JP6954214B2 - Filling member, battery assembly, and heat transfer control method - Google Patents

Description

The present invention relates to a filling member, an assembled battery, and a method for controlling heat transfer.

In recent years, the use of secondary batteries as a power source for vehicles and the like has increased rapidly. For the purpose of improving the degree of freedom when mounting in a limited space such as a vehicle and extending the cruising range that can be traveled for one charge, studies on increasing the energy density of the secondary battery are underway. Has been done.

The safety of the secondary battery tends to contradict the energy density, and the higher the energy density, the lower the safety of the secondary battery. For example, in a secondary battery mounted on an electric vehicle having a cruising range of several hundred km, the battery surface temperature exceeds several hundred ° C when the secondary battery is damaged due to overcharging or an internal short circuit, and the temperature exceeds 1000 ° C. It may reach nearby.

A secondary battery used as a power source for a vehicle or the like is generally used as an assembled battery composed of a plurality of cell cells (hereinafter, also referred to as "cells"). Therefore, if one of the cells constituting the assembled battery is damaged and reaches the above temperature range, the adjacent battery may be damaged by the heat generation, and the damage may spread to the entire assembled battery in a chain reaction. ..

By the way, an assembled battery formed by connecting a large number of cells generates heat by a current that charges and discharges. In particular, the amount of heat generated by the assembled battery used as a power supply device for a vehicle is large because the charging / discharging current is extremely large. The temperature rise due to heat generation causes the electrical characteristics of the battery to deteriorate. Further, in a vehicle assembly battery in which a large number of cells are connected to increase the output voltage, it is extremely important to minimize the temperature difference between the individual cells constituting the assembly battery. This is because the temperature difference between the cells upsets the balance of the electrical characteristics of the batteries, makes the remaining capacity non-uniform, and shortens the life of a specific cell. For this reason, a power supply device for a vehicle is usually provided with a device for cooling a battery in order to reduce a temperature rise during charging / discharging. For such a cooling device, it is important to cool a large number of connected cells as efficiently and evenly as possible.

For example, as described in Patent Document 1, the cooling device is usually composed of a metal having good thermal conductivity or the like. However, if the battery and the cooling device come into direct contact with each other, there is a risk of energization. Therefore, an insulating member is installed in the gap between the battery and the cooling device. Further, in order to prevent a gap between the battery and the cooling device and a decrease in cooling efficiency, a filler is installed for the purpose of bringing the battery and the cooling device into close contact with each other.

Further, Patent Document 2 proposes the following method. A power supply device for a vehicle in which a plurality of cells are connected is provided with a separator between the cells, which is in contact with the surface of the cells in a heat-bonded state. Further, the power supply device is provided with a blowing mechanism in which a cooling gap is provided between the cells and fixed so as to be stacked via a separator, and a cooling gas is forcibly blown into the cooling gap. Further, the power supply device includes a temperature equalizing plate formed by heat-bonding to the outer peripheral surface of each cell, and the thermal conductivity of the temperature equalizing plate is based on the thermal conductivity of the separator provided between the cells. Also increase.

Japanese Patent Application Laid-Open No. 2014-505333 Japanese Unexamined Patent Publication No. 2010-272430

However, a cooling device as described in Patent Document 1 promotes heat transfer to an adjacent battery even when one of the cells constituting the assembled battery is damaged and reaches a high temperature. There is a risk that it will end up. That is, as a result of the cooling device promoting heat conduction to the other cell, the other cell may also be damaged.

On the other hand, in Patent Document 2, when one of the cells constituting the assembled battery is damaged, the amount of heat transferred to the adjacent battery via the cooling member is determined by the amount of heat generated by the cells constituting the assembled battery. The study has not been sufficiently conducted after quantitatively considering the influence of heat transfer by members other than the batteries constituting the assembled battery. In addition, no studies have been made on the assumption that the refrigerant flow of the cooling device is stopped in the event of an abnormality. If the refrigerant flow of the cooling device is stopped in the event of an abnormality, the efficiency of heat removal to the outside of the assembled battery by the cooling device will decrease, and the contribution to heat transfer to the adjacent cells via the cooling device will increase, so there is a risk of further fire spread. There is. For this reason, it is extremely important to establish safety measures assuming a state in which the refrigerant flow of the cooling device is stopped.

An object of the present invention is to provide a filling member that suitably controls heat transfer between cells in an assembled battery including a plurality of cells.

The present inventor paid attention to the amount of heat transferred between the cells via the cooling member, which had not been sufficiently studied in the above-mentioned prior art, and conducted a detailed study on its influence. As a result, the partition member and the partition member for partitioning the first and second cell cells constituting the assembled battery, and the filling member interposed between the plurality of cell cells constituting the assembled battery and the cooling member are provided. We found that it is important to appropriately control the amount of heat transfer from the first cell to the second cell in which an abnormality has occurred by suppressing the heat transfer resistance of the filling member within an appropriate range. The present invention has been reached. The present invention is as follows.

[1] A filling member that constitutes an assembled battery together with a partition member that partitions the first cell, the second cell, and the first cell and the second cell.
The filling member has a thickness direction and a surface direction orthogonal to the thickness direction, has a first surface and a second surface along the surface direction, and has the first cell and the first unit. The second cell is in contact with the first surface, and the first and second cells are in contact with a cooling member capable of cooling the first and second cells on the second surface.
_{The heat transfer sensitivity S d of the} partition member when the heat generated from the first cell is transferred to the second cell via the partition member is defined by the following equation 1.
Heat transfer sensitivity of the partition member S _d [W / K] =
Thermal conductivity of the partition member k _d [W / m · K] × Contact area between the partition member and the first and second cells _Ad [m ² ] / Thickness of the partition member d [m] ... (Equation 1)
_{The heat transfer sensitivity S b of the} filling member when the heat generated from the first cell is transferred to the second cell via the filling member and the cooling member is defined by the following equation 2.
Heat transfer sensitivity of the filling member S _b [W / K] =
Thermal conductivity of the filling member k _b [W / m · K] × Contact area between the filling member and the first and second cells A _b [m ² ] / thickness of the filling member d [m] ... (Equation 2)
When the temperature of the first cell becomes equal to or higher than the temperature in the abnormal heat generation state, the heat transfer sensitivity S _{d of the} partition member satisfies the following equation 3.
0 <S _d ≤ 2 ... (Equation 3)
The relationship between the heat transfer sensitivity S _d and the heat transfer sensitivity Sb of the filling member satisfies the following equation 4 0.3 ≤ (S _d / S _b ) ≤ 4.0 ... (Equation 4)
A filling member characterized by that.

