case.

4. The battery pack according to claim 1 , wherein the heat-sensitive deformation portion includes a textured area.

5. The battery pack according to claim 4 , wherein the exterior case further includes a non-textured area adjacent to the textured area of ​​the heat-sensitive deformation portion on the outer surface.

6. The battery pack according to claim 1 , wherein the outer case has a recessed area in which the inner surface of the outer case is relatively recessed in a region where the heat-sensitive deformation portion is provided.

7. When viewed in cross section, the tab has a convex portion that protrudes toward the outer case, The battery pack according to claim 1 , wherein the fusible portion is located at the top of the convex portion.

8. The convex portion is elastically deformable in the thickness direction of the outer case, The battery pack according to claim 7 , wherein the convex portion is sandwiched between the battery and the exterior case in an elastically compressed state.

9. The battery pack according to claim 1 , wherein the fusible portion is in contact with the inner surface of the exterior case at a position facing the heat-sensitive deformation portion.

10. a heat transfer section located between the heat-sensitive deformation section and the fusible section; The battery pack according to claim 1 , wherein the heat-sensitive deformation portion and the fusible portion are connected to each other via the heat transfer portion so as to be capable of conducting heat therebetween.

11. the heat transfer portion has a first main surface and a second main surface facing each other, the first main surface is in contact with a region of the inner surface of the exterior case that faces the heat-sensitive deformation portion, The battery pack according to claim 10 , wherein the second main surface is in contact with the fusible portion.

12. The battery pack according to claim 10 , wherein an outer edge of the heat transfer portion is positioned outside an outer edge of the fusible portion when viewed in a thickness direction of the exterior case.

13. The battery pack according to claim 1 , wherein the exterior case is made of a resin material.

Images