JP2014093864A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery which can be protected from an overcurrent more surely.SOLUTION: A battery monitoring circuit 45 and a cell balance circuit 46 are connected through a harness to both terminals of a square-shaped battery cell 20 in a plurality of series-connected square-shaped battery cells 20. A circuit board 30 is disposed between both terminals on the top face of the square-shaped battery cell 20, and a fuse 36 connecting to the cathode terminal of the square-shaped battery cell 20 and a fuse 38 connecting to the anode terminal of the square-shaped battery cell 20 are mounted on the circuit board 30, the circuit board 30 being connected from both terminals of the square-shaped battery cell 20 to the battery monitoring circuit 45 and the cell balance circuit 46 via the fuse 36 and the fuse 38 through the harness.

Description

  The present invention relates to a battery in which a plurality of battery cells are connected in series.

  In a battery in which a plurality of battery cells are connected in series, a battery monitoring circuit that monitors the voltage of the battery cell is used (for example, Patent Document 1). Further, a protection circuit is configured using a diode or a fuse (for example, Patent Document 2).

JP 2008-151682 A JP 2010-233284 A

  Incidentally, as shown in FIG. 5, when the cell balance circuit 102 and the battery monitoring circuit 103 are connected to the battery cell 100 using the harness and the connector 101, fuses 104 and 105 and a diode 106 are provided as protection circuits. . This prevents the battery cell from being broken due to an open abnormality (for example, CID), an overcurrent flowing through the battery monitoring circuit (voltage measurement terminal) 103 and the cell balance circuit 102 connected by the harness. . That is, when the battery cell 100 becomes abnormal (for example, in an open state), current is passed through the connector 101, the fuses 104 and 105, and the diode 106 so that no overcurrent flows through the cell balance circuit 102 or the battery monitoring circuit 103. To protect the circuit.

  This will be described in more detail. As shown in FIG. 6, consider a case in which battery modules 110, 111, 112, and 113 are housed in a case 120 and each of the battery modules 110 to 113 is configured by a plurality of battery cells. In each of the battery modules 110 to 113, the voltage of the battery cell is taken out by the harness 130 and connected to the substrate 140. The substrate 140 is provided with a cell balance circuit 102 and a battery monitoring circuit 103. Therefore, it is necessary to provide a protection circuit (fuses 104 and 105, diode 106) for the cell balance circuit 102 on the substrate 140 as shown in FIG. 5, and a current path (harness, connector 101, fuses 104 and 105, diode 106). There is a possibility that an overcurrent flows.

  An object of the present invention is to provide a battery that can be more reliably protected from overcurrent.

  According to the first aspect of the present invention, in the battery in which at least one of a battery monitoring circuit and a cell balance circuit is connected to both terminals of the rectangular battery cells in a plurality of square battery cells connected in series through a harness, the rectangular battery A circuit board is disposed between both terminals on the upper surface of the cell, and a positive terminal overcurrent blocking element connected to the positive terminal of the rectangular battery cell and a negative terminal overcurrent connected to the negative terminal of the rectangular battery cell on the circuit board. A blocking element is mounted and connected to at least one of the battery monitoring circuit and the cell balance circuit through a harness from both terminals of the rectangular battery cell via the overcurrent blocking element for the positive terminal and the overcurrent blocking element for the negative terminal The summary is as follows.

  According to invention of Claim 1, the circuit board is arrange | positioned between the both terminals in the upper surface of a square battery cell. On the circuit board, a positive terminal overcurrent interrupting element connected to the positive terminal of the rectangular battery cell and a negative terminal overcurrent interrupting element connected to the negative terminal of the rectangular battery cell are mounted. Then, at least one of the battery monitoring circuit and the cell balance circuit is connected from both terminals of the rectangular battery cell through the harness via the positive current terminal overcurrent interrupt device and the negative current terminal overcurrent interrupt device.

