JP2017084582A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack that enables enhancement of responsibility associated with temperature management of battery cells when plural battery cells and an air blower are housed in a housing.SOLUTION: In a battery pack including plural batteries, a housing for housing the plural batteries, a circulation passage which is formed in the housing and through which heat exchange fluid circulates while contacting the plural batteries and the inner wall surface of the housing, a blower 140 which is housed in the housing to circulate the fluid in the circulation passage, and a controller 190 for controlling the operation of the blower 140, a calculator 193 for calculating the generated heat amount of a predetermined battery out of the plural batteries is provided, and the controller 190 determines the rotation speed of the blower 140 based on the generated heat amount acquired by the calculator 193.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a battery pack having a plurality of battery cells housed inside a case.

  As a conventional battery pack, for example, a battery pack described in Patent Document 1 is known. The battery pack described in Patent Document 1 is a fan control device that cools an in-vehicle battery. The in-vehicle battery supplies electric power to an electric motor serving as a driving source for traveling, and is disposed, for example, under a passenger seat. A fan for cooling the in-vehicle battery is provided at a position adjacent to the in-vehicle battery. The operation of the fan is controlled by a control device. The air-conditioned air in the passenger compartment is supplied to the in-vehicle battery by the operation of the fan.

  And in patent document 1, if the temperature of a vehicle-mounted battery becomes more than predetermined A level, a control apparatus will operate a fan and will cool a vehicle-mounted battery. At this time, in Patent Document 1, the higher the battery temperature (the higher it increases to A to E), and the higher the noise level in the passenger compartment (the higher it increases to 1 to 3), the higher the rotational speed of the fan. Controlled to increase.

  Thereby, the vehicle-mounted battery can be effectively cooled while reducing the sensible noise due to the operating sound of the fan.

Japanese Patent No. 3844356

  In Patent Document 1, as described above, the in-vehicle battery and the fan are arranged under a seat that is an open space in the vehicle interior, and the vehicle is operated by operating the fan when the temperature of the in-vehicle battery is equal to or higher than the A level. Effective cooling is enabled by supplying the air-conditioned indoor air to the vehicle-mounted battery. That is, Patent Document 1 is an open-type air-cooled battery pack. On the other hand, since the operating sound of the fan can be heard directly by the occupant, control of the rotational speed of the fan according to the noise level in the passenger compartment is incorporated.

  Here, the present inventors have considered a sealed battery pack in which a plurality of battery cells and a blower are accommodated in a casing, and the temperature of the plurality of battery cells is controlled by circulating a cooling fluid in the casing by the blower. doing. In such a sealed battery pack, since the blower is accommodated in the housing, it is possible to suppress the influence of the operating sound of the blower on the occupant.

  However, in the sealed battery pack, the heat of the battery cells is transferred in the order of the cooling fluid in the casing, the wall of the casing, and the external air of the casing. Therefore, compared to the case where the heat of the battery cell is directly released to the external air (air conditioned air) of the housing as in the case of the open type battery pack, the sealed battery pack takes time for heat transfer, and the battery cell In temperature management based on temperature, for example, there is a problem of poor response such that overshoot occurs with respect to the management temperature.

  The present invention has been made in view of the above problems, and provides a battery pack capable of improving responsiveness related to temperature management of battery cells in a case where a plurality of battery cells and a blower are housed in a casing. There is.

  In order to achieve the above object, the present invention employs the following technical means.

In the first invention, a plurality of batteries (121),
A housing (110) containing a plurality of batteries (121);
A circulation passage (130) formed in the housing (110) and through which a fluid for heat exchange flows so as to be in contact with the inner wall surfaces of the plurality of batteries (121) and the housing (110);
A blower (140) housed in the housing (110) and circulates fluid in the circulation passage (130);
In a battery pack comprising a control unit (190) for controlling the operation of the blower (140),
A calculation unit (193) for calculating a calorific value of a predetermined battery (121) among the plurality of batteries (121);
The control unit (190) is characterized in that the number of rotations of the blower (140) is determined based on the heat generation amount obtained by the calculation unit (193).

  According to this invention, the rotation speed of the blower (140) is controlled based on the heat generation amount of the battery (121). The temperature management using the calorific value of the battery (121) is feedforward control based on a factor system related to the temperature change of the battery (121), so that prospective prospective control becomes easy and the temperature as a result system is controlled. Responsiveness related to temperature management can be improved by suppressing temperature overshoot in the feedback control used.

In the second invention, a plurality of batteries (121),
A housing (110) containing a plurality of batteries (121);
A circulation passage (130) formed in the housing (110) and through which a fluid for heat exchange flows so as to be in contact with the inner wall surfaces of the plurality of batteries (121) and the housing (110);
A blower (140) housed in the housing (110) and circulates fluid in the circulation passage (130);
In a battery pack comprising a control unit (190) for controlling the operation of the blower (140),
A detector (183) for detecting a temperature of a predetermined battery (121) among the plurality of batteries (121);
An estimation unit (197) for estimating an internal resistance of a predetermined battery (121),
The control unit (190) calculates the basic rotational speed of the blower (140) based on the temperature obtained by the detector (183), and performs basic rotation according to the internal resistance obtained by the estimation unit (197). A command value for the blower (140) is determined by correcting the number.

  According to the present invention, after calculating the basic rotational speed based on the temperature, the basic rotational speed is corrected according to the internal resistance of the battery (121) and determined as the command value. The internal resistance of the battery (121) is a physical quantity related to the amount of heat generated by the battery (121). Therefore, by adding the internal resistance condition to the temperature of the battery (121), the meaning of the control based on the heat generation amount is added, and the prospective control with respect to the temperature becomes easy, and the temperature management of the battery (121) is performed. Responsiveness can be improved.

  Note that the reference numerals in parentheses in the scope of claims are intended only to exemplify corresponding configurations in the embodiments to be described later in order to facilitate understanding of the description, and are not intended to limit the content of the invention. Absent.

