Battery pack

Abstract

A battery pack 1 includes: a plurality of batteries 100 each including a charge / discharge body and an exterior body 101 housing the charge / discharge body; and a spacer 202 insulating between one of the batteries 100 and another one of the batteries 100. The spacer 202 includes a first part 202c in contact with the exterior body 101 in the stacking direction in which the one battery 100 and the other battery 100 are stacked together, and a second part 202d in contact with the exterior body 101 in a direction intersecting the stacking direction. The second part 202d includes a base part 202d1, and a high thermal conduction part 202d2 having higher thermal conductivity than the base part 202d1 and the first part 202c. The thermal conductivity efficiency from the batteries 100 to the outside of the spacer 202 via the second part 202d is higher than the thermal conductivity efficiency from the batteries 100 to the outside of the spacer 202 via the first part 202c.

Description

Battery pack

[0001] The present invention relates to a battery pack.

[0002] A battery module including a plurality of stacked batteries, a plurality of spacers for electrically insulating between the batteries, and a cooling unit thermally connected to the plurality of batteries is known (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-062288

[0004] There is a demand for a battery pack capable of effectively suppressing thermal runaway.

[0005] The battery pack according to one aspect of the present invention includes a plurality of batteries including a charge / discharge body and an exterior body housing the charge / discharge body, and a spacer insulating between one battery and another battery. The spacer includes a first portion in contact with the exterior body in the stacking direction of one battery and another battery, and a second portion in contact with the exterior body in a direction intersecting the stacking direction. The second portion includes a base portion and a high heat conductivity portion having higher heat conductivity than the base portion and the first portion. The efficiency of heat conduction from the battery through the second portion to the outside of the spacer is higher than the efficiency of heat conduction from the battery through the first portion to the outside of the spacer.

[0006] According to the present invention, a battery pack capable of effectively suppressing thermal runaway can be obtained.

[0007] A perspective view showing the battery pack 1 of the first embodiment. A top view of the battery pack 1 of Figure 1, with the busbar holder 311 removed. A perspective view showing a plurality of batteries 100 and a holding unit 200, with some of the components of the holding unit 200 disassembled in the width direction Y and the stacking direction X. A perspective view from Figure 3, with the first side plate 231, the second side plate 232 and the fastening bolt 241 removed, and the components of the battery 100 and the holding unit 200 disassembled in the stacking direction X. A perspective view showing the busbar unit 300, the voltage detection unit 400 and the temperature measurement unit 500. A perspective view showing the main part of the first embodiment in cross-section. A perspective view showing the main part of the second embodiment in cross-section. A perspective view showing the main part of the third embodiment in cross-section. A perspective view showing the main part of the fourth embodiment in cross-section. A perspective view showing the main part of the fifth embodiment in cross-section. A perspective view showing the main part of the sixth embodiment in cross-section. Cross-sectional view of the main part of the seventh embodiment. Explanatory diagram of a modified example of the lower plate 202d.

[0008] Embodiments for carrying out the present invention will be described with reference to the drawings. In order to facilitate understanding of each embodiment, the size and proportions of the components may be exaggerated in each drawing. In each drawing, the same reference numerals are assigned to the same components. In each drawing, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 are indicated by arrows. However, in each drawing, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 indicate the relative positional relationship within the same drawing. That is, if the battery pack 1 is rotated 180 degrees and the top and bottom surfaces are reversed, or if the battery pack 1 is rotated 90 degrees and the top surface is positioned as the side surface, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 will change. In each drawing, the threads on the outer surface of the fastening bolts and the grooves on the inner surface of the insert nuts are omitted from the illustration.

[0009] The stacking direction X of the battery pack 1 is the direction in which the multiple batteries 100 are stacked and arranged. The width direction Y of the battery pack 1 is the direction in which the external terminals (positive terminal 103 and negative terminal 104) of the batteries 100 are arranged, and corresponds to the width direction of the batteries 100. The height direction Z of the battery pack 1 corresponds to the height direction of the batteries 100. Hereafter, when describing the components of the battery pack 1, these directions will also be simply referred to as the stacking direction X, width direction Y, and height direction Z. The stacking direction X, width direction Y, and height direction Z are orthogonal to each other. Each figure shows the X-axis representing the stacking direction X, the Y-axis representing the width direction Y, and the Z-axis representing the height direction Z.

[0010] (Configuration of the battery pack 1 in the first embodiment) The configuration of the battery pack 1 in the first embodiment will be described with reference to Figures 1 to 5.

[0011] Figure 1 is a perspective view showing a battery pack 1 of the first embodiment. Figure 2 is a top view of the battery pack 1 of Figure 1, with the busbar holder 311 removed. Figure 3 is a perspective view showing a plurality of batteries 100 and a holding unit 200, with some of the components of the holding unit 200 disassembled in the width direction Y and the stacking direction X. Figure 4 is a perspective view showing Figure 3 with the first side plate 231, the second side plate 232 and the fastening bolt 241 removed, and with the components of the batteries 100 and the holding unit 200 disassembled in the stacking direction X. Figure 5 is a perspective view showing a busbar unit 300, a voltage detection unit 400 and a temperature measurement unit 500.

[0012] The battery pack 1 is configured, for example, as a power source to operate a motor for driving a vehicle. The battery pack 1 may also be configured, for example, as a power source to operate electrical equipment mounted on the vehicle.

[0013] As shown in Figure 1, the battery pack 1 includes a plurality of batteries 100, a holding unit 200 for holding the plurality of batteries 100, and a busbar unit 300 for electrically connecting the plurality of batteries 100. The battery pack 1 also includes a voltage detection unit 400 for detecting the voltage of the batteries 100 and a temperature measuring unit 500 for measuring the temperature of the batteries 100. The components included in the battery pack 1 will be described below.

[0014] (Configuration of Battery 100) The batteries 100 shown in Figures 1 to 4 are stacked along the stacking direction X via a holding unit 200. As shown in Figure 2, for example, 20 batteries 100 are stacked. The batteries 100 are composed of, for example, lithium-ion secondary batteries. The batteries 100 include a current collector and an electrolyte. As shown in Figure 4, the batteries 100 include a container 101, a lid 102, a positive electrode terminal 103, a negative electrode terminal 104, and a safety valve 105. The components included in the batteries 100 will be described below.

[0015] As shown in Figure 4, the battery 100 is formed in a rectangular shape. The battery 100 has an upper surface 100a, a lower surface 100d (see Figure 6) that faces the upper surface 100a in the height direction Z, a pair of main surfaces 100c that face each other in the stacking direction X, and a pair of side surfaces 100b that face each other in the width direction Y. The upper surface 100a of the battery 100, along the stacking direction X, is provided with external terminals, a positive electrode terminal 103 and a negative electrode terminal 104. The upper surface 100a is the mounting surface to which the external terminals are attached. In Figure 4, the upper surface 100a corresponds to the upper surface of the battery 100. The upper surface 100a is formed in a rectangular shape. The length of the upper surface 100a along the width direction Y of the battery 100 is longer than the length of the upper surface 100 along the stacking direction X of the battery 100. The upper surface 100a faces the busbar unit 300 shown in Figure 1. Two side surfaces 100b of the battery 100, along the stacking direction X, are perpendicular to and opposite the top surface 100a. The side surfaces 100b are formed in a rectangular shape. The length of the side surfaces 100b along the height direction Z of the battery 100 is longer than the length along the stacking direction X of the battery 100. Two main surfaces 100c of the battery 100, facing the stacking direction X, are in contact with the cell spacers 202 of the holding unit 200, etc.

