GB2607571A

GB2607571A - Battery system and method of assembly

Info

Publication number: GB2607571A
Application number: GB2107405.9A
Authority: GB
Inventors: Mehta Arjun; Cleary Sean
Original assignee: Edge Mobility Ltd
Current assignee: Edge Mobility Ltd
Priority date: 2021-05-25
Filing date: 2021-05-25
Publication date: 2022-12-14
Also published as: GB202107405D0

Abstract

A battery management and/or monitoring system printed circuit board (BMS PCB) 100 for installation over an array of cells includes conductive layer (104, Figure 17) with cell bonding pads 106 positioned on the opposite side of a substrate 102 to that intended to be positioned adjacent an array of cells. Through-holes 108 adjacent to the cell-bonding pads are sized and configured to allow a wire-bonded connection to be made from the cell-bonding pads to a cell terminal. Mounting pads 110 are provided for mounting BMS electronic components to allow for cell monitoring and/or management. Positive and negative power pads 112, 113 are coupled to the cell-bonding pads, to create a power circuit that allows for the transfer of power to and from the cells. A PCB includes a substrate; a first side having first connector mounting pads; and a second side, opposite the first side, having second connector mounting pads. The first and second connector mounting pads have at least one conductive connection to the PCB in common such that first or second connectors can be mounted to the respective first and second connector mounting pads depending upon the use to which the PCB is to be put.

Description

BATTERY SYSTEM AND METHOD OF ASSEMBLY

FIELD

The present invention relates to battery systems and printed circuit boards. BACKGROUND Battery systems can comprise an array of battery cells, connected together and controlled by a battery management system.

SUMMARY

According to a first aspect, there is provided a battery management and/or monitoring system printed circuit board (BMS PCB) for installation over an array of cells with cell terminals, the BMS PCB comprising: a substrate: a first conductive layer disposed on a side of the substrate that is opposite a side of the substrate intended to be positioned adjacent the array of cells in use, the first conductive layer comprising a plurality of cell-bonding pads, wherein each cell-bonding pad is for making a wire-bonded connection from the first conductive layer to a cell terminal; an array of through-holes, each of the through-holes being adjacent to at least one of the cell-bonding pads, each of the through-holes being sized and configured to allow a wire-bonded connection to be made from at least one of the cell-bonding pads, through the through-hole, to a cell terminal; mounting pads for mounting the electronic components of a batten: monitoring and/or management system (BMS) to allow for monitoring and/or management of the cells in use and positive and negative power pads that are conductively coupled to the cell-bonding pads, to create a power circuit that allows for the transfer of power to and from the array of cells in use.

Each cell-bonding pad may be for making a plurality of wire-bonded connections from the first conductive layer to one or more cell terminals. Each of the through-holes may be adjacent to at least one of the cell-bonding pads, each of the through-holes being sized and configured to allow a plurality of wire-bonded connections to be made from at least one of the cell-bonding pads, through the through-hole, to one or more cell terminals.

At least one of the cell-bonding pads may be for making a wire-bonded connection to a negative cell terminal, and at least one of the cell-bonding pads may be for making a wire-bonded connection to a positive cell terminal.

Each through-hole may be sized and configured for allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of one of the cells through the through-hole.

Each through-hole may be sized and configured for allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of a plurality of the cells through the through-hole.

Each through-hole may be elongate in plan, thereby allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of a plurality of the cells through the through-hole.

Each cell-bonding pad may extend parallel to the elongate direction of each through-hole. The BMS PCB may comprise at least one intermediate conductive layer within the substrate.

The at least one intermediate conductive layer may comprise power-carrying traces for transferring power to and from cells that are wire-bonded to the cell-bonding pads.

The mounting pads may comprise balancing component mounting pads for mounting balancing resistors and/or switches for balancing cell voltages under control of the BMS in use.

The balancing component mounting pads may be distributed in a region of the BMS PCB within which the cell-bonding pads are located.

The balancing component mounting pads may be positioned such that, in use, balancing components installed onto the balancing component mounting pads can be used to heat the cells that are wire-bonded to the BMS PCB under control of the BMS in use.

The first conductive layer may form part of the power circuit extending from the positive power pad to the negative power pad, the positive and negative power pads both being disposed at a same edge of the BMS PCB.

The first conductive layer may form part of the power circuit extending from the positive power pad to the negative power pad, and the mounting pads may comprise switching circuit pads coupled within the power circuit, for mounting switching circuitry for selectively opening and closing the power circuit under control of the BMS in use.

The switching circuit pads may be disposed at an opposite edge of the BMS PCB to the positive and negative power pads.

The switching circuits pads may be positioned at a mid-point of the power circuit.

The mounting pads may comprise thermal sensor mounting pads for mounting thermal sensors for providing signals to be monitored by the BMS in use.

The BMS PCB may comprise a further conductive layer on an opposite side of the substrate from the first conductive layer.

The thither conductive layer may comprise one or more thermal sensor mounting pads for mounting one or more thermal sensors for providing signals to be monitored by the BMS in use The further conductive layer may comprise one or more signal connector pads for mounting one or more signal connectors for transferring data and signals to and from the BMS in use According to a second aspect, there is provided a populated BMS PCB, comprising: the BMS PCB of the first aspect; and electronic components installed onto the mounting pads to comprise a BMS. According to a third aspect, there is provided a battery system comprising: an enclosure comprising: a base; and a wall extending upwards from the base; an array of vertically orientated cells held within the enclosure wherein each cell has at least one cell terminal at its top surface; and the populated BMS PCB of the second aspect, wherein the cell terminals on the top surface of the cells are wire-bonded to corresponding cell-bonding pads on the BMS PCB through the through-holes.

The battery system may comprise balancing components installed onto the balancing component mounting pads, wherein the balancing components are thermally connected to the cells, and the BMS configured, to provide for selective heating of the cells.