It is a top view which shows the structure of the battery pack in 1st Embodiment. It is sectional drawing which shows the II-II part in FIG. It is sectional drawing which shows the III-III part in FIG. It is sectional drawing which shows the IV-IV part in FIG. It is a disassembled perspective view which shows an internal fin. It is a perspective view which shows an external fin. It is a perspective view which shows an external duct. It is explanatory drawing which shows the structure of the battery management unit in 1st Embodiment. It is a graph which shows the electric current with respect to time passage, and a cell voltage. It is a graph (1st map) which shows the rotation speed with respect to cell calorific value. It is a top view which shows the flow of the fluid in a case. It is a side view which shows the flow of the fluid in a case. It is a perspective view which shows the flow of the fluid by the internal fin in a case. It is a perspective view which shows the flow of the fluid in an external duct. It is a graph which shows the cell calorific value, cell temperature, and rotation speed with respect to time passage. It is explanatory drawing which shows the structure of the battery management unit in 2nd Embodiment. It is a graph (2nd map) which shows the rotation speed with respect to cell temperature. It is explanatory drawing which shows the structure of the battery management unit in the modification of 2nd Embodiment. It is a table | surface (3rd map) which shows the rotation speed with respect to cell calorific value and cell temperature. It is explanatory drawing which shows the structure of the battery management unit in 3rd Embodiment. It is a graph (correction coefficient map) which shows the correction coefficient with respect to cell internal resistance. It is a graph which shows the correction | amendment point of the basic rotation speed based on a correction coefficient.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that the combination is possible in each embodiment, but also a combination of the embodiments even if they are not clearly specified unless there is a problem with the combination. It is also possible.

(First embodiment)
The configuration of the battery pack 100 according to the first embodiment, which is an example of the present invention, will be described with reference to FIGS. The battery pack 100 is used, for example, in a hybrid vehicle using a motor driven by electric power charged in a battery and an internal combustion engine as a travel drive source, or an electric vehicle using a motor as a travel drive source. The plurality of battery cells 121 included in the battery pack 100 are, for example, a nickel hydride secondary battery, a lithium ion secondary battery, an organic radical battery, or the like.

  The battery pack 100 is installed in a pack accommodation space such as a trunk room of a vehicle or a back area of the trunk room provided below the trunk room. This pack storage space can also store spare tires, tools, and the like, for example. The battery pack 100 is installed in the pack housing space in a posture in which a bottom wall 112 and a bottom wall side passage 135 (to be described later) are on the lower side.

  Further, the battery pack 100 may be installed below a front seat or a rear seat provided in a vehicle interior of the vehicle. In this case, the battery pack 100 is installed below the front seat, the rear seat, etc. with the bottom wall 112 and the bottom wall side passage 135 positioned downward. Further, the space where the battery pack 100 is installed below the rear seat may be communicated with the trunk room back area below the trunk room. The installation space can also be configured to communicate with the outside of the vehicle.

  The battery pack 100 includes a case 110, an assembled battery 120 (cell stack 120A) including a plurality of battery cells 121, a circulation passage 130, a blower 140 (140A, 140B) provided with a PTC heater 144, an internal fin 150 (151, 152), an external fin 160 (161, 162), an external duct 170 having a blower 172, a voltage sensor 181, a current sensor 182, a temperature sensor 183, a battery management unit 190, and the like.

  In this embodiment, in FIG. 1, Fr indicates the vehicle front side, Rr indicates the vehicle rear side, LH indicates the vehicle left side, and RH indicates the vehicle right side. When showing the direction in the battery pack 100, the direction of Fr-Rr will be called the front-back direction, and the direction of LH-RH will be called the left-right direction. In addition, the action direction of gravity is referred to as the vertical direction.

  The case 110 is a housing that forms a sealed internal space that is isolated from the outside. The assembled battery 120, the blower 140 (140A, 140B), the internal fin 150, the voltage sensor 181, the current sensor 182, and A battery management unit 190 and the like are housed inside.

  The case 110 has a box shape composed of a plurality of walls surrounding an internal space, and is formed of a molded product of an aluminum plate or an iron plate. The case 110 is, for example, a rectangular parallelepiped flat in the vertical direction, and has six surfaces, that is, a top wall 111, a bottom wall 112, a side wall 113, a side wall 114, a side wall 115, and a side wall 116. The case 110 also has a partition wall 117 that partitions the inside, and a reinforcing beam 118 on the bottom wall 112.

  The top wall 111 is a wall that forms the upper surface of the case 110, and is a rectangular wall having long sides in the front-rear direction. The bottom wall 112 is a wall that forms the lower surface of the case 110 and has the same shape as the top wall 111.

  The side walls 113 and 114 are walls that form the left and right sides of the case 110, and are elongated rectangular walls having long sides in the front-rear direction. The side walls 113 and 114 are in a positional relationship facing each other. The side walls 115 and 116 are walls that form the front and rear surfaces of the case 110, and are elongated rectangular walls having long sides in the left-right direction. The side walls 115 and 116 are in a positional relationship facing each other. Further, the side walls 115 and 116 are walls orthogonal to the side walls 113 and 114.

  The case 110 may be manufactured by forming a box-like space inside the case 110 by joining and assembling a plurality of case bodies instead of using the walls 111 to 116 described above. Moreover, you may make it form a some convex part or a recessed part in the surface of a predetermined wall among the several walls of case 110, in order to enlarge a thermal radiation area.

  In the battery pack 100, the direction along the long sides of the side walls 113, 114 corresponds to the front-rear direction, and the direction along the long sides of the side walls 115, 116 corresponds to the left-right direction.

  The partition wall 117 is disposed on the side of the side wall 116 inside the case 110 and is a wall that is parallel to the side wall 116 and connects the side walls 113 and 114. The partition wall 117 extends from the upper surface of the bottom wall 112 (the surface on the inner side of the case 110) to an intermediate position in the vertical direction of the case 110. A space 117 a is formed between the partition wall 117 and the side wall 116. A battery management unit 190 described later is accommodated in the space 117a.

  As shown in FIGS. 1 to 3, the beam 118 is a reinforcing member for improving the strength of the case 110, and is parallel to the upper surface of the bottom wall 112 (the surface that is the inner side of the case 110). A plurality are provided. In the present embodiment, five beams 118 are set. The beam 118 is formed in an elongated bar shape, and is provided on the bottom wall 112 so that the longitudinal direction thereof faces the front-rear direction with respect to the case 110 and is arranged at equal intervals in the left-right direction. The pitch (distance between center lines) between the beams 118 is set to be equal to the horizontal dimension of the battery cell 121.

  The beam 118 is formed separately from the case 110, and is, for example, a prismatic member that is hollow and has a square cross section. More specifically, the beam 118 has a U-shaped cross section, and the U-shaped opening side is fixed to the bottom wall 112. The beam 118 is made of, for example, an aluminum material or an iron material.