[2] the thickness direction of the thermal conductivity of the filling member is ^{2.0 × 10 -2 W / m ·} K or more 10.0 W / m · K or less, the filling member according to [1].

[3] The filling member according to [1] or [2], wherein the thickness of the filling member is 5.0 × 10 ^-5 m or more and 5.0 × 10 ^{-3 m or less.}

[4] In the partition member according to [1], when the first cell and the second cell have not been heated to a temperature in an abnormal heat generation state, the heat transfer sensitivity S _d . A partition member with a value greater than 2.

[5] The partition member according to [1], which has a thickness direction and a surface direction orthogonal to the thickness direction, and the average temperature of one of the two surfaces of the partition member in the thickness direction is 180 ° C. in the case where more than the thermal conductivity of the thickness direction is ^{2.0 × 10 -2 W / m ·} K or more 2.0 W / m · K or less, the partition member.

[6] When the average temperature of both of the two surfaces of the partition member in the thickness direction does not exceed 80 ° C., the thermal conductivity in the thickness direction is 5.0 × ^10-2 W / m · K or more and 50 W / The partition member according to [4] or [5], which is m · K or less.

[7] The partition according to any one of [4] to [6], wherein when the thickness of the first and second cells is L mm, the thickness is L / 50 mm or more and L / 10 mm or less. Element.

[8] An assembled battery including the filling member according to any one of [1] to [3].
[9] An assembled battery including the partition member according to any one of [4] to [7].

[10] The heat transfer sensitivity S _d is fulfills Equation 3, the relationship between the heat transfer sensitivity Sb and the heat transfer sensitivity S _d satisfies the equation 4, the partition member and the filling member according to [1] A method for controlling heat transfer, which controls the amount of heat transferred from the first cell cell to the second cell cell via the partition member, the filling member, and the cooling member.

According to the present invention, in an assembled battery including a plurality of cells, heat transfer between the cells can be suitably controlled.

FIG. 1 is a diagram for explaining the configurations of the filling member and the cooling member and explaining the heat transfer sensitivity of the filling member. FIG. 2 is a top view showing an example of the assembled battery according to the embodiment. FIG. 3 is a side view schematically showing the side surface of the assembled battery shown in FIG. 2 with the side plate on the front side removed. FIG. 4 is a diagram showing an example of a cell. FIG. 5 is a front view of the cell cell shown in FIG. FIG. 6 is a side view of the cell cell shown in FIG. FIG. 7 is an explanatory view of the partition member. FIG. 8 is a diagram schematically showing a heat transfer path generated inside the cell.

Hereinafter, the filling member, the assembled battery, and the heat transfer control method according to the embodiment of the present invention will be described with reference to the drawings. The description of the embodiments described below is an example, and the present invention is not limited to the configuration described in the embodiments.

The filling member according to the present embodiment constitutes an assembled battery together with a partition member that partitions the first cell, the second cell, and the first cell and the second cell. Further, the filling member has a thickness direction and a plane direction orthogonal to the thickness direction, has a first plane and a second plane along the plane direction, and has the first cell and the second. The first and second cells are in contact with the cooling member capable of cooling the first and second cells on the first surface. _{Further, regarding the filling member, the heat transfer sensitivity S b} of the filling member when the heat generated from the first cell is transferred to the second cell via the filling member and the cooling member is given by the following equation (1). Defined by.
Thermal transfer sensitivity S _b [W / K] = Thermal conductivity of the filling member k _b [W / m · K] × Contact area between the filling member and the first and second cells _Ab [m ² ] / filling the thickness of the member _{d b [m] ··· (1} )

Here, in the present invention, some or all of the chemical substances constituting the electrodes and the electrolytic solution constituting a certain cell cause a decomposition reaction inside the cell with heat generation, thereby causing the cell cell to undergo a decomposition reaction. A state in which the temperature rises and a part or the whole area of the cell becomes 200 ° C. or higher is called an "abnormal heat generation state".

[Heat transfer sensitivity]
FIG. 1 is a diagram for explaining the configurations of the filling member and the cooling member and explaining the heat transfer sensitivity of the filling member. In FIG. 1, for example, the first cell is a cell 200a (cell # 1), and the second cell is a cell 200b (cell # 2). The heat transfer sensitivity S _b of the filling member 10 will be described with reference to FIG. The heat transfer sensitivity S _b means that the filling member 10 and the first cell (cell # 1) constituting the assembled battery 100 and the second cell (cell # 2) different from the first cell come into contact with each other. When the heat generated from the first cell is transferred to the second cell, the degree of heat transferred via the contact portion between the filling member and the first and second cells is determined. It is a scale to show.

Heat transfer sensitivity _{S b} is the thermal conductivity in the thickness direction of the material used as the filler member _{10 (k b [W / m} · K]) and the filling member 10 and the cell # 1 and cell # 2 (first and second area of the contact portion between the second cell) of the ^{_{(a b [m 2])}} , can be represented by the thickness of the filler member _{10 (d b [m])} .

Here, consider the amount of heat transferred from the cell # 1 to the cell # 2 via the filling member 10 and the cooling member 400. Regarding the two surfaces of the filling member 10 in the thickness direction (two surfaces along the surface direction), the surface in contact with the cell # 1 and the cell # 2 is the surface 10a, and the back surface thereof is the surface 10b. In FIG. 1, the thickness direction of the filling member 10 extends in the height direction of the paper surface of FIG. 1, and the surface direction of the filling member 10 extends in the left-right direction of the paper surface of FIG. In the example of FIG. 1, the cooling member 400 is formed in a plate shape having a flat surface in close contact with the surface 10b of the filling member 10. Further, the thermal conductivity in the thickness direction of _{the filling member 10 is defined as kb} [W / m · K], and the thickness of the filling member 10 is defined as _db [m].