[0016] The current collector of battery 100 corresponds to the charge / discharge element to which power is input and output. The current collector of battery 100 is constructed by winding or stacking a positive electrode and a negative electrode via a separator. The charge / discharge element is housed in an outer casing. The outer casing has a container 101 and a lid 102. The container 101 houses the current collector and electrolyte. The lid 102, together with the container 101, seals the current collector and electrolyte. The lid 102 is joined to the container 101. The current collector (charge / discharge element) is electrically connected to a positive electrode terminal 103 and a negative electrode terminal 104 provided on the lid 102. The positive electrode terminal 103 and the negative electrode terminal 104 relay power input and output between the current collector and the electrical equipment. The positive electrode terminal 103 and the negative electrode terminal 104 are attached to the lid 102. As shown in Figure 4, the positive terminal 103 of one battery 100 and the negative terminal 104 of the other battery 100, which are adjacent along the stacking direction X, face each other in the stacking direction X. The safety valve 105 ruptures outward from the battery 100 when the internal pressure of the battery 100 exceeds a predetermined value. The safety valve 105 is also called a rupture valve. The safety valve 105 is provided, for example, on the lid 102.

[0017] (Configuration of the holding unit 200) The holding unit 200 holds a plurality of batteries 100, as shown in Figures 1 to 4. The holding unit 200 includes a first end spacer 201, a cell spacer 202, and a second end spacer 203, as shown in Figure 4. The holding unit 200 also includes a first end block 211, a second end block 212, an insulating member 221, and an insert nut 222. The holding unit 200 also includes a first side plate 231, a second side plate 232, and fastening bolts 241, as shown in Figure 3. The configuration included in the holding unit 200 will be described below.

[0018] As shown in Figure 4, the first end spacer 201 is provided between the first end block 211 and the battery 100. The first end spacer 201 is in contact with the first battery 100 located at one end of the 20 stacked batteries 100. This battery 100 corresponds to the battery 100 located at the left end in Figure 2. The first end spacer 201 insulates the first end block 211 from the battery 100. The first end spacer 201 is formed in the shape of a rectangular flat plate. The thickness of the first end spacer 201 along the stacking direction X is sufficiently thinner than the thickness of the battery 100 along the stacking direction X. The first end spacer 201 is made of an insulating material.

[0019] As shown in Figure 4, the cell spacer 202 is installed between adjacent batteries 100. The cell spacer 202 holds and insulates the batteries 100. The cell spacer 202 covers each main surface 100c of adjacent batteries 100 along the width direction Y. The cell spacer 202 covers two sides 100b of the batteries 100. The thickness of each plate constituting the cell spacer 202, which will be described later, is sufficiently thinner than the thickness along the stacking direction X of the batteries 100. The cell spacer 202 is made of an insulating material.

[0020] The configuration of the cell spacer 202 will be described in detail with reference to Figure 6. Figure 6 is a perspective view showing the main parts of the first embodiment in cross-section. In Figure 6, a cross-section is shown obtained by cutting the battery 100 and the cell spacer 202 at the center in the width direction Y. As shown in Figure 6, the cell spacer 202 according to this embodiment is formed in the shape of a rectangular box. The cell spacer 202 comprises a main plate 202c that covers the main surface 100c of the battery 100, two side plates 202b that cover the two sides 100b of the battery 100, an upper plate 202a that covers the upper surface 100a of the battery 100, and a lower plate 202d that covers the lower surface 100d of the battery 100.

[0021] The main plate 202c is in contact with the main surface 100c of one battery 100 and the main surface 100c of the other battery 100 in the stacking direction X of one battery 100 and the other battery 100. The main plate 202c insulates between one battery 100 and the other battery 100. In this specification, the portion of the cell spacer 202 that is in contact with the container 101 of the battery 100 in the stacking direction X is also referred to as the first part.

[0022] The lower plate 202d is in contact with the lower surface 100d of the battery 100 in the height direction Z. The upper plate 202a is in contact with the upper surface 100a of the battery 100 in the height direction Z. The side plate 202b is in contact with the side surface 100b of the battery 100 in the width direction Y. In this specification, the portion of the cell spacer 202 that is in contact with the battery 100 in a direction intersecting the stacking direction X (height direction Z or width direction Y) is also referred to as the second part.

[0023] The cell spacer 202 and the battery 100 are assembled by moving them relative to each other along the stacking direction X. This houses the battery 100 within the cell spacer 202. The upper plate 202a has a notch 202a1 formed on the end opposite to the end to which the main plate 202c is connected. This prevents the positive terminal 103 and negative terminal 104 from interfering with the cell spacer 202 when the battery 100 is housed within the cell spacer 202. The upper plate 202a has a rectangular opening 202a2 formed on it that corresponds to the shape of the safety valve 105.

[0024] The lower plate 202d comprises a base portion 202d1 and a high heat conductivity portion 202d2. The base portion 202d1 is a rectangular frame-shaped member that holds the high heat conductivity portion 202d2 and has a rectangular opening in which the high heat conductivity portion 202d2 is positioned. The high heat conductivity portion 202d2 is a rectangular plate-shaped member.

[0025] The base portion 202d1, the top plate 202a, the side plate 202b, and the main plate 202c are formed from the same insulating material. The base portion 202d1 is formed from a thermoplastic resin such as polypropylene, polybutylene terephthalate, or polycarbonate. The high thermal conductivity portion 202d2 is formed from a material with a higher thermal conductivity than the base portion 202d1 and the main plate 202c. Therefore, the high thermal conductivity portion 202d2 has higher thermal conductivity (i.e., lower thermal resistance) than the base portion 202d1 and the main plate 202c. The high thermal conductivity portion 202d2 is formed from a thermoplastic resin such as polyamide, polycarbonate, or acrylic. The base portion 202d1 and the high thermal conductivity portion 202d2 are integrally formed, for example, by two-color molding.

[0026] The high thermal conductivity portion 202d2 is not limited to being formed from a resin material. For example, the high thermal conductivity portion 202d2 may be formed from a metal material such as aluminum. In this case, for example, the cell spacer 202 is formed by insert molding a thermoplastic resin into the high thermal conductivity portion 202d2, which is a metal plate.

[0027] The method for forming the cell spacer 202 is not limited to the example described above. For example, the high thermal conductivity portion 202d2 may be attached with adhesive to a structure in which the base portion 202d1, upper plate 202a, side plate 202b, and main plate 202c are integrally molded. In this case, various high thermal conductivity materials can be used for the high thermal conductivity portion 202d2, such as those made of a resin material having a metal filler.

[0028] The lower plate 202d is formed such that the thickness of the high thermal conductivity portion 202d2 (dimension in the height direction Z) is equal to the thickness of the base portion 202d1 (dimension in the height direction Z). The upper surfaces of the base portion 202d1 and the high thermal conductivity portion 202d2 are in contact with the lower surface 100d of the battery 100. In other words, in this embodiment, the lower surface 100d, which faces the upper surface 100a, which is the mounting surface for the external terminals via the charge / discharge body 110, is mainly used as the cooling surface. When the high thermal conductivity portion 202d2 is formed from a conductive material, it is preferable to place an insulating member, such as a thin insulating sheet, between the high thermal conductivity portion 202d2 and the lower surface 100d of the battery 100.

