Patent Description:
<CIT> is a prior art document that discloses a configuration of a power storage module. The power storage module described in <CIT> includes: a detection object that is a power storage element; and a sensor unit. The sensor unit includes a conductive path member, a sensor element, a mount, and a biasing member. The conductive path member is disposed on the detection object. The sensor element is connected to a conductive path on a surface of the conductive path member. The mount is provided on the conductive path member to cover the sensor element. The biasing member biases the mount toward the detection object to bring the conductive path member into contact with the detection object. A protector composed of a resin is provided between the mount and the sensor element to cover the sensor element. A structure in which a temperature sensor is pressed against the battery side by a protuberance or an elastic body to measure the temperature of the battery is moreover disclosed by <CIT>, <CIT> and <CIT>.

In the power storage module described in <CIT>, the configuration of the sensor unit is complicated. When detecting the temperature of the power storage cell by pressing a thermistor element toward the power storage cell by the biasing member, precision in temperature detection may be decreased due to heat conduction through the biasing member and the thermistor element.

The present technology has been made to solve the above-described problem and has an object to provide a power storage module having a simple configuration to suppress decreased precision in temperature detection by a thermistor element.

A power storage module according to the present technology includes a stack, a resin plate, a flexible printed circuit board, a thermistor element, a cover member composed of a resin, and an elastic body. In the stack, a plurality of power storage cells are stacked. The resin plate is placed on the stack. The flexible printed circuit board is placed on the resin plate and has an electric circuit electrically connected to the plurality of power storage cells. The thermistor element is provided on the electric circuit and is in contact with one power storage cell of the plurality of power storage cells to detect a temperature of the power storage cell. The cover member is provided on the resin plate to cover the flexible printed circuit board. The elastic body is located between the cover member and the thermistor element to press the thermistor element toward the power storage cell. The cover member includes a main body, a protuberance that protrudes toward the resin plate side, and an opening/closing window provided adjacent to the protuberance to open and close an opening formed at a corner portion of the main body, allowing surroundings of the elastic body to be visually recognizable from the outside of the cover member. The elastic body is disposed on the protuberance. A contact state between the elastic body and the thermistor element is visually recognizable with the opening/closing window being opened.

Hereinafter, embodiments of the present technology will be described. It should be noted that the same or corresponding portions are denoted by the same reference characters, and may not be described repeatedly.

It should be noted that in the embodiments described below, when reference is made to number, amount, and the like, the scope of the present technology is not necessarily limited to the number, amount, and the like unless otherwise stated particularly. Further, in the embodiments described below, each component is not necessarily essential to the present technology unless otherwise stated particularly.

It should be noted that in the present specification, the terms "comprise", "include", and "have" are open-end terms. That is, when a certain configuration is included, a configuration other than the foregoing configuration may or may not be included. Further, the present technology is not limited to one that necessarily exhibits all the functions and effects stated in the present embodiment.

In the present specification, the term "battery" is not limited to a lithium ion battery, and may include another battery such as a nickel-metal hydride battery. In the present specification, the term "electrode" may collectively represent a positive electrode and a negative electrode. Further, the term "electrode plate" may collectively represent a positive electrode plate and a negative electrode plate.

In the present specification, the "power storage cell" or the "power storage module" is not limited to a battery cell or a battery module, and may include a capacitor cell or a capacitor module.

<FIG> is a diagram showing a basic configuration of a battery pack <NUM>. <FIG> is a diagram showing battery cells <NUM> and end plates <NUM> included in battery pack <NUM>.

As shown in <FIG>, battery pack <NUM>, which serves as an exemplary "power storage module", includes battery cells <NUM>, end plates <NUM>, and a restraint member <NUM>.

The plurality of battery cells <NUM> are provided side by side in a Y axis direction (arrangement direction). Thus, a stack of battery cells <NUM> is formed. A separator (not shown) is interposed between the plurality of battery cells <NUM>. The plurality of battery cells <NUM>, which are interposed between two end plates <NUM>, are pressed by end plates <NUM>, and are therefore restrained between two end plates <NUM>.

End plates <NUM> are disposed beside both ends of battery pack <NUM> in the Y axis direction. Each of end plates <NUM> is fixed to a base such as a case that accommodates battery pack <NUM>. Stepped portions <NUM> are formed at both ends of end plate <NUM> in an X axis direction.

Restraint member <NUM> connects two end plates <NUM> to each other. Restraint member <NUM> is attached to stepped portions <NUM> formed on two end plates <NUM>.

Restraint member <NUM> is engaged with end plates <NUM> with compression force in the Y axis direction being exerted to the stack of the plurality of battery cells <NUM> and end plates <NUM>, and then the compression force is released, with the result that tensile force acts on restraint member <NUM> that connects two end plates <NUM> to each other. As a reaction thereto, restraint member <NUM> presses two end plates <NUM> in directions of bringing them closer to each other.