  In this case, the overcurrent interrupting element is disposed near the terminal of the battery cell, the harness is extended from the portion, and at least one of the battery monitoring circuit and the cell balance circuit is connected through the harness. Since the overcurrent is interrupted by the overcurrent interrupting element and does not flow to the circuit side than the harness and the harness, the overcurrent can be more reliably protected from the overcurrent.

  As described in claim 2, in the battery according to claim 1, on the circuit board, a first fuse as the positive current terminal overcurrent interrupting element, and a second fuse as the negative current terminal overcurrent interrupting element. And a diode between the first fuse and the second fuse are connected in series between the two terminals, and between the first fuse and the diode on the circuit board and A connection member for connecting to the harness may be provided between the second fuse and the diode.

  As described in claim 3, in the battery according to claim 1 or 2, the battery monitoring circuit and the cell balance circuit may be connected through the harness.

  According to the present invention, it is possible to more reliably protect against overcurrent.

The figure which shows the electrical structure of the battery in embodiment. (A) is a partial top view of a battery, (b) is a longitudinal cross-sectional view in the AA line of (a). The perspective view of a battery cell. The schematic plan view of a battery. The figure which shows the electrical structure of the battery for demonstrating a subject. The schematic plan view of the battery for demonstrating a subject.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
2, 3, and 4, the horizontal plane is defined by the orthogonal X and Y directions, and the vertical direction is defined by the Z direction.

  The overall configuration of the battery 10 includes a plurality of prismatic battery cells 20 connected in series, as shown in FIGS. A battery monitoring circuit 45 and a cell balance circuit 46 are connected to both terminals (indicated by reference numerals 20b and 20c in FIGS. 2 and 3) of the rectangular battery cell 20 through harnesses 43 and 44, respectively. The battery monitoring circuit 45 is used to monitor the voltage of the battery cell 20. Specifically, the voltage of the battery cell is measured, A / D converted and converted into a digital signal, which is sent to an external controller, and the controller determines whether or not it is between the upper limit value and the lower limit value. In addition, when the battery is charged / discharged using the cell balance circuit 46, a current is passed between the battery cells through the cell balance circuit 46 to balance the charge / discharge amount between the battery cells 20. Specifically, the cell balance circuit 46 of the present embodiment is an active type cell balance circuit, and actively flows current between the battery cells so as to make the voltage between the battery cells uniform.

  As shown in FIG. 4, battery modules 60, 61, 62, and 63 are housed in a battery pack case 70. Each of the battery modules 60 to 63 is composed of seven battery cells 20. The battery cells 20 in the battery modules 60 to 63 are connected in series. Further, the battery modules 60 to 63 are used in parallel connection. This battery is used for a battery-type industrial vehicle, for example, a battery forklift.

  For each of the battery modules 60 to 63, seven rectangular battery cells 20 are arranged in a row in the horizontal direction (Y direction). As shown in FIG. 3, each square battery cell 20 is disposed in an upright state, and a positive electrode terminal 20b and a negative electrode terminal 20c are provided on the upper surface of the battery cell body 20a. The positive terminal 20b and the negative terminal 20c are screws. At this time, in the rectangular battery cell 20, the positive electrode terminal 20b and the negative electrode terminal 20c are arranged at both ends of the battery cell body 20a in the X direction, but each battery cell 20 is in the Y direction (see FIG. 4). And the negative electrode terminal 20c are alternately arranged. That is, the battery cells 20 arranged side by side in the Y direction are arranged such that the positive electrode terminal 20b of one battery cell 20 and the negative electrode terminal 20c of the battery cell 20 adjacent thereto are adjacent to each other in the Y direction. Moreover, a lithium ion secondary battery can be mentioned as the battery cell 20.