  Between the partition wall 117 and the plurality of battery cells 121 (the assembled battery 120), a plate-shaped blocking wall 119 a connected from the side wall 113 to the side wall 114 is provided on the upper surface of the plurality of beams 118. The upper side of the space between the beams 118 is blocked by the blocking wall 119a.

  Similarly, between the side wall 115 and the plurality of battery cells 121 (the assembled battery 120), a plate-shaped blocking wall 119 b connected from the side wall 113 to the side wall 114 is provided on the upper surface of the plurality of beams 118. The upper side of the space between the beams 118 is blocked by the blocking wall 119b.

  The assembled battery 120 is formed by providing a plurality of cell stacks 120A in which a plurality of battery cells 121 are stacked. In the present embodiment, for example, one cell stack 120A is formed by 20 battery cells 121, and four cell stacks 120A are arranged to form an assembled battery 120 (FIG. 1).

  The battery cell 121 has a rectangular parallelepiped flat in the front-rear direction, and includes a positive electrode terminal and a negative electrode terminal that protrude outward from the outer case. The battery cell 121 corresponds to the battery of the present invention.

  The cell stack 120A is formed by stacking a plurality of battery cells 121 and accommodating the stacked battery cells 121 in a battery case. That is, the plurality of battery cells 121 are stacked such that the surfaces perpendicular to the flat direction face each other. The battery case is a case in which the upper surface side and the lower surface side of each battery cell 121 are opened to cover the periphery of each battery cell 121.

  In cell stack 120A, terminals of different polarities in adjacent battery cells 121 are electrically connected (in series connection) by a conductive member such as a bus bar. The connection between the bus bar and the electrode terminal is performed, for example, by screwing or welding. Therefore, the total terminal portions arranged at both ends of the plurality of battery cells 121 electrically connected by a bus bar or the like are supplied with electric power from the outside or discharged toward other electric devices. Yes.

  Further, in the cell stack 120A, a predetermined gap is formed between each of the stacked battery cells 121. This gap is formed by a spacer member or the like provided between the battery cells 121. For example, in the battery case, the spacer member can be formed and provided by providing a partition wall portion between the battery cells 121 and providing unevenness or the like on the partition wall portion.

  The plurality of cell stacks 120 </ b> A (each battery cell 121) are fixed (arranged) on the upper surface of the beam 118 as shown in FIGS. 1 and 3. Specifically, in each cell stack 120A (each battery cell 121), both lower ends of the direction in which the plurality of beams 118 are arranged (left and right direction) are placed on the two beams 118, respectively. Is placed (fixed).

  The circulation passage 130 is formed in the case 110 and is used for heat exchange so as to contact each battery cell 121 and the inner wall surface of the case 110 (here, mainly the side walls 113 and 114, the top wall 111, and the bottom wall 112). Is a passage through which the fluid flows. The circulation passage 130 is mainly formed by a side wall side passage 131, a side wall side passage 132, a top wall side passage 133, a battery passage 134, a bottom wall side passage 135, and a series of flow passages connecting the respective fans 140A and 140B. Yes.

  The side wall-side passage 131 is orthogonal to both the top wall 111 and the bottom wall 112, extends in parallel to the side wall 113, and is formed between the plurality of battery cells 121 (the assembled battery 120) and the side wall 113. It is.

  The side wall-side passage 132 is orthogonal to both the top wall 111 and the bottom wall 112, extends parallel to the side wall 114, and is formed between the plurality of battery cells 121 (the assembled battery 120) and the side wall 114. It is.

  The ceiling wall side passage 133 is a passage that is formed between the ceiling wall 111 and the plurality of battery cells 121 (the assembled battery 120) and extends parallel to the ceiling wall 111.

  The side wall side passage 131 and the top wall side passage 133 are connected at the boundary between the top wall 111 and the side wall 113. Further, the side wall side passage 132 and the top wall side passage 133 are connected at the boundary between the top wall 111 and the side wall 114.

  Battery passage 134 is a passage formed by a gap between adjacent battery cells 121 in each cell stack 120A.

  The bottom wall side passage 135 is a passage formed as a space surrounded by the bottom wall 112, the lower end surfaces 121 a of the plurality of battery cells 121, and the beam 118. In addition, the bottom wall side passage 135 includes a space surrounded by the bottom wall 112, the blocking wall 119a, and the beam 118, and further includes a space surrounded by the bottom wall 112, the blocking wall 119b, and the beam 118. ing. The bottom wall side passage 135 is a passage formed between the adjacent beams 118 on the lower side of each battery cell 121. In the present embodiment, four passages are formed based on the five beams 118. It is formed as.

  Of the four bottom wall side passages 135, the second passage from the side wall 113 side communicates with the first passage by a communication portion (not shown) in the vicinity of the blower 140A. In addition, the third passage from the side wall 113 side communicates with the fourth passage by a communication portion (not shown) in the vicinity of the blower 140B.

  The upper side of the battery passage 134 is connected to the top wall side passage 133, and the lower side of the battery passage 134 is connected to the bottom wall side passage 135.

  The blower 140 is a fluid drive unit that is accommodated in the case 110 and forcibly circulates (circulates) a heat exchange fluid in the circulation passage 130. In the present embodiment, the blower 140 is set so that two of the first blower 140A and the second blower 140B are arranged. Hereinafter, the two blowers 140A and 140B may be collectively referred to as the blower 140. As the fluid circulated in the circulation passage 130, for example, air, various gases, water, a refrigerant, or the like can be used.

  As shown in FIGS. 1, 2, and 4, the first blower 140 </ b> A is a blower that circulates fluid through the circulation passage 130 corresponding to the region of the two cell stacks 120 </ b> A on the side wall 113 side. The second blower 140B is a blower that circulates fluid through the circulation passage 130 corresponding to the region of the two cell stacks 120A on the side wall 114 side. In the case 110, the first blower 140A and the second blower 140B are symmetrical with respect to the center line facing the front-rear direction of the case 110, and the side wall 115 and the cell stack 120A (a plurality of battery cells 121). It is arranged between.

  Each of the fans 140A and 140B includes a motor 141, a sirocco fan 142, and a fan casing 143.

  The motor 141 is an electric device that rotationally drives the sirocco fan 142, and is provided on the upper side of the sirocco fan 142.

  The sirocco fan 142 is a centrifugal fan that sucks fluid in the direction of the rotation axis and blows out the fluid in the centrifugal direction, and is arranged so that the rotation axis is directed in the vertical direction.