The balancing components may be thermally connected to the cells via a thermal interface material or dielectric fluid.

The battery system may comprise a lid for sealing the cells and populated BMS PCB within the enclosure.

The battery system may comprise a positive power connector and a negative power connector, the positive power connector being wire-bonded to the positive power pad of the BMS PCB, and the negative power connector being wire-bonded to the negative power pad of the BMS PCB.

The positive and negative power connectors may each comprise an insulating retainer, each insulating retainer being disposed on the shelf and comprising a supporting lip emending under the corresponding power pad on the BMS PCB, the supporting lip being configured to galvanically isolate the enclosure from the BMS PCB, and/or support the BMS PCB whilst the wire-bonds are being formed.

The battery system may comprise thermal sensors installed onto the thermal sensor mounting pads, thermally connected to one or more of the cells.

The thermal sensors may be thermally connected to the cells via a thermal interface material or dielectric fluid.

The enclosure may comprise an internal shelf, the shelf having an aperture, and a signal connector may be mounted onto the signal connector mounting pads on the PCB BMS, the signal connector passing through the aperture in the shelf, such that the signal connector is directly accessible from outside of the enclosure The battery system may comprise a gasket between the shelf and the PCB BMS, wherein the gasket has an aperture through which the signal connector can pass, such that when the PCB BMS is fixed to the enclosure, the gasket creates a seal between the connector and the enclosure.

According to a fourth aspect, there is provided a method of assembling the battery system of the third aspect, comprising: disposing thc array of cells within the enclosure; lowering the populated BMS PCB of the second aspect into position above the array of cells; and makingwire-bonded connections between the cell terminals and the cell-bonding pads.

The method may comprise fastening the BMS PCB to the enclosure prior to making the wire-bonded connections.

The method may comprise lowering the populated BMS PCB into position such that the signal connector passes through the aperture in the shelf.

The method may comprise: prior to lowering the populated BMS PCB into position, placing the gasket onto the shelf such that the aperture in the gasket is aligned with the aperture in the shelf, and fixing the populated BMS PCB to the shelf so as to compress the gasket between the shelf and the populated BMS PCB, thereby creating a seal between the signal connector and the shelf The method may comprise: prior to lowering the populated BMS PCB into position, placing the gasket onto the populated BMS PCB such that the aperture in the gasket fits around the signal connector; and fixing the populated BAN PCB to the shelf so as to compress the gasket between the shelf and the populated BMS PCB, thereby creating a seal between the signal connector and the shelf The method may comprise: prior to lowering the populated BMS PCB into position, lowering positive and negative power connectors into the enclosure, such that, when the BMS PCB has been lowered into position, the positive connector is positioned adjacent to the positive power pad and the negative connector is positioned adjacent to the negative power pad; and making wire-bonded connections between the power connectors and the corresponding power pads.

According to a fifth aspect, there is provided a PCB, the PCB comprising: a substrate: a first side, the first side comprising first connector mounting pads to which a first connector can be mounted; and a second side opposite the first side, the second side comprising second connector mounting pads to which a second connector can be mounted; the first and second connector mounting pads having at least one conductive connection to the PCB in common, such that the first connector or the second connector can be mounted to the respective first and second connector mounting pads, depending upon the use to which the PCB is to be put.

The first and second connector mounting pads may have the same conductive connections to the PCB. The first and second connector mounting pads may be coincident with each other.

The PCB may comprise: a first gasket sealing surface surrounding the first connector mounting pads and a second gasket sealing surface surrounding the second connector mounting pads.

The PCB may be a BMS PCB, The BMS PCB may be in accordance with the first aspect.

The PCB may be for use in at least first and second related products, wherein the first product uses a first connector mounted to the first connector mounting pads, and the second product uses a second connector mounted to the second connector mounting pads According to a sixth aspect, there is provided a first product comprising a PCB according to the fifth aspect and a second product comprising a PCB according to the fifth aspect, wherein: the PCB of the first product comprises a first connector mounted to the first connector mounting pads and the PCB of the second product comprises a second connector mounted to the second connector mounting pads.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a battery management and/or monitoring system printed circuit board (BMS PCB); Figure 2 is a perspective view of the reverse of the BMS PCB of Figure 1; Figure 3 is a plan view of the BMS PCB of Figures 1 and 2; Figure 4 is a plan view of the reverse of the BMS PCB of Figures 1-3; Figure 5 is a perspective view of a populated BMS PCB; Figure 6 is a perspective view of the reverse of the populated BMS PCB of Figure 5; Figure 7 is a perspective view of the BMS PCB of Figures Sand 6 installed over an array of cells; Figure is a perspective view of the underside of the BMS PCB and array of cells of Figure 7; Figure 9 is a perspective view of an enclosure for a battery system; Figure 10 is a perspective view of the enclosure of Figure 9, with an array of battery cells installed; Figure 11 is a perspective view of the enclosure of Figures 9 and 10, with the populated BMS PCB of Figures 5 and 6 installed over the array of battery cells; Figure 12 is a perspective view of a battery system comprising the enclosure of Figures 9-11 and a lid; Figure 13 is a plan view of the enclosure of Figures 9-11, showing wire bonded connections; Figure 14 is a detailed perspective view of wire bonds between a cell-bonding pad and terminals of batten' cells; Figure 15 is a detailed perspective view of a terminal forming part of the battery system of Figure 12: Figure 16 is a section through the terminal of Figure 15; Figure 17 is a schematic section through the BMS PCB of Figures 1-4; Figure 18 is a plan view of the BMS PCB and terminals of the batten' system of Figure 12; Figure 19 is a detailed perspective view of a PCB showing first connector mounting pads; Figure 20 is a detailed perspective view of the reverse of the PCB of Figure 19 showing second connector mounting pads; Figure 21 is the PCB of Figures 19 and 20 with a first connector mounted to the first connector mounting pads; Figure 22 is the PCB of Figures 19-21, with a second connector mounted to the second connector mounting pads: and Figure 23 is a flowchart showing a method of assembling a batten' system such as that shown in Figure 12,

DETAILED DESCRIPTION

S

The following description relates to a printed circuit board (PCB), a battery management and/or monitoring system (BMS), a battery system comprising such a PCB and BMS, a method of assembling such a battery system, and a PCB having first arid second connector mounting pads on opposite sides of a substrate. These aspects have initially been developed with a focus on electric and hybrid vehicle systems. However, the skilled person will appreciate that the principles described have application beyond such systems.