Restraint member <NUM> includes a first member <NUM> and a second member <NUM>. First member <NUM> and second member <NUM> are coupled to each other by butt welding, for example. Tip surfaces formed by folding second member <NUM> are brought into abutment with stepped portions <NUM> of end plate <NUM> in the Y axis direction.

<FIG> is a diagram showing battery cell <NUM> in battery pack <NUM>. As shown in <FIG>, battery cell <NUM> includes electrode terminal <NUM>, a housing <NUM>, and a gas discharge valve <NUM>.

Electrode terminal <NUM> includes a positive electrode terminal <NUM> and a negative electrode terminal <NUM>. Electrode terminal <NUM> is formed on housing <NUM>. Housing <NUM> is formed to have a substantially rectangular parallelepiped shape. An electrode assembly (not shown) and an electrolyte solution (not shown) are accommodated in housing <NUM>. Gas discharge valve <NUM> is fractured when pressure inside housing <NUM> becomes equal to or more than a predetermined value. Thus, gas in housing <NUM> is discharged to the outside of housing <NUM>.

<FIG> is a perspective view showing a state in which a wiring module is provided on battery pack <NUM>. As shown in <FIG>, a plate member <NUM> is placed on battery pack <NUM>, and a wiring member <NUM> is provided on plate member <NUM>. Wiring member <NUM> can be electrically connected to an external device via a connector <NUM>. A cover member <NUM> is provided on plate member <NUM> so as to cover wiring member <NUM>.

<FIG> is a schematic top view of the wiring module placed on battery pack <NUM>. As shown in <FIG>, the wiring module includes plate member <NUM>, wiring member <NUM>, and connector <NUM>.

Plate member <NUM> (bus bar plate) is a resin plate having insulation property and heat resistance. Plate member <NUM> has: a bottom surface portion 400A; and a side surface portion 400B formed to extend upward from bottom surface portion 400A in a Z axis direction.

Plate member <NUM> is provided with wall portions <NUM>, openings <NUM>, <NUM>, and protrusions <NUM>, <NUM>.

Each of wall portions <NUM> is formed to extend upward from bottom surface portion 400A of plate member <NUM> in the Z axis direction. Wall portion <NUM> includes: a first wall portion <NUM> formed on the center side in the X axis direction; and a second wall portion <NUM> provided on the outer side in the X axis direction in parallel with first wall portion <NUM>. Each of first wall portion <NUM> and second wall portion <NUM> is formed to extend discontinuously in the Y axis direction.

Each of first wall portion <NUM> and second wall portion <NUM> can serve as a protection wall that prevents sparking generated in plate member <NUM> from being directly exposed to outside while securing a path for discharging, to the outside of the battery pack, the gas discharged from housing <NUM> of battery cell <NUM>.

Opening <NUM> is located above a position between electrode terminal <NUM> and gas discharge valve <NUM> in battery cell <NUM> located at the end in the Y axis direction among the plurality of stacked battery cells <NUM>. Each of openings <NUM> is located above electrode terminal <NUM> of battery cell <NUM>.

Each of protrusions <NUM> (projections) extends through wiring member <NUM> in the vicinity of connector <NUM>. Thus, connector <NUM> is positioned.

The plurality of protrusions <NUM> are formed side by side in the Y axis direction. Each of the plurality of protrusions <NUM> extends through wiring member <NUM>. The number of protrusions <NUM> can be appropriately changed.

Wiring member <NUM> includes a flexible printed circuit board <NUM>, displacement absorbing portions <NUM>, bus bar joining portions <NUM>, elongated holes <NUM>, and a thermistor element <NUM>.

Flexible printed circuit board <NUM> is a board in which an electric circuit is formed on a base member including a base film having an insulation property and a conductive metal foil. The base film is composed of, for example, polyimide or the like. The conductive metal foil is composed of, for example, a copper foil or the like. Flexible printed circuit board <NUM> has flexibility and has such a characteristic that the electric characteristics of flexible printed circuit board <NUM> are maintained even when deformed.

Each of displacement absorbing portions <NUM> is formed by forming a portion of flexible printed circuit board <NUM> into a substantially U-shape so as to facilitate deformation. Displacement absorbing portion <NUM> is connected to bus bar joining portion <NUM>. Bus bar joining portion <NUM> is joined to bus bar 100A that couples electrode terminals <NUM> of the plurality of battery cells <NUM>. Thus, the electric circuit provided on flexible printed circuit board <NUM> and battery pack <NUM> are electrically connected to each other. With displacement absorbing portion <NUM>, displacements (in the X axis direction, the Y axis direction, and the Z axis direction) of bus bar joining portion <NUM> can be absorbed.