  The fan casing 143 is formed so as to cover the sirocco fan 142, and serves as a wind guide member that sets the suction and discharge directions of the fluid by the sirocco fan 142. The fan casing 143 includes a suction port 143a that opens below the sirocco fan 142, a blowout duct 143b that guides the flow of the blown fluid, and a blowout port 143c that opens at the tip of the blowout duct 143b.

  Each suction port 143a of each blower 140A, 140B is disposed so as to be connected to a region on the side wall 115 side in the bottom wall side passage 135. The suction port 143a of the blower 140A is connected to the first and second passages from the side wall 113 of the four bottom wall passages 135. Further, the suction port 143a of the blower 140B is connected to the third and fourth passages from the side wall 113 side among the four bottom wall side passages 135.

  Each blower duct 143b of each blower 140A, 140B is formed to extend once from the side surface of the sirocco fan 142 to the center side of the case 110 and to make a U-turn, and to extend to the side wall side passages 131, 132 side. ing.

  And the blower outlet 143c of the air blower 140A is arrange | positioned so that the side wall side channel | path 131 may be connected. Specifically, the air outlet 143c is located at a position closer to the lower side in the vertical direction in the side wall passage 131, in the vicinity of the battery cell 121 on the side wall 115 side among the plurality of stacked battery cells 121, and It arrange | positions so that it may face the side wall 116 side.

  Further, the outlet 143c of the blower 140B is disposed so as to be connected to the side wall-side passage 132. Specifically, the outlet 143c is located at a position closer to the lower side in the vertical direction in the side wall passage 132, in the vicinity of the battery cell 121 on the side wall 115 side among the plurality of stacked battery cells 121, and It arrange | positions so that it may face the side wall 116 side.

  As shown in FIGS. 1 and 4, the PTC heater 144 is a heating device for heating the fluid in the case 110 to a predetermined temperature, and is provided at an intermediate position inside the fan casing 143. The PTC heater 144 has a self-temperature control function, and its operation is controlled by a battery management unit 190 described later.

  As shown in FIG. 5, the internal fin 150 is a heat exchange promoting fin provided inside the case 110, and includes a first internal fin 151 and a second internal fin 152. Each of the internal fins 151 and 152 is formed of an aluminum material or an iron material having excellent thermal conductivity.

  The first internal fins 151 are provided on the side wall 113 side and the side wall 114 side so as to be symmetric with respect to the center line facing the front-rear direction of the case 110. The second internal fins 152 are provided at two locations on the side wall 113 side and the side wall 114 side of the top wall 111 so as to be symmetrical with respect to the center line facing the front-rear direction of the case 110.

  Here, as each of the internal fins 151 and 152, for example, a straight fin that can set a flow resistance to a fluid relatively small is employed. The straight fins are fins in which a large number of thin plate-like fin portions protruding vertically from the thin plate-like substrate portion are arranged in parallel, and fluid passages are formed between the fin portions.

  The internal fins 151 and 152 are not limited to the straight fins, but may be other corrugated fins (with or without louvers), offset fins, or the like.

  The fin portion of the first internal fin 151 protrudes vertically from the substrate portion toward the plurality of battery cells 121, and the protruding tip portion has a plurality of batteries so that more fluid flows through the fin portion. It extends to a position close to the side surface of the cell 121. Further, the plate surface of the fin portion is set to be inclined toward the side wall 116 from the lower side to the upper side with respect to the vertical direction. Moreover, the length of the fluid passage by a fin part becomes so long that it goes to the side wall 116 side from the side wall 115 side.

  The fin portion of the second internal fin 152 protrudes vertically from the substrate portion toward the plurality of battery cells 121, and the protruding tip portion has a plurality of protrusions so that more fluid flows inside the fin portion. The battery cell 121 extends to a position close to the upper surface. Further, the plate surface of the fin portion is set to be inclined toward the side wall 116 toward the center side of the case 110 with respect to the left-right direction. The length of the fluid passage by the fin portion is shortened from the side wall 115 side toward the side wall 116 side. And the fluid passage by the fin part of the 2nd internal fin 152 is connected so that the fluid path by the fin part of the 1st internal fin 151 may be followed.

  As shown in FIG. 6, the external fin 160 is a heat exchange promoting fin provided outside the case 110, and includes a first external fin 161 and a second external fin 162. Each of the external fins 161 and 162 is formed of an aluminum material or an iron material having excellent thermal conductivity.

  The first external fins 161 are provided on the side wall 113 side and the side wall 114 side so as to be symmetric with respect to the center line facing the front-rear direction of the case 110. The second external fins 162 are provided at two locations on the side wall 113 side and the side wall 114 side of the top wall 111 so as to be symmetric with respect to the center line facing the front-rear direction of the case 110.

  Here, for example, corrugated fins that can set heat transfer performance with respect to a fluid relatively large are employed as the external fins 161 and 162. The corrugated fin has a wave shape as a whole, and a large number of louvers are formed on the wavy surfaces facing each other, and a fluid passage is formed between the wavy surfaces facing each other and between the louvers. It has become a fin.

  The external fins 161 and 162 may be straight fins such as the internal fins 151 and 152, corrugated fins without louvers, or offset fins.

  The first outer fins 161 are provided as a set of a plurality (two in this case), and in the regions corresponding to the first inner fins 151 on the side walls 113 and 114, the direction in which the waves continue is set. It is arranged so as to face in the front-rear direction and to be slightly offset toward the side wall 116 side.

  The second external fins 162 are provided as a set of a plurality of (two in this case), and in the region corresponding to the second internal fins 152 on the side walls 113 and 114 side of the top wall 111, Are arranged in such a manner that the continuous direction is directed in the front-rear direction and slightly closer to the side wall 115 than the first external fin 161.

  As shown in FIG. 7 (FIG. 14), the external duct 170 is a duct that allows a cooling fluid to flow along the outer surface of the case 110. As the cooling fluid, for example, air-conditioned air (cooled cooling air) in the passenger compartment is used.

  The external duct 170 has a flat cross-sectional shape and is provided on the outer surface of the case 110, specifically, on the side walls 113 and 114 region, the side wall 113 and 114 side region of the top wall 111, and the side wall 115 region. The outer fins 161 and 162 are included (covered). The inside of the external duct 170 is mainly a flow path that connects the side walls 113 and 114 region, the side wall 113 and 114 side region of the top wall 111, and the side wall 115 region in this order.

