JP2014164859A - Battery unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system which reduces heat deterioration of a battery cell in a sealing part formation step without limiting flexibility in selection of the type of a resin which seals a protection circuit board and forms an outer package.SOLUTION: A battery unit includes: a battery cell 101; a protection circuit board 110 where a cell mounting part and a component mounting part are provided on the surface side, the battery cell 101 is fixed to the cell mounting part, a protection circuit 121 which protects the battery cell 101 is mounted on the component mounting part, and the battery cell 101 and the protection circuit 121 are electrically connected through a connection member 102a; a cover member 104 which covers the battery cell 101 fixed to the cell mounting part; and a sealing part 105 which seals the protection circuit 121, the connection member 102a, and a part of the cover member 104. The cover member 104 is formed by a material having heat conductivity lower than the battery cell 101. The sealing part 105 and the battery cell 101 are separated by the cover member 104.

Description

  The present invention relates to a battery unit in which, for example, a lithium ion secondary battery cell or the like is mounted on a substrate.

  As electronic devices such as digital still cameras, digital video cameras, and smartphones become smaller, battery units using lithium ion secondary battery cells or the like used as driving power sources are also required to be further miniaturized.

  Conventionally, a technique is known in which a battery unit in which a battery cell and a protection circuit board are electrically connected is fixed in a mold, and a molten synthetic resin is injected into the mold to form an exterior of the battery unit. Yes. However, if high-temperature molten synthetic resin is injected into the mold as described above, the battery cell may be thermally deteriorated.

  Thus, a technique has been proposed in which a battery cell is cooled in advance to a predetermined temperature, fixed in a mold, and molten synthetic resin is injected into the mold (Patent Document 1). In this proposal, since the battery cell is cooled in advance to a predetermined temperature before the molten resin is injected into the mold, it is possible to reduce the thermal deterioration of the battery cell.

JP 2004-200043 A

  However, in Patent Document 1, since a thermosetting resin is used as a synthetic resin material that covers the protective circuit board and forms the exterior, heat is transmitted to the battery cell during thermosetting. For this reason, it is difficult to sufficiently reduce the thermal deterioration of the battery cell due to an increase in the temperature of the battery cell.

  Accordingly, an object of the present invention is to provide a mechanism for reducing thermal deterioration of battery cells even when a thermosetting resin is used as a synthetic resin material for sealing a protective circuit board.

  In order to achieve the above object, the battery unit of the present invention includes a battery cell, a cell mounting portion and a component mounting portion provided on the front side, the battery cell being fixed to the cell mounting portion, and the component mounting. A protection circuit that protects the battery cell is mounted on the part, the battery cell and the protection circuit are electrically connected via a connection member, and the battery cell fixed to the cell mounting part A cover member that covers the protective circuit, the connection member, and a sealing portion that seals a part of the cover member, wherein the cover member is a material having a lower thermal conductivity than the battery cell. The sealing part and the battery cell are separated by the cover member.

  According to the present invention, even when a thermosetting resin is used as the synthetic resin for sealing the protective circuit board, the thermal deterioration of the battery cell can be reduced.

It is a perspective view of the battery unit which is an example of embodiment of this embodiment. It is the perspective view which looked at the battery unit shown in FIG. 1 from the back surface. It is a perspective view which shows the state before resin coating of the battery unit shown in FIG. FIG. 4 is an exploded perspective view of FIG. 3. It is the sectional view on the AA line of FIG. It is principal part sectional drawing which shows the state in which the resin coating part was formed in the battery unit installed in the jig | tool.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a battery unit as an example of an embodiment of the present invention, and FIG. 2 is a perspective view of the battery unit shown in FIG. 3 is a perspective view showing a state before the battery unit shown in FIG. 1 is sealed, FIG. 4 is an exploded perspective view of FIG. 3, and FIG. 5 is a cross-sectional view taken along line AA of FIG.

  As shown in FIGS. 1 to 5, the battery unit 100 of the present embodiment includes a protection circuit board 110 and battery cells 101 that are electrically connected to the protection circuit board 110.