Further, the average temperature of the region where the surface 10a of the filling member 10 and the cell # 1 are in contact (referred to as the region a1) is T1 [° C.], and the region on the surface 10b having a plane-symmetrical relationship with the region a1 (region b1). The average temperature of T2 [° C.] is T2 [° C.], the average temperature of the region where the surface 10a of the filling member 10 and the cell # 2 are in contact (referred to as region a2) is T4 [° C.], and the relationship is plane-symmetrical with the region a2. Let the average temperature of the region (region b2) be T3 [° C.].

When the average temperature T2 is lower than the average temperature T1, a surface temperature difference (T1-T2) occurs between the region a1 and the region b1 of the filling member 10. In this case, the heat flow rate (heat flux) q1 per unit cross-sectional area of the region a1 of the filling member 10 can be expressed by the following equation (3).
_{q1 = k b (T1-T2} ) / d b [W / m 2] ··· (3)

Further, when the average temperature T4 is lower than the average temperature T3, a surface temperature difference (T3-T4) occurs between the region b2 and the region a2 of the filling member 10. In this case, the heat flow rate (heat flux) q2 per unit cross-sectional area of the region b2 of the filling member 10 can be expressed by the following equation (4).
_{q2 = k b (T3-T4} ) / d b [W / m 2] ··· (4)

Here, the cooling member 400 can be made of, for example, a metal having good thermal conductivity. Therefore, when the heat removal efficiency from the cooling member 400 to the external environment is low and the surroundings of the cooling member 400 are in a state close to an insulated environment, the temperature inside the cooling member 400 can be regarded as substantially uniform. can. Under such conditions, the average temperature T2 and the average temperature T3 can be approximated to be substantially equal (T2≈T3). In this case, the heat flow rate (heat flux) q2 per unit cross-sectional area of the region b2 of the filling member 10 can be expressed by the following equation (4-2).
_{q2 ≒ k b (T2-T4} ) / d b [W / m 2] ··· (4-2)

_{From the above, the amount of heat Q1 per contact area Ab} [m ² ] that moves from the cell # 1 to the cooling member 400 via the filling member 10, and the amount of heat Q1 from the cooling member 400 to the cell # 2 via the filling member 10 The amount of heat Q2 per moving contact area _Ab [m ² ] can be expressed by the following equations (5) and (6).
_{Q1 = A b × q1 = A} b k b (T1-T2) / d b [W] ··· (5)
_{Q2 = A b × q2 = A} b k b (T2-T4) / d b [W] ··· (6)

Heat transfer sensitivity S _b of the filling member 10, when the heat from one unit cell to another of the cells to move, if their unit cells is in contact with the filling member 10, the contact portion of the filling member 10 Since it is a scale indicating the degree of heat transferred via the device, it can be defined by the following equations (7) and (8).
Q1 = S _b × (T1-T2) [W] ・ ・ ・ (7)
Q2 = S _b × (T2-T4) [W] ・ ・ ・ (8)

The heat transfer sensitivity S _b can be expressed by the following equation (9) from the equations (5), (6), (7), and (8).
S _b = Q1 / (T1-T2) = Q2 / (T2-T4)
_{= A b k b / d b} [W / K] ··· (9)

Further, the heat transfer sensitivity S _d of the partition member 1 is different from the first cell cell (for example, cell # 1) constituting the partition member 1 and the assembled battery 100 and the second cell cell (for example, cell) different from the first cell cell. # 2) is in contact with each other, and when the heat generated from the first cell is transferred to the second cell, it passes through the contact portion between the partition member 1 and the first and second cells. It is a scale that indicates the degree of heat transfer.

The thermal transfer sensitivity S _{d is the thermal conductivity (k d} [W / m · K]) in the thickness direction of the material used as the partition member 1 and the contact portion between the partition member 1 and the cells # 1 and # 2. It can be expressed using the area ( _Ad [m ² ]) and the thickness of the partition member 1 ( _{dd [m]).}

Here, consider the amount of heat transferred from the cell # 1 to the cell # 2 via the partition member 1. Regarding the two surfaces (surface 1c and surface 1d) in the thickness direction of the partition member 1, the surface in contact with the cell # 1 is defined as surface 1c, and the back surface thereof is defined as surface 1d. The surface 1d is in contact with the cell # 2 (see FIG. 2). Further, the thermal conductivity in the thickness direction of _{the partition member 1 is defined as k d} [W / m · K], and the thickness of the partition member 1 is d _d [m].

Further, the average temperature of the region where the surface 1c of the partition member 1 and the cell # 1 (referred to as the region a3 (not shown)) is T11 [° C.], and the surface 1d having a plane-symmetrical relationship with the region a2. The average temperature of the region (region b3 (not shown)) is T12 [° C.].

When the average temperature T12 is lower than the average temperature T11, a surface temperature difference (T11-T12) occurs between the region a2 and the region b2 of the partition member 1. In this case, the heat flow rate (heat flux) q3 per unit cross-sectional area of the region a2 of the partition member 1 can be expressed by the above equation (10). _{Further, the amount of heat Q3 per contact area Ad} [m ² ] moving from the cell # 1 to the cell # 2 via the partition member 1 can be expressed by the above equation (11).
q3 = k _d (T11-T12) / d _d [W / m ² ] ・ ・ ・ (10)
_{Q3 = A d × q3 = A} d k d (T11-T12) / d d [W] ··· (11)

The heat transfer sensitivity S _d can be expressed by the following equation (12) from the equations (10) and (11).
S _d = Q3 / (T11-T12) = A _d k _d / d _d [W / K] ... (12)

In the present embodiment, with respect to the partition member 1 and the filling member 10 constituting the assembled battery 100, when the temperature of the cell # 1 becomes equal to or higher than the temperature in the abnormal heat generation state, the heat transfer sensitivity S _d of the partition member 1 is 0 <. The condition of S _d ≤ 2 is satisfied, and the relationship between the _{heat transfer sensitivity S d} and the heat transfer sensitivity S _{b of the filling member 10 satisfies the condition of 0.3 ≤ (S d} / S _b ) ≤ 4.0. It is composed of. In this way, the heat from the cell # 1 can be controlled to be appropriately transferred to the cell # 2 via the filling member 10 and the cooling member 400. That is, heat transfer between suitable cells can be performed.