  Both end portions (side walls 113 and 114 side) on the side wall 116 side of the external duct 170 serve as suction portions for sucking conditioned air. A wind direction device 171 for diverting the sucked conditioned air to the lower side of the first external fin 161 and the center side of the case 110 of the second external fin 162 is provided on the downstream side immediately after the suction portion. .

  In addition, a blower 172 is provided in the center of the external duct 170 on the side wall 115 side, and the upper and lower portions of the blower 172 serve as blow-out portions that blow out conditioned air. For the blower 172, for example, a turbo fan is used.

  As shown in FIG. 8, the voltage sensor 181 is a sensor that detects the voltage in the battery cell 121. For example, in the plurality of battery cells 121, all the battery cells 121 or a predetermined (at least one) battery cell 121. Is provided. The voltage signal detected by the voltage sensor 181 is output to the battery management unit 190 described later.

  As shown in FIG. 8, the current sensor 182 is a sensor that detects a current in the battery cell 121 (the assembled battery 120). For example, among the conductive members of the battery cells 121 connected in series, a predetermined (one) ). The current signal detected by the current sensor 182 is output to the battery management unit 190 described later.

  The temperature sensor 183 (FIG. 1) is a sensor (detector) that detects the temperature in the battery cell 121. For example, in the plurality of battery cells 121, all the battery cells 121 or a predetermined (at least one) battery cell. Is provided. The temperature signal detected by the temperature sensor 183 is output to the battery management unit 190 described later.

  A battery management unit (Battery Management Unit) 190 is configured to be able to communicate with various electronic control devices mounted on a vehicle. The battery management unit 190 is a device that manages at least the amount of electricity stored in the battery cell 121, and is an example of a battery control unit that performs control related to the battery cell 121. In addition, the battery management unit 190 monitors the voltage, current, temperature, and the like related to the battery cell 121, and manages an abnormal state, electric leakage, and the like of the battery cell 121.

  In addition, the battery management unit 190 includes an input circuit, a microcomputer, an output circuit, and the like, similar to the vehicle ECU. Battery information is stored as data in the storage means of the microcomputer. The stored battery information data includes, for example, the battery voltage, the charging current, the discharging current, and the battery temperature in the battery pack 100.

  The battery management unit 190 also functions as a control device that controls the operation of each of the fans 140A and 140B, the PTC heater 144, and the fan 172. The battery management unit 190 uses the voltage detected by the voltage sensor 181, the current detected by the current sensor 182, and the amount of heat generated by the battery cell 121 calculated from the charging rate (open circuit voltage). In addition, the operation of the PTC heater 144 and the blower 172 is controlled. Details of the control contents of the battery management unit 190 will be described later.

  As shown in FIG. 8, the battery management unit 190 includes a charging rate calculation unit 191, an open circuit voltage calculation unit 192, a heat generation amount calculation unit 193, a rotation number calculation unit 194, a rotation number determination unit 196, and the like.

  The charging rate calculation unit 191 is a part that calculates the charging rate (State Of Charge = SOC) of the battery cell 121 based on the voltage and current of the battery cell 121, for example.

  The open circuit voltage calculation unit 192 is a part that calculates an open circuit voltage (Open Circuit Voltage = OCV) based on the charging rate of the battery cell 121, for example. The open circuit voltage indicates a voltage between both terminals in a state where no load is applied to the battery cell 121 (the assembled battery 120).

  The calorific value calculation unit 193 is a part that calculates the calorific value of the battery cell 121 based on, for example, the difference (ΔV) between the open circuit voltage of the battery cell 121 and the cell voltage to which the load is applied, and the current. The calorific value calculation unit 193 corresponds to the calculation unit of the present invention. Hereinafter, the heat generation amount of the battery cell 121 is referred to as a cell heat generation amount.

  The rotation speed calculation unit 194 is a part that calculates the rotation speed for each of the fans 140A and 140B based on the cell heat generation amount.

  The rotation speed determination unit 196 is a part that outputs a rotation command to each of the fans 140A and 140B at the calculated rotation speed.

  The operation of the battery pack 100 configured as described above will be described with reference to FIGS.

  The battery cell 121 self-heats at the time of output from which current is taken out and at the time of input to be charged. Further, the battery cell 121 is affected by the temperature outside the case 110 according to the season, the air conditioning conditions in the passenger compartment, and the like. The battery management unit 190 constantly monitors the amount of heat generated from the cells based on the voltages and currents obtained by the sensors 181 and 182 and the calculated charging rate (open circuit voltage), and each fan 140A is based on the amount of heat generated by the cells. 140B, and further controls the operation of the PTC heater 144 and the blower 172.

  First, the battery management unit 190 uses, for example, a voltage signal of the battery cell 121 obtained from the voltage sensor 181 (hereinafter referred to as a cell voltage) and a current signal of the battery cell 121 obtained from the current sensor 182 (in the charging rate calculation unit 191). Hereinafter, the charging rate (SOC) in the battery cell 121 is calculated from a predetermined map, calculation formula, and the like using the cell current.

  Next, the battery management unit 190 calculates an open circuit voltage (OCV) corresponding to the charging rate from a predetermined map in the open circuit voltage calculation unit 192, for example.

Next, the battery management unit 190 uses the cell voltage obtained from the voltage sensor 181, the cell current obtained from the current sensor 182, and the open circuit voltage calculated by the open circuit voltage calculator 192 in the calorific value calculation unit 193. The cell heat generation amount is calculated. Here, the cell heat generation amount is calculated by the following mathematical formula 1.

  (Open circuit voltage−cell voltage) in Equation 1 is ΔV shown in FIG. 9, and is a voltage drop (voltage increase) when a load is applied to the open circuit voltage in the battery cell 121 (during discharging and charging). is there. The voltage drop (voltage rise) corresponds to the product of the cell current and the internal resistance. As the cell heat generation amount data, when a plurality of cell heat generation amount data are obtained, the maximum value is used.

  Next, as shown in FIG. 10, the battery management unit 190 uses the rotation speed calculation unit 194 to calculate the cell heat generation amount calculated by the heat generation amount calculation unit 193 from a predetermined rotation speed calculation map (first map). The rotation speed of the blower 140 corresponding to is calculated. The first map is, for example, a map related to the cell heat generation amount so as to increase linearly in the cell heat generation amount range in which the battery cell 121 needs to be cooled.