Referring to the drawings, and Figures 1-4 in particular, there is shown a battery management and/or monitoring system printed circuit board (BMS PCB) 100, BMS PCB 100 is configured for installation over an array of cells with cell terminals. A non-limiting example of such an installation is described in detail below.

BMS PCB 100 comprises a substrate 102. In the illustrated example, substrate 102 comprises a multi-layer fibreglass PCB substrate, but substrate 102 can take any suitable form. As shown in Figure 17, substrate 102 has several fibreglass layers 190, separated by intermediate copper layers 192. Each copper layer is of 1-3 oz thickness, for example.

BMS PCB 100 also comprises first conductive layer, in the form of an upper conductive layer 104, disposed upon its surface. In the illustrated embodiment, upper conductive layer 104 comprises a layer of 2 oz copper, which has been etched or otherwise processed to form various conductive traces and other elements, as described in more detail below.

As best shown in Figures 1, 3, and 13, upper conductive layer 104 comprises a plurality of cell-bonding pads 106. in general, each cell-bonding pad 106 is for making at least one wire-bonded connection from upper conductive layer 104 to at least one cell terminal. In the illustrated example, each cell-bonding pad 106 is for making a plurality of wire-bonded connections from the upper conductive layer 104 to cell terminals as described below.

BMS PCB 100 also comprises an array of through-holes 108. Through-holes 108 arc machined or otherwise formed through substrate 102. In general, each of through-holes 108 is adjacent to at least one of cell-bonding pads 106, although in the illustrated embodiment, each of through-holes 108 is adjacent to a pair of cell-bonding pads 106.

In general, each through-hole 108 is sized and configured to allow a wire-bonded connection to be made from at least one of the cell-bonding pads 106, through through-hole 108, to at least one cell terminal, as described in more detail below. In the illustrated embodiment, each through-hole 108 is sized and configured for allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of a plurality of the cells through through-hole 108, as described in more detail below.

In the illustrated example, each cell-bonding pad 106 is elongate in plan and extends parallel to the elongate direction of its adjacent through-hole 108. In other implementations, each cell-bonding pad can extend along more than one through-hole, and each such through-hole optionally allows access to one or more cells for the making of one or more wire-bonding connections.

BMS PCB 100 comprises mounting pads 110 for mounting electronic components of the BMS, as described in more detail below. Mounting pads 110 are connected with each other and other pads on BMS PCB 100 via copper traces, wires, and/or other connectors. The electronic components can include, for example, at least one microcontroller or microprocessor, along with active and passive components that, when installed onto mounting pads 110, comprise a BMS for monitoring and/or management of the cells, as described in more detail below.

BMS PCB 100 comprises a positive power pad 112 and a negative power pad 113. Positive and negative power pads 112 and 113 are conductively coupled to cell-bonding pads 106. In the illustrated example, positive power pad 112 and negative power pad 113 are disposed on the same side or edge 117 at one end of BMS PCB 100. This may simplify power connections, as described in more detail below. However, power pads can be placed on different sides or edges relative to each other.

Conductive coupling between power pads 112, 113 and cell-bonding pads 106 is achieved by way of conductive traces 114 formed in conductive layer 104. In the illustrated example, conductive traces 114 are also connected to one or more additional conductive layers, such as intermediate copper layers 192, by way of via connections 116. The additional conductive layers can electrically mirror conductive traces 114. This mirroring of conductive traces 114 increases overall current-carrying capability without the need for, for example, bus bars or additional wiring. The skilled person will appreciate that any such additional conductive traces need not be the same size, shape or configuration as the conductive traces 114 they electrically mirror.

Cell-bonding pads 106, power pads 112, 113, conductive traces 114, and any additional conductive traces (not shown) together form a power circuit that allows for the transfer of power to and from the array of cells in use, as described in more detail below. Figure 18 shows the general current flow 194 through the power circuit. The skilled person will appreciate that the term "power circuit" means that the circuit carries a relatively high current relative to, for example, the current involved in signalling and control circuitry. As a non-limiting example, six cells in parallel, each capable of 30A peak current, would result in a power circuit carrying a peak current of around 180A, compared with signalling current that is typically less than a few amps, or sub 1A, or even sub 200mA. In general, the power circuit can be characterised by a current capacity that is an order of magnitude, two orders of magnitude, or more, greater than a current associated with signalling.

BMS PCB 100 comprises balancing component mounting pads 118. Balancing component mounting pads 118 are for mounting balancing resistors and/or switches for balancing cell voltages under control of the BMS in use, as described in more detail below. At least some of the balancing component mounting pads 118 can be distributed through a region of the BMS PCB within which cell-bonding pads 106 are located. For example, balancing resistors can be installed on balancing component mounting pads 118 disposed adjacent to one or more cell-balancing pads 106 connected to one or more cells for which the resistors provide balancing. This allows for heat generated by such balancing resistors to be distributed across BMS PCB 100, which reduces excessive heat build-up that can occur when balancing resistors are localised in one area of a BMS PCB. Balancing component mounting pads 118 can also be used for switching components that control current to balancing resistors via operation of the BMS. as described in more detail below.