<Assembled battery>
The assembled battery according to the embodiment of the present invention will be described. The assembled battery includes, for example, an electric vehicle (EV, Electric Vehicle), a hybrid electric vehicle (HEV, Hybrid Electric Vehicle), a plug-in hybrid electric vehicle (PHEV, Plug-in Hybrid Electric Vehicle), an electric heavy machine, an electric motorcycle, and an electric assist. Bicycles, ships, aircraft, trains, power supply devices without power failure (UPS, Universal Power Supply), household power storage systems, storage battery systems for power system stabilization using renewable energy such as wind power / solar power / tidal power / geothermal power, etc. Applies to the battery pack installed in. However, the assembled battery 100 can also be used as a power source for supplying power to a device other than the above-mentioned EV or the like.

FIG. 2 shows a top view of an example of an assembled battery 100 formed by using a plurality of cell batteries (also referred to as “cells”) 200, and FIG. 3 shows a side plate 300d removed from the assembled battery 100 shown in FIG. It is a side view which shows the state typically.

[Batteries]
FIG. 4 is a diagram showing an example of the cell 200 constituting the assembled battery 100, FIG. 5 is a front view of the cell 200 shown in FIG. 4, and FIG. 6 is a right side view of the cell. In the example shown in FIGS. 4, 5 and 6, the cell 200 is formed in a rectangular parallelepiped shape having a height direction (H), a width direction (W), and a thickness direction (D), and terminals are formed on the upper surface thereof. 210 and terminal 220 are provided. The cell 200 is, for example, a lithium ion secondary battery including a positive electrode and a negative electrode capable of storing and releasing lithium ions, and an electrolyte. In addition to the lithium ion secondary battery, a secondary battery such as a lithium ion all-solid-state battery, a nickel hydrogen battery, a nickel cadmium battery, and a lead storage battery can be applied.

[Battery set]
In FIGS. 2 and 3, the assembled battery 100 includes a housing 300 and a plurality of single batteries 200 housed in the housing 300. The plurality of cell cells 200 are arranged side by side in a row in the thickness direction "D" (left-right direction in FIG. 2), and a partition member 1 is interposed between the cell cells 200. The housing 300 has side plates 300a, 300b, 300c and 300d provided so as to surround the sides of the plurality of arranged cell batteries 200. Pressure is applied to the side plate 300a and the side plate 300b so as to shorten the distance between them by using a jig (not shown), and each cell 200 sandwiched between the side plate 300a and the side plate 300b is pressured (constrained) in the thickness direction thereof. It is held in a state where pressure) is applied. In addition, in FIG. 2 and FIG. 3, five cell batteries 200 are illustrated as an example, but the number of cell cells can be appropriately selected. Further, in the examples of FIGS. 2 and 3, the assembled battery 100 shows an example in which the terminals 210 and 220 are arranged so as to face upward, but the assembled battery 100 has the terminals 210 and 220 facing sideways. It may be arranged as follows.

As described above, in the housing 300, the plurality of cell cells 200 are arranged in the thickness direction thereof, and the partition member 1 is arranged between the cell cells 200. The positive electrode terminal (for example, terminal 210) and the negative electrode terminal (for example, terminal 220) of the adjacent (opposing) cell 200 via the partition member 1 are electrically connected in series by the bus bar 301. As a result, the assembled battery 100 outputs electric power having a predetermined voltage.

[Partition member]
As shown in FIG. 7, the partition member 1 has a parallel flat plate shape having a height direction (H), a width direction (W), and a thickness direction (D), or a sheet-like overall shape.
The partition member 1 has a surface 1c and a surface 1d facing in the direction opposite to the surface 1c in the thickness direction (D), and is used to partition the cell 200 constituting the assembled battery 100. .. The partition member 1 can be made of a heat insulating material 110 or the like. Further, the thickness of the partition member 1 is usually in the range of L / 50 mm or more and L / 10 mm or less, preferably L / 30 mm or more and L / 15 mm or less when the thickness of the cell 200 is L [mm]. Is the range of.

[Insulation]
The heat insulating material 110 is made of a porous material or the like. Examples of the porous body include those formed of fibrous materials (also referred to as fibrous inorganic substances) and particles (also referred to as powdery inorganic substances). The heat insulating material 110 can be formed by using a predetermined molding technique such as compacting fibers or particles.

The fiber (fibrous inorganic substance) is selected from the group consisting of, for example, paper, cotton sheet, polyimide fiber, aramid fiber, polytetrafluoroethylene (PTFE) fiber, glass fiber, rock wool, ceramic fiber and biosoluble inorganic fiber. Of these, at least one selected from glass fibers, rock wool, ceramic fibers and biosoluble inorganic fibers is particularly preferable. The ceramic fiber is a fiber mainly composed of silica and alumina (silica: alumina = 40: 60 to 0: 100), and specifically, silica-alumina fiber, mullite fiber, and alumina fiber can be used.

Further, the particles (powdered inorganic substances) are at least one selected from the group consisting of, for example, silica particles, alumina particles, calcium silicate, clay minerals, vermiculite, mica, cement, pearlite, fumed silica and aerogel. Of these, silica particles, alumina particles, and clay minerals are mainly magnesium silicate (including talc and sepiolite), montmorillonite, and kaolinite.

[Filling member and cooling member]
As shown in FIG. 3, a cooling member (also referred to as a cooling device) 400 is arranged at the bottom of the housing 300. The bottom surface of each of the plurality of cell cells 200 is in contact with the upper surface of the parallel flat plate-shaped filling member 10, and a part or the entire surface of the lower surface of the filling member 10 is in contact with the cooling member 400. The heat from each cell 200 can be transferred to the cooling member 400 via the filling member 10.

The cooling member 400 is, for example, a heat sink or the like. The cooling member 400 may or may not move (circulate, etc.) a fluid (refrigerant) inside the cooling member 400. The filling member 10 is formed, for example, by one or more kinds of materials, for example, one or more kinds of plastics, plastic compounds, plastic / metal composite materials, etc., alone or in an appropriate combination.

FIG. 8 schematically shows a heat transfer path generated inside the cell 200. The heat generated inside the cell 200 is transmitted to the other cell 200 via various transmission paths. In the example of FIG. 6, the heat transfer path from the cell # 1 (CELL # 1), which is one of the plurality of cell 200, is schematically shown. For example, the heat generated inside the cell 200 (cell # 1) can be transmitted to another cell 200 (cell # 2) via the partition member 1. Further, the heat from the cell 200 is dissipated to the outside via the bus bar 301. Further, the heat from the cell 200 is transferred to the cooling member 400 via the filling member 10, and can be dissipated from the cooling member 400 to the outside.