[0029] The heat generated inside the container 101 of the battery 100 is transferred from the container 101 to the cell spacer 202 and dissipated to the outside of the battery pack 1. In this embodiment, the thermal transmittance (heat transfer coefficient) of the lower plate 202d of the cell spacer 202 is smaller than the thermal transmittance (heat transfer coefficient) of the main plate 202c of the cell spacer 202. The thermal transmittance of the cell spacer 202 is the amount of heat that passes through a unit area per unit time when there is a temperature difference of 1 degree between one end face and the other end face of the plates constituting the cell spacer 202, and corresponds to the reciprocal of the thermal resistance.

[0030] Thus, in this embodiment, the efficiency of heat conduction from the inside of the container 101 (inside the battery 100) to the outside of the cell spacer 202 (outside the battery 100) via the lower plate 202d is higher than the efficiency of heat conduction from the inside of the container 101 (inside the battery 100) to the outside of the cell spacer 202 (outside the battery 100) via the main plate 202c. Therefore, the amount of heat dissipated per unit area through the lower plate 202d of the cell spacer 202 is greater than the amount of heat dissipated per unit area through the main plate 202c of the cell spacer 202.

[0031] It is preferable that the battery pack 1 be cooled by a cooling device (not shown). The cooling device is, for example, a fan or other blower that blows cooling air onto the lower surface of the lower plate 202d of the cell spacer 202. However, the cooling device is not limited to a blower. The cooling device may also consist of a cooling plate in contact with the lower surface of the lower plate 202d of the cell spacer 202, a circulation pump that circulates the refrigerant flowing through the refrigerant passage in the cooling plate, and a heat exchanger that cools the refrigerant.

[0032] As described above, a high-thermal-conductivity portion 202d2 is formed in a predetermined area of ​​the lower plate 202d that contacts the lower surface 100d of the battery 100. Therefore, the amount of heat dissipated from the battery 100 via the lower plate 202d can be increased compared to when the high-thermal-conductivity portion 202d2 is not provided.

[0033] On the other hand, the main plate 202c that contacts the main surface 100c of the battery 100 does not have a high thermal conductivity portion 202d2. In other words, the main plate 202c is made only of a material with a lower thermal conductivity than the high thermal conductivity portion 202d2. Therefore, if one battery 100 overheats abnormally, the heat from that battery 100 can be suppressed from propagating to other batteries 100 adjacent to that battery 100 along the stacking direction X. As a result, thermal runaway, a phenomenon in which other batteries 100 overheat in a chain reaction when one battery 100 overheats abnormally, can be suppressed.

[0034] As shown in Figure 4, the second end spacer 203 is provided between the battery 100 and the second end block 212. The second end spacer 203 is in contact with the 20th battery 100, which is located on the other end of the stacked 20 batteries 100. This battery 100 corresponds to the battery 100 located at the right end in Figure 2. The second end spacer 203 insulates the battery 100 from the second end block 212. The shape of the second end spacer 203 is the same as the shape of the cell spacer 202.

[0035] As shown in Figure 4, the first end block 211 is stacked with the first battery 100 located at one end of the stacked 20 batteries 100, via a first end spacer 201. The first end block 211 extends along the width direction Y, which intersects the stacking direction X of the batteries 100. The first end block 211 is adjacent to the battery 100 located at the end along the stacking direction X and supports the battery 100. The first end block 211 is formed in a rectangular shape extending in the width direction Y. Fastening bolts 241 are screwed into a plurality of screw holes 211m formed on the side surface of the first end block 211 along the width direction Y, as shown in Figure 3. As shown in Figure 1, the first end block 211 is fixed to the first side plate 231 by fastening bolts 241. Similarly, the first end block 211 is fixed to the second side plate 232 by fastening bolts 241. The first end block 211 has an insertion hole 211n for inserting bolts or the like to secure the battery pack 1. The first end block 211 is made of, for example, metal or resin.

[0036] As shown in Figure 4, the second end block 212 is stacked with the 20th battery 100, which is located at the other end of the stacked 20 batteries 100, via a second end spacer 203. The second end block 212 extends along the width direction Y of the battery 100. The second end block 212 is adjacent to the battery 100 located at the end along the stacking direction X and supports the battery 100. The second end block 212 is formed in a rectangular parallelepiped shape extending in the width direction Y. Fastening bolts 241 are screwed into a plurality of screw holes formed on the side surface of the second end block 212 along the width direction Y, as shown in Figure 3. As shown in Figure 1, the second end block 212 is fixed to the first side plate 231 by fastening bolts 241. Similarly, the second end block 212 is fixed to the second side plate 232 by fastening bolts 241. The second end block 212 has an insertion hole 212n for inserting bolts, etc., for fixing the battery pack 1. The second end block 212 is formed of, for example, metal or resin.

[0037] As shown in Figure 4, the insulating member 221 is inserted into the first end block 211. The insulating member 221 is also inserted into the second end block 212. The insulating member 221 is formed, for example, in a rectangular shape. The insulating member 221 is made of an insulating material.

[0038] The insulating member 221 may have the following configuration. That is, the insulating member 221 may be molded integrally with the first end spacer 201, or it may be molded separately from the first end spacer 201 and then joined to the first end spacer 201. In such cases, the first end block 211 is provided with a recess on the surface facing the first end spacer 201 for accommodating the insulating member 221 along the stacking direction X. Similarly, the insulating member 221 may be molded integrally with the second end spacer 203, or it may be molded separately from the second end spacer 203 and then joined to the second end spacer 203. In such cases, the second end block 212 is provided with a recess on the surface facing the second end spacer 203 for accommodating the insulating member 221 along the stacking direction X.

[0039] As shown in Figure 3, the insert nut 222 is embedded in a recess formed on the upper surface of the insulating member 221. The fastening bolt is secured to the insert nut 222, for example, via a busbar that is electrically connected to an external control device.

[0040] As shown in Figure 1, the first side plate 231 is positioned along the stacking direction X of the stacked batteries 100, and at one end of the batteries 100 in the width direction Y. The first side plate 231 holds the batteries 100 along the stacking direction X. Both ends of the first side plate 231 extending along the stacking direction X are bent toward the width direction Y. As shown in Figure 3, fastening bolts 241 are inserted into a plurality of insertion holes 231m formed on the side surface of the first side plate 231 along the width direction Y. As shown in Figure 1, the first side plate 231 is fixed to the first end block 211 and the second end block 212 by the fastening bolts 241.

[0041] As shown in Figure 1, the second side plate 232 is positioned along the stacking direction X of the stacked batteries 100, at the other end of the batteries 100 in the width direction Y. The second side plate 232 holds the batteries 100 along the stacking direction X. Both ends of the second side plate 232 extending along the stacking direction X are bent toward the width direction Y. As shown in Figure 3, fastening bolts 241 are inserted into a plurality of insertion holes 232m formed on the side surface of the second side plate 232 along the width direction Y. As shown in Figure 1, the second side plate 232 is fixed to the first end block 211 and the second end block 212 by the fastening bolts 241.

[0042] As shown in Figure 2, the fastening bolts 241 fasten the first side plate 231 to the first end block 211, and the first side plate 231 to the second end block 212. Also, as shown in Figure 2, the fastening bolts 241 fasten the second side plate 232 to the first end block 211, and the second side plate 232 to the second end block 212.

[0043] (Configuration of Busbar Unit 300) The busbar unit 300 shown in FIGS. 1, 2, and 5 electrically connects a plurality of batteries 100. As shown in FIG. 5, the busbar unit 300 includes a first end busbar 301, a plurality of busbars 302, a second end busbar 303, and a busbar holder 311. Hereinafter, the configuration included in the busbar unit 300 will be described.