In the illustrated example, balancing component mounting pads 118 are positioned such that, in use, balancing components installed onto the balancing component mounting pads can be used to heat cells that are wire-bonded to the BMS PCB, under control of the BMS in use, as described in more detail below.

In the illustrated example, mounting pads include switching circuit pads 120 coupled within the power circuit. Switching circuit pads 120 are for mounting switching circuitry for selectively opening and closing the power circuit under control of the BMS in use, as described in more detail below. Switching circuit pads 120 are disposed at an opposite edge 121 of the BMS PCB relative to the positive and negative terminals, although other positions are possible. Switching circuit pads 120 are positioned at a mid-point of the power circuit, which may offer physical advantages, such as improved space for the switching circuit. The skilled person will appreciate that other positions for switching circuit pads 120 are possible.

BMS PCB 100 comprises a further conductive layer in the form of a lower conductive layer 122 on the opposite side of the substrate 102 from the upper conductive layer 104.

Lower conductive layer 122 comprises a plurality of thermal sensor mounting pads 124 for mounting thermal sensors for providing temperature signals to be monitored by the BMS in use, as described in more detail below.

Lower conductive layer 122 also comprises signal connector pads 180 for mounting one or more signal connectors for transferring data and signals to and from the BMS in use.

Turning to Figures 5 and 6, there is shown a populated BMS PCB 126. Populated BMS PCB 126 is based on the PCB of Figures Ito 4, but with electronic components 128 installed onto the mounting pads to comprise a BMS. Electronic components 128 can include, for example, one or more microcontrollers or microprocessors (not shown), along with active and passive components (not shown) that are configured to allow for monitoring and/or management of the cells in use.

Other components can also be installed on populated BMS PCB 126. For example, thermal sensors in the fonn of, for example, thermistors 130 can be installed on themml sensor mounting pads 124, balancing resistors 132 can be installed on balancing component mounting pads 118, and switching components (such as one or more relays or transistors, such as field effect transistors) 134 can be installed on switching circuit pads 120.

Populated BMS PCB 126 includes a signal connector 178, connected to signal connector mounting pads 180 on the underside of populated BMS PCB 126. Signal connector 178 extends away from the plane of substrate 102.

Additional supporting components and circuitry (not shown) can also be installed. This can include circuits and components for switching, scaling, filtering or otherwise modifying signals that pass around populated BMS PCB 126 in use. The skilled person is familiar with such supporting circuits and components, and so they are not described in detail.

Once all components have been installed, populated BMS PCB 126 can itself be installed as part of a battery system, such as battery system 136 shown in Figure 12. The skilled person will appreciate that populated BMS PCB 126 can also be installed within battery systems differing from that shown in Figure 12.

Battery system 136 includes an enclosure 138. Enclosure 138 includes a generally planar base 140. A wall 142 extends upwards from edges of base 140 to define an interior space 144. Enclosure 138 is formed from aluminium, although any other suitable material or combination of materials may be used in construction of enclosure 138. Preferably, enclosure 138 is at least partly formed from electrically conductive materials to shield the populated PCB BMS inside from electromagnetic interference. However, electrically non-conductive materials may be used in particular implementations.

In the illustrated example, a support framework 146 (see Figures 7 and 8) is disposed within interior space 144. Support framework 146 is formed from a plastic, such as ABS plastic, although any other suitable polymeric or other material may be used in construction of support framework 146. Preferably, support framework 146 is formed from materials that are not electrically conductive. Populated BMS PCB 126 is screwed to support framework 146 and enclosure 138 by screws 147 passing through holes 149 in substrate 102, although in other implementations, populated PCB 126 can be screwed only to holes 149 or enclosure 138, or to neither.

In other implementations, a separate support framework is not provided. In that case, battery cells can be self-supporting, and/or the enclosure itself can be configured to provide any necessary support.

Enclosure 138 includes a recessed shelf 160 along one edge. Shelf 160 is sized and configured to receive a corresponding portion of populated BMS PCB 126, and includes a shelf aperture 161.

Battery system 136 includes an array 148 of vertically orientated cells 150 disposed within interior space 144 of enclosure 138. Cells 150 are typically rechargeable, and can use any suitable rechargeable battery technology. in the illustrated implementation, alternate rows of cells 150 within array 148 are offset relative to each other, to reduce space between the cells and improve packing density.

In the illustrated implementation, each cell 150 has a positive cell terminal 152 and a negative cell terminal 154 at its upper end. Positive cell terminal 152 is centrally located on the upper end, and negative cell terminal 154 is located around a periphery of the upper cnd. Positive and negative cells terminals may alternatively be placed at opposite ends of the cells, or in any other suitable position.

A positive power connector 156 and a negative power connector 158 are disposed on recessed shelf 160. Positive power connector 156 comprises an insulating retainer 162 formed from a polymer, within which is disposed a positive terminal 164. Similarly, negative power connector 158 comprises insulating retainer 166 formed from a polymer, within which is disposed a negative terminal 168. Insulating retainers 162 and 166 are screwed to shelf 161 of enclosure 138, adjacent to respective positive and negative power pads 112, 113 As best shown in Figures 15 and 16, insulating retainer 166 includes a supporting lip 170 that extends beneath populated BMS PCB 126 to provide vertical support to negative power pad 113. Supporting lip 170 assists during the wire bonding process described below, and galvanically isolates enclosure 138 from populated BMS PCB 126. Insulating retainer 162 includes a corresponding supporting lip (not shown) that provides similar support to positive power pad 112.

Several wire bonds are formed between populated BMS PCB 126 and other components of battery system 136. Wire bonding is a way of making electrical interconnections between components. A bonding head uses ultrasonic energy to create a bond between an aluminium or copper bond wire and a first surface. The wire is then drawn to a second surface and a second bond is made in a similar fashion. The bonding head then cuts the wire leaving behind a wire bond connection between the two surfaces.