<Heat generation and heat transfer in the assembled battery>
Here, heat generation and heat transfer in the assembled battery 100 will be described. Some or all of the chemical substances that make up the electrodes and electrolytes that make up the cellar 200 cause a decomposition reaction inside the cellar 200 with heat generation, which raises the temperature of the cellar 200 and causes the cellar battery 200 to rise in temperature. A part or all of 200 may reach 200 ° C. or higher. That is, the cell 200 may be in an abnormal heat generation state.

In general, it is known that the stability of the crystal structure after delithiumization by charging has a great influence on the safety of the positive electrode material among the materials constituting the cell 200. _{Materials such as LiCoO 2} , Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ , Li (Ni _0.8 Co _0.15 Al _0.05 ) O _{2, which} are generally used as positive electrode materials, can be charged. In the state, crystal collapse accompanied by oxygen release occurs at high temperature. Oxygen released from the positive electrode causes oxidation of the electrolytic solution and the like, accompanied by a rapid exothermic reaction. Structural analysis using synchrotron radiation has reported that the phase transition of crystals occurs at around 200 ° C. in the above positive electrode material species. Therefore, when a part or the whole region of the cell 200 is 200 ° C. or higher, it means that the crystal decay of the positive electrode is progressing, that is, the cell 200 is in a thermal runaway state (Reference 1: Lithium). High Safety Technology and Materials for Ion Batteries CMC Publishing, P.44 / Reference 2: J. Dahn et al., Electrochemical Communication, 9, 2534-2540 (2007) / Reference 3: Hironori Kobayashi, "Radiation Light Evaluation and analysis technology for positive electrode materials for lithium-ion secondary batteries used "Spring-8 Utilization Promotion Council Glass and Ceramics Study Group (2nd) (2011)).

Regarding the safety of the negative electrode material among the materials constituting the cell 200, the charged negative electrode (lithium-inserted carbon negative electrode) basically exhibits the same strong reducing property as that of lithium metal, and reacts with the electrolytic solution on the negative electrode surface. It is known that a film is formed on the electrode, thereby suppressing further reactions. Therefore, the chemical composition, structure, and thermal stability of the protective coating have a great influence on the thermal stability of the charging negative electrode when the temperature rises. Usually, the reaction between the charged negative electrode and the electrolytic solution is explained by the formation of a protective film and the subsequent explosive reduction decomposition reaction due to film destruction. In general, it has been reported that the protective film forming reaction on the negative electrode proceeds from around 130 ° C., the subsequent film decomposition reaction proceeds at around 200 ° C., and finally reaches an explosive reduction decomposition reaction. Therefore, when a part or the entire region of the cell 200 is 200 ° C. or higher, it means that the coating on the negative electrode surface is being destroyed, that is, the cell 200 is in a thermal runaway state (Reference 4: Reference 4: Battery Handbook 1st Edition Ohm, P.591 / Reference 5: Forefront of high safety technology and evaluation technology for lithium-ion batteries CMC Publishing, p.90).

Further, in the present invention, a state in which the chemical substances constituting the electrodes and the electrolytic solution constituting the cell 200 do not undergo a decomposition reaction accompanied by a heat generation rate of a certain level or higher inside the cell 200 is referred to as a "normal state". .. Here, the heat generation state of the cell 200 is evaluated by using ARC (Accelerating rate assessment), which is a means for quantitatively measuring the thermal behavior when the reactive chemical substance self-heats and decomposes under adiabatic conditions. Can be done. For example, Dahn et al. Define that the self-exothermic reaction is proceeding inside the cell when the exothermic rate observed in ARC exceeds 0.04 ° C / min, which can be followed (reference). Reference 6: J. Dachn et al., Electrochimica Acta, 49, 4599-4604 (2004)).

Further, in the present invention, the cell 200 in the normal state is referred to as a "cell that holds the normal state", and the cell 200 that deviates from the normal state and does not reach the abnormal heat generation state is referred to as a "cell that deviates from the normal state". ". The upper limit of the surface average temperature assumed when the cell 200 does not deviate from the normal state is usually 80 ° C. Here, the boiling point of the general-purpose electrolytic solution component is 90 ° C. or higher as shown in Table 1 below. General-purpose electrolyte components are, for example, ethylene carbonate (EC), diethyl carbonate, dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC). When the surface average temperature of the cell 200 is lower than 80 ° C., the general-purpose electrolytic solution itself constituting the cell 200 does not boil.

For example, the upper limit of the surface average temperature assumed when the cell 200 in contact with the partition member 1 deviates from the normal state and does not reach the abnormal heat generation state is 180 ° C. Here, it is assumed that the material of the partition member 1 is made of polyethylene or polypropylene, which is a general-purpose separator material. In this case, the meltdown temperature is known to be 160-200 ° C. Therefore, when the surface average temperature of the cell 200 exceeds 180 ° C., a part of the general-purpose separator material constituting the cell 200 may melt down, resulting in an abnormal heat generation state.

On the other hand, the average temperature of one of the two surfaces of the partition member 1 in the thickness direction (two surfaces orthogonal to the thickness direction, that is, the surfaces 1c and 1d) that partition the cell 200 constituting the assembled battery 100 is Within a range not exceeding 100 ° C., the partition member 1 transfers heat from the cell 200 (for example, cell # 1) in the assembled battery 100 in the thickness direction thereof, and faces the cell # 1 via the partition member 1. It can be transmitted to other members other than the cell 200 (cell # 2) and the cell 200 (for example, the bus bar 301 and the cooling member 400). On the other hand, when the average temperature exceeds 100 ° C., the partition member 1 is opened by heat and the contained liquid flows out of the partition member 1 in a vapor phase state or a liquid phase state. Due to this outflow, air (having a heat insulating action) enters the heat insulating material 110 in the partition member 1, and the heat insulating property (thermal resistance) in the thickness direction is increased. As a result, the amount of heat transferred from the cell # 1 to the cell # 2 via the partition member 1 can be reduced. That is, it is possible to prevent another cell 200 from deviating from the normal state when a certain cell 200 deviates from the normal state.