[0044] The first end busbar 301 is joined to the positive electrode terminal 103 of the battery 100 closest to the first end block 211 among the 20 stacked batteries 100 as shown in FIG. 2. As shown in FIG. 5, the first end busbar 301 includes a plate-shaped first joint portion 301a, a plate-shaped second joint portion 301b, a curved connecting portion 301c, and an insertion hole 301d. The first joint portion 301a is joined to a busbar that conducts with an external control device. The second joint portion 301b is joined to the positive electrode terminal 103 of the battery 100. The connecting portion 301c connects the first joint portion 301a and the second joint portion 301b. The insertion hole 301d is formed in the first joint portion 301a. A fastening bolt is inserted into the insertion hole 301d. The first joint portion 301a and the busbar that conducts with an external control device are joined by the fastening bolt. The first end busbar 301 is formed of, for example, aluminum. When the first end busbar 301 is formed of a clad material, for example, the first joint portion 301a is formed of copper and the second joint portion 301b is formed of aluminum. When the negative electrode terminal 104 of the battery 100 is configured to be converted from copper to aluminum, the first end busbar 301 may be configured such that the first joint portion 301a and the second joint portion 301b are integrally formed of aluminum.

[0045] As shown in Figure 2, the busbar 302 electrically connects one adjacent battery 100 to another battery 100 along the stacking direction X. As shown in Figure 2, the busbar 302 is joined to the positive terminal 103 of one adjacent battery 100 along the stacking direction X and to the negative terminal 104 of the other adjacent battery 100 along the stacking direction X. As shown in Figure 5, the busbar 302 includes a plate-shaped first joint portion 302a, a plate-shaped second joint portion 302b, and a curved connecting portion 302c. The first joint portion 302a is joined to the negative terminal 104 of one adjacent battery 100. The second joint portion 302b is joined to the positive terminal 103 of the other adjacent battery 100. The connecting portion 302c connects the first joint portion 302a and the second joint portion 302b. The busbar 302 is formed of, for example, a clad material formed by joining copper and aluminum, copper, or aluminum. When the busbar 302 is formed of a clad material, for example, the first joint portion 302a is formed of copper and the second joint portion 302b is formed of aluminum. If the negative terminal 104 of the battery 100 is converted from copper to aluminum, the busbar 302 may be configured such that the first joint portion 302a, the second joint portion 302b, and the connecting portion 302c are integrally formed from aluminum.

[0046] As shown in Figure 2, the second end busbar 303 is joined to the negative terminal 104 of the battery 100 closest to the second end block 212 among the 20 stacked batteries 100. As shown in Figure 5, the second end busbar 303 includes a plate-shaped first joint portion 303a, a plate-shaped second joint portion 303b, a curved connecting portion 303c, and an insertion hole 303d. The first joint portion 303a is joined to the negative terminal 104 of the battery 100. The second joint portion 303b is joined to a busbar that is electrically connected to an external control device. The connecting portion 303c connects the first joint portion 303a and the second joint portion 303b. The insertion hole 303d is formed in the second joint portion 303b. A fastening bolt is inserted into the insertion hole 303d. The second joint portion 303b and the busbar that is electrically connected to the external control device are joined by a fastening bolt. The second end busbar 303 is formed of, for example, copper.

[0047] As shown in FIG. 1, the bus bar holder 311 integrally holds the first end bus bar 301, a plurality of bus bars 302, and the second end bus bar 303. Also, the bus bar holder 311 covers and insulates a plurality of stacked batteries 100. The bus bar holder 311 is formed in a plate shape as shown in FIG. 5. A plurality of openings 311a are formed in the bus bar holder 311. Each opening 311a exposes the first joint portion or the second joint portion of the first end bus bar 301, the plurality of bus bars 302, and the second end bus bar 303 toward the battery 100 side. Each opening 311a is larger than the first joint portion or the second joint portion of the corresponding bus bar. A plurality of holding portions 311b are formed in the bus bar holder 311. Each holding portion 311b holds the end portion of the first joint portion or the second joint portion of the first end bus bar 301, the plurality of bus bars 302, and the second end bus bar 303. Each holding portion 311b is formed at the edge of the opening 311a. Each holding portion 311b has a linear groove along the surface of the bus bar holder 311. The end portion of the first joint portion or the second joint portion of the corresponding bus bar is inserted into the groove provided in each holding portion 311b. A plurality of insertion portions 311c are formed in the bus bar holder 311. The electric wire 502 of the temperature measurement unit 500 is inserted into the insertion portion 311c.

[0048] (Configuration of Voltage Detection Unit 400) The voltage detection unit 400 shown in FIGS. 1, 2, and 5 detects the voltage of the battery 100, for example, based on control by an external control device. The voltage detection unit 400 includes a voltage detection terminal 401 and an electric wire 402 as shown in FIG. 5. Hereinafter, the configuration included in the voltage detection unit 400 will be described.

[0049] The voltage detection terminal 401 is conductive and formed in a plate shape as shown in FIG. 5. The voltage detection terminal 401 is joined to the first end bus bar 301, the plurality of bus bars 302, and the second end bus bar 303 of the bus bar unit 300, respectively.

[0050] The electric wire 402 is joined to the voltage detection terminal 401 as shown in FIG. 5. The electric wire 402 conducts the voltage detection terminal 401 and an external control device.

[0051] (Configuration of Temperature Measurement Unit 500) The temperature measurement unit 500 shown in Figures 1, 2, and 5 measures the temperature of the battery 100, for example, based on control by an external control device. As shown in Figure 2, the temperature measurement unit 500 includes a temperature sensor 501 and an electric wire 502. The configuration included in the temperature measurement unit 500 will be described below.

[0052] The temperature sensor 501 measures the temperature of the battery 100. As shown in Figure 2, the temperature sensor 501 is, for example, attached to the lid 102 of the battery 100, which is located 7th and 14th from the first end block 211 toward the second end block 212.

[0053] As shown in Figure 2, the electric wire 502 is attached to the temperature sensor 501. The electric wire 502 provides electrical conductivity between the temperature sensor 501 and the external control equipment.

[0054] (Effects of the battery pack 1 of the first embodiment) The effects of the battery pack 1 of the first embodiment will be described.

[0055] The battery pack 1 includes a plurality of batteries 100 and cell spacers (spacers) 202 that insulate one battery 100 from another battery 100. The battery 100 includes a charge / discharge unit 110 (see Figure 13(a)) and an outer casing (container 101 and lid 102) that houses the charge / discharge unit 110. The cell spacer 202 includes a main plate (first part) 202c and a lower plate (second part) 202d. The main plate 202c is in contact with the container 101 in the stacking direction X of one battery 100 and another battery 100. The lower plate 202d is in contact with the container 101 in a direction intersecting the stacking direction X (height direction Z). The lower plate 202d includes a base portion 202d1 and a high thermal conductivity portion 202d2. The thermal conductivity of the high thermal conductivity section 202d2 is higher than that of the base section 202d1 and the main plate 202c. The efficiency of heat conduction from the battery 100 to the outside of the cell spacer 202 via the lower plate 202d is higher than the efficiency of heat conduction from the battery 100 to the outside of the cell spacer 202 via the main plate 202c.