The plurality of elongated holes <NUM> are formed side by side in the Y axis direction. The number of elongated holes <NUM> can be appropriately changed. Each of the plurality of protrusions <NUM> is inserted into a corresponding one of the plurality of elongated holes <NUM>. The lengths of elongated holes <NUM> in the Y axis direction are longer in the direction further away from connector <NUM>. In this way, positioning can be readily performed when placing wiring member <NUM> and connector <NUM> on plate member <NUM>.

Thermistor element <NUM> is provided on the electric circuit of flexible printed circuit board <NUM>. Thermistor element <NUM> is disposed on one battery cell <NUM> located at the end in the Y axis direction among the plurality of battery cells <NUM> in battery pack <NUM>. Thermistor element <NUM> is in contact with the above-described one battery cell <NUM> via opening <NUM> to detect the temperature of this battery cell <NUM>. Thus, thermistor element <NUM> detects the temperature of battery cell <NUM> having the lowest temperature in battery pack <NUM>. It should be noted that thermistor element <NUM> may detect the temperature of battery cell <NUM> having the highest temperature in battery pack <NUM>, or a plurality of thermistor elements <NUM> may be used to detect the temperatures of a plurality of battery cells <NUM>.

Connector <NUM> is fixed to flexible printed circuit board <NUM>. The electric circuit in flexible printed circuit board <NUM> and an external electric device can be electrically connected to each other via connector <NUM>.

<FIG> is a schematic top view of cover member <NUM> (bus bar cover) that covers the wiring module shown in <FIG>. Cover member <NUM> is provided on plate member <NUM> to cover flexible printed circuit board <NUM>.

As shown in <FIG>, cover member <NUM> includes a main body <NUM>, tubular protrusions <NUM>, a protuberance <NUM>, and an opening/closing window <NUM>. Each of tubular protrusions <NUM> protrudes toward flexible printed circuit board <NUM> on plate member <NUM>.

Protuberance <NUM> protrudes from main body <NUM> toward the plate member <NUM> side. Protuberance <NUM> has a tubular shape having a bottom to bulge from main body <NUM>. Protuberance <NUM> is formed at a position beside thermistor element <NUM> in the Z axis direction.

An elastic body <NUM> is disposed on protuberance <NUM>. Elastic body <NUM> is adhered to protuberance <NUM>. Elastic body <NUM> is, for example, a resin foam such as a sponge. It should be noted that elastic body <NUM> may be elastically deformable at least in the Z axis direction, and may be another resin elastic body such as a rubber or a resin spring, or may be a metal elastic body.

Protuberance <NUM> is provided with a through hole <NUM> that extends, in the Z axis direction, to a position to reach elastic body <NUM> from the side opposite to the side on which elastic body <NUM> is disposed. Thus, elastic body <NUM> is visually recognizable from the outside of cover member <NUM> via through hole <NUM>.

The colors of the surfaces of elastic body <NUM> and cover member <NUM> are different from each other. The color of the surface of elastic body <NUM> is, for example, a black color. The color of the surface of cover member <NUM> is, for example, a milky-white color. Thus, it can be confirmed whether or not elastic body <NUM> is disposed on protuberance <NUM> in accordance with whether or not the black color portion of elastic body <NUM> in conformity with the shape of through hole <NUM> can be confirmed in the milky-white color background when visually checking from the outside of cover member <NUM> via through hole <NUM>.

Opening/closing window <NUM> is provided adjacent to protuberance <NUM>. Opening/closing window <NUM> is provided to open and close an opening formed at a corner portion of main body <NUM> by using a hinge (not shown) or the like. By opening opening/closing window <NUM>, the surroundings of elastic body <NUM> can be visually recognized from the outside of cover member <NUM>.

<FIG> is a cross sectional view showing a state immediately before pressing the thermistor element toward the battery cell by the elastic body located between the cover member and the thermistor element. As shown in <FIG>, a plate-like member <NUM> is provided on the side of flexible printed circuit board <NUM> opposite to the thermistor element side. Plate-like member <NUM> is provided to improve heat conductivity between thermistor element <NUM> and battery cell <NUM> and to facilitate mounting of thermistor element <NUM> on flexible printed circuit board <NUM>. Plate-like member <NUM> is composed of, for example, aluminum.

Elastic body <NUM> is located between cover member <NUM> and thermistor element <NUM> in the Z axis direction to press thermistor element <NUM> toward battery cell <NUM>. Specifically, elastic body <NUM> presses thermistor element <NUM>, flexible printed circuit board <NUM>, and plate-like member <NUM> toward battery cell <NUM> by a repulsive force when elastic body <NUM> is sandwiched between protuberance <NUM> and thermistor element <NUM> and is elastically deformed. Thus, thermistor element <NUM> is brought into close contact with battery cell <NUM> with flexible printed circuit board <NUM> and plate-like member <NUM> being interposed therebetween.