If the average temperature of both the two surfaces (surfaces 1c and 1d) of the partition member 1 in the thickness direction that partition the cells constituting the assembled battery is lower than 80 ° C., the thickness direction is due to the contained liquid. Heat transfer to is promoted. When all the cells 200 constituting the assembled battery 100 are in the normal state, the heat transfer resistance of the partition member 1 is lower than that of the conventional product, so that the temperature can be leveled between the cells 200 in the assembled battery 100 and the temperature can be adjusted. The effect of reducing the deterioration of the cell 200 due to unevenness can be expected.

<Cooling of a single battery in an abnormal heat generation state>
The partition member 1 according to the present embodiment is in the thickness direction when the average temperature of one of the two surfaces (surface 1c and surface 1d) in the thickness direction of the partition member 1 exceeds 180 ° C. depending on the selection of the material and structure. The thermal conductivity is configured to be 2.0 × 10 ^-2 W / m · K or more and 2.0 W / m · K or less. ^{Further, the partition member 1 has a thermal conductivity of 5.0 × 10-2} W in the thickness direction when the average temperature of both of the two surfaces (surface 1c and surface 1d) in the thickness direction does not exceed 80 ° C. It is configured to be at least / m · K and at least 50 W / m · K.

For example, as shown in FIGS. 3 and 8, there are two cell cells 200 (for example, cell # 1 and cell # 2) partitioned by the partition member 1, cell # 1 comes into contact with surface 1c, and cell # 2 becomes. When the average temperature of both the surface 1c and the surface 1d is 80 ° C. or lower in the state of being in contact with the surface 1d, heat transfer is performed through the partition member 1. On the other hand, when the temperature of one of cell # 1 and cell # 2 (for example, cell # 1) rises and the average temperature of the surface 1c in contact with cell # 1 exceeds 180 ° C., the heat conduction of the partition member 1 The rate is reduced (insulation is improved), and heat is less likely to be transferred to cell # 2. This avoids damage to cell # 2.

Most of the heat generated from the cell # 1 is transferred to the cooling member 400 via the filling member 10.

Further, a part of the heat transferred to the filling member 10 is transferred to the cell 200 other than the cell 200 which has become abnormally heat-generating through the filling member 10 and the cooling member 400. The cell 200 other than the cell 200 in the abnormal heat generation state is, for example, the cell 200 facing the cell battery 200 in the abnormal heat generation state via the partition member 1 (adjacent with the partition member interposed therebetween). .. For example, in the example shown in FIG. 8, when the cell # 1, which is one of the cell 200, is in an abnormal heat generation state, a part of the heat from the cell # 1 passes through the filling member 10 and the cooling member 400. Is transmitted to cell # 2.

The thermal conductivity of the filling member is preferably ^{2.0 × 10 -2 W / m ·} K or more 50.0W / m · K or less. Further, the thickness of the filling member ^{is preferably 5.0 × 10-5} m or more and 5.0 × 10 ⁻² m or less.

[Filling member]
Therefore, the filling member 10 according to the embodiment includes the configuration shown in FIG. 1 as an example. In the present embodiment, the filling member 10 is formed in a parallel flat plate shape, the thickness direction thereof is arranged in the height direction (H) of the partition member 1, and the surface direction of the filling member 10 is the thickness direction of the partition member 1. It is arranged in (D). Further, the filling member 10 has first and second surfaces along the surface direction thereof. In the present embodiment, the filling member 10 is formed in a parallel flat plate shape and has a surface 10a corresponding to the first surface and a surface 10b corresponding to the second surface. The surface 10a faces upward, and the surface 10b faces in the opposite direction (downward). The filling member 10 comes into contact with a plurality of batteries including the first and second batteries constituting the assembled battery 100 on the surface 10a. In this embodiment, cell # 1 corresponds to the first cell and cell # 2 corresponds to the second cell. Further, the filling member 10 comes into contact with the cooling member 400 capable of cooling a plurality of cells including the first and second cells on the surface 10b.

<Example>
Next, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.

In the examples and comparative examples described below, among the heat transfer paths from the cell 200 in the abnormally generated state to the other cell 200, the heat transfer amount of the partition member 1 partitioning between the cells 200 and the single unit. Focusing on the amount of heat transfer through the filling member 10 arranged between the battery 200 and the cooling member 400, the possibility of suppressing the amount of heat transfer between the cell 200 by the partition member 1 and the filling member 10 was examined.

As the assembled battery 100 to be evaluated, a assembled battery model in which five cell batteries 200 as shown in FIG. 8 are connected is constructed, and the calorific value corresponding to the abnormal heat generation state is 1.4 × 10 ⁹ [J]. / ^{M 3} ] (total calorific value estimated from the calorific value evaluation of cell # 2 using the NMC-based positive electrode) was given, and the heat conduction equation was finite under the conditions of Examples 1 to 5 and Comparative Examples 1 and 2 below. By solving by the element method, the temperature transition of the cell # 2 adjacent to the cell # 1 was estimated, and the effect of suppressing the heat transfer amount between the cells due to the change in the heat transfer sensitivity of the filling member 10 was evaluated. Here, COMSOL Multiphysics, which is general-purpose physics simulation software manufactured by COMSOL AB, was used for the analysis, and the analysis was performed with reference to the following references 9 and 10. As the heat transfer path between cell # 1 and cell # 2, the path described in FIG. 8 is assumed (Reference 9: Japanese Patent Application Laid-Open No. 2006-010648, Reference 10: RM. Spotnitz et al., J. Power Sources 163, 1080-1086 (2007)).

In Examples and Comparative Examples, the sizes of cells # 1 to # 5 were PHEV2 sizes (length 91 mm, width 148 mm, thickness 26.5 mm) specified by the German Association of the Automotive Industry. For simplicity, the cooling member 400 is assumed to be a plate-like material having a thickness of about 4 mm and made of a metal such as aluminum or an aluminum alloy, and has a thermal conductivity of 200 W / m · K. It is assumed that the filling member 10 installed between the cells # 1 and # 2 and the cooling member 400 is a coating film such as an insulating paint or a plastic film. Regarding the filling member 10, the heat transfer resistance can be changed by the film thickness, the type and filling amount of the filler (filling in the filling member 10), or the type of plastic forming the structure of the filling member 10. Further, it is assumed that the partition member 1 installed between the cells # 1 and the cell # 2 is a heat insulating material. The bus bar 301 was assumed to be made of aluminum and had a thermal conductivity of 237 W / m · K. Further, regarding the cooling member 400, assuming a state in which the flow of the refrigerant is stopped, a heat transfer coefficient equivalent to natural convection is given to the environment around the cooling member 400. Under these conditions, the temperature transition in the cell # 2 was estimated for 300 seconds after the cell # 1 reached the abnormal heat generation state.