[0056] With this configuration, most of the heat generated by the battery 100 can be dissipated to the outside of the battery pack 1 through the lower plate 202d having a high thermal conductivity portion 202d2. This prevents the heat from one battery 100 from propagating to other batteries 100 adjacent to it along the stacking direction X if one battery 100 overheats abnormally. As a result, thermal runaway, a phenomenon in which other batteries 100 overheat in a chain reaction when one battery 100 overheats abnormally, can be suppressed.

[0057] The thermal conductivity of the high thermal conductivity section 202d2 is higher than that of the main plate (first part) 202c. In this configuration, by using a material with high thermal conductivity for the high thermal conductivity section 202d2, the thermal conductivity of both the high thermal conductivity section 202d2 and the lower plate 202d can be improved.

[0058] The main plate (first part) 202c contains resin. By using a material containing metal in the high thermal conductivity section 202d2, the thermal conductivity of the lower plate 202d can be easily increased.

[0059] The battery 100 has external terminals (positive terminal 103 and negative terminal 104) electrically connected to the charge / discharge unit 110. The casing has an upper surface (mounting surface) 100a to which the external terminals are attached, and a lower surface (cooling surface) 100d that faces the upper surface 100a via the charge / discharge unit 110. The lower plate (second part) 202d is in contact with the lower surface 100d of the casing.

[0060] As described above, the high thermal conductivity portion 202d2 is provided on the lower plate 202d that is in contact with the lower surface 100d of the battery 100. The lower surface 100d is positioned opposite the upper surface 100a, to which the external terminals (positive electrode terminal 103 and negative electrode terminal 104) are attached, with the charge / discharge body 110 in between. In this configuration, in particular, when the charge / discharge body (current collector) 110 of the battery 100 is in contact with the bottom plate 101d of the container 101 (see Figure 13(a)), the battery 100 can be effectively cooled via the lower plate 202d. The bottom plate 101d of the container 101 includes the lower surface 100d of the battery 100.

[0061] The charge / discharge body 110 shown in Figure 13(a) is constructed, for example, by winding a positive electrode and a negative electrode with a separator in between. The charge / discharge body 110 is housed in an outer casing such that the winding axis is parallel to the width direction Y. Joints are provided at both ends of the charge / discharge body 110 in the width direction Y, to which the charge / discharge body 110 is joined. At one end of the charge / discharge body 110 in the width direction Y, a positive electrode joint is formed by compressing a bundle of multiple positive electrodes. At the other end of the charge / discharge body 110 in the width direction Y, a negative electrode joint is formed by compressing a bundle of multiple negative electrodes. A positive electrode current collector plate is joined to the positive electrode joint. A negative electrode current collector plate is joined to the negative electrode joint. The positive electrode current collector plate extends along the height direction Z and is connected to the positive electrode terminal 103. The negative electrode current collector plate extends along the height direction Z and is connected to the negative electrode terminal 104. The charging / discharging body 110 has a semi-circular curved portion 110R positioned opposite the upper surface 100a and lower surface 100d of the battery 100. The curved portion 110R of the charging / discharging body 110 is in contact with the bottom plate 101d of the container 101.

[0062] (Battery pack 2 of the second embodiment) The battery pack 2 of the second embodiment includes a cell spacer 702 as shown in Figure 7.

[0063] (Cell spacer 702 of the second embodiment) The configuration of the cell spacer 702 will be described with reference to Figure 7. Figure 7 is a perspective view showing the main part of the second embodiment in cross-section.

[0064] In the second embodiment, components identical to those in the first embodiment are given the same reference numerals as in the first embodiment and their descriptions are omitted. In the second embodiment, components different from those in the first embodiment are given different reference numerals and described accordingly. In the first embodiment, as shown in Figure 6, a single high-heat-conductivity portion 202d2 was provided on the lower plate 202d of the cell spacer 202.

[0065] In contrast, in the second embodiment, as shown in Figure 7, four high-heat-conductivity sections 702d2 are provided on the lower plate 702d of the cell spacer 702 (two high-heat-conductivity sections 702d2 are shown in the figure). Four openings are provided in the base portion 702d1. Each high-heat-conductivity section 702d2 is positioned to cover each opening. The width (dimension in the width direction Y) of each high-heat-conductivity section 702d2 is equal. Each high-heat-conductivity section 702d2 is positioned at equal intervals along the width direction Y.

[0066] (Effects of the battery pack 2 of the second embodiment) The effects of the battery pack 2 of the second embodiment will now be described. According to this second embodiment, in addition to the same effects as the first embodiment, the following effects can be obtained.

[0067] In the second embodiment, the cell spacer 702 is provided with four high-heat-conductivity sections 702d2 on its lower plate 702d. In this configuration, for example, when forming the cell spacer 702 by first forming an opening in the base 702d1 and then attaching the high-heat-conductivity sections 702d2 to the formed opening, the following effects can be obtained. Since beams (three beams in this embodiment) are formed between each opening in the lower plate 702d, the rigidity of the base 702d1 can be improved. This prevents damage to the cell spacer 702 when attaching the high-heat-conductivity sections 702d2 to each opening in the base 702d1.

[0068] (Modified Battery Pack 2 of the Second Embodiment) In the second embodiment, an example was described in which four high-thermal-conductivity sections 702d2 are arranged on the lower plate 702d along the width direction Y. However, the number and arrangement of the high-thermal-conductivity sections 702d2 are not limited thereto. The high-thermal-conductivity sections 702d2 formed on the lower plate 702d may be two, three, or five or more. Multiple high-thermal-conductivity sections 702d2 may be arranged in the stacking direction X. Alternatively, multiple high-thermal-conductivity sections 702d2 may be arranged in a matrix along the stacking direction X and the width direction Y. For example, the high-thermal-conductivity section may be divided into two in the stacking direction X and into six in the width direction Y. In this case, twelve high-thermal-conductivity sections 702d2 are arranged in a matrix on the lower plate 702d.

[0069] (Battery pack 3 of the third embodiment) The battery pack 3 of the third embodiment includes a cell spacer 802 as shown in Figure 8.

[0070] (Cell spacer 802 of the third embodiment) The configuration of the cell spacer 802 will be described with reference to Figure 8. Figure 8 is a perspective view showing the main part of the third embodiment in cross-section.

[0071] In the third embodiment, components identical to those in the first embodiment are given the same reference numerals as in the first embodiment and their descriptions are omitted. In the third embodiment, components different from those in the first embodiment are given different reference numerals and described accordingly. In the first embodiment, as shown in Figure 6, an example was described in which the entirety of a single battery 100 is housed in a rectangular box-shaped cell spacer 202.

[0072] In contrast, in the third embodiment, the cell spacer 802 is formed to accommodate a portion of one battery 100 and a portion of another battery 100, as shown in Figure 8. The cell spacer 802 covers a portion of each main surface 100c along the width direction Y of adjacent batteries 100 and a portion of each side surface 100b along the stacking direction X of adjacent batteries 100.

[0073] The cell spacer 802 is placed between a pair of batteries 100. The cell spacer 802 has a main plate 802c, a bottom plate 802d, and a pair of side plates 802b. The main plate 802c is a rectangular flat plate member that covers the main surface 100c of each of the pair of batteries 100. The main plate 802c is a member (first part) that is in contact with the main surface 100c of the batteries 100 in the stacking direction X of adjacent batteries 100 and the other battery 100.

[0074] The main plate 802c is connected to the center of the width (dimension in the stacking direction X) of the side plate 802b. In other words, the side plate 802b protrudes from the main plate 802c in one direction and the other in the stacking direction X. The side plate 802b is a component (second part) that is in contact with the side surface 100b of the battery 100 in the width direction Y which is perpendicular to the stacking direction X.