Referring to Figure 14, each cell 150 has a single wire bond connection 172 from its positive cell terminal 152 to an adjacent cell-bonding pad 106 via through-hole 108, and a single wire bond connection 173 from its negative cell terminal 154 to an opposite adjacent cell-bonding pad 106 via through-hole 108. Since, in this implementation, there are two cells 150 exposed by each through-hole 108, there are two wire bond connections 172, 173 made to each cell bonding pad 106.

Each cell 150 is wire-bonded Lo iLs adjacent cell-bonding pads 106 in a similar fashion. In other implementations, different wire-bonding connection numbers and configuration can be used between cells and cell-bonding pads.

Although Figure 14 shows single wire bond connections 172, 173 between each cell terminal 152, 154 and adjacent cell-bonding pads 106, the skilled person will appreciate that one or more wire bond connections can extend from each cell terminal 152, 154 to one or more adjacent cell-bonding pads 106.

Also, although the through-hole 108 of Figure 14 exposes two cells 150 for wire bonding connection, the skilled person will appreciate that each through-hole 108 can be configured to expose only a single cell, or more than two cells. One potential advantage of exposing more than one cell is improved access for a wire bonding head and reduced cost of manufacturing the PCB due to a smaller number of holes.

Referring to Figure 15, negative terminal 168 of negative power connector 158 is wire-bonded to negative power pad 113 by way of several wire bond connections 174. Multiple wire bond connections 174 are used to meet the current capacity requirements of battery system 136. Similar wire bond connections (not shown) are used to wire-bond positive terminal 164 of positive power connector 156 to positive power pad 112.

Optionally, one or more of balancing resistors 132 are thermally connected to one or more of 150 cells, and the BMS is configured to provide for selective heating of the cells. Such thermal connection can be conductive ancUor convective, for example. Optionally, a thermal transfer medium (not shown), comprising a material having a high thermal conductivity relative to air can be used, in contact with one or more of the balancing resistors and cells. Such a thermal transfer medium can be, for example, a solid, a liquid or a paste, preferably a non-electrically conductive or dielectric material.

Optionally, one or more of thermistors 130 are thermally connected to one or more of the cells, and, as for the balancing resistors, such thermal connection can include the use of a thermal transfer medium.

A gasket 182 is located between shelf 160 and the surface of populated 126 BMS PCB surrounding signal connector 178. Gasket 182 has a gasket aperture 184 that overlaps shelf aperture 161 of shelf 160. Populated BMS PCB 126 is positioned such that signal connector 178 passes through gasket aperture 182 and shelf aperture 161. Screws 186 pull populated BMS PCB 126 towards shelf 160. This urges a lower surface of BMS PCB 126 into contact with an upper surface of gasket 182, which compresses gasket 182 such that it seals around signal connector 178. Due to signal connector 178 passing through gasket aperture 184 and shelf aperture 161, it is accessible from outside enclosure 138.

In alternative implementations, signal cormector 178 does not pass through gasket aperture 184 and/or shelf aperture 161. In that case, a complementary connector (not shown) extends through gasket aperture 184 and/or shelf aperture 161 to connect with signal connector 178.

Battery system 136 includes a lid 176 for sealing populated BMS PCB 126 and cells 150 within enclosure 138. Lid 176 includes a first aperture 198 positioned to expose a portion of positive terminal 164 and a second aperture 200 positioned to expose a portion of negative terminal 168. Gaskets (not shown) may be used to seal between lid 176 and positive and negative terminals -164, 168, similar to how gasket 182 seals around signal connector 178. In use, power connections (not shown) can be made to positive terminal 164 and negative terminal 168, while cells 150 and populated BMS PCB 126 remain sealed within interior space 144.

The BMS PCB described above provides a number of advantages, some of which are subtle but important.

One advantage of the described BMS PCB is that it enables a particular assembly sequence that relies solely on top-down interactions. This enables top-down automated assembly to be employed, which can be cheaper and/or simpler than automated assembly approaches requiring more degrees of freedom. This is particularly the case when compared with using individual wires, which requires relatively high levels of dexterity, making it difficult to automate at a low cost.

The use of a BMS PCB that allows for direct wire-bonding to an array of cells can result in a significantly reduced number of parts. For example, there is no need for separate wires and connectors from a busbar to the BMS for measuring voltage or temperature of cells.

The use of a BMS PCB may also significantly reduce the number of assembly steps, because some or all intercoimectors, components and connectors can be pre-integrated onto the BMS PCB beforc assembly into an enclosure with a battery array. Depending upon the implementation, only the wire-bonded connections may need to be made during assembly. Where the BMS PCB includes intermediate lavers, these can be used to shield signal-carrying traces from electromagnetic interference, which can result in reduced noise and increased measurement accuracy. Shielding is more challenging when wires are used.

The use of a PCB that at least partly covers the array of cells may allow BMS components, such as such as temperature sensors, signal filtering and amplifying components, balancing components and (power) switching components, to be positioned closer to the cells, resulting in improved sensing accuracy, improved thermal management and/or a mom compact battery system.

Referring to Figure 23, there is shown a method 202 of assembling a battery system. The battery system can be, for example, of the type that incorporates a BMS PCB as described above and defined in the claims.

An array of cells, such as cells 150, is disposed 204 within an enclosure, such as enclosure 138. Optionally, the enclosure can include scaffolding, fatmwork, or other fatmations or structures that do one or more of holding the cells in position within the enclosure, insulating the cells from each other and/or the enclosure, and providing attachment points to which components can be attached, as described elsewhere A PCB, such as populated BMS PCB 126, is lowered 206 into position above the array of cells. In this position, the PCB can cover some or all of the upper surface of the array.

The PCB is then optionally fastened to the enclosure. Fastening can be done using any suitable fastening method or technique, including, but not limited to, screws, clips, rivets, nuts, bolts and adhesives. The fastening may be to the enclosure directly, or to any scaffolding or support structure within the enclosure, such as scaffolding for the battery array. This prevents movement of the PCB during subsequent wire-bonding operations.