  The electrode terminals of adjacent rectangular battery cells in each of the arranged square battery cells 20 are connected by a bus bar 21. Specifically, the positive electrode terminal 20 b and the negative electrode terminal 20 c in adjacent rectangular battery cells 20 are connected by a bus bar 21. The bus bar 21 is made of a rectangular copper plate. One end of the bus bar 21 in the longitudinal direction is screwed into the battery cell 20 with the terminal (positive electrode terminal 20b or negative electrode terminal 20c) of one of the adjacent rectangular battery cells penetrating therethrough. Yes. On the other hand, the other end in the longitudinal direction of the bus bar 21 is screwed into the battery cell 20 in a state where the terminal (negative electrode terminal 20c or positive electrode terminal 20b) of the other rectangular battery cell among the adjacent rectangular battery cells penetrates. Has been. Thereby, each square battery cell 20 arranged in parallel is connected in series by the bus bar 21.

  As shown in FIGS. 2 and 3, the upper surface of the battery cell body 20a is rectangular in plan view. A circuit board 30 is disposed on the upper surface of the battery cell main body 20a. In the circuit board 30, conductor patterns 32, 33, 34, and 35 are formed on the upper surface of the insulating substrate 31. The circuit board 30 (insulating board 31) has a rectangular shape. The circuit board 30 (insulating substrate 31) extends in the longitudinal direction (X direction) of the battery cell body 20a between the pair of bus bars 21 on the upper surface of the battery cell body 20a. Further, a fuse 36 is mounted between the end portion of the conductor pattern 32 and the end portion of the conductor pattern 33. A diode 37 is mounted between the end of the conductor pattern 33 and the end of the conductor pattern 34. A fuse 38 is mounted between the end of the conductor pattern 34 and the end of the conductor pattern 35. The ends of the conductor pattern 32 and the bus bar 21 are connected by a wiring board 39. The ends of the conductor pattern 35 and the bus bar 21 are connected by the wiring board 40. The wiring boards 39 and 40 are screwed.

  In addition, a columnar connection member 41 is erected at the center in the longitudinal direction (X direction) of the conductor pattern 33. A columnar connection member 42 is erected in the center in the longitudinal direction (X direction) of the conductor pattern 34.

  As shown in FIG. 3, one end of a thick conducting wire 43 a and one end of a thin conducting wire 43 b of the harness 43 are connected to the connection member 41. The harness 43 is extended in a state where both the conductive wires 43a and 43b are covered with an insulating material. In the harness 43, the thick conductor 43a forms a large current line with the cell balance circuit 46, and the thin conductor 43b forms a voltage sense line with the battery monitoring circuit 45. Similarly, one end of a thick conducting wire 44 a and one end of a thin conducting wire 44 b of the harness 44 are connected to the connection member 42. The harness 44 is extended in a state where both the conductive wires 44a and 44b are covered with an insulating material. In the harness 44, the thick conductor 44a forms a large current line with the cell balance circuit 46, and the thin conductor 44b forms a voltage sense line with the battery monitoring circuit 45.

  As shown in FIG. 4, each battery cell 20 in each battery module 60 to 63 has the configuration shown in FIGS. The other ends of the harnesses 43 and 44 are collectively extended from each battery cell 20 and extend to the circuit board 80. A cell balance circuit 46 and a battery monitoring circuit 45 are mounted on the circuit board 80. That is, since the battery cell 20 generates heat, the cell balance circuit 46 and the battery monitoring circuit 45 configured by semiconductor elements or the like are disposed in a place that is not easily affected by heat.

  The thick conductors 43 a and 44 a of the harnesses 43 and 44 are connected to the cell balance circuit 46. Further, the thin conducting wires 43 b and 44 b of the harnesses 43 and 44 are connected to the battery monitoring circuit 45. In the battery monitoring circuit 45, the voltage across the battery cell 20 is monitored, that is, A / D converted and output to the controller. This data is determined by the controller whether or not the voltage across the battery cell is between the upper limit value and the lower limit value, and an abnormal signal is output when the voltage across the battery cell 20 falls outside the upper limit value and lower limit value. Is done. Further, the cell balance circuit 46 moves electric power (current) from the battery cell 20 with a large amount of stored electricity to the battery cell 20 with a small amount of stored charge in order to equalize the amount of stored electricity between the battery cells 20.