In Examples 1 to 5 and Comparative Examples 1 and 2, in order to clarify the degree of temperature rise due to the heat transferred from the cell 200 that has reached the temperature of the abnormal heat generation state, other than cell # 1. Regarding cells # 2 to cell # 5, the temperature rise due to the self-heating of the cells is not taken into consideration.

Table 2 below shows the results of Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-2.

In Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-2, the film thickness (dimension in the thickness direction) of the partition member 1 was fixed at 1 mm. Further, the thermal conductivity k _d of the partition member 1 was set to be constant (0.1 W / (m · K)) regardless of the change in the average temperature of the surface 1c and the surface 1d. Since the film thickness and the thermal conductivity k _d were constant, the heat transfer sensitivity S _d was also a constant value (1.35 W / K). This heat transfer sensitivity S _d falls within the range of 0 <S _{d ≦ 2.} On the other hand, with respect to the filling member 10, the measurement was carried out by changing the thermal conductivity k _b. The heat transfer sensitivity S _b and the sensitivity ratio (S _d / S _b ) for each thermal conductivity k _b were determined.

(Comparative Example 1-1)
The thermal conductivity _{k b} is a material of 2.0 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 would reach 212.4 ° C. 152 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 7.84 W / K, and the sensitivity ratio S _d / S _b was 0.172.

(Example 1-1)
The thermal conductivity _{k b} is a material of 1.0 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 208.7 ° C. 168 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 3.92 W / K, and the sensitivity ratio S _d / S _b was 0.344.

(Example 1-2)
The thermal conductivity _{k b} is a material of 0.8 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 207.9 ° C. 168 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 3.13 W / K, and the sensitivity ratio S _d / S _b was 0.431.

(Example 1-3)
The thermal conductivity _{k b} is a material of 0.6 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 would reach 207.1 ° C. 175 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 is 2.35 W / K.
The sensitivity ratio S _d / S _b was 0.574.

(Example 1-4)
The thermal conductivity _{k b} is a material of 0.4 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 207.3 ° C. 188 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 1.57 W / K, and the sensitivity ratio S _d / S _b was 0.860.

(Example 1-5)
The thermal conductivity _{k b} is a material of 0.2 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 208.1 ° C. 179 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 0.784 W / K, and the sensitivity ratio S _d / S _b was 1.72.

(Comparative Example 1-2)
The thermal conductivity _{k b} is a material of 0.1 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 would reach 211.0 ° C. 208 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 0.196 W / K, and the sensitivity ratio S _d / S _b was 6.89.

From the results of Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-2, the following can be seen. _{The heat transfer sensitivity S d} of the partition member 1 is constant with respect to the filling member 10 installed between the cell 200 constituting the assembled battery 100 and the cooling member 400 provided for cooling and equalizing the battery temperature. when the heat transfer resistance of the filler member 10 (the thermal conductivity k _b) by fall within an appropriate range, the amount of heat transferred through the cooling member 400 from the abnormality occurs cell # 1 (the first unit cell) The degree of temperature rise of cell # 2 (second cell) due to this can be controlled, that is, according to Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-2, the cooling member 400 is used. It was shown that there is a possibility that the heat transfer between the cells 200 via the cell 200 can be suitably controlled.

In Examples 1-1 to 1-5, the maximum temperature of cell # 2 can be set to a value lower than 210 ° C., whereas in Comparative Examples 1-1 and 1-2, the maximum temperature exceeds 210 ° C. became. From these, it can be seen that suitable heat transfer control is performed in the range where the relationship between the heat transfer sensitivity S _d and the heat transfer sensitivity S _b satisfies 0.3 ≦ (S _d / S _{b) ≦ 4.0.} all right.

Table 3 shows the results of Examples 2-1 to 2-6 and Comparative Examples 2-1 and 2-2.

In Examples 2-1 to 2-6 and Comparative Examples 2-1 and 2-2, the film thickness (dimension in the thickness direction) of the partition member 1 was fixed at 1 mm. _{On the other hand, the partition member 1 whose thermal conductivity k d} decreases from 1.0 W / (m · K) to 0.1 W / (m · K) according to the change in the average temperature of the surface 1c and the surface 1d is used. board. The film thickness was constant, and the heat transfer sensitivity S _{d after the change in thermal conductivity k d} was a constant value (1.35 W / K). This heat transfer sensitivity S _d falls within the range of 0 <S _{d ≦ 2.} On the other hand, with respect to the filling member 10, the measurement was carried out by changing the thermal conductivity k _b. The heat transfer sensitivity S _b and the sensitivity ratio (S _d / S _b ) for each thermal conductivity k _b were determined.

(Comparative Example 2-1)
The thermal conductivity _{k b} is a material of 2.0 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 210.4 ° C. 137 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 7.84 W / K, and the sensitivity ratio S _d / S _b was 0.172.

(Example 2-1)
The thermal conductivity _{k b} is a material of 1.0 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 would reach 204.1 ° C. 160 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 3.92 W / K, and the sensitivity ratio S _d / S _b was 0.344.

(Example 2-2)
The thermal conductivity _{k b} is a material of 0.8 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 would reach 202.5 ° C. 168 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 3.13 W / K, and the sensitivity ratio S _d / S _b was 0.431.

(Example 2-3)
The thermal conductivity _{k b} is a material of 0.6 W / m · K in the filling member 10, the film thickness was 1 mm.
It was estimated that the maximum temperature inside cell # 2 would reach 200.6 ° C. 180 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 2.35 W / K, and the sensitivity ratio S _d / S _b was 0.574.

(Example 2-4)
The thermal conductivity _{k b} is a material of 0.4 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 199.6 ° C. 162 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 1.57 W / K, and the sensitivity ratio S _d / S _b was 0.860.

(Example 2-5)
The thermal conductivity _{k b} is a material of 0.2 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 200.1 ° C. 169 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 0.784 W / K, and the sensitivity ratio S _d / S _b was 1.72.