Wire-bonded connections are then made 210 between the cell terminals and cell-bonding pads on the PCB, for example as described above.

Optionally, the PCB comprises a signal connector extending from one side, such as the signal connector 178 described above. In that case, the method can comprise lowering the PCB into position such that the signal connector passes through an aperture in a shelf, such as shelf 160, formed in the interior of the enclosure. The PCB is connected to the shelf so as to compress a gasket, such as gasket 182, between the shelf and the PCB, thereby creating a seal between the signal connector and the shelf Where a gasket is used, it can comprise an aperture, such as aperture 184. In that case, the method can comprise, prior to lowering the PCB into position, placing the gasket onto the shelf such that the aperture in the gasket is aligned with the aperture in the shelf Alternatively, the gasket can be placed over the signal connector before the PCB is lowered into position, as shown in Figure 8 Optionally, prior to lowering the PCB into position, positive and negative power connectors, such as positive and negative power connectors 156 and 158, are lowered into the enclosure. The positive and negative power connectors are positioned such that, when the PCB has been lowered into position, the positive connector is positioned adjacent one of the power pads and the negative connector is positioned adjacent the other of the power pads. Wire-bonded connections between the power connectors and the corresponding power pads can then be made, for example as described above.

Turning to Figures 19 to 22, there is shown a PCB 212. In one implementation. PCB 212 can be a BMS PCB such as any of the implementations described above, and/or as defined by the claims. Alternatively. PCB 212 can be for a different circuit or circuits, which can be for a different application to that described above. There are, however, additional advantages that arise when the PCB is used (or usable) in at least two different but related products, and where the connectors on those different products need to be located on different surfaces of the products' respective enclosures. Rechargeable batteries with two or more different configurations, using the same PCB but having connectors on opposite sides of the PCB, is one non-limiting example of such related products.

PCB 212 includes a substrate 214, which can be, for example, substrate 102 of any of the implementations described above, and/or as defined by the claims. However, substrate 214 can take any other suitable form, depending upon the intended application of PCB 212, Substrate 214 includes a first side 218. First side 218 comprises first connector mounting pads 220 to which a first connector 221 can be mounted, as described in more detail below. First side 218 also includes a first gasket sealing surface 222 surrounding first connector mounting pads 220. First gasket sealing surface 222 can be relatively smooth, and free of, for example, holes or other features that might prevent a gasket from forming a seal.

Substrate 214 includes a second side 224 opposite first side 218. Second side 224 comprises second connector mounting pads 226 to which a second connector 227 can be mounted, as described in more detail below. Second side 224 also includes a second gasket sealing surface 228 surrounding second connector mounting pads 226. Second gasket sealing surface 228 is relatively smooth, and free of, for example, any features that might prevent a gasket from forming a seal First and second connector mounting pads 220, 226 have at least some conductive connections to PCB 212 in common. Conductive connections can include, for example, conductive traces formed on one or both surfaces of PCB 212, and/or any internal traces when PCB 212 is a multilayer PCB. By having at least some conductive connections in common, a first connector 221 or a second connector 227 can be mounted to the respective first and second connector mounting pads 220, 226, depending upon the use to which the PCB is to be put.

An exception to avoiding any features within first gasket sealing surface 222 and second gasket sealing surface 228 is screw holes 229, which allow screws (not shown) to pass through PCB 212. As with screws 186 in Figure 11, for example, such screws can be used to pull PCB 212 towards a further sealing surface, formed, for example, on an inner surface of an enclosure or lid. The surface of shelf 160 is an example of such a further sealing surface. A gasket between the first or second sealing surface 222, 228 and the further sealing surface is compressed, causing a seal around the corresponding first or second connector 221, 227. Alternatively, some of all of screw holes 229 can be positioned inside or outside first or second sealing surfaces 222, 228 In some implementations, first and second connector mounting pads 220, 226 have exactly the same combination of conductive connections to the PCB 212. This enables the first and second connectors 221, 227 to have the same functionality, irrespective of which is used with PCB 212. Optionally, first and second connector mounting pads 220, 226 also have the same layout and electrical connection configuration as each other, enabling the use of the same connector type for both the first and second connectors 221, 227.

In use, a decision is made as to whether first or second connector mounting pads 220, 226 are to be used for a particular application. For example, if PCB 212 is to be installed in a product that requires a connector on first side 218, then first connector 221 is mounted to first connector mounting pads 220. Alternatively, if PCB 212 is to be installed in a related product that requires a connector on second side 224, then second connector 227 is mounted to second connector mounting pads 226.

The mounting can take any suitable form, such as soldering, wire-bonding, or other forms of conductive connection. First and second connectors 221, 227 can be, for example, surface mount or through-hole connectors that are soldered directly to conductive traces carrying power and/or signals. Optionally, the mounting can include attaching the first or second connector 22 I. 227 to PCB 212 at a point that is not connected to any circuitry carried by PCB 212, such as a pad that is not connected to any other circuitry, or is merely grounded.

In general, PCB 212 and first and second connector mounting pads 220, 226 are configured such that a connector is only mounted to one or the other of first and second connector mounting pads 220, 226. It is possible, however, to have connectors mounted to both first and second connector mounting pads 220, 226.

First and second connectors 221, 227 can be for transferring power and/or signals between PCB 212 and another component or system. As an example, rechargeable batteries can have various types of connector arrangements that make power and/or data connections when the battery is connected to a device it is intended to power. First and second connectors 221, 227 can include contacts (not shown) that enable such connections to be made when the product into which PCB 212 is installed is connected to the device it is intended to power.