  FIG. 1 shows an equivalent circuit. The cathode of the diode 37 is connected to the positive electrode terminal of the battery cell 20 via the fuse 36. The anode of the diode 37 is connected to the negative electrode terminal of the battery cell 20 through the fuse 38. The diode 37 is used for preventing reverse insertion, that is, considering the case where the terminals are connected in reverse. Both ends (anode / cathode) of the diode 37 are connected to the cell balance circuit 46 via the thick conductors 43a, 44a of the harnesses 43, 44. A current flows through the conductors 43a and 44a of the harnesses 43 and 44 for cell balancing. Further, both ends (anode / cathode) of the diode 37 are connected to the battery monitoring circuit 45 via the thin conductive wires 43b and 44b of the harnesses 43 and 44. The conducting wires 43b and 44b of the harnesses 43 and 44 are used for voltage measurement.

Next, the operation of the battery 10 will be described.
The fuses 36 and 38 and the diode 37 as protection circuits are arranged in the vicinity of the battery terminal, and are branched by the conductors 43a, 43b, 44a, and 44b of the harnesses 43 and 44 to each circuit (the cell balance circuit 46 and the battery monitoring circuit 45). Connect. Therefore, since the circuit protection mechanism functions in the vicinity of the battery terminal as compared with FIGS. 5 and 6, the connector 101, the harness 130, and the substrate 140 in FIGS. 5 and 6 can be protected from overcurrent.

  Further, by separating the influence of the wiring resistance from the large current circuit (for example, the cell balance circuit 46), the influence of voltage drop (= current drop), noise, etc. is reduced, and the voltage measurement accuracy of the battery monitoring circuit 45 is reduced. Deterioration can be prevented.

  explain in detail. In the case of FIG. 5, the battery cell 100 is connected to the cell balance circuit 102 and the battery monitoring circuit 103 by a common harness (conductive wire), and a fuse or the like is provided on the circuits 102 and 103 side. Therefore, since current is passed through the common impedance portion and the change in potential is measured, it is easily affected by noise. On the other hand, in this embodiment, as shown in FIG. 1, the fuses 36 and 38 and the diode 37 are arranged on the upper surface of the rectangular battery cell 20, and the harness is connected to the cell balance circuit and the battery monitoring circuit from there. The common impedance portion can be shortened. As a result, it is possible to make the battery monitoring circuit less susceptible to the influence of voltage fluctuations due to current changes during voltage measurement.

  In this way, it is possible to construct a structure in which no overcurrent flows through the battery monitoring circuit 45 and the cell balance circuit 46 even when the battery is abnormally opened. In addition, the battery monitoring circuit 45 is protected against overcurrent, and safety can be ensured.

  5 and 6, when the cell balance circuit 102 exists as a parallel circuit in the battery monitoring circuit 103, a similar protection circuit is required for each of them, and the number of parts, physique, and cost increase. On the other hand, in the present embodiment of FIGS. 1 to 4, even when the cell balance circuit 46 exists as a parallel circuit in the battery monitoring circuit 45, it is only necessary to provide the fuses 36 and 38 and the diode 37 as the protection circuit. The circuit can be protected from overcurrent with a simple configuration. That is, the number of parts can be reduced and the physique can be reduced, and the cost can be further reduced.

According to the above embodiment, the following effects can be obtained.
(1) As a configuration of the battery 10, a battery monitoring circuit 45 and a cell balance circuit 46 are connected to both terminals of the prismatic battery cells 20 in a plurality of prismatic battery cells 20 connected in series through harnesses 43 and 44. Here, the circuit board 30 is arranged between both terminals on the upper surface of the prismatic battery cell 20, and the fuse 36 and the prismatic battery cell as the positive current terminal overcurrent blocking element connected to the positive terminal of the prismatic battery cell 20 on the circuit board 30. A fuse 38 as a negative current terminal overcurrent interrupting element connected to the negative electrode terminal 20 is mounted, and the battery monitoring circuit 45 and the cell balance circuit are passed from both terminals of the rectangular battery cell 20 via the fuses 36 and 38 through the harnesses 43 and 44. 46.