In the state before elastic body <NUM> is sandwiched between cover member <NUM> and thermistor element <NUM>, a ratio of size L2 of the minimum width of elastic body <NUM> in a direction perpendicular to a direction (Z axis direction) in which elastic body <NUM> is sandwiched between cover member <NUM> and thermistor element <NUM>, with respect to size L1 of the height of elastic body <NUM> in the Z axis direction is more than or equal to <NUM>. Thus, when elastic body <NUM> is sandwiched between protuberance <NUM> and thermistor element <NUM>, elastic body <NUM> is less likely to be buckled.

<FIG> is a perspective view showing a state in which the opening/closing window provided in the cover member is opened. As shown in <FIG>, a contact state between elastic body <NUM> and thermistor element <NUM> is visually recognizable with opening/closing window <NUM> being opened. Thus, it can be confirmed whether or not elastic body <NUM> presses thermistor element <NUM> toward battery cell <NUM>.

In the power storage module according to the present embodiment, with such a simple configuration that thermistor element <NUM> is pressed toward battery cell <NUM> by elastic body <NUM> that is composed of a resin and that is disposed on protuberance <NUM> provided in cover member <NUM> composed of a resin, thermistor element <NUM> can be brought into close contact with battery cell <NUM> with flexible printed circuit board <NUM> being interposed therebetween in such a state that elastic body <NUM> composed of a resin and having a low heat conductivity is interposed between thermistor element <NUM> and cover member <NUM> while securing a long heat conduction distance between thermistor element <NUM> and main body <NUM> of cover member <NUM>, with the result that precision in temperature detection by thermistor element <NUM> can be suppressed from being decreased due to heat conduction through elastic body <NUM> and thermistor element <NUM>.

In the power storage module according to the present embodiment, in the state before elastic body <NUM> is sandwiched between cover member <NUM> and thermistor element <NUM>, the ratio of size L2 of the minimum width of elastic body <NUM> in the direction perpendicular to the direction in which elastic body <NUM> is sandwiched between cover member <NUM> and thermistor element <NUM>, with respect to size L1 of the height of elastic body <NUM> in the direction in which elastic body <NUM> is sandwiched between cover member <NUM> and thermistor element <NUM> is more than or equal to <NUM>, so that elastic body <NUM> is less likely to be buckled and elastic body <NUM> is less likely to be inclined in the X axis direction and the Y axis direction when elastic body <NUM> is compressed in the Z axis direction, thereby stably pressing thermistor element <NUM> toward battery cell <NUM> by elastic body <NUM>.

In the power storage module according to the present embodiment, since cover member <NUM> is provided with opening/closing window <NUM> and the contact state between elastic body <NUM> and thermistor element <NUM> is visually recognizable from the outside of cover member <NUM> with opening/closing window <NUM> being opened, it can be confirmed whether or not elastic body <NUM> presses thermistor element <NUM> toward battery cell <NUM> after cover member <NUM> is assembled to plate member <NUM>.

In the power storage module according to the present embodiment, since protuberance <NUM> is provided with through hole <NUM> that extends to the position to reach elastic body <NUM> from the side opposite to the side on which elastic body <NUM> is disposed, it can be confirmed whether or not elastic body <NUM> is disposed on protuberance <NUM> by visually checking through hole <NUM> from the outside of cover member <NUM>.

Claim 1:
A power storage module comprising:
a stack in which a plurality of power storage cells (<NUM>) are stacked;
a resin plate (<NUM>) placed on the stack;
a flexible printed circuit board (<NUM>) placed on the resin plate (<NUM>) and having an electric circuit electrically connected to the plurality of power storage cells (<NUM>);
a thermistor element (<NUM>) provided on the electric circuit and in contact with one power storage cell (<NUM>) of the plurality of power storage cells (<NUM>) to detect a temperature of the power storage cell (<NUM>);
a cover member (<NUM>) provided on the resin plate (<NUM>) to cover the flexible printed circuit board (<NUM>), the cover member (<NUM>) being composed of a resin; and
an elastic body (<NUM>) located between the cover member (<NUM>) and the thermistor element (<NUM>) to press the thermistor element (<NUM>) toward the power storage cell (<NUM>), characterized in that
the cover member (<NUM>) includes:
a main body (<NUM>),
a protuberance (<NUM>) that protrudes toward the resin plate (<NUM>) side, wherein the elastic body (<NUM>) is disposed on the protuberance (<NUM>), and
an opening/closing window (<NUM>) that is provided adjacent to the protuberance (<NUM>) to open and close an opening formed at a corner portion of the main body (<NUM>), allowing surroundings of the elastic body (<NUM>) to be visually recognizable from the outside of the cover member (<NUM>), wherein
a contact state between the elastic body (<NUM>) and the thermistor element (<NUM>) is visually recognizable with the opening/closing window (<NUM>) being opened.