Optionally, first and second connector mounting pads 220, 226 are coincident with each other on PCB 212. That is, the areas of first and second connector mounting pads 220, 226 at least partly overlap each other. This allows for shorter routing of conductive connections to first and second connector mounting pads 220, 226.

PCB design and production can be expensive. This is particularly the case for complex PCBs, especially where multiple layers are involved. Producing smaller numbers of PCBs can also add to costs, because, in general, the unit rate for PCBs falls as the number of PCBs produced or ordered rises. Providing connector mounting pads on opposite sides of PCB 212 allows for a single PCB 212 to be used for multiple implementations with different connector requirements.

The use of gasket sealing surfaces on both sides of PCB 212 further increases the flexibility of PCB 212.

"Cells", in the context of the present application, includes battery cells, whether rechargeable or not, and other forms of energy storage devices that output electrical power and may be arranged in an array, including, for example, capacitors and supercapacitors.

"BMS" is intended to include any circuit suitable for managing and/or monitoring the type of energy storage devices with which the BMS PCB is to be used.

Directional references, such as "upper" and "lower", are for convenience of description. While certain advantages may apply when the described components are used with such orientations, in the broadest form, the invention and its various aspects are not Limited to particular orientations.

The drawings are schematic, and do not show details such as, for example, individual mounting pads for all terminals of components that arc to be mounted to such pads. Similarly, various components, such as thennistors, switches. balancing resistors, and the like, are shown schematically.

Although the invention has been described reference to a number of specific non-exhaustive and non-limiting examples, the skilled person will appreciate that the invention may be embodied in many other forms.