  Next, the battery management unit 190 outputs a command for operating at the rotation speed calculated by the rotation speed calculation section 194 to each of the fans 140A and 140B in the rotation speed determination section 196.

  As described above, when each of the blowers 140A and 140B is operated, the fluid inside the case 110 circulates in the circulation passage 130 as shown in FIGS.

  That is, the fluid sucked from the suction ports 143a of the blowers 140A and 140B and blown out from the blowout port 143c through the blowout duct 143b flows into the side wall side passage 131 and the side wall side passage 132, respectively.

  The fluid flowing into the side wall passages 131 and 132 is directed from the lower side (bottom wall 112 side) to the upper side (top wall 111 side) along the fin portion in which the first internal fin 151 is inclined. Flows smoothly. In each of the side wall passages 131 and 132, the heat of the fluid accompanied by the flow velocity is transmitted to the first internal fin 151 and further released to the outside through the side walls 113 and 114.

  Next, the fluid smoothly flows into the fin portion of the second internal fin 152 continuously connected to the first internal fin 151, and flows into the top wall side passage 133 along this fin portion. The fluid that has flowed into the top wall side passage 133 extends into the top wall side passage 133.

  As shown in FIG. 11, the fluid that has flowed into the ceiling wall side passage 133 from the side wall side passage 131 mainly spreads in the region of the two cell stacks 120 </ b> A on the side wall 113 side. In addition, the fluid that has flowed into the top wall side passage 133 from the side wall side passage 132 mainly spreads in the region of the two cell stacks 120A on the side wall 114 side. Then, the heat of the fluid flowing into the ceiling wall side passage 133 is transmitted from the second internal fins 152 to the ceiling wall 111 or directly transmitted to the ceiling wall 111 and released to the outside.

  Next, the fluid flowing into the top wall side passage 133 passes through the battery passages 134 formed between the battery cells 121 and reaches the bottom wall side passage 135. Here, the side wall side passages 131 and 132 and the top wall side passage 133 become positive pressure spaces due to the blowout of the respective fans 140A and 140B, and the bottom wall side passage 135 is drawn by the suction of the respective blowers 140A and 140B. A negative pressure space is formed, and fluid is continuously moved from the top wall side passage 133 side to the bottom wall side passage 135 side due to the pressure difference between the two. When the fluid passes through the battery passage 134, the heat of each battery cell 121 is transmitted to the fluid.

  Next, the fluid flowing into the bottom wall side passage 135 moves along the longitudinal direction of each beam 118 and reaches the suction port 143a of each of the fans 140A and 140B. Then, the heat of the fluid flowing into the bottom wall side passage 135 is transmitted to the bottom wall 112 and released to the outside.

  As described above, the fluid circulates through the circulation passage 130 in the case 110, so that the heat of the fluid, that is, the heat of the battery cell 121, mainly from the top wall 111, the side walls 113, 114, and the bottom wall 112 is externally exposed. Released. At this time, heat exchange is promoted by the internal fins 151 and 152. Therefore, each battery cell 121 is effectively cooled and adjusted to an appropriate temperature.

  Here, for example, when the battery cell 121 is in a low temperature environment and the cell heat generation amount calculated by the heat generation amount calculation unit 193 is less than a predetermined heat generation amount (first heat generation amount), the battery management unit. 190 operates the PTC heater 144 in addition to each of the fans 140A and 140B. In this case, the minimum value is used when a plurality of cell heat generation amount data is obtained as the cell heat generation amount data.

  When the PTC heater 144 is activated in addition to the fans 140A and 140B, the fluid flowing through the blowout duct 143b is heated by the PTC heater 144. As the heated fluid circulates in the circulation passage 130 in the case 110 as described above, each battery cell 121 is heated to a temperature at which it can be properly operated by the heated fluid. The performance deterioration at the time of calorific value (under low temperature) is corrected.

  For example, when the battery cell 121 is in a high temperature environment and the cell heat generation amount calculated by the heat generation amount calculation unit 193 exceeds a predetermined heat generation amount (second heat generation amount), the battery management unit 190. Activates the blower 172 in addition to each of the blowers 140A, 140B. The second calorific value is a threshold set on the larger side than the first calorific value. In this case, when a plurality of cell heat generation amount data is obtained as the cell heat generation amount data, the maximum value is used.

  By operating the blower 172, the conditioned air in the passenger compartment is sucked into the external duct 170 from the suction portion of the external duct 170. As shown in FIG. 14, the conditioned air sucked from the suction portion is diverted by the wind direction device 171 and is diverted toward the lower side of the first external fin 161 and the center side of the case 110 of the second external fin 162. The And each flow passes and merges so that each external fin 161,162 may be crossed, and it blows off from the blowing part provided in the upper and lower part of the air blower 172.

  At this time, the heat of the fluid in the case 110 is transmitted to the conditioned air through the internal fins 151 and 152, the side walls 113 and 114, the top wall 111, and the external fins 161 and 162, and is released to the outside. Therefore, heat exchange of the fluid in the case 110 is further promoted by the external fins 161 and 162 in addition to the internal fins 151 and 152. And each battery cell 121 is forcibly cooled so that it may become an appropriate calorific value (temperature) in a short time.

  As described above, in this embodiment, the rotational speed of the blower 140 (140A, 140B) is controlled based on the cell heat generation amount. Since the temperature management using the cell heat generation amount is feedforward control based on a factor system related to the temperature change of the battery cell 121, the prospective control in anticipation of the future becomes easy. Therefore, as shown in FIG. 15, it is possible to suppress the temperature overshoot in the feedback control using the temperature as the result system and improve the responsiveness regarding the temperature management.

  In addition, the calorific value calculation unit 193 calculates the cell calorific value using the open circuit voltage based on the voltage, current, and charging rate of the battery cell 121, so that the cell calorific value can be easily and reliably calculated. Can be calculated.

(Second Embodiment)
A second embodiment is shown in FIGS. In the second embodiment, the battery management unit 190 of the battery pack 100 is changed to a battery management unit 190A with respect to the first embodiment. The battery management unit 190A takes into account the temperature of the battery cell 121 obtained from the temperature sensor 183 (hereinafter, cell temperature) in addition to the cell heat generation amount, that is, the blower 140 ( 140A and 140B) are determined (controlled).