[0075] The main plate 802c is connected to the center of the width (dimension in the stacking direction X) of the lower plate 802d. In other words, the lower plate 802d protrudes from the main plate 802c in one direction and the other in the stacking direction X. The portion protruding in one direction in the stacking direction X is denoted as the first protruding plate 802d3, and the portion protruding in the other direction in the stacking direction X is denoted as the second protruding plate 802d4. The lower plate 802d is a component (second part) that is in contact with the lower surface 100d of the battery 100 in the height direction Z perpendicular to the stacking direction X.

[0076] Furthermore, the cell spacer 802 does not have a member that covers the upper surface 100a of the battery 100. With this configuration, not only can the cell spacer 802 and the battery 100 be assembled by moving them relatively along the stacking direction X, but a method of assembly by moving them relatively along the height direction Z can also be employed. In other words, the configuration of the cell spacer 802 in this second embodiment provides a high degree of freedom in the method of assembling the cell spacer 802 and the battery 100.

[0077] The lower plate 802d comprises a base portion 802d1 and a high-thermal-conductivity portion 802d2 that has higher thermal conductivity than the base portion 802d1 and the main plate 802c. The base portion 802d1 and the high-thermal-conductivity portion 802d2 are provided on the first protruding plate 802d3 and the second protruding plate 802d4, respectively. The first protruding plate 802d3 and the second protruding plate 802d4 have similar configurations. Therefore, in the following description, the first protruding plate 802d3 will be described as a representative example, and the description of the second protruding plate 802d4 will be omitted.

[0078] The base portion 802d1 has a portion that is connected to the lower end of the main plate 802c and a portion that is connected to the lower ends of each of the pair of side plates 802b. The base portion 202d1 of the first embodiment was rectangular frame-shaped (see Figure 6). In contrast, as shown in Figure 8, the base portion 802d1 of this third embodiment does not have any members constituting the base portion 802d1 at both ends of the lower plate 802d in the stacking direction X.

[0079] (Effects of the battery pack 3 of the third embodiment) The effects of the battery pack 3 of the third embodiment will now be described. According to this third embodiment, in addition to the same effects as the first embodiment, the following effects can be obtained.

[0080] In the third embodiment, the cell spacer 802 and the battery 100 can be assembled by moving them relative to each other in the height direction Z. Therefore, assembly methods such as arranging multiple cell spacers 802 and then inserting multiple batteries 100 into the multiple cell spacers 802 from above can also be employed. Due to the high degree of freedom in the assembly method, manufacturing man-hours and manufacturing costs can be reduced.

[0081] (Battery pack 4 of the fourth embodiment) The battery pack 4 of the fourth embodiment includes a cell spacer 902 as shown in Figure 9.

[0082] (Cell spacer 902 of the fourth embodiment) The configuration of the cell spacer 902 will be described with reference to Figure 9. Figure 9 is a perspective view showing the main part of the fourth embodiment in cross-section.

[0083] In the fourth embodiment, components identical to those in the first embodiment are given the same reference numerals as in the first embodiment and their descriptions are omitted. In the fourth embodiment, components different from those in the first embodiment are given different reference numerals and described accordingly. In the first embodiment, as shown in Figure 6, a high heat conductivity portion 202d2 was provided on the lower plate 202d of the cell spacer 202.

[0084] In contrast, in the fourth embodiment, as shown in Figure 9, a high thermal conductivity portion 902b2 is provided on the side plate 902b of the cell spacer 902. A single opening is provided in the base portion 902b1, and the high thermal conductivity portion 902b2 is positioned to cover this opening.

[0085] The high thermal conductivity portion 902b2 may be provided on both of the pair of side plates 902b, or on only one of the pair of side plates 902b. When the high thermal conductivity portion 902b2 is provided on only one of the pair of side plates 902b, it is preferable to arrange each cell spacer 902 such that the high thermal conductivity portion 902b2 of each cell spacer 902 is located on one side in the width direction Y of the battery pack 4. This allows the battery pack 4 to be effectively cooled by cooling only one side in the width direction Y of the battery pack 4 using a cooling device (not shown).

[0086] (Effects of the battery pack 4 of the fourth embodiment) The effects of the battery pack 4 of the fourth embodiment will now be described. According to this fourth embodiment, in addition to the same effects as the first embodiment, the following effects can be obtained.

[0087] In the fourth embodiment, the battery 100 can be effectively cooled when the side surface 100b of the outer surface of the battery 100's casing is the surface that is mainly cooled by a cooling device (not shown). For example, the battery pack 4 can be installed so that one of the pair of side surfaces 100b is located vertically downward, and the bottom surface (side surface 100b) of the battery pack 4 can be cooled by a cooling plate or the like. The cooling plate is thermally connected to the cell spacer 902 via a side plate (first side plate 231 or second side plate 232).

[0088] When cooling the battery pack 4 with cooling air, the cooling air is directed onto the side plate. As a result, the heat generated in the battery 100 is transferred from the cell spacer 902 to the side plate, and the heat from the side plate is then transported away by the cooling air.

[0089] In particular, when the charge / discharge element (current collector) of the battery 100 is configured to be in contact with the side plate of the container 101, the battery 100 can be effectively cooled via the side plate 902b. The side plate of the container 101 includes the side surface 100b of the battery 100. This charge / discharge element is constructed, for example, by winding a positive electrode and a negative electrode with a separator in between. The charge / discharge element is housed in an outer casing such that the winding axis is parallel to the height direction Z. The charge / discharge element is provided with a plurality of positive electrode tabs and a plurality of negative electrode tabs protruding from one side in the height direction Z. The bundled plurality of positive electrode tabs are connected to the positive electrode terminal 103, and the bundled plurality of negative electrode tabs are connected to the negative electrode terminal 104. The semi-circular curved portion of this charge / discharge element is positioned opposite the side surface 100b of the battery 100 and is in contact with the side plate of the container 101.

[0090] (Battery pack 5 of the fifth embodiment) The battery pack 5 of the fifth embodiment includes a cell spacer 1002 as shown in Figure 10.

[0091] (Cell spacer 1002 of the fifth embodiment) The configuration of the cell spacer 1002 will be described with reference to Figure 10. Figure 10 is a perspective view showing the main part of the fifth embodiment in cross-section.

[0092] In the fifth embodiment, components identical to those in the first embodiment are given the same reference numerals as in the first embodiment and their descriptions are omitted. In the fifth embodiment, components different from those in the first embodiment are given different reference numerals and described accordingly. In the first embodiment, as shown in Figure 6, a high heat conductivity portion 202d2 was provided on the lower plate 202d of the cell spacer 202.

[0093] In contrast, in the fifth embodiment, as shown in Figure 10, a high thermal conductivity portion 1002a2 is provided on the upper plate 1002a of the cell spacer 1002. Multiple openings are provided in the base portion 1002a1, and the high thermal conductivity portion 1002a2 is positioned to cover these openings.

[0094] (Effects of the battery pack 5 of the fifth embodiment) The effects of the battery pack 5 of the fifth embodiment will now be described. According to this fifth embodiment, in addition to the same effects as the first embodiment, the following effects can be obtained.

[0095] In the fifth embodiment, the battery 100 can be effectively cooled when the upper surface 100a of the outer surface of the battery 100's casing is the surface that is mainly cooled by a cooling device (not shown). For example, the battery pack 5 can be installed so that the upper surface 100a is located vertically downward, and the bottom surface (upper surface 100a) of the battery pack 5 can be cooled by a cooling plate or a blower.