Claims

CLAIMS1. A battery' management and/or monitoring system printed circuit board (BMS PCB) for installation over an array of cells with cell terminals, the BMS PCB comprising: a substrate: a first conductive layer disposed on a side of the substrate that is opposite a side of the substrate intended to be positioned adjacent the array of cells in use, the first conductive layer comprising a plurality of cell-bonding pads, wherein each cell-bonding pad is for making a wire-bonded connection from the first conductive layer to a cell terminal; an array of through-holes, each of the through-holes being adjacent to at least one of the cell-bonding pads, each of the through-holes being sized and configured to allow a wire-bonded connection to be made from at least one of the cell-bonding pads, through the through-hole, to a cell terminal; mounting pads for mounting the electronic components of a battery monitoring and/or management system (BMS) to allow for monitoring and/or management of the cells in use; and positive and negative power pads that are conductively coupled to the cell-bonding pads, to create a power circuit that allows for the transfer of power to and from the array of cells in use.
2. The BMS PCB of claim 1, wherein: each cell-bonding pad is for making a plurality of wire-bonded connections from the first conductive layer to one or more cell terminals; and each of the through-holes is adjacent to at least one of the cell-bonding pads, each of the through-holes being sized and configured to allow a plurality of wire-bonded connections to be made from at least one of the cell-bonding pads, through the through-hole, to one or more cell terminals.
3. The BMS PCB of claim I or 2, wherein at least one of the cell-bonding pads is for making a wire-bonded connection to a negative cell terminal, and at least one of the cell-bonding pads is for making a wire-bonded connection to a positive cell terminal.
4. The BMS PCB of any one of claims I to 3, wherein each through-hole is sized and configured for allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of one of the cells through the through-hole.
The BMS PCB of any one of claims 1 to 3, wherein each through-hole is sized and configured for allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of a plurality of the cells through the through-hole.
6. The BMS PCB of claim 5, wherein each through-hole is elongate in plan, thereby allowing a plurality of wire-bonded connections to be made between a plurality of adjacent cell-bonding pads and the cell terminals of a plurality of the cells through the through-hole.
7 The BMS PCB of claim 6, wherein each cell-bonding pad extends parallel to the elongate direction of each through-hole.
8. The BMS PCB of any preceding claim, comprising at least one intermediate conductive layer within the substrate.
9. The BMS PCB of claim 8 wherein the at least one intermediate conductive layer comprises power-carrying traces for transferring power to and from cells that are wire-bonded to the cell-bonding pads.
JO, The BMS PCB of any preceding claim, wherein the mounting pads comprise balancing component mounting pads for mounting balancing resistors and/or switches for balancing cell voltages under control of the BMS in use.
11. The BMS PCB of claim 10, wherein the balancing component mounting pads are distributed in a region of the BMS PCB within which the cell-bonding pads are located.
12. The BMS PCB of claim 11, wherein the balancing component mounting pads are positioned such that, in use, balancing components installed onto the balancing component mounting pads can be used to heat the cells that are wire-bonded to the BMS PCB under control of the BMS in use.
13. The BMS PCB of any preceding claim, wherein the first conductive layer forms part of the power circuit extending from the positive power pad to the negative power pad, the positive and negative power pads both being disposed at a same edge of the BMS PCB.
14, The BMS PCB of any preceding claim, wherein the first conductive layer forms part of the power circuit extending from the positive power pad to the negative power pad, and the mounting pads comprise switching circuit pads coupled within the power circuit, for mounting switching circuitry for selectively opening and closing the power circuit under control of the BMS in use.
15. The BMS PCB of claim 14, wherein the switching circuit pads are disposed at an opposite edge of the BMS PCB to the positive and negative power pads.
16 The BMS PCB of claim 14 or 15, wherein the switching circuits pads arc positioned at a mid-point of the power circuit.
17. The BMS PCB of any preceding claim, wherein the mounting pads comprise thermal sensor mounting pads for mounting thermal sensors for providing signals to be monitored by the BMS in use.
18. The BMS PCB of any preceding claim, comprising a further conductive layer on an opposite side of the substrate from the first conductive layer.
19. The BMS PCB of any preceding claim, when dependent on claim 18, wherein the further conductive layer comprises one or more thermal sensor mounting pads for mounting one or more thermal sensors for providing signals to be monitored by the BMS in use.
20. The BMS PCB of any preceding claim, when dependent on claim 18, wherein the further conductive layer comprises one or more signal connector pads for mounting one or more signal connectors for transferring data and signals to and from the BMS in use.
21. A populated BMS PCB, comprising: the BMS PCB of any preceding claim; and electronic components installed onto the mounting pads to comprise a BMS.
22. A battery system comprising: an enclosure comprising: a base; and a wall extending upwards from the base; an array of vertically orientated cells held within the enclosure, wherein each cell has at least one cell terminal at its top surface; and the populated BMS PCB of claim 21, wherein the cell terminals on the top surface of the cells are wire-bonded to corresponding cell-bonding pads on the BMS PCB through the through-holes.
23. The battery system of claim 22 when dependent upon any one of claims 10 to 12, comprising balancing components installed onto the balancing component mounting pads, wherein the balancing components are thermally connected to the cells, and the BMS configured, to provide for selective heating of the cells
24. The battery system of claim 23, wherein the balancing components are thermally connected to the cells via a thermal interface material or dielectric fluid
25. The battery systcm of any one of claims 22 to 24, comprising a lid for scaling the cells and populated BMS PCB within the enclosure.
26. The battery system of any one of claims 22 to 25, comprising a positive power connector and a negative power connector, the positive power connector being wire-bonded to the positive power pad of the BMS PCB, and the negative power connector being wire-bonded to the negative power pad of the BMS PCB.
27. The battery system of claim 26, wherein the positive and negative power connectors each comprise an insulating retainer, each insulating retainer being disposed on the shelf and comprising a supporting lip extending under the corresponding power pad on the BMS PCB, the supporting lip being configured to galvanically isolate the enclosure from the BMS PCB, and/or support the BMS PCB whilst the wire-bonds are being formed.
28. The battery system of any one of claims 22 to 27, when dependent upon either claim 17 or 19, comprising thermal sensors installed onto the thermal sensor mounting pads, thermally connected to one or more of the cells.
29. The battery system of claim 28, wherein the thermal sensors are thermally connected to the cells via a thermal interface material or dielectric fluid.
30. The battery system of any one of claims 22 to 29, when dependent on claim 20, wherein: the enclosure comprises an internal shelf, the shelf having an aperture; a signal connector is mounted onto the signal connector mounting pads on the PCB BMS, the signal connector passing through the aperture in the shelf, such that the signal connector is directly accessible from outside of the enclosure.
31. The battery system of claim 30, comprising a gasket between the shelf and the PCB BMS, wherein the gasket has an aperture through which the signal connector can pass, such that when the PCB BMS is fixed to the enclosure, die gasket creates a seal between the connector and the enclosure.
32. A method of assembling the battery system of any one of claims 22 to 31, comprising: disposing the array of cells within the enclosure; lowering the populated BMS PCB of claim 21 into position above the array of cells and making wire-bonded connections between the cell terminals and the cell-bonding pads.
33. A method of assembling the battery system of claim 32, comprising prior to making wire-bonded connections between the cell terminals and the cell-bonding pads, fastening the BMS PCB to the enclosure.
34. The method of claim 33, comprising lowering the populated BMS PCB into position such that the signal connector passes through the aperture in the shelf.
35. The method of claim 34, when used to assemble the battery system of claim 31, comprising: prior to lowering the populated BMS PCB into position, placing the gasket onto the shelf such that the aperture in the gasket is aligned with the aperture in the shelf; and fixing the populated BMS PCB to the shelf so as to compress the gasket between the shelf and the populated BMS PCB, thereby creating a seal between the signal connector and the shelf
36. The method of claim 34, when used to assemble the battery system of claim 31, comprising: prior to lowering the populated BMS PCB into position, placing the gaskct onto the populated BMS PCB such that the aperture in the gasket fits around the signal connector; and fixing the populated BMS PCB to the shelf so as to compress the gasket between the shelf and the populated BMS PCB, thereby creating a seal between the signal connector and the shelf
37 The method of any one of claims 32 to 36, when used to assemble the battery system of claim 26 or the battery system of any one of claims 27 to 31 when dependent on claim 26, comprising: prior to lowering the populated BMS PCB into position, lowering positive and negative power connectors into the enclosure, such that, when the BMS PCB has been lowered into position, the positive connector is positioned adjacent to the positive power pad and the negative connector is positioned adjacent to the negative power pad; and makingwire-bonded connections between the power connectors and the corresponding power pads
38. A PCB, the PCB comprising: a substrate; a first side, the first side comprising first connector mounting pads to which a first connector can be mounted; and a second side opposite the first side, the second side comprising second connector mounting pads to which a second connector can be mounted; the first and second connector mounting pads having at least one conductive connection to the PCB in common, such that the first connector or the second connector can be mounted to the respective first and second connector mounting pads, depending upon the use to which the PCB is to be put.
39. The PCB of claim 38, wherein the first and second connector mounting pads have the same conductive connections to the PCB.
40. The PCB of claim 38 or 39, wherein the first and second connector mounting pads are coincident with each other.
41. The PCB of any one of claims 38 to 40, comprising: a first gasket sealing surface surrounding the first connector mounting pads; and a second gasket sealing surface surrounding the second connector mounting pads.
42. The PCB of any one of claims 38 to 41, wherein the PCB is a BMS PCB.
43. The PCB of claim 42, wherein the B1\4S PCB is in accordance with any one of claims 1 to 20.
44. The PCB of any one of claims 38 to 43, for use in at least first and second related products, wherein the first product uses a first connector mounted to the first connector mounting pads, and the second product uses a second connector mounted to the second connector mounting pads.
45. A first product comprising the PCB of any one of claims 38 to 44 and a second product comprising the PCB of any one of claims 38 to 44, wherein: the PCB of the first product comprises a first connector mounted to the first connector mounting pads; and the PCB of the second product comprises a second connector mounted to the second connector mounting pads.