  In this case, since the fuses 36 and 38 as the overcurrent interrupting elements are arranged near the terminals of the battery cell, they can be immediately branched (connected to the harness), and the common impedance in the battery monitoring circuit 45 and the cell balance circuit 46 Can be reduced. Then, the harnesses 43 and 44 are extended from the arrangement portions of the fuses 36 and 38, and the battery monitoring circuit 45 and the cell balance circuit 46 are connected through the harnesses 43 and 44, and the overcurrent is cut off by the fuses 36 and 38. In addition, since it does not flow to the circuit side than the harness and the harness, it can be more reliably protected from overcurrent.

  (2) On the circuit board 30, the first fuse 36, the second fuse 38, and the diode 37 between the first fuse 36 and the second fuse 38 are connected in series between both terminals, On the circuit board 30, connection members 41 and 42 for connecting to the harnesses 43 and 44 are provided between the first fuse 36 and the diode 37 and between the second fuse 38 and the diode 37, respectively. Yes. As a result, it is possible to protect against overcurrent by the fuses 36 and 38 and to take measures when the terminals are connected reversely by the diode 37.

The embodiment is not limited to the above, and may be embodied as follows, for example.
In the above embodiment, the battery monitoring circuit 45 and the cell balance circuit 46 are connected through the harnesses 43 and 44. However, the cell balance circuit may be connected only to the battery monitoring circuit 45 through the harnesses 43 and 44 or through the harnesses 43 and 44. You may connect only to 46. In short, it is only necessary to connect to at least one of the battery monitoring circuit 45 and the cell balance circuit 46 through the harnesses 43 and 44.

  ・ The overcurrent interrupting element may be a relay switch instead of a fuse (a configuration in which a relay contact is inserted in the wiring to detect the overcurrent in the wiring and the relay coil is excited to open the relay contact). Any element may be used as long as it is arranged and cut off when a large current flows.

  DESCRIPTION OF SYMBOLS 10 ... Battery, 20 ... Rectangular battery cell, 20b ... Positive electrode terminal, 20c ... Negative electrode terminal, 30 ... Circuit board, 36 ... Fuse, 37 ... Diode, 38 ... Fuse, 41 ... Connection member, 42 ... Connection member, 43 ... Harness 44 ... Harness, 45 ... Battery monitoring circuit, 46 ... Cell balance circuit.

Claims (3)

In a battery in which at least one of a battery monitoring circuit and a cell balance circuit is connected to both terminals of the prismatic battery cells in a plurality of prismatic battery cells connected in series through a harness,
A circuit board is disposed between both terminals on the upper surface of the rectangular battery cell, and a positive terminal overcurrent blocking element connected to the positive terminal of the rectangular battery cell and a negative terminal connected to the negative terminal of the rectangular battery cell on the circuit board At least one of the battery monitoring circuit and the cell balance circuit through a harness from both terminals of the rectangular battery cell via the overcurrent blocking element for the positive terminal and the overcurrent blocking element for the negative terminal. A battery characterized by being connected to one side.   On the circuit board, a first fuse as the overcurrent interrupting element for the positive terminal, a second fuse as the overcurrent interrupting element for the negative terminal, and between the first fuse and the second fuse Are connected in series between the two terminals, and on the circuit board, between the first fuse and the diode and between the second fuse and the diode, respectively, The battery according to claim 1, further comprising a connection member for connection.   The battery according to claim 1 or 2, wherein the battery monitoring circuit and the cell balance circuit are connected through the harness.