  As described in the first embodiment, the temperature sensor 183 is a detector that detects a cell temperature in a predetermined battery cell 121 among the plurality of battery cells 121. The predetermined battery cell 121 can be at least one place as a part from which a representative temperature can be obtained among the plurality of battery cells 121. Here, in order to increase the reliability of temperature detection, for example, the temperature sensors 183 are provided on both end sides and the center side in the stacking direction in each cell stack 120A.

  Then, as shown in FIG. 16, the battery management unit 190 </ b> A includes the charging rate calculation unit 191, the open circuit voltage calculation unit 192, the heat generation amount calculation unit 193, the rotation number calculation unit 194, and the rotation number determination described in the first embodiment. In addition to the unit 196, a rotation number calculation unit 195 is provided. Therefore, the battery management unit 190A has two parts (the rotational speed calculation units 194 and 195) for calculating the rotational speed of the blower 140.

  The rotation speed calculation unit 195 calculates the rotation speed of the blower 140 from the rotation speed calculation map (second map) shown in FIG. 17 based on the cell temperature obtained from the temperature sensor 183. The second map associates the cell temperature with the rotation speed to be set in advance. The second map is set such that in the region where the cell temperature is relatively low, the rotation speed is constant, and the rotation speed increases linearly as the cell temperature increases.

  In the present embodiment, the rotation number calculated by the rotation number calculation unit 194 (hereinafter referred to as the first rotation number) and the rotation number calculated by the rotation number calculation unit 195 (hereinafter referred to as the second rotation number) are the rotation number. The data is output to the determination unit 196.

  Battery management unit 190A commands rotation speed determination unit 196 to operate blower 140 at a first rotation speed based on the amount of heat generated from the cell, as the first operating condition for blower 140 to be turned on from the off state. Thereafter, the blower 140 is controlled to operate under the condition of the larger one of the first number of revolutions based on the cell heat generation amount and the second number of revolutions based on the cell temperature.

  As a result, as the first operating condition, the operation of the blower 140 is controlled based on the cell heat generation amount. Therefore, as described in the first embodiment, the temperature management is performed so that overshoot can be suppressed. Responsiveness can be improved.

  In addition, while the operation of the battery pack 100 is continued, the rotational speed of the blower 140 is determined by looking at the conditions of both the amount of heat generated by the cell and the cell temperature, so that more reliable temperature management is possible. Become.

(Modification of the second embodiment)
A modification of the second embodiment is shown in FIGS. The modification of 2nd Embodiment changes the battery management unit 190A into the battery management unit 190B with respect to the said 2nd Embodiment. In the battery management unit 190B, the rotation speed calculation units 194 and 195 in the battery management unit 190A are abolished, and the rotation speed determination unit 196 is provided with a rotation speed calculation map (third map) shown in FIG. Yes.

  In the third map, the rotation speed of the blower 140 is determined in advance when the cell heat generation amount obtained from the heat generation amount calculation unit 193 and the cell temperature obtained from the temperature sensor 183 are variables. In the third map, the rotation speed is set to increase as the cell heat generation amount increases, and the rotation speed is set to increase as the cell temperature increases. Further, in the third map, even when the cell temperature is low, the rotation speed is set to the medium level from the stage where the cell heat generation amount is low. That is, as the first operating condition of the blower 140, the rotational speed setting based on the cell heat generation amount is prioritized.

  In the third map of FIG. 19, for the sake of simplicity of explanation, the respective rotation speed levels are indicated as “OFF”, “medium”, and “large”, but for example, at a predetermined rotation speed pitch, The rotation speed may be set over multiple stages.

  Battery management unit 190 </ b> B determines the number of rotations of blower 140 based on the third map in rotation number determination unit 196 as described above, and controls the operation of blower 140. Thereby, the effect similar to the said 2nd Embodiment can be acquired.

(Third embodiment)
A third embodiment is shown in FIGS. In the third embodiment, the battery management unit 190A of the battery pack 100 is changed to a battery management unit 190C with respect to the second embodiment. The battery management unit 190C calculates the basic rotational speed of the blower 140 based on the cell temperature and corrects the basic rotational speed according to the internal resistance of the battery cell 121 to determine a command value for the blower 140. Yes.

  As shown in FIG. 20, the battery management unit 190C includes a rotation speed calculation unit 195, an internal resistance estimation unit 197, a correction coefficient calculation unit 198, a rotation speed determination unit 199, and the like.

  The rotational speed calculation unit 195 is the same as that described in the second embodiment, and is a part that calculates the rotational speed of the blower 140 based on the cell temperature obtained from the temperature sensor 183 (the second in FIG. 17). map). Here, the rotation speed calculated by the rotation speed calculation unit 195 is a basic rotation speed that is a basis of control.

  The internal resistance estimation unit 197 is a part that estimates the internal resistance of the battery cell 121 (hereinafter, cell internal resistance) using, for example, the cell voltage obtained from the voltage sensor 181 and the cell current obtained from the current sensor 182. is there. The internal resistance estimation unit 197 corresponds to the estimation unit of the present invention. As shown in FIG. 20, the cell internal resistance corresponds to the coordinate gradient in the relationship between the cell voltage and the cell current. The greater the cell internal resistance, the greater the amount of cell heat generated during operation.

  The correction coefficient calculation unit 198 is a part that calculates a correction coefficient for correcting the basic rotational speed in accordance with the cell internal resistance estimated (obtained) by the internal resistance estimation unit 197. For example, the correction coefficient is calculated from a correction coefficient map shown in FIG. The correction coefficient map is set so that the correction coefficient is set to 1 in a region where the cell internal resistance is relatively small, and the correction coefficient is larger than 1 as the cell internal resistance increases.

  The rotation speed determination unit 199 corrects the basic rotation speed calculated by the rotation speed calculation unit 195 with the correction coefficient calculated by the correction coefficient calculation unit 198 to determine the correction rotation speed, and On the other hand, it is a part that outputs a rotation command.

  As shown in FIG. 22, the battery management unit 190C uses the correction coefficient calculated by the correction coefficient calculation unit 198 for the basic rotation number calculated by the rotation number calculation unit 195, as shown in FIG. Multiplication is performed to determine the correction rotational speed and output to the blower 140.

  In this embodiment, after calculating the basic rotation speed based on the cell temperature, the basic rotation speed is corrected according to the internal resistance of the cell (corrected rotation speed is calculated) and determined as a command value. The cell internal resistance is a physical quantity related to the amount of heat generated by the cell. Therefore, by adding the cell internal resistance condition to the cell temperature, the meaning of the control based on the cell heat generation amount is added, and the prospective control with respect to the cell temperature is facilitated, and the responsiveness regarding the temperature management of the battery cell 121 is achieved. Can be improved.