  The battery cell 101 is composed of a lithium ion secondary battery cell or the like, and is bonded and fixed to the cell mounting portion 130 of the protective circuit board 110 via a spacer 103 formed of, for example, a silicon sheet having thermal conductivity.

  The spacer 103 is arranged avoiding the central portion of the battery cell 101 so as not to increase the thickness of the battery unit 100 due to thermal expansion of the battery cell 101 due to repeated charge and discharge.

  On the side surface of the battery cell 101, a positive electrode 101a and a negative electrode 101b are provided. One end of the positive electrode lead plate 102a is electrically connected to the positive electrode 101a of the battery cell 101 by spot welding or the like, and the other end of the positive electrode lead plate 102a is electrically connected to the positive electrode connection portion 122a of the protective circuit board 110 by soldering or the like. Connected.

  Further, one end of the negative electrode lead plate 102b is electrically connected to the negative electrode 101b of the battery cell 101 by spot welding or the like, and the other end of the negative electrode lead plate 102b is soldered to the negative electrode connection portion 122b of the protection circuit board 110 or the like. Are electrically connected. Here, the positive electrode lead plate 102a and the negative electrode lead plate 102b correspond to an example of the connection member of the present invention.

  In the protective circuit board 110, the component mounting part 120 and the cell mounting part 130 are arranged adjacent to each other on the surface side. The cell mounting portion 130 is provided with a heat conduction pattern 131a, and the battery cell 101 is bonded and fixed on the heat conduction pattern 131a via the spacer 103 described above.

  The component mounting unit 120 is provided with a protection circuit 121 for protecting overcharge and overdischarge of the battery cell 101, for example, COB (Chip On Board), and also provided with a positive electrode connection unit 122a and a negative electrode connection unit 122b. It is done. As described above, the other end of the positive electrode lead plate 102a and the other end of the negative electrode lead plate 102b are electrically connected to the positive electrode connecting portion 122a and the negative electrode connecting portion 122b, respectively, by soldering or the like.

  On the back surface side of the component mounting part 120 of the protection circuit board 110, there is a temperature terminal 141 in which a thermistor is connected between the + terminal 140, the − terminal 142, and the − terminal 142 for charging and discharging the battery cell 101. Has been placed.

  Further, a heat conduction pattern 131 b is disposed on the back side of the cell mounting part 130 of the protection circuit board 110. The heat conduction pattern 131 b on the back surface side of the protection circuit board 110 and the heat conduction pattern 131 a on the front surface side are connected through a through hole 132. Thereby, the battery cell 101 can be efficiently cooled through the spacer 103 in the step of forming the sealing portion 105 described later. Here, the heat conducting patterns 131a and 131b correspond to an example of the heat conducting portion of the present invention.

  The cover member 104 is formed of a material such as ceramic having a lower thermal conductivity than the battery cell 101, is disposed so as to cover the battery cell 101, and is fixed to the protective circuit board 110 by adhesion or the like. By forming the cover member 104 with a material having a relatively low thermal conductivity, the heat of the heater 312 (see FIG. 6) is hardly transmitted to the battery cell 101 in the step of forming the sealing portion 105 described later. The thermosetting temperature of the thermosetting resin is ensured sufficiently.

  The sealing portion 105 is formed using, for example, a thermosetting resin such as an epoxy resin as a sealing material, and the protection circuit 121 of the component mounting portion 120, the positive electrode connection portion 122 a, the negative electrode connection portion 122 b, and the cover member 104. Cover part. The sealing part 105 is isolated from the battery cell 101 by the cover member 104.

  Next, an example of a process for forming the sealing portion 105 will be described with reference to FIG. FIG. 6 is a main part cross-sectional view showing a state in which the sealing part 105 is formed on the battery unit 100 installed in the jig 300.

  As shown in FIG. 6, the jig 300 includes a lower unit 301 and an upper unit 311. The lower unit 301 is provided with stoppers 302 and 303 for positioning the protection circuit board 110 of the battery unit 100 and a cooling unit 304. A cooling circuit 305 is built in the cooling unit 304. The upper unit 311 is provided with a heater 312.