(Example 2-6)
The thermal conductivity _{k b} is a material of 0.1 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 202.1 ° C. 172 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 0.392 W / K, and the sensitivity ratio S _d / S _b was 3.44.

(Comparative Example 2-2)
The thermal conductivity _{k b} is a material of 0.02 W / m · K in the filling member 10, the film thickness was 1 mm. It was estimated that the maximum temperature inside cell # 2 reached 207.4 ° C. 186 seconds after the abnormality occurred in cell # 1. In this case, the heat transfer sensitivity S _b of the filling member 10 was 0.078 W / K, and the sensitivity ratio S _d / S _b was 17.3.

From the results of Examples 2-1 to 2-6 and Comparative Examples 2-1 and 2-2, the following can be seen. With respect to the filling member 10, when the heat transfer sensitivity S _{d after the decrease in the heat conductivity k d} of the partition member 1 is constant, the heat transfer resistance (heat conductivity k _b ) of the filling member 10 is kept within an appropriate range. , The degree of temperature rise of cell # 2 (second cell) due to the amount of heat transferred from cell # 1 (first cell) in which the abnormality has occurred via the cooling member 400 can be controlled, that is, in the embodiment. According to 2-1 to 2-6 and Comparative Examples 2-1 and 2-2, it was shown that the heat transfer between the cell 200 via the cooling member 400 may be suitably controlled.

In Examples 2-1 to 2-6, the maximum temperature of cell # 2 can be set to 204.1 ° C or lower , whereas in Comparative Examples 2-1 and 2-2, the maximum temperature is 207.4 ° C or higher. It became the temperature. From the results of Examples 2-1 to 2-6, even when the partition member 1 has a mechanism (switching function) for changing (decreasing) _{the thermal conductivity dd according to the surface temperature, the heat transfer sensitivity} It was found that suitable heat transfer control was performed in the range where the relationship between S _d and the heat transfer sensitivity S _b satisfied 0.3 ≦ (S _d / S _{b) ≦ 4.0.}

Here, in Examples 1 to 5 and Comparative Examples 1 and 2, the thickness (film thickness) of the filling member 10 was fixed to 1 mm, but the thickness of the filling member 10 was 5.0 × ^10-5 m or more. It may be 0 × 10 ^-3 m or less. Therefore, from the results of Examples 1 to 5 and Comparative Examples 1 and 2, the thermal conductivity _{k b} is ^{2.0 × 10 -2 W / m ·} K or more in the thickness direction of the filling member 10 10.0 W / m · It was found that it is preferably K or less. Further, it is preferable that the value _{of the heat transfer sensitivity S d} is larger than 2 when the temperature of the cells # 1 and the cell # 2 is not raised to the temperature in the abnormal heat generation state.

1 Partition member 10 Filling member 10a, 10b Surface 100 Assembly battery 110 Inner body 120 Exterior body 200 Single battery 300 Housing 400 Cooling member

Claims (10)

A filling member that constitutes an assembled battery together with a partition member that partitions the first cell, the second cell, the first cell, and the second cell.
The filling member has a thickness direction and a surface direction orthogonal to the thickness direction, has a first surface and a second surface along the surface direction, and has the first cell and the first unit. The second cell is in contact with the first surface, and the first and second cells are in contact with a cooling member capable of cooling the first and second cells on the second surface.
_{The heat transfer sensitivity S d of the} partition member when the heat generated from the first cell is transferred to the second cell via the partition member is defined by the following equation 1.
Heat transfer sensitivity of the partition member S _d [W / K] =
Thermal conductivity of the partition member k _d [W / m · K] × Contact area between the partition member and the first cell cell _Ad [m ² ] / Thickness of the partition member d _d [m] ...・ (Equation 1)
The heat transfer sensitivity Sb of the filling member when the heat generated from the first cell is transferred to the second cell via the filling member and the cooling member is defined by the following equation 2.
Heat transfer sensitivity of the filling member S _b [W / K] =
Thermal conductivity of the filling member k _b [W / m · K] × Contact area between the filling member and the first and second cells A _b [m ² ] / Thickness of the filling member d _b [m ] ... (Equation 2)
When the temperature of the first cell becomes equal to or higher than the temperature in the abnormal heat generation state, the heat transfer sensitivity S _{d of the} partition member satisfies the following equation 3.
0 <S _d ≤ 2 ... (Equation 3)
The relationship between the heat transfer sensitivity S _d and the heat transfer sensitivity Sb of the filling member satisfies the following equation 4 0.3 ≤ (S _d / S _b ) ≤ 4.0 ... (Equation 4)
A filling member characterized by that. The thickness direction of the thermal conductivity of the filling member is ^{2.0 × 10 -2 W / m ·} K or more 10.0 W / m · K or less, the filling member of claim 1. The thickness of the filling member is 5.0 × 10 ^-5 m or more and 5.0 × 10 ^-3 m or less.
The filling member according to claim 1 or 2. In the partition member according to claim 1, when the first cell and the second cell have not been heated to a temperature in an abnormal heat generation state, the value of the _{heat transfer sensitivity S d is 2.} Larger, divider. The partition member according to claim 1, which has a thickness direction and a surface direction orthogonal to the thickness direction, and the average temperature of one of the two surfaces of the partition member in the thickness direction exceeds 180 ° C. , The partition member having a thermal conductivity in the thickness direction of 2.0 × 10 ^-2 W / m · K or more and 2.0 W / m · K or less. When the average temperature of both of the two surfaces of the partition member in the thickness direction does not exceed 80 ° C., the thermal conductivity in the thickness direction is 5.0 × ^10-2 W / m · K or more and 50 W / m · K. Is below,
The partition member according to claim 4 or 5. The partition member according to any one of claims 4 to 6, wherein when the thickness of the first and second cells is L mm, the thickness is L / 50 mm or more and L / 10 mm or less. An assembled battery including the filling member according to any one of claims 1 to 3. An assembled battery including the partition member according to any one of claims 4 to 7. The heat transfer sensitivity S _d is fulfills Equation 3, the relationship between the heat transfer sensitivity S _b and the heat transfer sensitivity S _d satisfies the equation 4, using the partition member and the filling member of claim 1 A method for controlling heat transfer, which controls the amount of heat transferred from the first cell cell to the second cell cell via the partition member, the filling member, and the cooling member.

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