(Other embodiments)
In the above-described embodiment, the preferred embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. It is. The structure of the above-described embodiment is merely an example, and the scope of the present invention is not limited to the scope of these descriptions. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

In each of the above embodiments, the cell heat generation amount is calculated from the cell voltage, the cell current, and the charging rate (open circuit voltage). However, the present invention is not limited thereto, and may be calculated from the cell current and the cell internal resistance. Good. The cell internal resistance is estimated from the cell voltage and the cell current as described in the third embodiment. The cell heat generation amount is calculated by (cell current) ² × cell internal resistance.

  Further, the first map described with reference to FIG. 10, the second map described with reference to FIG. 17, and the correction coefficient map described with reference to FIG. 21 increase linearly according to the amount of heat generated by the cell, the cell temperature, and the cell internal resistance, respectively. However, it may be increased stepwise.

  The essential configuration of the present invention includes a case 110, a battery pack 120, a circulation passage 130, a blower 140, a voltage sensor 181, a current sensor 182, a temperature sensor 183 (second to third embodiments), and a battery management unit (control). Part) 190, 190A to 190C, and the PTC heater 144, the internal fin 150, the external fin 160, and the external duct 170 may be set as necessary.

  In addition, the fluid in the case 110 of each of the embodiments described above is configured so that the circulation passage 130 passes through the blower 140 (140A, 140B), the side wall side passages 131 and 132, the top wall side passage 133, the battery passage 134, and the bottom wall side passage. Although the circulation is performed in the order of 135, the reverse may be possible.

  In the battery pack 100 of each of the above embodiments, the fluid is circulated through the circulation passage 130 using the two blowers 140A and 140B. However, the circulation passage 130 is formed by one blower or three or more blowers. You may make it circulate a fluid to.

  In addition to the sirocco fan described in the above embodiments, an axial fan, a turbo fan, or the like can be used as a fan built in the blower 140 (140A, 140B) provided inside the case 110.

  Moreover, when setting the internal fin 150 and the external fin 160, it is good also as a fin integrally formed in each side wall 113,114 and the top wall 111. FIG.

  When the PTC heater 144 as a heating device is provided, an electric heater, a heat pump (heating heat exchanger), or a combustion heater may be used instead of the PTC heater 144. Further, the PTC heater 144 may be provided not only inside the fan casing 143 but also outside the fan casing 143 inside the case 110.

  In the above embodiment, the case (housing) 110 forms a hexahedron and a rectangular parallelepiped, but the housing included in the invention is not limited to this shape. For example, the case 110 may be a polyhedron having more than six surfaces, or at least one surface may include a curved surface. Further, the case 110 may be formed in a dome shape in which the top wall 111 includes a curved surface, or the case 110 may have a trapezoidal vertical cross-sectional shape. Further, in the case 110, the top wall 111 is a wall having a positional relationship facing the bottom wall 112, and the shape thereof may include either a flat surface or a curved surface. In the case 110, the side walls 113 to 116 may be walls extending from the bottom wall 112 in a direction intersecting the bottom wall 112, or walls extending from the top wall 111 in a direction intersecting the top wall 111. It may be. The boundary between the top wall 111 and the side walls 113 to 116 in the case 110 may form a corner or a curved surface. The boundary between the bottom wall 112 and the side walls 113 to 116 in the case 110 may form a corner or may form a curved surface.

  In the above embodiment, the cell stack 120A included in the battery pack 100 is four, but the number is not limited to this. That is, when only one cell stack 120A included in the battery pack 100 is accommodated inside the case 110, or when a plurality of cell stacks 120A are installed side by side in one direction, the cell stack 120A is arranged in another direction that intersects the one direction. This also includes the case where a plurality are installed side by side.

100 Battery pack 110 Case (housing)
121 Battery cell (battery)
130 Circulating passage 140 Blower 183 Temperature sensor (detector)
190, 190A to 190C Battery management unit (control unit)
193 Heat generation amount calculation unit (calculation unit)
197 Internal resistance estimator (estimator)

Claims (7)

A plurality of batteries (121);
A housing (110) for housing a plurality of the batteries (121);
A circulation passage (130) formed in the housing (110) and through which a fluid for heat exchange flows so as to be in contact with an inner wall surface of the plurality of batteries (121) and the housing (110);
A blower (140) housed in the housing (110) and causing the fluid to flow through the circulation passage (130);
In a battery pack comprising a control unit (190) for controlling the operation of the blower (140),
A calculation unit (193) for calculating a calorific value of the predetermined battery (121) among the plurality of batteries (121);
The control unit (190) determines the number of rotations of the blower (140) based on the calorific value obtained by the calculation unit (193). A detector (183) for detecting a temperature of the predetermined battery (121);
The battery pack according to claim 1, wherein the controller (190) determines the rotational speed of the blower (140) according to the heat generation amount and the temperature.   The battery pack according to claim 1 or 2, wherein the calculation unit (193) calculates the calorific value from the current, voltage, and charging rate of the battery (121).   The battery pack according to claim 1 or 2, wherein the calculation unit (193) calculates the calorific value from the current and internal resistance of the battery (121).   The battery pack according to claim 4, wherein the calculation unit (193) estimates the internal resistance from the current and the voltage of the battery (121). A plurality of batteries (121);
A housing (110) for housing a plurality of the batteries (121);
A circulation passage (130) formed in the housing (110) and through which a fluid for heat exchange flows so as to be in contact with an inner wall surface of the plurality of batteries (121) and the housing (110);
A blower (140) housed in the housing (110) and causing the fluid to flow through the circulation passage (130);
In a battery pack comprising a control unit (190) for controlling the operation of the blower (140),
A detector (183) for detecting a temperature of the predetermined battery (121) among the plurality of batteries (121);
An estimation unit (197) for estimating an internal resistance of the predetermined battery (121),
The controller (190) calculates the basic rotational speed of the blower (140) based on the temperature obtained by the detector (183), and the internal part obtained by the estimation unit (197). A battery pack, wherein the basic rotational speed is corrected according to resistance to determine a command value for the blower (140).   The battery pack according to claim 6, wherein the estimation unit (196) estimates the internal resistance from a current and a voltage of the battery (121).

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