Disclosed is a method and a device for detecting states of a battery and a battery pack. The disclosure obtains a first state of charge and a second state of charge of the battery by use of a charge calculation method and a method based on battery model, respectively. The charge calculation method is more accurate when the charge-discharge current is large and the method based on battery model performs better in handling a small current, so that a chemistry state of charge obtained by performing a weighted calculation for the first state of charge and the second state of charge can represent the real state of charge of the battery more precisely. The disclosure settles the difficulty on parameter extraction of the conventional model method, eliminates the influence of the accumulated error of the charge calculation method, and combines the advantages of the method based on the battery model and the coulometer method.

The present invention provides a sequential and efficient method of assembling a battery with a desired number of layers while reliably separating positive and negative electrode sides from each other with one or more separator structures. According to the invention, the method of assembling a battery includes stacking one or multiple combinations each comprising a frame and a positive electrode plate to be disposed in a region defined by the frame and one or multiple combinations each comprising a frame and a negative electrode plate to be disposed in a region defined by the frame, once or alternately, such that the positive and adjacent negative electrode plates are separated from each other by a separator structure and the periphery of the separator structure is held between the adjacent frames. The separator structure includes a separator exhibiting hydroxide ion conductivity and water impermeability.

A temperature sensor is described for detecting a temperature of a battery cell. The temperature sensor has a first electrical conductor having a first end for connecting the first conductor to an element of the battery cell and having a second end for connecting the first conductor to a first input of a measuring device and a second electrical conductor having a first end for connecting the second conductor to the element of the battery cell and having a second end for connecting the second conductor to a second input of the measuring device.

Disclosed herein is a battery pack which includes a plurality of battery modules housed in a housing. The battery modules are connected in series to each other via connecting members that connects external terminals of the battery modules to each other. The battery modules are classified into groups, each being comprised of at least two of the battery modules, two terminal ones of which have a potential difference of at most V or less between themselves. A first connecting member connects the external terminals of the battery modules to each other between two adjacent ones of the groups. A second connecting member connects the external terminals of the battery modules to each other within an identical one of the groups. If water penetrates into the housing, the first connecting member is electrically cut off, preferentially relative to the second connecting member.

An assembly according to an exemplary aspect of the present disclosure includes, among other things, a plurality of battery cells and a bus bar assembly received over the plurality of battery cells. The bus bar assembly comprises a housing, a bus bar received within the housing and a retention device disengageable from the bus bar to move the bus bar between a first position and a second position.

Disclosed are a mixed battery group and battery grouping method. The mixed battery group forms a battery group via a serial connection between a primary power supply battery sub-group and an auxiliary power supply battery sub-group, wherein a unit voltage rated capacity of the auxiliary power supply battery sub-group is higher than that of the primary power supply battery sub-group. The mixed battery group provides an entire voltage output of a whole battery group to supply power outwards, and also provides one or more auxiliary power supply having a voltage lower than the entire voltage of the whole battery group to supply power outwards.

A battery system includes a plurality of battery cells; a busbar that is laser-welded to electrode terminals of the adjacent battery cells and electrically connects the battery cells; and a plastic insulating wall disposed between the adjacent electrode terminals. The surface color of the insulating wall is a heat-ray reflecting color having far-infrared reflectance of 50% or more.

A plurality of battery cells are connected by a busbar. Electrode terminals of the battery cells each include a protruding portion and a welding surface around the protruding portion. The busbar includes a welding plate portion being in surface-contact with the welding surface and having a cut-away portion for guiding the protruding portion, and an exposure gap that exposes the welding surface between the inner side of the cut-away portion and the protruding portion. The busbar is welded to the welding surface in a predetermined welding width (H) by both of a fillet weld part and a penetration welding portion such that the inner edge of the cut-away portion as the fillet weld part is welded to the welding surface, and the boundary between the busbar and the welding surface is welded by the penetration welding portion.

According to one embodiment, a nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The negative electrode includes a negative electrode current collector and a negative electrode mixed-material layer on the negative electrode current collector. The negative electrode mixed-material layer includes a titanium-containing metal oxide and a binder including an acrylic resin. The negative electrode satisfies α/β>1.36×10.sup.−2, where “α” is a peel strength (N/m) between the current collector and the negative electrode mixed-material layer, and “β” is a cutting strength (N/m) according to a surface and interfacial cutting method in the negative electrode mixed-material layer.

A secondary battery pack includes: a secondary battery module including battery cells and cooling fins; a first structure formed under the secondary battery module and including a cooling channel and coupling brackets; a second structure which is formed in a shape mounted on side faces of the secondary battery module and includes a printed circuit board; and a cover mounted over the second structure.