  Between the stoppers 302 and 303 of the lower unit 301, the protective circuit board 110 of the battery unit 100 before the sealing portion 105 is formed is placed and positioned. In this state, the heat conduction pattern 131 b on the back surface side of the protection circuit board 110 contacts the cooling unit 304 of the lower unit 301.

  Then, the protection circuit 121 of the component mounting part 120 of the protection circuit board 110, the positive electrode connection part 122a, the negative electrode connection part 122b, and a part of the cover member 104 are covered with a molten epoxy resin.

  Thereafter, the upper unit 311 is fitted to the lower unit 301, the epoxy resin is heated and cured by the heater 312, and the cooling water is circulated through the cooling circuit 305 built in the cooling unit 304.

  Thereby, the sealing portion 105 is formed, and the battery cell 101 is cooled from the heat conduction pattern 131 b on the back surface side of the protection circuit substrate 110 through the heat conduction pattern 131 a on the front surface side and the spacer 103.

  As described above, in the present embodiment, the battery cell 101 and the sealing portion 105 are separated from each other by the cover member 104, thereby making it difficult for the heat of the epoxy resin heated by the heater 312 to be transmitted to the battery cell 101. Can do. Thereby, the thermal deterioration of the battery cell 101 in the process of forming the sealing portion 105 can be reduced without restricting the degree of freedom in selecting the type of resin that covers the protective circuit board 110 and forms the exterior.

  In the present embodiment, while the epoxy resin is heated by the heater 312, the cooling water is circulated through the cooling circuit 305 of the cooling unit 304 to cool the battery cell 101. For this reason, it can prevent that the battery cell 101 becomes high temperature by the heat | fever of the heater 312, and can reduce the thermal deterioration of the battery cell 101 in the formation process of the sealing part 105 more effectively.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

  For example, in the above-described embodiment, the case where the patterns of the + terminal 140, the − terminal 142, and the temperature terminal 141 are arranged on the back surface side of the protection circuit board 110 is illustrated, but these patterns are arranged on the front surface side of the protection circuit board 110. You may arrange. Further, the + terminal 140, the − terminal 142, and the temperature terminal 141 may be connected with a cable by mounting a connector instead of a pattern.

  In the above embodiment, the case where the thermosetting resin is heated and cured by the heater 312 after the protective circuit 121 and the like of the component mounting portion 120 of the protective circuit board 110 are coated with the molten thermosetting resin is exemplified. However, the present invention is not limited to this. For example, the protective circuit board 110 is fixed in a mold having a cooling part with a built-in cooling circuit so that the heat conduction pattern 131b on the back side is in contact with the cooling part, and then molten resin is injected into the mold. Then, the sealing portion 105 may be integrally formed by solidifying.

DESCRIPTION OF SYMBOLS 100 Battery unit 101 Battery cell 102a Positive electrode lead board 102b Negative electrode lead board 103 Spacer 104 Cover member 105 Sealing part 110 Protection circuit board 120 Component mounting part 121 Protection circuit 130 Cell mounting part 131a, 131b Thermal conduction pattern 132 Through hole

Claims (3)

A battery cell;
A cell mounting part and a component mounting part are provided on the surface side, the battery cell is fixed to the cell mounting part, and a protection circuit for protecting the battery cell is mounted on the component mounting part, and the battery cell and the A protective circuit board to which the protective circuit is electrically connected via the connection member;
A cover member that covers the battery cell fixed to the cell mounting portion;
A sealing portion that seals a part of the protection circuit, the connection member, and the cover member;
The cover member is formed of a material having a lower thermal conductivity than the battery cell,
The battery unit, wherein the sealing portion and the battery cell are separated by the cover member. On the back surface side of the cell mounting portion of the protection circuit board and the cell mounting portion, heat conduction portions connected to each other by through holes are provided, respectively.
The battery cell is fixed to the heat conducting portion provided in the cell mounting portion via a spacer having thermal conductivity,
The heat conduction part provided on the back side of the cell mounting part is cooled in a step of forming the sealing part after fixing the battery cell to the cell mounting part. The battery unit described in 1.   The battery unit according to claim 1, wherein the sealing portion is formed by thermosetting a thermosetting resin.

Images