[0096] (Battery pack 6 of the sixth embodiment) The battery pack 6 of the sixth embodiment includes the cell spacer 1102 shown in Figure 11.

[0097] (Cell spacer 1102 of the sixth embodiment) The configuration of the cell spacer 1102 will be described with reference to Figure 11. Figure 11 is a perspective view showing the main part of the sixth embodiment in cross-section.

[0098] In the sixth embodiment, components identical to those in the first, fourth, and fifth embodiments are given the same reference numerals as in the first, fourth, and fifth embodiments and their descriptions are omitted. In the sixth embodiment, components different from those in the first, fourth, and fifth embodiments are described using different reference numerals. In the first embodiment, a high thermal conductivity section 202d2 is provided only on the lower plate 202d of the cell spacer 202 (see Figure 6), in the fourth embodiment, a high thermal conductivity section 902b2 is provided only on the side plate 902b of the cell spacer 902 (see Figure 9), and in the fifth embodiment, a high thermal conductivity section 1002a2 is provided only on the upper plate 1002a of the cell spacer 1002 (see Figure 10).

[0099] In contrast, in the sixth embodiment, as shown in Figure 11, high thermal conductivity sections 202d2, 902b2, and 1002a2 are provided on the lower plate 202d, the pair of side plates 902b, and the upper plate 1002a of the cell spacer 1102, respectively.

[0100] (Effects of the battery pack 6 of the sixth embodiment) The effects of the battery pack 6 of the sixth embodiment will now be described. According to this sixth embodiment, in addition to the same effects as the first embodiment, the following effects can be obtained.

[0101] In the sixth embodiment, the outer surface of the battery 100's casing is not limited to the surface that is mainly cooled by the cooling device (not shown). In other words, according to the sixth embodiment, a battery pack 6 with a high degree of freedom in arrangement can be obtained.

[0102] For example, by flowing cooling air from one side to the other in the stacking direction X, the top surface 100a, bottom surface 100d, and a pair of side surfaces 100b of the battery 100 can be cooled uniformly, thereby effectively cooling the battery pack 6. The heat from the pair of side surfaces 100b is dissipated through the side plates (first side plate 231 and second side plate 232). Since the cooling area of ​​the battery 100 can be increased, the amount of heat dissipated through the main surface 100c can be further suppressed. As a result, thermal runaway of the battery pack 6 can be suppressed more effectively.

[0103] (Battery pack 7 of the seventh embodiment) The battery pack 7 of the seventh embodiment includes a cell spacer 1202 as shown in Figure 12.

[0104] (Cell Spacer 1202 of the Seventh Embodiment) The configuration of the cell spacer 1202 will be described with reference to Figure 12. Figure 12 is a cross-sectional view of the main part of the seventh embodiment. Figure 12 shows an enlarged cross-sectional view of the lower plate 1202d. Figure 12 shows three examples of the lower plate 1202d (Figures 12(a) to 12(c)).

[0105] In the seventh embodiment, components identical to those in the first embodiment are given the same reference numerals as in the first embodiment and their descriptions are omitted. In the seventh embodiment, components different from those in the first embodiment are given different reference numerals and described accordingly. In the first embodiment, an example was described in which the cell spacer 202 is formed such that the thickness of the high heat conductivity portion 202d2 is equal to the thickness of the base portion 202d1 and the main plate 202c.

[0106] In contrast, in the seventh embodiment, as shown in Figure 12, the thickness t2 of the high thermal conductivity portion 1202d2 is thinner than the thickness t1 of the base portion 1202d1 and the thickness t3 (not shown) of the main plate 202c (t2 < t1, t2 < t3). The thickness t1 of the base portion 1202d1 and the thickness t3 of the main plate 202c may be the same or different. From the viewpoint of suppressing thermal runaway, it is preferable that the thickness t3 of the main plate 202c be thicker than the thickness t1 of the base portion 1202d1.

[0107] In the examples shown in Figures 12(a) and 12(b), the high thermal conductivity portion 1202d2 is positioned to be in contact with the lower surface 100d of the battery 100. In the example shown in Figure 12(a), the lower surface of the high thermal conductivity portion 1202d2 is exposed. In contrast, in the example shown in Figure 12(b), a base portion 1202d1 is provided on the lower surface of the high thermal conductivity portion 1202d2, and the lower surface of the high thermal conductivity portion 1202d2 is not exposed. In other words, in the example shown in Figure 12(b), the opening of the base portion 1202d1 is a non-penetrating recess in the height direction Z.

[0108] Although Figure 12(b) shows an example where the opening (recess) of the base 1202d1 is located on the upper surface, the base 1202d1 may also be configured to have the opening (recess) located on the lower surface.

[0109] In the example shown in Figure 12(c), the high thermal conductivity portion 1202d2 is embedded inside the base portion 1202d1. The cell spacer 1202 shown in Figure 12(c) can be formed by two-color molding or insert molding.

[0110] In this seventh embodiment, as in the first embodiment, the battery pack 7 may be cooled by a blower, or it may be cooled by a cooling system equipped with a cooling plate. In the example shown in Figure 12(a), when a cooling plate is installed, it is preferable to interpose a sheet with excellent flexibility and thermal conductivity between the cooling plate and the lower plate 1202d. In other words, it is preferable to fill the gap between the cooling plate and the high thermal conductivity portion 1202d2 with a highly flexible sheet. By bringing the highly flexible sheet into contact with the high thermal conductivity portion 1202d2 and the cooling plate, the battery pack 7 can be effectively cooled.

[0111] (Effects of the battery pack 7 of the seventh embodiment) The effects of the battery pack 7 of the seventh embodiment will now be described. According to this seventh embodiment, in addition to the same effects as the first embodiment, the following effects can be obtained.

[0112] The thickness t2 (dimension in the height direction Z) of the high thermal conductivity section 1202d2 is thinner than the thickness t3 (dimension in the lamination direction X) of the main plate (first part) 202c. In this configuration, by reducing the thickness of the high thermal conductivity section 1202d2, the thermal conductivity of both the high thermal conductivity section 1202d2 and the lower plate 1202d can be improved.

[0113] With this configuration, similar to the first embodiment, the efficiency of heat conduction from the inside of the container 101 (inside the battery 100) via the lower plate 1202d to the outside of the cell spacer 1202 (outside the battery 100) is higher than the efficiency of heat conduction from the inside of the container 101 (inside the battery 100) via the main plate 202c to the outside of the cell spacer 202 (outside the battery 100). Therefore, the same effects as in the first embodiment can be obtained.

[0114] Furthermore, with this configuration, in the example shown in Figure 12(a), the same material can be used for the high thermal conductivity portion 1202d2 as for the base portion 1202d1 and the main plate 202c. Therefore, the cell spacer 1202 equipped with the high thermal conductivity portion 1202d2 can be integrally formed by single-color molding. Consequently, material costs can be reduced according to this embodiment.

[0115] Furthermore, similar to the first embodiment, by using a material with higher thermal conductivity than the main plate 202c or base 202d1 for the high thermal conductivity section 1202d2, the battery 100 can be cooled more effectively.

[0116] The thickness t1 (dimension in the height direction Z) of the base portion 1202d1 is greater than the thickness t2 (dimension in the height direction Z) of the high heat conductivity portion 1202d2. This configuration improves cooling performance while increasing the strength of the lower plate 1202d of the cell spacer 1202.

[0117] (Battery packs of other embodiments) The battery pack of the present invention is not limited to the configuration of the battery pack described in the embodiments, but can be appropriately configured based on the contents described in the claims.

[0118] In the first to sixth embodiments, an example was described in which a high thermal conductivity portion with a higher thermal conductivity than the first part (main plate) in contact with the exterior in a direction intersecting the stacking direction X is provided on at least one of the multiple second parts (bottom plate, top plate, side plate) that are in contact with the exterior in a direction intersecting the stacking direction X. Furthermore, in the seventh embodiment, an example was described in which thermal conductivity is increased by reducing the thickness of the high thermal conductivity portion 1202d2. However, thermal conductivity can also be increased by reducing the surface roughness.

[0119] For example, in the first embodiment, by making the surface roughness R2 of the surface of the high thermal conductivity portion 202d2 in contact with the battery 100 smaller than the surface roughness R1 of the surface of the main plate (first part) 202c in contact with the battery 100, the thermal conductivity of the lower plate 202d can be increased compared to that of the main plate 202c. Surface roughness is expressed, for example, by the arithmetic mean roughness Ra or the ten-point mean roughness Rz.

[0120] With this configuration, similar to the first embodiment, the efficiency of heat conduction from the inside of the container 101 (inside the battery 100) via the lower plate 202d to the outside of the cell spacer 202 (outside the battery 100) is higher than the efficiency of heat conduction from the inside of the container 101 (inside the battery 100) to the outside of the cell spacer 202 (outside the battery 100) via the main plate 202c. Therefore, the same effects as in the first embodiment can be obtained.

[0121] The positional relationship between the high heat conductivity portion 202d2 and the base portion 202d1 is not limited to the embodiments described above. Figure 13 is an explanatory diagram of a modified lower plate 202d of the cell spacer 202. Figure 13(a) is a diagram for comparison with the modified lower plate 202d and is an enlarged cross-sectional view of the lower plate 202d of the first embodiment. Figure 13(b) is an enlarged cross-sectional view of the lower plate 202d of modified example 1 of the first embodiment, and Figure 13(c) is an enlarged cross-sectional view of the lower plate 202d of modified example 2 of the first embodiment.

[0122] As shown in Figure 13(a), in the first embodiment, the cell spacer 202 was formed such that the upper surface of the high heat conductivity portion 202d2 and the upper surface of the base portion 202d1 were flush, and the lower surface of the high heat conductivity portion 202d2 and the lower surface of the base portion 202d1 were flush.

[0123] In contrast, in the example shown in Figure 13(b), the high thermal conductivity portion 202d2 is positioned above the base portion 202d1. In the example shown in Figure 13(c), the thickness t2 of the high thermal conductivity portion 202d2 is greater than the thickness t1 of the base portion 202d1. Furthermore, the high thermal conductivity portion 202d2 protrudes vertically from the opening of the base portion 202d1. Even with these modifications, thermal runaway of the battery pack can be effectively suppressed, similar to the above embodiment.

[0124] The embodiments are described in detail or in a simplified manner to clearly illustrate the present invention, and it is not necessary to have all the configurations described, or to have configurations that are not shown. Furthermore, some of the configurations of the embodiments may be deleted, replaced with configurations from other embodiments, or combined with configurations from other embodiments.

[0125] The number of batteries 100 included in the battery pack 1 is not limited to 20. The number of batteries 100 may be, for example, 2 to 19 or 21 or more. The batteries 100 are not limited to lithium-ion batteries. For example, nickel-metal hydride batteries or lead-acid batteries can be used for the batteries 100. The batteries 100 are not limited to secondary batteries. For example, primary batteries can be used for the batteries 100.

[0126] 1-7...Battery pack, 100...Battery, 100a...Top surface (mounting surface), 100b...Side, 100c...Main surface, 100d...Bottom surface (cooling surface), 101...Container (outer casing), 101d...Bottom plate, 102...Lid (outer casing), 103...Positive terminal (external terminal), 104...Negative terminal (external terminal), 105...Safety valve, 110...Charging / discharging element (current collector), 110R...Curved section, 200...Holding unit, 201...First end spacer, 202...Cell spacer (spacer), 202a...Top plate (second part), 202a1...Notch, 202a2...Opening, 202b...Side plate (second part), 202c...Main plate (first part) ), 202d...Bottom plate (second part), 202d1...Base, 202d2...High heat conductivity part, 203...Second end spacer, 211...First end block, 211m...Screw hole, 211n...Insertion hole, 212...Second end block, 212n...Insertion hole, 221...Insulating member, 222...Insert nut, 231...First side plate, 231m...Insertion hole, 232...Second side plate, 232m...Insertion hole, 241...Fastening bolt, 300...Busbar unit, 301...First end busbar, 301a...First joint, 301b...Second joint, 301c...Connecting part, 301d...Insertion hole, 302...Busbar, 302a...First joint, 302b...Second joint, 302c...Connecting part, 303...Second end busbar, 303a...First joint, 303b...Second joint, 303c...Connecting part, 303d...Insertion hole, 311...Busbar holder, 311a...Opening, 311b...Holding part, 311c...Insertion part, 400...Voltage detection unit, 401...Voltage detection terminal, 402...Electric wire, 500...Temperature measurement unit, 501...Temperature sensor, 502...Electric wire, 702...Cell spacer (spacer), 702d...Bottom plate (second part), 702d1...Base, 702d2...High thermal conductivity part, 802...Cell Pacer (spacer), 802b...side plate (second part), 802c...main plate (first part), 802d...bottom plate (second part), 802d1...base, 802d2...high thermal conductivity part, 802d3...first protruding plate, 802d4...second protruding plate, 902...cell spacer (spacer), 902b...side plate (second part), 902b1...base, 902b2...high thermal conductivity part, 1002...cell spacer (spacer), 1002a...top plate (second part), 1002a1...base, 1002a2...high thermal conductivity part, 1102...cell spacer (spacer), 1202...cell spacer (spacer), 1202d...bottom plate (second part),1202d1...base, 1202d2...high heat conductivity section, X...stack direction, Y...width direction, Z...height direction.

Claims

1. A battery pack comprising a plurality of batteries, each including a charge / discharge element and an outer casing housing the charge / discharge elements, and a spacer insulating one of the batteries from the other batteries, wherein the spacer includes a first portion in contact with the outer casing in the stacking direction of the batteries, and a second portion in contact with the outer casing in a direction intersecting the stacking direction, the second portion comprising a base and a high thermal conductivity portion having higher thermal conductivity than the base and the first portion, and the efficiency of heat conduction from the batteries to the outside of the spacer via the second portion is higher than the efficiency of heat conduction from the batteries to the outside of the spacer via the first portion.

2. The thermal conductivity of the high thermal conductivity portion is higher than that of the first portion, as described in claim 1.

3. The battery pack according to claim 1, wherein the thickness of the high thermal conductivity portion is thinner than the thickness of the first portion.

4. The battery pack according to claim 1, wherein the surface roughness of the surface of the high thermal conductivity portion in contact with the battery is smaller than the surface roughness of the surface of the first portion in contact with the battery.

5. The battery pack according to claim 1, wherein the first part comprises resin, and the high thermal conductivity part comprises metal.

6. The battery pack according to claim 1, wherein the battery has an external terminal electrically connected to the charge / discharge element, the casing has a mounting surface to which the external terminal is attached, and a cooling surface facing the mounting surface via the charge / discharge element, and the second part is in contact with the cooling surface.

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